CA1321780C - Packaging apparatus and method - Google Patents
Packaging apparatus and methodInfo
- Publication number
- CA1321780C CA1321780C CA000615132A CA615132A CA1321780C CA 1321780 C CA1321780 C CA 1321780C CA 000615132 A CA000615132 A CA 000615132A CA 615132 A CA615132 A CA 615132A CA 1321780 C CA1321780 C CA 1321780C
- Authority
- CA
- Canada
- Prior art keywords
- bag
- web
- bar
- pressure bar
- webs
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
- B65B43/00—Forming, feeding, opening or setting-up containers or receptacles in association with packaging
- B65B43/12—Feeding flexible bags or carton blanks in flat or collapsed state; Feeding flat bags connected to form a series or chain
Abstract
Packaging Apparatus and Method Abstract of the Disclosure A packaging machine and method for simultaneously loading, sealing and severing bags forming parts of at least two independent chains of bags. Two juxtaposed nip roll assemblies including axially aligned feed roll portions can be independently actuated in order to selectively feed one or two webs. A drive motor, having a dual output, is selectively coupled to the nip roll assemblies by clutch/brake units which can be selective-ly actuated. After a bag or bags are loaded, a sealing mechanism is actuated to seal the loaded bag or bags.
sensor monitors movement in a seal unit member and ter-minates the sealing cycle if movement in the seal member occurs prior to a pressure bar reaching a predetermined position. While a bag or bags are being sealed, a tear off mechanism including a rod-lika member is advanced into and through the web path in order to sever the loaded bag from the remainder of the web. Actuators operatively connected to distal ends of the member are actuated sequentially in order to move one end of the rod into contact with the web before the other end makes contact. As a consequence, severance of a bag along a line of weakness begins at one marginal edge of the tag and proceeds towards its opposite marginal edge. In an alternate embodiment, the stepper motor drive is used to advance bags to a loading station and when using loading funnels, are used to retract the bag in order to have a mouth of the bag engage a loading funnel. In addition, the stepper motor drive can be used to sever loaded bags from the remainder of the web by reverse feeding the webs either concurrently or in a staggered relationship.
sensor monitors movement in a seal unit member and ter-minates the sealing cycle if movement in the seal member occurs prior to a pressure bar reaching a predetermined position. While a bag or bags are being sealed, a tear off mechanism including a rod-lika member is advanced into and through the web path in order to sever the loaded bag from the remainder of the web. Actuators operatively connected to distal ends of the member are actuated sequentially in order to move one end of the rod into contact with the web before the other end makes contact. As a consequence, severance of a bag along a line of weakness begins at one marginal edge of the tag and proceeds towards its opposite marginal edge. In an alternate embodiment, the stepper motor drive is used to advance bags to a loading station and when using loading funnels, are used to retract the bag in order to have a mouth of the bag engage a loading funnel. In addition, the stepper motor drive can be used to sever loaded bags from the remainder of the web by reverse feeding the webs either concurrently or in a staggered relationship.
Description
132:1~80 11-125 Packaaing Apparatus and Method Technical Field The present invention relates generally to packaging systems and in particular to a method and apparatus ~or loading and separating a container from a chain or web of containers.
Back round Art Various~methods and apparatus for packaging articles in plastic bags are available today or have been suggested in the past. In one packaging method, the bags form part of a continuous plastic web, each bag being conneated to a contiguous bag along a line of weakness. Typically, the bags define an opening on one face through which the bag is loaded. t In early bagging machines, an operator manually loaded the product into the bag and the bag was pulled t' downwardly to position the next bag at the loading t station. The loaded bag was then manually severed from the web.
Machines and methods for automatically loading a chain of interconnected plastic bags have been developed or have bean suggested by the prior art~ In general, these machines include a mechanism for sequentially feeding a lead bag to a loading station; a mechanism for expanding the mouth of the bag and maintaining it in the expanded condition during a loading opera~ion; and, a mechanism for ssvering the loaded bag from the chain.
After the loaded bag is severed, ~he packaging sequence begins again with the next bag~
The individual bags are usually joined to the chain or web by a line of weakness generally formed by a plurality of perforations. After the bag is loaded, it is severed from the web along ~he perforations. Various f~' ~3211 7~0 mechanisms for automatically severing the loaded bag from the web have been developed or suggested. In one known method, the separation along ~he perforations is initiated by a projection that begins the tearing action near the center o~ the line of weakness. Sev~rance o-f the bag then commences at the center of the line of weakness and proceeds outwardly toward the marginal edges. An example of such a mechanism is shown in U.S.
Pat. No. 3,477,196, which is owned by the present assignee.
An alternate method for severing a loaded bag ~rom the web is disclosed in U.S. Pat. No. 4,202,153 which is also owned by the present assignee. In the method and apparatus shown in this patent, a transversely movable product carrier enters an opened bag, positioned horizontally, and simultaneously loads the bag and severs it from the web. Severance is achieved by overdriving the product carrier so that it engages the bottom of the loaded bag and drives it away from the web while the remainder of the web is held stationary, thus tearing the loaded bag from the web. In the disclosed apparatus, the per~oration breakage commences near the marginal edges of the web and advances inwardly from the marginal edges toward the center. Because the perfora-tions are broken serially, the force needed to sever thecontainer is less than that required if the perforations were broken simultaneously.
In U.S. Pat. No. 3,815,318 (also owned by the present assignee), a packaging method and apparatus is ` disclosed which illustrates another apparatus for severing a loaded bag along a line of weakness. In this apparatus, the tearing action is produced by a pivoting mechanism which engages a loaded hag and pivots the bag about an axis locatad near one marginal edge while the web is held stationary. ~he tearing action then 3 ~ ~J~7 c~mmences at a remote marginal portion and advances towards the edge of the bag that is located at or near the pivot axis.
A method and apparatus for simultaneously ~illing two adjacent bags have also been suggested in the past.
In particular, U.S. Pat. No. 4,041,846, owned by the present assignee, illustrates detachable, interconnected container strips and a method of making these strips.
The strips are connected in a side-by-side relationship in order to define adjacent bags. In this patent, however, the adjacent bags are attached and aannot move independently of each other prior to Pilling. After filling, the attached side-by-side bags are separated.
Disclosure of the Invention The present invention provides a new and improved packaging apparatus and method for sequen ially loading, sealing and severing bags from a chain or web of interconnected bags. In particular, the disalosed apparatus and method is capable of simultaneously loading side-by-side positioned ~ags that ~orm part of at least two independent webs and in addition includes an improved sealer and tear off mechanism. The mechanism is operative to seal and sever the loaded bags from their respective webs.
The present invention can also be used to load, seal and sever bags formed in webs of the type disclosed in U.s. Pat. No. 4~041,846. In particular, each web may comprise two side-by-side, interconnected strips of bags. In the illustrated embodiment of the invention, two such webs can be handled by the mechanism simul-taneously in order to load four bags with each machine cycle.
According to the invention, the apparatus includes structure defining a ~eed path for at least two chains of interconnected bags extending from a supply station ~^ `
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to a bag loading station. A web feed unit including a nip roll mechanism advances successive bags to the loading station~ Tne web feed mechanism includes drive roll portions associated with each web that may be independently driven by a multiple output drive system.
According to the invention, a dual drive is utilized to independently drive at least two individual webs (each web may include two side-by-side, intercon-nected longitudinal strips of bags3. In one embodiment, a drive motor having two output sha~ts is used. Each output shaft is connected through a clutch/brake mechanism to an associated nip roll assembly. In particular`, each output sha~t is operatively connected to a drive roll por~ion forming part o~ an associated nip roll assembly. Wikh this construc~ion, rotation o~
the motor output shaft can be selectively coupled to one or both drive roll portions to effect advancement of one or both webs.
In another embodiment, a stepper motor drive is employed utilizing individual stapper motors for selectively rotating the drive roll portions. In the stepper motor embodiment, each stepper motor is preferably coupled directly to an associated drive roll portion eliminating the need for clutch/brake units.
According to another feature o~ the invention, a tear off mechanism is selectively activated in oxder to separate the loaded bag from the rest of the web along a line of weakness, such as a line of per~orations. In the preferred and illustrated embodiment, the tear o~f mechanism comprises a rod-like member extending transversely with respect to the web ~eed path which is movable into and through the web pa~h by an actuating system. In the preferred embodiment, only a portion of the per~oration breaking rod initially moves into the ~5 web feed path and preferably initially contacts the bag . ~ ~
~ ~ /
, 7 '~ ~
to be severed near one o~ its marginal edges. The tear off rod p~rtion moves through the web path and begins the severance of the bag at the marginal edge. The remainder of the tear off member then moves through the web path to complete the severing operation. In short the tear off begins at one marginal edge of the loaded bag and proceeds towards the opposi~e marginal edge.
With this arrangement, the tear off force necessary to , sever the bag is reduced since the tear o~f does not have to occur concurrently across the entire width of the bag but proceeds gradually from one marginal edge to the other.
In the preferred and illustrated actuating system, the rod-like member is supported at its opposite ends by a pair of actuators, pre~erably fluid pressure operated.
In the preferred control system, the actuation of one of the actuators is delayed or slowed so that one end of the tear of~ rod extends into and through the web path and begins the severing process be~ore the other end of the rod moves into the web path. In the examplary embodiment, this differential actuation is achieved by restricting the fluid pressure flow to one of the actuators in order to delay its extension.
According to another feature of the invention, the sealer assembly includes a monitoring system to prevent or inhibit the actuation of the sealer should an obstruction be present between a clamping bar and a heat sealing head. In the preferred embodiment, spring loaded grippers are positioned above and below a heating element. The position of the grippers with respect to the heating element is monitored by a gripper position sensor. During the sealing process, ~hese grippers are moved to a retracted position as the clamping bar clamps the loaded bag between itsel~ and the grippers. A
clamping bar sensor is also used to monitor the position 13 2 ~
of the clamping bar. A sealer control circuit monitors the position of the grippers and the clamping bar and should the grippers move to a retracted position before the clamping bar reaches a predetermined location (which would indicate the presence of an obstruction between the clamping bar and the grippers~, the control system immediately retracts the clamping bar to abort the sealing cycle. During a normal sealing cycle, only the plies of the bag should be located between the clamping bar and the grippers. Consequently, in normal opera-tion, the grippers should not begin their movement towards a retracted position until the gripper bar is in very close proximity to the grippers i~e. less than one eigh~h of a inch ~rom the grippers. Movement in the grippers before the clamp bar reaches the position at which it is in close proximity (i.e. one eighth of a inch away) from the grippers, is an indication that an obstacle or obstruction is present.
In one embodiment of the invention, a bag to be ~0 loaded is precisely positioned at a loading station by first sensing the location of a line of perforations (along which the loaded bag will ultimately be severed) and then continuing the advancement o~ the web for a -~
predetermined time that corresponds to the time required ~5 for the bag to traverse the web path distance that must be traveled from the perfoxation detector to the bag loading station.
In the embodiment that employs the stepper motor drive arrangement, a slightly different control system can be used. In this latter embodiment, after the line of perforations in the web is detected, the web is advanced a predetermined nllmber of steps that correspond to the web path distance between the sen~ed perforations and the bag loading position at the load station.
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~ According to this embodiment, the a stepper motor control system can reverse feed a bag at the loading station in order to have a mouth o~ th~ bag engage a loading funnel, after the bag is opened.
According to another feature of this embodiment, the stepper motors and stepper motor control system can replace the function provided by the tear-off mechanism described above. In particular, after the bag or bags are loaded and are being held by the sealing mechanism, the stepper motors ~an be reverse actuated in order to retract the web. Since the bags are substantially immobilized by the sealing mechanism, the web~ are severed from the bags along the respective~lines of weakness ~i.e. perforations) that ~oin the bags to the webs. MoreQver, the stepper motor control system can reverse actuate the stepper motors in a staggered relationship so that a di~ferential retraction can be imparted to the webs so that tear-o~f begins on one web before commencing on the other web. With this arrange-ment, the severance does not occur simultaneously across the entire width o~ the bag or bags, and as a result, substantially less ~orce is impaxted to the web or webs by the stepper motors.
With the disclosed invention, a highly productive bagging machine can ~e realized~ At least two bags, forming part of independent webs can be loaded, sealed and severed from the respective webs simultaneously.
Thus ~or each machine cycle~ two loaded bags can be produced. The disclosed machine can also load bags of dissimilar sizes and/or shapes, at the same time because each web is driven and controlled separately by the dual drive system. In addition, the web feed mechanism can opera~e in unison in order to drive a single web made up o~ wide bags that span both nip roll assemblies.
Although the invention has been described in connection with the feeding of two individual webs, with each web comprising a chain of in~erconnected bags joined along transverse lines o~ weakness, the present invention can also load, sever and seal webs of the type di~closed and claimed in U.S. Patent No. 4,041~846. In particular, each web may comprise two interconnected, side-by~side strips of bags. With this type of web, four bags can be loaded, severed and sealed with each machine cycle.
Additional feakures of the invention will become apparent and a fuller understanding obtained by reading the following detailed description made in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE pRAWINGS
Figures lA and lB are front and rear perspective views, respectively, of a machine embodying the present invention;
Figure 2 is a side elevational view of a bag handling head constructed in accordance with a preferred embodiment of the invention;
Figure 3 is a fragm~ntary, plan view of the head shown in Figure 2;
Figure 4 is a plan view of a tear off/sealing sub-assembly forming part of t~e bag handling head shown in Figure 2;
Figure 5 is a side elevational view of the sub-assembly shown in Figure 4;
Figure 6 is a front elevational view of the sub-assembly shown in Figure 4:
Figure 7 is a fragmentary, sectional view as s0en from the plane indicated by the line 7~7 in Figure 4;
Figure 8 is a fragmentary, sectional view as seen from the plane indicated by the line 8-8 in Figure 7;
Figure 9 is a fragmentary, sectional view as seen from the plane indicated by the line 9-9 in Figure 7;
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g ~ Figure lo is a plan Yiew, shown somswhat schemati-cally, of an alternate web drive system constructed in accordance with the invention, Figure 11 is a fragmentary, plan view of the drive system shown in Figure 10: and, Figure 12 is a plan view of web feed mechanism constructed in accordance wi~h another preferred embodiment o~ the inventionO
BEST MODE FOR CARRYING OUT THE INVENTION
lo Figures lA and lB illustrate the overall construc-tion of a packaging apparatus constructed in accordance with a preferred embodiment o~ the invention. ~he illustrated apparatus can be termed a "bagging machine"
and is a`dapted to load bags interconnected to form a chain. The bags are preferably joined together along a line of weakness.
The bagging machine comprises of a support frame lO
defined by a pair of vertically standing uprights lOa, lOb sitting atop a base 12. The base 12 includes a pair of transversely extending members 12a, 12ba intercon-nected by a cross member 12c. ~ plurality of wheels 14 are located at distal ends of the transverse members 12a, 12b and enable the bagging machine to be moved about an office or plant. A bag handling head 20 including a web advancing and loading/sealing mechanism is supported atop the support 10. The head 20 includes a housing or cover 20a that encloses a bag/web hand}ing unit 22 (shown in Figure 2) to be described. A main control box 24 including a control panel 24a is at~aahed to the upright lOb and houses control circuitry (not shown) for controlling the various functions of the machine.
The base 10 also supports a supply o~ bags, indicated generally by the reference character S. In the illustrated embodiment, the supply S comprises at 1 3?J~7g~
least two supply spools 25a, 25b, the spools carrying wound webs 26a, 26b of interconnected bags join~d together by lines of weakness, such as transverse lines of perforations. The bag loading/sealing head 20 is S operative to advance one or bo~h webs 26a, 26b to sequentially position associated lead bags 28a, 28b at a bag loading station. With the disclosed apparatus, each web 26a, 26b can be advanced concurrently or separately in order to position a bag at one or both load stations.
As seen in Figure lB, the webs 26a, 26b are fed rom their associated spools 25a, 25b around a pair of dancer roll assemblies 29a, 29~. The spools 25a, 25b are independently mounted on a two-part spindle 31 and the dancer roll assemblies 29a, 29b are operative to control the payout of the associated webs 26a, 26b. In particular, the dancer roll assemblies include conventional friction brake arrangements (not ~hown) such as the type disclosed in U.S. patent No. 4,928,455, issued May 29, 1990. The friction brakes are engageable ~0 with spindle portions 31a, ~lb in ord~r to inhibit rotation of the associated supply spools 25a, 25b when a predetermined amount of web material has been paid out by the associated spool.
As seen in Figure lB, the bag handling head mounts a plurality of guide rolls 33a~f which at least partially define a web path for the webs. A bag sensor 35 (shown in Figure 2) which may comprise a conventional perforation detector and a fixed web guide ara also disposed in the web path.
A~ter the bag or bags are loaded, the bagæ are sealed and severed from the remainder of the web by a sealing unit 30 and a bag tear off uni~ 32, respec~ivsly.
~he severed bag or bags are then dropped into a suitable receptacle or onto a conveyor (not shown).
~ .
~ 3 ~
~ The bag/web handling unit 22, as best in Figure 2, includes upper and lower sub-assemblie~ indicated generally by the reference characters 40, 42. In the disclosed embodiment, the upper and lower sub-assemblies 40,42 are hingedly connected at a pivot 44 which enables the lower sub-assembly 42 to swing downwardly with respect to the upper sub-assembly 40 to facilitate loading of the web or webs. Pr~ssurized, pneumatic actuators 46 often termed a "gas springs" interconnect the two sub-assemblies and act as a counter balance for the lower sub-assembly 42 tshown best in Figures 4 and 5) to facilitate the raising and lowering of the lower sub-assembly 42 by the operator.
When the lower sub-assembly 42 is pivoted to its upper position (shown in Figure 2) a pinch roll arrangement 50 carried by the lower sub-assembly 42 engages and is driven by a feed roll arrangement 52 carried by the upper sub-assembly 40.
Referring also to Figures 3 and 12, the upper sub-assembly 40 carries the drive mechanism for driving the feed roll arrangement 52. According to tha invention, the feed roll arrangement 52 comprises a pair of independently rotatable, axially aligned feed rolls 52a, ~ .
52b rollingly supported at their inner ends by a bearing 56. The drive system can selectively rotate either of the rolls 52a, 52b or rotate them in unison.
In one embodiment of the invention (shown in Figures 3 and 12) the drive system includes a drive motor 60 having output shaft ends 60a, 60b. The output shaft ends 60a, 60b are operatively connected to a pair of clutch/brake mechanisms 62a, 62b by drive belts 64.
The clutch/brake mechanisms 62a, 62b are in turn coupled to respective drive shafts 66a, 66b. The clutch/brake units are secured to a frame member 70 by brackets 72a, 72b which interlock with slotted tongues 74a, 74b 12 ~ ' forming part of the clutch units 6~a, 62b0 The clutch/bxake units ~a, 62b may be conventional.
An outboard end 68 of the output sha~t 66a is interconnected with the outer end of the feed roll 52a by a drive belt 80. The feed roll 52b is operatively connected with the drive shaft 66b through a similar arrangement. With the disclosed apparatus, rotation of the drive motor 60 can be selectively coupled to the feed rolls 52a, 52b by selective actuation of the clutch/brake units 62a, 62b. The upper sub-assembly 40 also rotatably supports a pair of guide rollers 82, 84 between side plates 86a, 86b, which are operative to guide one or both webs.
Turning now to Figuras 4-6, the lower sub-assembly 42, as indicated above, rotatably mounts a pinch roll arrangement 50. As seen best in Figure 6, the pinch roll arrangement 50 compri~es a pair of independently rotatable, axially aligned rolls 90a, 90b. Inner ends of the rolls 90a, 90b are rotatably supported by a bearing and bearing support assembly 92. Outer ends of the rolls 90a, 90b are definad by stub sha~ts 93a, 93b which are rotatably supported in respective shaft receiving bores 95a, 95b formed in frame portions 94a, 94b.
When the lower subassembly 42 is raised to its opera~ive position, shown in Figure 2, the pinch rolls 90a, 90b frictionally engage the feed rolls 52a, 52b, respectively. The feed rolls 52a, 52b and pinch rolls 90a, 90b together define independently actuatable, juxtaposed nip roll assemblies. Eccentric clamps 97a, 97b are mounted at opposite sides of the lower assembly 42 and are engageable with associated clamp ~tructure formed on the upper assembly 40. When the lower assembly is raised, the eccentric clamps are used to lock the lower assembly to the upper assembly and cause the feed rolls 52a, 52b to engage the pinch rolls, 58a, 58b with a predetermined clamping pressure~
In normal operation, the lower sub-assembly ~2 is lowered in order to load the web or webs 26at 2~b from the supply S. In particular, i~ two independent webs or chains of bags are to be loaded, the respective webs are fed around one or both guide rolls 82, 84 then are draped across the pinch rolls sna, 90b, respectively.
When the lower unit 42 is raised to its oper~tive position, the web 26a is clamped between the feed roll 52a and the associated pinch roll 90a whereas the web 26b is clamped betwPen the feed roll 52b and the associated pinch roll 90b. In normal operation, when the machine is turned on, the drive motor SO is continuously energized. The individual webs are advanced by selectively actuating the clutch/brake units 62a, 62b associated with the webs 26a, 26b. In particular, i~ the web 26a (which is clamped between the nip roll assembly formed by the feed/pinch rolls 52a, goa) is to be advan~ed, the clutch/brak~ unit 62a is actuated. After the web is advanced, the associated clutch/brake unit is normally energized into its braking mode so that movement in the web 26a upstream o the lead bag 28a is resisted. As a consequence, uncon-trolled movement in the web 26a (and web 28a, i~applicable) is inhibited or prevented.
As the bags 28a, 28b reach the load position (shown in Figure l), they are blown or "popped" open in order to receive a product or products. In general the bags each include a transverse slit in one o~ the plies that define an outer sidewall. As seen best in Figure 12, the bag handling head 22 includes a pair of bag opening units 97, 99 conneck~d to a common blower 95. Each unit 97, 99 includes a nozzle for directing blower air downwardly towards the mouth o~ a bag positioned below ^ ~
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the unit. The blower is normally opera~ed continuously during the loading process and provides a source of relatively low pressure air for maintaining inflation of the bag. In addition! the blower preferably includes 5 a speed control (not shown) for adjusting the blower pressure. With this control arrangemen~, when relative-ly light products are being loaded, i.e., such as powders, the blower pressure can be raduced to a minimum level so that the product is not blown from the bag during filling.
In the preferred and illustrated embodiment, the bag is initially popped opened by a blast of air from a "blip" tu~e 93 mounted to each opening Unit 97, 99. The blip tube 93 is connec~ed to a source of pressurized air, the communication of which is determined by a valve (not shown) that may be actuated by a conventional valve control system. In general, the tube is connected with a source of pressurized air momentarily as the as-sociated bag reaches the load position. The blower 95 ~0 is then used to maintain the opening of the bag.
After the lead bags 28a, 28b have been loaded, the sealing mechanism 30 is operated in order to form a heat seal across the top of the bags (if the machine is being used to load two webs). Referring to Figures 4-9, the mechanism for forming the heat seal includes a recipro-cally moveable pressure bar 100 (shown best in Figures 3-5), which is moved towards and away from a heating unit 102 (shown best in Figures 7-9) by an actuator 104.
As seen best in Figure 4, the actuator 104 is mounted centrally in a ~rame 106 forming part of the lower sub-assembly 42 and includes an actuating rod 104a which mounts a channel-like cross member 108. Guide rods 110 are secured to distal ends 108a of the sealer cross member 108 and extend toward the ~ront Q~ the ~ 3 ~ 0 machine and are slidably received (and supported) by bores 112 formed in the frame 106. Other bores (not shown) slidably received the guide rod~ 110 and support the rods 110 near the front of the machine. The pressure bar 100 extends bstween ~he front ends of the guide rods 110 so that when the actuator 104 is energized to e~tend the actuating rod 104a, the pressure bar 100 is pulled inwardly towards the heating unit 10~. A position detector 120, (the functio~ of which will be described further on) is mounted to the actuator 104 and detects when a portion of the actuator i.e., the piston, moves to a predetermined position within the actuator housin~
which corresponds to a predetermined position of the pressure bar 100.
Referring also to Figures 7-9, the hea~er unit 102 includes a heating element 124 shown best in Figure 7.
Various heating elements can be employed. For example, the sealing unit may include the heating element and control ~ystem disclosed in U.S. patent No. 4,901,506 issued February 20, 1990, which is owned by the present assignee.
As seen best in Figure 7, a non-stick material 126, such as a band of teflon is wrapped over the heating region and around a pair of shafts 130, 132. Tension springs 128 maintain the positions of the sha~ts 130, 132. One of the shafts serves as a supply spindle whereas the other shaft serves as a take-up spindle. The teflon band 126 inhibits the ba~ being sealed from sticking to the heating unit when the heat sealing cycle is completed. The shafts 130, 132 include knurled end~
130a, 132a (shown best in Figure 6), which enabl~ a user to rotate at least one of the sha~ts in order to pull ~resh anti-stick mat~rial from the other shaft. The bag contacting surface on the pressure bar 100 is also covered with a non-stick material such a~ teflon. As ~ `
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16 132~ ~80 seen best in Figures 4 and 5, a band of mater~al 136 is wrapped around the inside of the pressure bar 100 and between supply and take-up shafts 137, 138. Each shaft includes knurled ends 137a, 138a.
A sealer bar assembly 140 is mounted to the heating unit 102 and includes a pair of gripper elements 142, 144 (shown best in ~igure 7) disposed above and below, respectively the heating element 124. The entire sealer bar assembly 140 is reciprocally mounted in a housing indicated generally by the reference character 146 and retracts inwardly as a bag is clamp between the pressure bar 100 and the gripper elements 142, 144 thereby contacting tha teflon covered heating element 124 in order to form a heat seal on the bag. Referring lS to Figurs 9, the sealer bar 140 is resiliently biased towards the position shown in Figure 7. In particular, at least two relatively light springs 150 (only 1 is shown in Figure 9) urges the sealer bar 140 outwardly, towards the pressure bar 100 i.e., to the pcsition shown ~0 in Figure ~.
When the pressure bar lG0 contacts the seal bar 140, it moves the seal bar rearwardly since the force applied by the pressure bar 100 easily exceeds the force applied by the relatively light-force biasing springs 150. After the bar moves a predetermined distance, further movement in the seal bar 140 i5 resisted by a relatively heavy-force spring biased plunger unit 152 which is threadedly mounted to the frame 106 and is locked in position by a jam nut 154. A plunger stem 156 extends outwardly from the unit 152 and is abuttably engageable with the back of the sealer bar 140. In the illustrated embodiment, the rear of the sealer bar 140 includes recesses adapted to receive a tip of ~he plunger stem 156. ~he spriny force exerted by the plunger unit 152 is substantially higher than the *orce l32~7~a applied by the po~itioning springs 150 and further rearward movement of the s~ler bar 140 is substantially resisted. This resistance to movement generates a clamping force between the pressure bar 100 and the seal bar 140. The clamping force is needed in order to provide a strong heat seal because it ensures that the plies of the loaded bag are placed in intimate contact.
In addition the ~lamping force isolates the loaded bag from the rest of the wab and as a result further movement in the bag due ~o external forces generated by product weight and web severance, is substantially resisted.
This-arrangement provides a significant feature of the invention. With the disclosed clamping arrangement, obstructions in the path of travel of the pressure bar 100 can be detected enabling the sealing cycle to be terminated before damage occurs to the obstruction and/or the sealing mechanism. In particular, a sensor 155 (shown only in Figure 7) monitors the position of the sealing bar 140. When the sealing bar 140 is not in contact with the pressure bar 100, the sealing bar 140, as descxibed above, should be in the position shown in Figure 9. During the sealing operation, the sealQr bar 140 is moved inwardly until it contacts the spring biased plunger 156. In a normal heat sealing cycle, the seal bar 140 should not move to the position at which it engages the plunger lS6 until the pressure bar 100 has moved into substantially abutting engagement with the gripper elements 142, 144 since in normal operation the pressure bar 100 and the grlpper elements 142, 144 should only be separated by the thickness of the sidewalls or plies of the bag. If the path of travel of the pressure bar 100 is obstructed by an improperly loaded or improperly positionad bag, the seal bar 140 will move rearwardly into contact with the plunger 156 .
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well before the pressure bar loO reaches a position immediately adjacent the gripper elements 142, 144. By monitoring the position of the seal bar 140 and the pressuxe bar 100, the presence o~ an obstruction can be detected. The position of the pressure bar 100 is monitored by ~he sensor 120 mounted to ~he actuator 104.
In the disclosed embodiment, the position of the actuator piston (not shown) that corresponds to ~he adjacent position of the pressure bax 100 is monitored.
If tha seal bar assembly 140 moves rearwardly before the piston reaches the predetermined sensor positlon, control circuitry immediately terminates the heat seal cycle and-returns the pressure bar 100 to its outward or retracted position. Consequently, significant forces are not applied to the bag if an obstruction is present or if the bag is improperly positioned.
According to the invention, the loaded bag iS
severed ~rom the remainder of the web while the bag is clamped by the heat sealing unit 102. In the preferred embodiment, the bag is severed by a bag tear Off mech~nism which is operative to sever the load~d bag along a line of perforations, commencing at a marginal edge of the bag and proceeding towards the opposite marginal edge of the bag. The apparatus for achieving 2~ this function is best shown in Figures 3 and 4. In particular, a pair of double acting actuators 170, 172 are mounted on opposite ~ides of the frame 106. Each actuator includes a respective actuating rod 170a, 172a~
A rod-like tear off member 176 is supported between the ends of the rods 170a, 172a. In the preferred construc-tion, spherical bearings are mounted at opposite ends of the tear off rod 176 and are conventionally held in spherical bearing retainers 180, 1~2 mounted to the ends of the actuator rods 170a, 172a. Retaining collars 174 are fixed to the ends of the tear off rod 176 and 2~7~0 maintain its position between the actuators 170, 172 while allowing some axial movement in the tear off rod 17~.
According to the invention, the actuators 170, 172 are not operated in unison so that movement in the tear off rod 176 occurs non-linearly or angularly with respect to the plane of the web. In particular, the actuation of the actuators 170, 172 is controlled so that one end of the rod 176 moves outwardly before the other end so that contact occurs with a bag to be served at its marginal edge closest to the end of the tear off rod 176 being moved first. For example, the actuator 170 may be energized first in order to move the upper end of the tear off rod 17 6 ( as viewed in Figure 4) outwardly to the position indicated by the phantom line 185. After the upper end of the rod has movèd a predetermined distance, the actuator 172 is en~rgized to move the lower end (as viewed in Figure 4) outwardly in order to complete the tear of~ cycle. With the disclosed arrangement, separation of the loaded bag from the rest of the web (along the line of weakness) does not occur simultaneously across the entire width of the bag but begins at one marginal edge and moves towards the other marginal edge. As a result, reduced ~orces are applied to the bag to effect the severance1 In the illustrated embodiment, the actuators 170, 172 are pneumatically operated and in the preferred control system, the seguential movement of the actuating rods 170a, 1~2a is achieved by restricting the flow of the fluid pressure to one of the actuators. In particular, an adjustable flow restrictor 185 (shown best in Figure 5) is disposed in the flow path feeding the actuator 172 and restricts fluid flow into the rod end of the actuator. With this arrangement, the control system is simplified. When bag sevsrance is to occur, ~ ~ 2 ~
supply lines fe~ding both actuators 170, 172 can be pressurized simultaneously by the operation of a single valve. The delay in extension of one of the actuating rods (i.e. the actuator 172) is achieved by restricting the flow o~ pressurized fluid to the one actuator.
Ultimately, both actuators are fully pressurized ~or maximum force.
Thus far the invention has been described as it would be used to simultaneou~ly handle, two independent lo chains of bags. The invention, howaver, can be used to load and seal a single chain of bags. The disclosed apparatus can handle a narrow web of bags, i.e., a web having a transverse dimension less than the transverse dimension of the drive roll portions 52a, 52b as well as a relatively wide web i.e. a web having a transverse dimension that exceeds the transVerse dimension of the individual feed roll portions 52a, 52b. In fact, a single web having a width equalling the total transverse dimension of the axially aligned ~eed roll portions 52a, 52b can be used. Although the clutch units 62a, 62b can be simultaneously actuated in ~rder to provide coor-dinated movement in both nip roll assemblies, in the preferred embodiment, a mechanical coupling 192 can be used to mechanically interconnect inner ends 194a, lg4b of the drive shafts 66a, 66b. With the mechanical coupling 192, synchronized movement in both drive roll portions 52a, 52b is assured.
As should be apparent, the present invention provides a vexsatile machine which can be used to simultaneously load two individual chains of bags. The bags comprising the chains are not required to be the same size and bags having substantially dissimilar dimensions can be simultaneously handled by the disclosed machine. In addition, the machine can be used to~fill extremely wide bags by synchronizing movement in 21 ~3~:~ 7~
the individual feed roll portions 52a, 52b, in order to feed a single wide web through the machine.
Turn~ng now to Figures lo and 11, an alternative embodiment of the invention is illustrated. In describing this alternate embodiment, the components having similar counterparts in the earlier described embodiment will be designated with the same reference character followed by an apostrophe (').
In this embodiment, individual stepper motors 200, 202 are used to selectively drive the individual nip roll assemblies foxmed by feed roll portions 52al, 52b' and associated pinch roll portions. In particular, the stepper motors 200, 202 are directly connected to an associated ends of the feed roll portions 52b', 52a' by a drive belt 204 (only the drive belt 204 ~onnecting the stepper motor 2Q0 to the feed roll 52bl is shown in Figure 10).
As seen best in Figure 11, a web comprising a chain of bags 206 defines a web path through the unit 22'.
Guide rolls 208, 210, 212 are provided and at least partially define the web path. A conventional perfora-tion dete~ting sensor 214 is used to detect the position of the bag. With this embodiment, a conventional stepper motor control circuit is employed to advance a lead bag "L" to a load position by advancing the web a certain number of steps after a line of perforations (along which contiguous bags ar~ joined) is detected.
The number of steps corresponds to the distance that must be traveled by the lead bag in order to be properly positioned at that load station.
In addition, the disclosed stepper motor drive system can be used to cause an open bag to engage a mouth 220a of a loading funnel 220. In particular, with the disclosed mechanism, the lead bag 'IL'l is advanced to an initial load position at which it is inflated by a ~ 3 rJ ~L 7 ~ O
bl~ower/blip tube unit (or units) such as the units 97, 99 shown in Figure 12 and described above. After the bag L is opened, the associated stepper motor is reverse actuated to raise the bag ~ upwardly (as viewed in Figure ll) in order for the opening in the bag to engage the mouth 220a o~ the funnel 220. The stepper motor would be retracted a certain number of steps correspond-ing to the distance a bag must be raised in order to engage the mouth of the funnel. At the completion of the loading cycle, the bag is sealed and severed by a sealing and severing mechanisms 30, 32 shown in Figure lA and described above.
~he stepper motor drive system can also be used to replace the function provided by the tear-off mechanism 32. In particular, when the loaded bag or bags are being held by the sealer assembly 30, the st2pper motors 200~ 202 can be actuated to reverse feed the web. since the bags are held by the sealer assembly 30, the web or webs are severed from the loaded bags along their ~0 respective lines of weakness.
According to a feature of this embodiment, the forces applied to the webs during ~he ~everance process aan be substantially reduced. In particular, the J
stepper motors 200, 202 can be reverse stepped in a staggered ~ashion so that one web begins the severance process before the other web. As a result, the severance occurs gradually across both the webs and the stepper motors 200, 202 need not apply a force to the web~ in an amount that would be needed to produce a concurrent severance across both webs simultaneou ly.
In short, the power needed to produce severance is substantially reduced when the stepper motors 200, 202 are reverse stepped in a staggered fashion.
The disclosed stepper motor drive is capable o~
extremely precise positioning of a bag. In addition, .
- .
13 2 ~ ~ 3 ~
t~e drive can either advance and/or retract the webs individually or concurrently. Lik~ the first embodi-ment, this alternate embodiment can be used to handle two webs simultaneously or a single relatively wide web i.e. a web having a transverse dimension substantially equal to the total transverse dimension of the feed roll portions 52a', 52b'.
Although, the invention has been described with a certain degree of particularity, it should be understood that those skilled in the art can make various changes to it without departing fxom the spirit or scope of the invention as hereinafter claimed.
Back round Art Various~methods and apparatus for packaging articles in plastic bags are available today or have been suggested in the past. In one packaging method, the bags form part of a continuous plastic web, each bag being conneated to a contiguous bag along a line of weakness. Typically, the bags define an opening on one face through which the bag is loaded. t In early bagging machines, an operator manually loaded the product into the bag and the bag was pulled t' downwardly to position the next bag at the loading t station. The loaded bag was then manually severed from the web.
Machines and methods for automatically loading a chain of interconnected plastic bags have been developed or have bean suggested by the prior art~ In general, these machines include a mechanism for sequentially feeding a lead bag to a loading station; a mechanism for expanding the mouth of the bag and maintaining it in the expanded condition during a loading opera~ion; and, a mechanism for ssvering the loaded bag from the chain.
After the loaded bag is severed, ~he packaging sequence begins again with the next bag~
The individual bags are usually joined to the chain or web by a line of weakness generally formed by a plurality of perforations. After the bag is loaded, it is severed from the web along ~he perforations. Various f~' ~3211 7~0 mechanisms for automatically severing the loaded bag from the web have been developed or suggested. In one known method, the separation along ~he perforations is initiated by a projection that begins the tearing action near the center o~ the line of weakness. Sev~rance o-f the bag then commences at the center of the line of weakness and proceeds outwardly toward the marginal edges. An example of such a mechanism is shown in U.S.
Pat. No. 3,477,196, which is owned by the present assignee.
An alternate method for severing a loaded bag ~rom the web is disclosed in U.S. Pat. No. 4,202,153 which is also owned by the present assignee. In the method and apparatus shown in this patent, a transversely movable product carrier enters an opened bag, positioned horizontally, and simultaneously loads the bag and severs it from the web. Severance is achieved by overdriving the product carrier so that it engages the bottom of the loaded bag and drives it away from the web while the remainder of the web is held stationary, thus tearing the loaded bag from the web. In the disclosed apparatus, the per~oration breakage commences near the marginal edges of the web and advances inwardly from the marginal edges toward the center. Because the perfora-tions are broken serially, the force needed to sever thecontainer is less than that required if the perforations were broken simultaneously.
In U.S. Pat. No. 3,815,318 (also owned by the present assignee), a packaging method and apparatus is ` disclosed which illustrates another apparatus for severing a loaded bag along a line of weakness. In this apparatus, the tearing action is produced by a pivoting mechanism which engages a loaded hag and pivots the bag about an axis locatad near one marginal edge while the web is held stationary. ~he tearing action then 3 ~ ~J~7 c~mmences at a remote marginal portion and advances towards the edge of the bag that is located at or near the pivot axis.
A method and apparatus for simultaneously ~illing two adjacent bags have also been suggested in the past.
In particular, U.S. Pat. No. 4,041,846, owned by the present assignee, illustrates detachable, interconnected container strips and a method of making these strips.
The strips are connected in a side-by-side relationship in order to define adjacent bags. In this patent, however, the adjacent bags are attached and aannot move independently of each other prior to Pilling. After filling, the attached side-by-side bags are separated.
Disclosure of the Invention The present invention provides a new and improved packaging apparatus and method for sequen ially loading, sealing and severing bags from a chain or web of interconnected bags. In particular, the disalosed apparatus and method is capable of simultaneously loading side-by-side positioned ~ags that ~orm part of at least two independent webs and in addition includes an improved sealer and tear off mechanism. The mechanism is operative to seal and sever the loaded bags from their respective webs.
The present invention can also be used to load, seal and sever bags formed in webs of the type disclosed in U.s. Pat. No. 4~041,846. In particular, each web may comprise two side-by-side, interconnected strips of bags. In the illustrated embodiment of the invention, two such webs can be handled by the mechanism simul-taneously in order to load four bags with each machine cycle.
According to the invention, the apparatus includes structure defining a ~eed path for at least two chains of interconnected bags extending from a supply station ~^ `
4 lL~7~
to a bag loading station. A web feed unit including a nip roll mechanism advances successive bags to the loading station~ Tne web feed mechanism includes drive roll portions associated with each web that may be independently driven by a multiple output drive system.
According to the invention, a dual drive is utilized to independently drive at least two individual webs (each web may include two side-by-side, intercon-nected longitudinal strips of bags3. In one embodiment, a drive motor having two output sha~ts is used. Each output shaft is connected through a clutch/brake mechanism to an associated nip roll assembly. In particular`, each output sha~t is operatively connected to a drive roll por~ion forming part o~ an associated nip roll assembly. Wikh this construc~ion, rotation o~
the motor output shaft can be selectively coupled to one or both drive roll portions to effect advancement of one or both webs.
In another embodiment, a stepper motor drive is employed utilizing individual stapper motors for selectively rotating the drive roll portions. In the stepper motor embodiment, each stepper motor is preferably coupled directly to an associated drive roll portion eliminating the need for clutch/brake units.
According to another feature o~ the invention, a tear off mechanism is selectively activated in oxder to separate the loaded bag from the rest of the web along a line of weakness, such as a line of per~orations. In the preferred and illustrated embodiment, the tear o~f mechanism comprises a rod-like member extending transversely with respect to the web ~eed path which is movable into and through the web pa~h by an actuating system. In the preferred embodiment, only a portion of the per~oration breaking rod initially moves into the ~5 web feed path and preferably initially contacts the bag . ~ ~
~ ~ /
, 7 '~ ~
to be severed near one o~ its marginal edges. The tear off rod p~rtion moves through the web path and begins the severance of the bag at the marginal edge. The remainder of the tear off member then moves through the web path to complete the severing operation. In short the tear off begins at one marginal edge of the loaded bag and proceeds towards the opposi~e marginal edge.
With this arrangement, the tear off force necessary to , sever the bag is reduced since the tear o~f does not have to occur concurrently across the entire width of the bag but proceeds gradually from one marginal edge to the other.
In the preferred and illustrated actuating system, the rod-like member is supported at its opposite ends by a pair of actuators, pre~erably fluid pressure operated.
In the preferred control system, the actuation of one of the actuators is delayed or slowed so that one end of the tear of~ rod extends into and through the web path and begins the severing process be~ore the other end of the rod moves into the web path. In the examplary embodiment, this differential actuation is achieved by restricting the fluid pressure flow to one of the actuators in order to delay its extension.
According to another feature of the invention, the sealer assembly includes a monitoring system to prevent or inhibit the actuation of the sealer should an obstruction be present between a clamping bar and a heat sealing head. In the preferred embodiment, spring loaded grippers are positioned above and below a heating element. The position of the grippers with respect to the heating element is monitored by a gripper position sensor. During the sealing process, ~hese grippers are moved to a retracted position as the clamping bar clamps the loaded bag between itsel~ and the grippers. A
clamping bar sensor is also used to monitor the position 13 2 ~
of the clamping bar. A sealer control circuit monitors the position of the grippers and the clamping bar and should the grippers move to a retracted position before the clamping bar reaches a predetermined location (which would indicate the presence of an obstruction between the clamping bar and the grippers~, the control system immediately retracts the clamping bar to abort the sealing cycle. During a normal sealing cycle, only the plies of the bag should be located between the clamping bar and the grippers. Consequently, in normal opera-tion, the grippers should not begin their movement towards a retracted position until the gripper bar is in very close proximity to the grippers i~e. less than one eigh~h of a inch ~rom the grippers. Movement in the grippers before the clamp bar reaches the position at which it is in close proximity (i.e. one eighth of a inch away) from the grippers, is an indication that an obstacle or obstruction is present.
In one embodiment of the invention, a bag to be ~0 loaded is precisely positioned at a loading station by first sensing the location of a line of perforations (along which the loaded bag will ultimately be severed) and then continuing the advancement o~ the web for a -~
predetermined time that corresponds to the time required ~5 for the bag to traverse the web path distance that must be traveled from the perfoxation detector to the bag loading station.
In the embodiment that employs the stepper motor drive arrangement, a slightly different control system can be used. In this latter embodiment, after the line of perforations in the web is detected, the web is advanced a predetermined nllmber of steps that correspond to the web path distance between the sen~ed perforations and the bag loading position at the load station.
~3~ g~
~ According to this embodiment, the a stepper motor control system can reverse feed a bag at the loading station in order to have a mouth o~ th~ bag engage a loading funnel, after the bag is opened.
According to another feature of this embodiment, the stepper motors and stepper motor control system can replace the function provided by the tear-off mechanism described above. In particular, after the bag or bags are loaded and are being held by the sealing mechanism, the stepper motors ~an be reverse actuated in order to retract the web. Since the bags are substantially immobilized by the sealing mechanism, the web~ are severed from the bags along the respective~lines of weakness ~i.e. perforations) that ~oin the bags to the webs. MoreQver, the stepper motor control system can reverse actuate the stepper motors in a staggered relationship so that a di~ferential retraction can be imparted to the webs so that tear-o~f begins on one web before commencing on the other web. With this arrange-ment, the severance does not occur simultaneously across the entire width o~ the bag or bags, and as a result, substantially less ~orce is impaxted to the web or webs by the stepper motors.
With the disclosed invention, a highly productive bagging machine can ~e realized~ At least two bags, forming part of independent webs can be loaded, sealed and severed from the respective webs simultaneously.
Thus ~or each machine cycle~ two loaded bags can be produced. The disclosed machine can also load bags of dissimilar sizes and/or shapes, at the same time because each web is driven and controlled separately by the dual drive system. In addition, the web feed mechanism can opera~e in unison in order to drive a single web made up o~ wide bags that span both nip roll assemblies.
Although the invention has been described in connection with the feeding of two individual webs, with each web comprising a chain of in~erconnected bags joined along transverse lines o~ weakness, the present invention can also load, sever and seal webs of the type di~closed and claimed in U.S. Patent No. 4,041~846. In particular, each web may comprise two interconnected, side-by~side strips of bags. With this type of web, four bags can be loaded, severed and sealed with each machine cycle.
Additional feakures of the invention will become apparent and a fuller understanding obtained by reading the following detailed description made in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE pRAWINGS
Figures lA and lB are front and rear perspective views, respectively, of a machine embodying the present invention;
Figure 2 is a side elevational view of a bag handling head constructed in accordance with a preferred embodiment of the invention;
Figure 3 is a fragm~ntary, plan view of the head shown in Figure 2;
Figure 4 is a plan view of a tear off/sealing sub-assembly forming part of t~e bag handling head shown in Figure 2;
Figure 5 is a side elevational view of the sub-assembly shown in Figure 4;
Figure 6 is a front elevational view of the sub-assembly shown in Figure 4:
Figure 7 is a fragmentary, sectional view as s0en from the plane indicated by the line 7~7 in Figure 4;
Figure 8 is a fragmentary, sectional view as seen from the plane indicated by the line 8-8 in Figure 7;
Figure 9 is a fragmentary, sectional view as seen from the plane indicated by the line 9-9 in Figure 7;
~3~7~
g ~ Figure lo is a plan Yiew, shown somswhat schemati-cally, of an alternate web drive system constructed in accordance with the invention, Figure 11 is a fragmentary, plan view of the drive system shown in Figure 10: and, Figure 12 is a plan view of web feed mechanism constructed in accordance wi~h another preferred embodiment o~ the inventionO
BEST MODE FOR CARRYING OUT THE INVENTION
lo Figures lA and lB illustrate the overall construc-tion of a packaging apparatus constructed in accordance with a preferred embodiment o~ the invention. ~he illustrated apparatus can be termed a "bagging machine"
and is a`dapted to load bags interconnected to form a chain. The bags are preferably joined together along a line of weakness.
The bagging machine comprises of a support frame lO
defined by a pair of vertically standing uprights lOa, lOb sitting atop a base 12. The base 12 includes a pair of transversely extending members 12a, 12ba intercon-nected by a cross member 12c. ~ plurality of wheels 14 are located at distal ends of the transverse members 12a, 12b and enable the bagging machine to be moved about an office or plant. A bag handling head 20 including a web advancing and loading/sealing mechanism is supported atop the support 10. The head 20 includes a housing or cover 20a that encloses a bag/web hand}ing unit 22 (shown in Figure 2) to be described. A main control box 24 including a control panel 24a is at~aahed to the upright lOb and houses control circuitry (not shown) for controlling the various functions of the machine.
The base 10 also supports a supply o~ bags, indicated generally by the reference character S. In the illustrated embodiment, the supply S comprises at 1 3?J~7g~
least two supply spools 25a, 25b, the spools carrying wound webs 26a, 26b of interconnected bags join~d together by lines of weakness, such as transverse lines of perforations. The bag loading/sealing head 20 is S operative to advance one or bo~h webs 26a, 26b to sequentially position associated lead bags 28a, 28b at a bag loading station. With the disclosed apparatus, each web 26a, 26b can be advanced concurrently or separately in order to position a bag at one or both load stations.
As seen in Figure lB, the webs 26a, 26b are fed rom their associated spools 25a, 25b around a pair of dancer roll assemblies 29a, 29~. The spools 25a, 25b are independently mounted on a two-part spindle 31 and the dancer roll assemblies 29a, 29b are operative to control the payout of the associated webs 26a, 26b. In particular, the dancer roll assemblies include conventional friction brake arrangements (not ~hown) such as the type disclosed in U.S. patent No. 4,928,455, issued May 29, 1990. The friction brakes are engageable ~0 with spindle portions 31a, ~lb in ord~r to inhibit rotation of the associated supply spools 25a, 25b when a predetermined amount of web material has been paid out by the associated spool.
As seen in Figure lB, the bag handling head mounts a plurality of guide rolls 33a~f which at least partially define a web path for the webs. A bag sensor 35 (shown in Figure 2) which may comprise a conventional perforation detector and a fixed web guide ara also disposed in the web path.
A~ter the bag or bags are loaded, the bagæ are sealed and severed from the remainder of the web by a sealing unit 30 and a bag tear off uni~ 32, respec~ivsly.
~he severed bag or bags are then dropped into a suitable receptacle or onto a conveyor (not shown).
~ .
~ 3 ~
~ The bag/web handling unit 22, as best in Figure 2, includes upper and lower sub-assemblie~ indicated generally by the reference characters 40, 42. In the disclosed embodiment, the upper and lower sub-assemblies 40,42 are hingedly connected at a pivot 44 which enables the lower sub-assembly 42 to swing downwardly with respect to the upper sub-assembly 40 to facilitate loading of the web or webs. Pr~ssurized, pneumatic actuators 46 often termed a "gas springs" interconnect the two sub-assemblies and act as a counter balance for the lower sub-assembly 42 tshown best in Figures 4 and 5) to facilitate the raising and lowering of the lower sub-assembly 42 by the operator.
When the lower sub-assembly 42 is pivoted to its upper position (shown in Figure 2) a pinch roll arrangement 50 carried by the lower sub-assembly 42 engages and is driven by a feed roll arrangement 52 carried by the upper sub-assembly 40.
Referring also to Figures 3 and 12, the upper sub-assembly 40 carries the drive mechanism for driving the feed roll arrangement 52. According to tha invention, the feed roll arrangement 52 comprises a pair of independently rotatable, axially aligned feed rolls 52a, ~ .
52b rollingly supported at their inner ends by a bearing 56. The drive system can selectively rotate either of the rolls 52a, 52b or rotate them in unison.
In one embodiment of the invention (shown in Figures 3 and 12) the drive system includes a drive motor 60 having output shaft ends 60a, 60b. The output shaft ends 60a, 60b are operatively connected to a pair of clutch/brake mechanisms 62a, 62b by drive belts 64.
The clutch/brake mechanisms 62a, 62b are in turn coupled to respective drive shafts 66a, 66b. The clutch/brake units are secured to a frame member 70 by brackets 72a, 72b which interlock with slotted tongues 74a, 74b 12 ~ ' forming part of the clutch units 6~a, 62b0 The clutch/bxake units ~a, 62b may be conventional.
An outboard end 68 of the output sha~t 66a is interconnected with the outer end of the feed roll 52a by a drive belt 80. The feed roll 52b is operatively connected with the drive shaft 66b through a similar arrangement. With the disclosed apparatus, rotation of the drive motor 60 can be selectively coupled to the feed rolls 52a, 52b by selective actuation of the clutch/brake units 62a, 62b. The upper sub-assembly 40 also rotatably supports a pair of guide rollers 82, 84 between side plates 86a, 86b, which are operative to guide one or both webs.
Turning now to Figuras 4-6, the lower sub-assembly 42, as indicated above, rotatably mounts a pinch roll arrangement 50. As seen best in Figure 6, the pinch roll arrangement 50 compri~es a pair of independently rotatable, axially aligned rolls 90a, 90b. Inner ends of the rolls 90a, 90b are rotatably supported by a bearing and bearing support assembly 92. Outer ends of the rolls 90a, 90b are definad by stub sha~ts 93a, 93b which are rotatably supported in respective shaft receiving bores 95a, 95b formed in frame portions 94a, 94b.
When the lower subassembly 42 is raised to its opera~ive position, shown in Figure 2, the pinch rolls 90a, 90b frictionally engage the feed rolls 52a, 52b, respectively. The feed rolls 52a, 52b and pinch rolls 90a, 90b together define independently actuatable, juxtaposed nip roll assemblies. Eccentric clamps 97a, 97b are mounted at opposite sides of the lower assembly 42 and are engageable with associated clamp ~tructure formed on the upper assembly 40. When the lower assembly is raised, the eccentric clamps are used to lock the lower assembly to the upper assembly and cause the feed rolls 52a, 52b to engage the pinch rolls, 58a, 58b with a predetermined clamping pressure~
In normal operation, the lower sub-assembly ~2 is lowered in order to load the web or webs 26at 2~b from the supply S. In particular, i~ two independent webs or chains of bags are to be loaded, the respective webs are fed around one or both guide rolls 82, 84 then are draped across the pinch rolls sna, 90b, respectively.
When the lower unit 42 is raised to its oper~tive position, the web 26a is clamped between the feed roll 52a and the associated pinch roll 90a whereas the web 26b is clamped betwPen the feed roll 52b and the associated pinch roll 90b. In normal operation, when the machine is turned on, the drive motor SO is continuously energized. The individual webs are advanced by selectively actuating the clutch/brake units 62a, 62b associated with the webs 26a, 26b. In particular, i~ the web 26a (which is clamped between the nip roll assembly formed by the feed/pinch rolls 52a, goa) is to be advan~ed, the clutch/brak~ unit 62a is actuated. After the web is advanced, the associated clutch/brake unit is normally energized into its braking mode so that movement in the web 26a upstream o the lead bag 28a is resisted. As a consequence, uncon-trolled movement in the web 26a (and web 28a, i~applicable) is inhibited or prevented.
As the bags 28a, 28b reach the load position (shown in Figure l), they are blown or "popped" open in order to receive a product or products. In general the bags each include a transverse slit in one o~ the plies that define an outer sidewall. As seen best in Figure 12, the bag handling head 22 includes a pair of bag opening units 97, 99 conneck~d to a common blower 95. Each unit 97, 99 includes a nozzle for directing blower air downwardly towards the mouth o~ a bag positioned below ^ ~
~L32~7~
the unit. The blower is normally opera~ed continuously during the loading process and provides a source of relatively low pressure air for maintaining inflation of the bag. In addition! the blower preferably includes 5 a speed control (not shown) for adjusting the blower pressure. With this control arrangemen~, when relative-ly light products are being loaded, i.e., such as powders, the blower pressure can be raduced to a minimum level so that the product is not blown from the bag during filling.
In the preferred and illustrated embodiment, the bag is initially popped opened by a blast of air from a "blip" tu~e 93 mounted to each opening Unit 97, 99. The blip tube 93 is connec~ed to a source of pressurized air, the communication of which is determined by a valve (not shown) that may be actuated by a conventional valve control system. In general, the tube is connected with a source of pressurized air momentarily as the as-sociated bag reaches the load position. The blower 95 ~0 is then used to maintain the opening of the bag.
After the lead bags 28a, 28b have been loaded, the sealing mechanism 30 is operated in order to form a heat seal across the top of the bags (if the machine is being used to load two webs). Referring to Figures 4-9, the mechanism for forming the heat seal includes a recipro-cally moveable pressure bar 100 (shown best in Figures 3-5), which is moved towards and away from a heating unit 102 (shown best in Figures 7-9) by an actuator 104.
As seen best in Figure 4, the actuator 104 is mounted centrally in a ~rame 106 forming part of the lower sub-assembly 42 and includes an actuating rod 104a which mounts a channel-like cross member 108. Guide rods 110 are secured to distal ends 108a of the sealer cross member 108 and extend toward the ~ront Q~ the ~ 3 ~ 0 machine and are slidably received (and supported) by bores 112 formed in the frame 106. Other bores (not shown) slidably received the guide rod~ 110 and support the rods 110 near the front of the machine. The pressure bar 100 extends bstween ~he front ends of the guide rods 110 so that when the actuator 104 is energized to e~tend the actuating rod 104a, the pressure bar 100 is pulled inwardly towards the heating unit 10~. A position detector 120, (the functio~ of which will be described further on) is mounted to the actuator 104 and detects when a portion of the actuator i.e., the piston, moves to a predetermined position within the actuator housin~
which corresponds to a predetermined position of the pressure bar 100.
Referring also to Figures 7-9, the hea~er unit 102 includes a heating element 124 shown best in Figure 7.
Various heating elements can be employed. For example, the sealing unit may include the heating element and control ~ystem disclosed in U.S. patent No. 4,901,506 issued February 20, 1990, which is owned by the present assignee.
As seen best in Figure 7, a non-stick material 126, such as a band of teflon is wrapped over the heating region and around a pair of shafts 130, 132. Tension springs 128 maintain the positions of the sha~ts 130, 132. One of the shafts serves as a supply spindle whereas the other shaft serves as a take-up spindle. The teflon band 126 inhibits the ba~ being sealed from sticking to the heating unit when the heat sealing cycle is completed. The shafts 130, 132 include knurled end~
130a, 132a (shown best in Figure 6), which enabl~ a user to rotate at least one of the sha~ts in order to pull ~resh anti-stick mat~rial from the other shaft. The bag contacting surface on the pressure bar 100 is also covered with a non-stick material such a~ teflon. As ~ `
. ~
16 132~ ~80 seen best in Figures 4 and 5, a band of mater~al 136 is wrapped around the inside of the pressure bar 100 and between supply and take-up shafts 137, 138. Each shaft includes knurled ends 137a, 138a.
A sealer bar assembly 140 is mounted to the heating unit 102 and includes a pair of gripper elements 142, 144 (shown best in ~igure 7) disposed above and below, respectively the heating element 124. The entire sealer bar assembly 140 is reciprocally mounted in a housing indicated generally by the reference character 146 and retracts inwardly as a bag is clamp between the pressure bar 100 and the gripper elements 142, 144 thereby contacting tha teflon covered heating element 124 in order to form a heat seal on the bag. Referring lS to Figurs 9, the sealer bar 140 is resiliently biased towards the position shown in Figure 7. In particular, at least two relatively light springs 150 (only 1 is shown in Figure 9) urges the sealer bar 140 outwardly, towards the pressure bar 100 i.e., to the pcsition shown ~0 in Figure ~.
When the pressure bar lG0 contacts the seal bar 140, it moves the seal bar rearwardly since the force applied by the pressure bar 100 easily exceeds the force applied by the relatively light-force biasing springs 150. After the bar moves a predetermined distance, further movement in the seal bar 140 i5 resisted by a relatively heavy-force spring biased plunger unit 152 which is threadedly mounted to the frame 106 and is locked in position by a jam nut 154. A plunger stem 156 extends outwardly from the unit 152 and is abuttably engageable with the back of the sealer bar 140. In the illustrated embodiment, the rear of the sealer bar 140 includes recesses adapted to receive a tip of ~he plunger stem 156. ~he spriny force exerted by the plunger unit 152 is substantially higher than the *orce l32~7~a applied by the po~itioning springs 150 and further rearward movement of the s~ler bar 140 is substantially resisted. This resistance to movement generates a clamping force between the pressure bar 100 and the seal bar 140. The clamping force is needed in order to provide a strong heat seal because it ensures that the plies of the loaded bag are placed in intimate contact.
In addition the ~lamping force isolates the loaded bag from the rest of the wab and as a result further movement in the bag due ~o external forces generated by product weight and web severance, is substantially resisted.
This-arrangement provides a significant feature of the invention. With the disclosed clamping arrangement, obstructions in the path of travel of the pressure bar 100 can be detected enabling the sealing cycle to be terminated before damage occurs to the obstruction and/or the sealing mechanism. In particular, a sensor 155 (shown only in Figure 7) monitors the position of the sealing bar 140. When the sealing bar 140 is not in contact with the pressure bar 100, the sealing bar 140, as descxibed above, should be in the position shown in Figure 9. During the sealing operation, the sealQr bar 140 is moved inwardly until it contacts the spring biased plunger 156. In a normal heat sealing cycle, the seal bar 140 should not move to the position at which it engages the plunger lS6 until the pressure bar 100 has moved into substantially abutting engagement with the gripper elements 142, 144 since in normal operation the pressure bar 100 and the grlpper elements 142, 144 should only be separated by the thickness of the sidewalls or plies of the bag. If the path of travel of the pressure bar 100 is obstructed by an improperly loaded or improperly positionad bag, the seal bar 140 will move rearwardly into contact with the plunger 156 .
.
132~
well before the pressure bar loO reaches a position immediately adjacent the gripper elements 142, 144. By monitoring the position of the seal bar 140 and the pressuxe bar 100, the presence o~ an obstruction can be detected. The position of the pressure bar 100 is monitored by ~he sensor 120 mounted to ~he actuator 104.
In the disclosed embodiment, the position of the actuator piston (not shown) that corresponds to ~he adjacent position of the pressure bax 100 is monitored.
If tha seal bar assembly 140 moves rearwardly before the piston reaches the predetermined sensor positlon, control circuitry immediately terminates the heat seal cycle and-returns the pressure bar 100 to its outward or retracted position. Consequently, significant forces are not applied to the bag if an obstruction is present or if the bag is improperly positioned.
According to the invention, the loaded bag iS
severed ~rom the remainder of the web while the bag is clamped by the heat sealing unit 102. In the preferred embodiment, the bag is severed by a bag tear Off mech~nism which is operative to sever the load~d bag along a line of perforations, commencing at a marginal edge of the bag and proceeding towards the opposite marginal edge of the bag. The apparatus for achieving 2~ this function is best shown in Figures 3 and 4. In particular, a pair of double acting actuators 170, 172 are mounted on opposite ~ides of the frame 106. Each actuator includes a respective actuating rod 170a, 172a~
A rod-like tear off member 176 is supported between the ends of the rods 170a, 172a. In the preferred construc-tion, spherical bearings are mounted at opposite ends of the tear off rod 176 and are conventionally held in spherical bearing retainers 180, 1~2 mounted to the ends of the actuator rods 170a, 172a. Retaining collars 174 are fixed to the ends of the tear off rod 176 and 2~7~0 maintain its position between the actuators 170, 172 while allowing some axial movement in the tear off rod 17~.
According to the invention, the actuators 170, 172 are not operated in unison so that movement in the tear off rod 176 occurs non-linearly or angularly with respect to the plane of the web. In particular, the actuation of the actuators 170, 172 is controlled so that one end of the rod 176 moves outwardly before the other end so that contact occurs with a bag to be served at its marginal edge closest to the end of the tear off rod 176 being moved first. For example, the actuator 170 may be energized first in order to move the upper end of the tear off rod 17 6 ( as viewed in Figure 4) outwardly to the position indicated by the phantom line 185. After the upper end of the rod has movèd a predetermined distance, the actuator 172 is en~rgized to move the lower end (as viewed in Figure 4) outwardly in order to complete the tear of~ cycle. With the disclosed arrangement, separation of the loaded bag from the rest of the web (along the line of weakness) does not occur simultaneously across the entire width of the bag but begins at one marginal edge and moves towards the other marginal edge. As a result, reduced ~orces are applied to the bag to effect the severance1 In the illustrated embodiment, the actuators 170, 172 are pneumatically operated and in the preferred control system, the seguential movement of the actuating rods 170a, 1~2a is achieved by restricting the flow of the fluid pressure to one of the actuators. In particular, an adjustable flow restrictor 185 (shown best in Figure 5) is disposed in the flow path feeding the actuator 172 and restricts fluid flow into the rod end of the actuator. With this arrangement, the control system is simplified. When bag sevsrance is to occur, ~ ~ 2 ~
supply lines fe~ding both actuators 170, 172 can be pressurized simultaneously by the operation of a single valve. The delay in extension of one of the actuating rods (i.e. the actuator 172) is achieved by restricting the flow o~ pressurized fluid to the one actuator.
Ultimately, both actuators are fully pressurized ~or maximum force.
Thus far the invention has been described as it would be used to simultaneou~ly handle, two independent lo chains of bags. The invention, howaver, can be used to load and seal a single chain of bags. The disclosed apparatus can handle a narrow web of bags, i.e., a web having a transverse dimension less than the transverse dimension of the drive roll portions 52a, 52b as well as a relatively wide web i.e. a web having a transverse dimension that exceeds the transVerse dimension of the individual feed roll portions 52a, 52b. In fact, a single web having a width equalling the total transverse dimension of the axially aligned ~eed roll portions 52a, 52b can be used. Although the clutch units 62a, 62b can be simultaneously actuated in ~rder to provide coor-dinated movement in both nip roll assemblies, in the preferred embodiment, a mechanical coupling 192 can be used to mechanically interconnect inner ends 194a, lg4b of the drive shafts 66a, 66b. With the mechanical coupling 192, synchronized movement in both drive roll portions 52a, 52b is assured.
As should be apparent, the present invention provides a vexsatile machine which can be used to simultaneously load two individual chains of bags. The bags comprising the chains are not required to be the same size and bags having substantially dissimilar dimensions can be simultaneously handled by the disclosed machine. In addition, the machine can be used to~fill extremely wide bags by synchronizing movement in 21 ~3~:~ 7~
the individual feed roll portions 52a, 52b, in order to feed a single wide web through the machine.
Turn~ng now to Figures lo and 11, an alternative embodiment of the invention is illustrated. In describing this alternate embodiment, the components having similar counterparts in the earlier described embodiment will be designated with the same reference character followed by an apostrophe (').
In this embodiment, individual stepper motors 200, 202 are used to selectively drive the individual nip roll assemblies foxmed by feed roll portions 52al, 52b' and associated pinch roll portions. In particular, the stepper motors 200, 202 are directly connected to an associated ends of the feed roll portions 52b', 52a' by a drive belt 204 (only the drive belt 204 ~onnecting the stepper motor 2Q0 to the feed roll 52bl is shown in Figure 10).
As seen best in Figure 11, a web comprising a chain of bags 206 defines a web path through the unit 22'.
Guide rolls 208, 210, 212 are provided and at least partially define the web path. A conventional perfora-tion dete~ting sensor 214 is used to detect the position of the bag. With this embodiment, a conventional stepper motor control circuit is employed to advance a lead bag "L" to a load position by advancing the web a certain number of steps after a line of perforations (along which contiguous bags ar~ joined) is detected.
The number of steps corresponds to the distance that must be traveled by the lead bag in order to be properly positioned at that load station.
In addition, the disclosed stepper motor drive system can be used to cause an open bag to engage a mouth 220a of a loading funnel 220. In particular, with the disclosed mechanism, the lead bag 'IL'l is advanced to an initial load position at which it is inflated by a ~ 3 rJ ~L 7 ~ O
bl~ower/blip tube unit (or units) such as the units 97, 99 shown in Figure 12 and described above. After the bag L is opened, the associated stepper motor is reverse actuated to raise the bag ~ upwardly (as viewed in Figure ll) in order for the opening in the bag to engage the mouth 220a o~ the funnel 220. The stepper motor would be retracted a certain number of steps correspond-ing to the distance a bag must be raised in order to engage the mouth of the funnel. At the completion of the loading cycle, the bag is sealed and severed by a sealing and severing mechanisms 30, 32 shown in Figure lA and described above.
~he stepper motor drive system can also be used to replace the function provided by the tear-off mechanism 32. In particular, when the loaded bag or bags are being held by the sealer assembly 30, the st2pper motors 200~ 202 can be actuated to reverse feed the web. since the bags are held by the sealer assembly 30, the web or webs are severed from the loaded bags along their ~0 respective lines of weakness.
According to a feature of this embodiment, the forces applied to the webs during ~he ~everance process aan be substantially reduced. In particular, the J
stepper motors 200, 202 can be reverse stepped in a staggered ~ashion so that one web begins the severance process before the other web. As a result, the severance occurs gradually across both the webs and the stepper motors 200, 202 need not apply a force to the web~ in an amount that would be needed to produce a concurrent severance across both webs simultaneou ly.
In short, the power needed to produce severance is substantially reduced when the stepper motors 200, 202 are reverse stepped in a staggered fashion.
The disclosed stepper motor drive is capable o~
extremely precise positioning of a bag. In addition, .
- .
13 2 ~ ~ 3 ~
t~e drive can either advance and/or retract the webs individually or concurrently. Lik~ the first embodi-ment, this alternate embodiment can be used to handle two webs simultaneously or a single relatively wide web i.e. a web having a transverse dimension substantially equal to the total transverse dimension of the feed roll portions 52a', 52b'.
Although, the invention has been described with a certain degree of particularity, it should be understood that those skilled in the art can make various changes to it without departing fxom the spirit or scope of the invention as hereinafter claimed.
Claims (22)
1. A packaging apparatus, comprising:
a) structure establishing a path of travel for at least two independent packaging webs, each web comprising at least one longitudinal chain of intercon-nected, bag-like containers, contiguous containers being interconnected with each other along a transverse line of weakness;
b) an advancing means including a nip roll assembly associated with each of said webs and a drive means for selectively actuating said nip roll assemblies to selectively advance said webs: and, c) each of said nip roll assemblies including a first roller and a second roller in frictional engagement, said first rollers being axially aligned;
d) said drive means including:
i) a stepper motor operative-ly connected with each nip roll assembly; and, ii) a control system for selectively actuating each of said stepper motors in order to advance a web associated with the nip roll assembly connected to said stepper motor.
a) structure establishing a path of travel for at least two independent packaging webs, each web comprising at least one longitudinal chain of intercon-nected, bag-like containers, contiguous containers being interconnected with each other along a transverse line of weakness;
b) an advancing means including a nip roll assembly associated with each of said webs and a drive means for selectively actuating said nip roll assemblies to selectively advance said webs: and, c) each of said nip roll assemblies including a first roller and a second roller in frictional engagement, said first rollers being axially aligned;
d) said drive means including:
i) a stepper motor operative-ly connected with each nip roll assembly; and, ii) a control system for selectively actuating each of said stepper motors in order to advance a web associated with the nip roll assembly connected to said stepper motor.
2. A packaging apparatus, comprising:
a) structure establishing a path of travel for at least two independent packaging webs, each web comprising at least one longitudinal chain of intercon-nected, bag-like containers, continuous containers being interconnected with each other along a transverse line of weakness b) an advancing means including a nip roll assembly associated with each of said webs and a drive means for selectively actuating said nip roll assemblies to selectively advance said webs:
c) each of said nip roll assemblies including a feed roller and a pinch roller, said feed rollers being axially aligned;
d) a tear off member mounted for movement into and out of a web path; and, e) actuating means operative to drive one end portion of said tear off member into said web path before another end portion of said tear off member moves such that said web is engaged by said one end portion, in a region including said line of weakness, before said other end portion of said tear off member engages said web whereby severance of a bag-like container from said web begins at one marginal edge and proceeds towards another marginal edge of said web.
a) structure establishing a path of travel for at least two independent packaging webs, each web comprising at least one longitudinal chain of intercon-nected, bag-like containers, continuous containers being interconnected with each other along a transverse line of weakness b) an advancing means including a nip roll assembly associated with each of said webs and a drive means for selectively actuating said nip roll assemblies to selectively advance said webs:
c) each of said nip roll assemblies including a feed roller and a pinch roller, said feed rollers being axially aligned;
d) a tear off member mounted for movement into and out of a web path; and, e) actuating means operative to drive one end portion of said tear off member into said web path before another end portion of said tear off member moves such that said web is engaged by said one end portion, in a region including said line of weakness, before said other end portion of said tear off member engages said web whereby severance of a bag-like container from said web begins at one marginal edge and proceeds towards another marginal edge of said web.
3. The apparatus of claim 2 wherein said drive means comprises a drive motor having an output shaft and a clutch unit associated with each of said nip roll assemblies, said clutch unit selectively actuatable in order to couple said drive motor output shaft to a nip roll assembly associated with said clutch unit.
4. A sealing apparatus for closing a bag-like container having two overlapping sidewalls, said sealing apparatus comprising;
a) a heat sealing unit including a heating element and a resiliently biased sealer bar:
b) a pressure bar, reciprocally mounted for movement towards and away from said sealer bar, said pressure bar operative to exert a clamping force to sidewalls of a bag held between said sealer bar and said pressure bar;
c) monitoring means for monitoring a position of said sealer bar and said pressure bar, said monitoring means operative to cause said pressure bar to retract to a spaced positioned upon sensing movement in said sealer bar before said pressure bar has moved to a predetermined position with respect to said sealer bar.
a) a heat sealing unit including a heating element and a resiliently biased sealer bar:
b) a pressure bar, reciprocally mounted for movement towards and away from said sealer bar, said pressure bar operative to exert a clamping force to sidewalls of a bag held between said sealer bar and said pressure bar;
c) monitoring means for monitoring a position of said sealer bar and said pressure bar, said monitoring means operative to cause said pressure bar to retract to a spaced positioned upon sensing movement in said sealer bar before said pressure bar has moved to a predetermined position with respect to said sealer bar.
5. Apparatus for severing a loaded bag from a web of bags interconnected along transverse lines of weakness, said apparatus comprising:
a) a tear off member mounted for movement into and out of a web path;
b) actuating means operative to drive one end portion of said tear off member into said web path before another end portion of said tear off member moves such that said web is engaged by said one end portion, in a region including said line of weakness, before said other end portion of said tear off member engages said web whereby severance of said bag from said web begins at one marginal edge and proceeds towards the other marginal edge of said web.
a) a tear off member mounted for movement into and out of a web path;
b) actuating means operative to drive one end portion of said tear off member into said web path before another end portion of said tear off member moves such that said web is engaged by said one end portion, in a region including said line of weakness, before said other end portion of said tear off member engages said web whereby severance of said bag from said web begins at one marginal edge and proceeds towards the other marginal edge of said web.
6. The apparatus of claim 5 wherein said tear off member is supported at opposite ends by actuators and a control system begins extending one of said actuators before extending the other actuator.
7. The apparatus of claim 6 wherein a delay in the extension of said other actuator is achieved by restricting the flow of pressurized fluid to said other actuator.
8. The apparatus of claim 3 wherein said drive means is operative to reverse-step said stepper motors in order to sever a web from a loaded bag, while said loaded bag is being held by a holding means.
9. The apparatus of claim 8 wherein said stepper motors are reverse stepped in a staggered fashion in order to produce a gradual severance of said webs from said loaded bags.
10. The apparatus of claim 9, wherein said holding means comprises a sealing apparatus.
11. The apparatus of claim 10 wherein said sealing apparatus includes:
a) a heat sealing unit including a heating element and a resiliently biased sealer bar;
b) a pressure bar, reciprocally mounted for movement towards and away from said sealer bar, said pressure bar operative to exert a clamping force to sidewalls of a bag held between said sealer bar and said pressure bar;
c) monitoring means for monitoring a position of said sealer bar and said pressure bar, said monitoring means operative to cause said pressure bar to retract to a spaced position upon sensing movement in said sealer bar before said pressure bar has moved to a predetermined position with respect to said sealer bar.
a) a heat sealing unit including a heating element and a resiliently biased sealer bar;
b) a pressure bar, reciprocally mounted for movement towards and away from said sealer bar, said pressure bar operative to exert a clamping force to sidewalls of a bag held between said sealer bar and said pressure bar;
c) monitoring means for monitoring a position of said sealer bar and said pressure bar, said monitoring means operative to cause said pressure bar to retract to a spaced position upon sensing movement in said sealer bar before said pressure bar has moved to a predetermined position with respect to said sealer bar.
12. In an apparatus for loading two chains of interconnected bags, a bag severing arrangement for severing at least two loaded bags held by a sealing mechanism, comprising:
a) a stepper motor and nip roll assembly connected to said stepper motor associated with each web;
b) control means for forward and reverse stepping each of said stepper motors;
c) means for reverse stepping said stepper motors while said loaded bags are held by said sealing apparatus in order to produce severance of said web along associated transverse lines of weakness located between said webs and said loaded bags.
a) a stepper motor and nip roll assembly connected to said stepper motor associated with each web;
b) control means for forward and reverse stepping each of said stepper motors;
c) means for reverse stepping said stepper motors while said loaded bags are held by said sealing apparatus in order to produce severance of said web along associated transverse lines of weakness located between said webs and said loaded bags.
13. The apparatus of claim 12 wherein said control means includes means for reverse stepping said stepper motors in a staggered fashion in order to produce gradual severance of said bags from said webs.
14. A packaging apparatus comprising:
a) structure establishing a path of travel for at least two independent packaging webs, each web comprising at least one longitudinal chain of intercon-nected, bag-like containers, contiguous containers being interconnected with each other along a transverse line of weakness;
b) an advancing means including a nip roll assembly associated with each of said webs and a drive means for selectively actuating said nip roll assemblies to selectively advance said associated web;
c) each of said nip roll assemblies including a feed roller and a pinch roller;
d) a sealing mechanism for closing said bag-like containers after loading including:
i) a heat sealing unit including a heating element and a spring biased sealer bar;
ii) a pressure bar, reciprocally mounted for movement towards and away from said sealer bar, said pressure bar operative to exert a clamping force to a container held between said sealing bar and said pressure bar:
iii) monitoring means for monitoring the position of said sealer bar and said pressure bar, said monitoring means operative to cause said pressure bar to retract to a spaced position upon sensing movement in said sealer bar before said pressure bar is moved to a predetermined position with respect to said sealer bar;
e) a tear-off mechanism for severing said loaded containers from their associated webs including:
i) a tear off member mounted for movement into and out of a web path;
ii) actuating means operative to drive one end portion of said tear off member into said web path before another end portion of said tear off member moves such that said web is engaged by said one end portion, in a region including said line of weakness, before said other end portion of said tear off member engages said web whereby severance of said bag from said web begins at one marginal edge and proceeds towards the other marginal edge of said web.
a) structure establishing a path of travel for at least two independent packaging webs, each web comprising at least one longitudinal chain of intercon-nected, bag-like containers, contiguous containers being interconnected with each other along a transverse line of weakness;
b) an advancing means including a nip roll assembly associated with each of said webs and a drive means for selectively actuating said nip roll assemblies to selectively advance said associated web;
c) each of said nip roll assemblies including a feed roller and a pinch roller;
d) a sealing mechanism for closing said bag-like containers after loading including:
i) a heat sealing unit including a heating element and a spring biased sealer bar;
ii) a pressure bar, reciprocally mounted for movement towards and away from said sealer bar, said pressure bar operative to exert a clamping force to a container held between said sealing bar and said pressure bar:
iii) monitoring means for monitoring the position of said sealer bar and said pressure bar, said monitoring means operative to cause said pressure bar to retract to a spaced position upon sensing movement in said sealer bar before said pressure bar is moved to a predetermined position with respect to said sealer bar;
e) a tear-off mechanism for severing said loaded containers from their associated webs including:
i) a tear off member mounted for movement into and out of a web path;
ii) actuating means operative to drive one end portion of said tear off member into said web path before another end portion of said tear off member moves such that said web is engaged by said one end portion, in a region including said line of weakness, before said other end portion of said tear off member engages said web whereby severance of said bag from said web begins at one marginal edge and proceeds towards the other marginal edge of said web.
15. The apparatus of claim 14 wherein at least one of said webs comprises two side-by-side interconnected longitudinal chains of bag-like containers.
16. The apparatus of claim l wherein at least one of said webs comprises two side-by-side connected packaging strips, each strip comprising a chain of interconnected bag-like containers joined together along transverse lines of weakness.
17. The apparatus of claim 8 wherein said stepper motors are reverse stepped in a staggered fashion in order to produce a sequential severance of said webs from said loaded bags.
18. The apparatus of claim 7 wherein said delay in actuating one of said actuators is achieved by a flow restriction disposed in a flow path feeding pressurized fluid to said one actuator.
19. A sealing apparatus for closing a bag-like container having two overlapping sidewalls, said sealing apparatus comprising:
a) a heat sealing unit including a heating element and a sealer bar having a first bag engaging surface;
b) a pressure bar including a second bag engaging surface, reciprocally mounted for movement towards and away from said sealer bar, said pressure bar operative to exert a clamping force to sidewalls of a bag held between said sealer bar and said pressure bar;
c) biasing means resiliently biasing one of said bag engaging surfaces towards an extended position;
d) monitoring means for monitoring movement in said resiliently biased bag engaging surface and a position of said pressure bar, said monitoring means operative to cause said pressure bar to retract to a spaced positioned upon sensing movement in said resiliently biased surface before said pressure bar has moved to a predetermined position with respect to said heat sealing unit.
a) a heat sealing unit including a heating element and a sealer bar having a first bag engaging surface;
b) a pressure bar including a second bag engaging surface, reciprocally mounted for movement towards and away from said sealer bar, said pressure bar operative to exert a clamping force to sidewalls of a bag held between said sealer bar and said pressure bar;
c) biasing means resiliently biasing one of said bag engaging surfaces towards an extended position;
d) monitoring means for monitoring movement in said resiliently biased bag engaging surface and a position of said pressure bar, said monitoring means operative to cause said pressure bar to retract to a spaced positioned upon sensing movement in said resiliently biased surface before said pressure bar has moved to a predetermined position with respect to said heat sealing unit.
20. The apparatus of claim 19 wherein said resiliently biased surface is said first bag engaging surface.
21. A packaging apparatus, comprising:
a) structure establishing a path of travel for at least two independent packaging webs, each web comprising at least one longitudinal chain of intercon-nected, bag-like containers, contiguous containers being interconnected with each other along a transverse line of weakness;
b) an advancing means including a nip roll assembly associated with each of said webs and a drive means for selectively actuating said nip roll assemblies to selectively advance said webs; and, c) each of said nip roll assemblies including a feed roller and a pinch roller, said feed rollers being axially aligned;
d) a heat sealing unit including a heating element and a sealer bar having a first bag engaging surface;
e) a pressure bar including a second bag engaging surface, reciprocally mounted for movement towards and away from said sealer bar, said pressure bar operative to exert a clamping force to sidewalls of a bag held between said sealer bar and said pressure bar;
f) biasing means resiliently biasing one of said bag engaging surfaces towards an extended position;
g) monitoring means for monitoring said extended position of said resiliently biased bag engaging surface and a position of said pressure bar, said monitoring means operative to cause said pressure bar to retract to a spaced positioned upon sensing movement in said resiliently biased surface before said pressure bar has moved to a predetermined position with respect to said heat sealing unit.
a) structure establishing a path of travel for at least two independent packaging webs, each web comprising at least one longitudinal chain of intercon-nected, bag-like containers, contiguous containers being interconnected with each other along a transverse line of weakness;
b) an advancing means including a nip roll assembly associated with each of said webs and a drive means for selectively actuating said nip roll assemblies to selectively advance said webs; and, c) each of said nip roll assemblies including a feed roller and a pinch roller, said feed rollers being axially aligned;
d) a heat sealing unit including a heating element and a sealer bar having a first bag engaging surface;
e) a pressure bar including a second bag engaging surface, reciprocally mounted for movement towards and away from said sealer bar, said pressure bar operative to exert a clamping force to sidewalls of a bag held between said sealer bar and said pressure bar;
f) biasing means resiliently biasing one of said bag engaging surfaces towards an extended position;
g) monitoring means for monitoring said extended position of said resiliently biased bag engaging surface and a position of said pressure bar, said monitoring means operative to cause said pressure bar to retract to a spaced positioned upon sensing movement in said resiliently biased surface before said pressure bar has moved to a predetermined position with respect to said heat sealing unit.
22. The packaging apparatus of claim 1 wherein said first roller is a feed roller and said second roller is a pinch roller.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/174,824 US4899520A (en) | 1988-03-29 | 1988-03-29 | Packaging apparatus and method |
| CA000615132A CA1321780C (en) | 1988-03-29 | 1989-09-28 | Packaging apparatus and method |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/174,824 US4899520A (en) | 1988-03-29 | 1988-03-29 | Packaging apparatus and method |
| CA000615132A CA1321780C (en) | 1988-03-29 | 1989-09-28 | Packaging apparatus and method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1321780C true CA1321780C (en) | 1993-08-31 |
Family
ID=25673196
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000615132A Expired - Fee Related CA1321780C (en) | 1988-03-29 | 1989-09-28 | Packaging apparatus and method |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US4899520A (en) |
| CA (1) | CA1321780C (en) |
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| NL8902711A (en) * | 1989-11-02 | 1991-06-03 | Audion Elektro Bv | DEVICE FOR PACKING PRODUCTS. |
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| US5433060A (en) * | 1994-02-10 | 1995-07-18 | Recot, Inc. | Automated method and apparatus for detachably securing flexible packages to a display strip |
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| US5772565A (en) * | 1995-08-30 | 1998-06-30 | Automated Packaging Systems, Inc. | Heat sealer |
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| US6470648B1 (en) * | 2000-06-22 | 2002-10-29 | Advanced Poly-Packaging, Inc. | Packaging sealer printer |
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| AT5677U1 (en) * | 2001-10-11 | 2002-10-25 | Card Casinos Austria Res & Dev | CARD MIXER |
| US6789963B2 (en) * | 2002-07-31 | 2004-09-14 | Sharp Packaging Systems, Inc. | Continuous strip bag feeder and loader with pivotable integrated printer assembly |
| US20040025317A1 (en) * | 2002-08-07 | 2004-02-12 | Belt James G. | Apparatus and method for producing a pre-loaded display strip |
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| WO2009036237A1 (en) * | 2007-09-12 | 2009-03-19 | Automated Packaging Systems, Inc. | Packaging machine |
| US9623622B2 (en) | 2010-02-24 | 2017-04-18 | Michael Baines | Packaging materials and methods |
| WO2014031364A2 (en) * | 2012-08-21 | 2014-02-27 | Gess Larry C | Method and apparatus for changing a strip of sealed bag precursors in to open bags |
| US9139317B2 (en) | 2012-08-21 | 2015-09-22 | Intertape Polymer Corp. | Method and apparatus for opening bags while maintaining a continuous strip of bag precursors |
| WO2015112552A1 (en) * | 2014-01-21 | 2015-07-30 | Tidi Products, Llc | Machine for making sheaths |
| MX2016016551A (en) * | 2014-06-18 | 2017-07-28 | Sharp Packaging Systems Llc | Bagging machine and method. |
| CN108602575B (en) * | 2015-11-16 | 2021-01-05 | 自动化包装系统公司 | Bag with cut |
| EP3634876B1 (en) | 2017-06-07 | 2023-08-02 | Automated Packaging Systems, LLC. | Web of preformed bags |
| WO2020205915A1 (en) | 2019-04-02 | 2020-10-08 | Automated Packaging Systems, Llc | Packaging machine for opening bags on a web of bags and methods of using the same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3138074A (en) * | 1962-02-01 | 1964-06-23 | Crown Zellerbach Corp | Cutting device |
| US3477196A (en) * | 1967-04-27 | 1969-11-11 | Automated Packaging Corp | Mechanism for automatically feeding,loading,and sealing bags |
| US3882656A (en) * | 1971-05-03 | 1975-05-13 | Automated Packaging Syst Inc | Packaging method and apparatus |
| US3965653A (en) * | 1971-05-03 | 1976-06-29 | Bernard Lerner | Packaging apparatus |
| US3815318A (en) * | 1971-05-03 | 1974-06-11 | Automated Packaging Syst Inc | Packaging method and apparatus |
| US3815313A (en) * | 1972-10-04 | 1974-06-11 | R Heisler | Apparatus and method for automatically sizing and wrapping a shrink wrap envelope around advancing luggage |
| US3938299A (en) * | 1973-02-28 | 1976-02-17 | Automated Packaging Systems, Inc. | Packaging system and method |
| US4014154A (en) * | 1973-02-28 | 1977-03-29 | Automated Packaging Systems, Inc. | Packaging method and apparatus |
| US3956866A (en) * | 1974-06-28 | 1976-05-18 | Automated Packaging Systems, Inc. | Packaging method and apparatus |
| US4041846A (en) * | 1975-09-11 | 1977-08-16 | Automated Packaging Systems, Inc. | Method of making container strips |
| US4202153A (en) * | 1977-10-25 | 1980-05-13 | Automated Packaging Systems, Inc. | Method and apparatus for loading containers horizontally |
| US4586318A (en) * | 1983-12-22 | 1986-05-06 | All Packaging Machinery & Supplies Corp. | Bag forming and bagger apparatus and method |
| US4651506A (en) * | 1985-01-04 | 1987-03-24 | Automated Packaging Systems, Inc. | Packaging apparatus and method |
-
1988
- 1988-03-29 US US07/174,824 patent/US4899520A/en not_active Expired - Lifetime
-
1989
- 1989-09-28 CA CA000615132A patent/CA1321780C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| US4899520A (en) | 1990-02-13 |
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| MKLA | Lapsed |