US2660219A - Heat-sealing machine - Google Patents

Description

NOV. 24, 1953 w. HAAs ET AL HEAT-SEALING MACHINE Filed March l5, 1950 5 Sheets-Sheet 1 Nov. 24, 1953 W` HAAS ET AL 2,660,219

HEAT-SEALING MACHINE Filed March l5, 1950 v 5 Sheets-Sheet 2 mm -f Y SL v IN V EN TORS 4 a Mz Tf1? H445 BY N fA/v# .554,65 rsf/v,

@ya M Nov. 24, 1953 w. HAAs ET AL HEAT-SEALING MACHINE Filed March l5, 1950 5 Sheets-Sheet 3 INVENTORS.

ATTQPNE-YS.

W. HAAs ET AL HEAT- SEALING MACHINE Nov. v24, 1953 5 Sheets-Sheet 4 Filed March l5, 1950 ATTORNEYS.

IN VEN TORS /f MATER Hans ofauxfrasrf/M Nov. 24, 1953 w. HAAS ET AL 2,660,219

HEAT-SEALING MACHINE Filed March l5, 1950 5 Sheets-Sheet 5 NN um Qw mf i Q Patented Nov. 24, 1953 HEATJSE'ALING MACHINE Walter IHaasf Middletown, 4and. .FrankqNDBeifgg stein, Hamilton, HOhio, assignorslto The flirter, state ,Foldingoxompanm Middletown, Ohio, a vcorporation4 of "Ohio Application March 15, 1950, Serial No. 149,708

(C1: isis-42)" 10 vClaiiilS.. l

yQur ,inventionv hasato do -withthe` joiningofv ufactureoff-liningtubes Vor-baglike liners for.VV

paperboardcartons such ,as are-inwideuse. for

frozen; foods or,A otherf. products which4 must-be tightbagsfor such uses. Certain typesof lms:

offen little-diiculty in the-formationof heat-.-V selfliol,,longitudinal` seams.. For example, cello-4 Dhane fcoatezdiwithra `fusible sealingi substance, is

readily tubedfandeis readilyfsealed bythe applica.. tion. of I pressure and r sufficient heat .to s melt or.

softenthefsealing4 substance, the film` itself re tainingv its `strength substantially unimpaired throughout the sealing operation. Other films.

have the property of vsoftening- Vsuiiciently. to become. sealed together while-retaining over afwide.r

rangel ofV Vtemperature suiiicientinherent strength tot-behandled without f. .disruption at ftheV seam area.,

sirablevfor various-qualities ofprooiness, strength, inertness,nonetoxicity `and the like, ,which have Only a verynarrowrange of temperature flying between a solidY condition and avery soft condition .in v.which 'they are non-self-sustaining. Such lms, when heated, lose their strength very rapid;

ly; so that handling becomes diicult. They also become sticky when heated, so that it is difficult to-separate the joined partsfrOm thev seam-- forming instrumentalities in the heat softened conditionof the seamecll parts; Also, on slight overheating, such films tend to liquefy and even to collect in dropletslor to pull apart through surface tension elects, thusdestroying .the in.

tegrity of the lms and Atheseams .formedtherein. Thesedifculties, havel presented yserious problems to thepractical art, and .in the case of some l'llms have hithertov prevented the formation kof .adequate sealsor seams by machinery fin automatici or continuous operation.

An example of such a film, presentingthe above difficulties ink a `high degree, is a film of polyethylene. Polyethylene ink thin films is quite strong at. room temperatures and` is highly desirable by reason of its proofness and otherchar-l acteristics yfor the manufacture of Y liquid-tight and moisture-tight f bags. r But it i is inherentlyV readily fusible, in the sense that the application,

of heat sufficient to soften the material for y sealing purposes is likely, unless controlled more` exactlythanfhasfhitherto been possible in automatic machines, to sof-teny it -too much, rendering the production. of seams impossible, or producing seams which are notsound.,- Pliolm, which` is. an.` amorphous lrn'formed from chlorinated-rubber hydrocarbon, presentsfsimilar difficulties; al:-:` though. infsomewhat lessertdegree, and is of-that type ofY film which for-:conveniencey hereinafter weshall-refer to as freadily fusible.

The primary object of .ourinvention is to provideaseaminggmethod and mechanismffor readily iusiblef'iilms wherebyc adequate and. reliable continuous4 seams maybe formed. therein With the avoidance ofy they diieultieswa havev discussed.` Withcoated fllms,-such as-thesoV-called moistureproof.cellophane; no substantial difculty is encountered-in tubingthe -material .and forming ya longitudinalcenter seam. The chief prob. lem arises in.the;making;of.end closures Yon bag lengthscut Vfromthebag tube, where the inclusion of:- foldswor` .lapped `portions inwtheclosure may give rise1-to.difficulty,v especially Where .the thickness of the fusible coating is less thanfthe thicknessfof v.the cellophane itself.v Conversely, inthe end closing-offbag tubes` -made lof. readily fusible fllmsfthex fusibilityY of the` body vo f.the seamV diminishes the difficulty with :folds and lapped portions.- But great. difliculty.I` is eny countered in the formation of continuous longitudinal-.seams in bagtubesso much .so thatwe heat could be applied through" the paper strips,

and 4so .that these, .could fassistjin nthe ltransporta"- tion of "the, material over afornienl. This,fhw

ever, is bothexpensive and inconvenient-Ta d faty they Sametime Vinterferes Withthe formation-ini" end-closure seamson .the bag-tubes; I

The primary object vand other objectsiof-'the invention,. which...,.Will,bemade` clear as the. -de' scription,.proceedsg.l or. `Will beapparent tof? one.

skilled in the art upon readingthesegspecicaetions, weffaccomplish in: that: `procedure andnby the use of that mechanism of which Weshall.4

noW- ,describef an-` exemplary embodiment This;

embodiment-Will 4have -to dor-with. ther .manufacfture ofr continuousu .lengths-of ,bag `l-tubes, ...which 3 may be cut apart into bag lengths as desired. Reference is made to the accompanying drawings wherein:

Figure 1 is a partial plan View of a bag tube forming apparatus embodying mechanical aspects of our invention.

Figure 2 is a View partially in elevation and partially in section of the same apparatus, taken along the section line 2-'2 of Figure 1.

Figure -3 is a perspective View of an exemplary bag.

Figure 4 is an enlarged, partial plan View with parts in section of the overhead sealing apparatus of Figures 1 and 2, the section being taken along the line 4 4 of Figure 5.

Figure 5 is an elevational View of the same apparatus.

Figure 6 is a partial sectional View taken along the line 6-6 of Figure 5.

Figure 7 is a sectional view of the belt sheave and sprocket of the apparatus of Figures 4 and 5, taken along the section lines 1 1 of the latter figure.

Figure 8 is a plan View of one of our roller elements.

Figure 9 is a partial sectional view through a seam formed in accordance with our invention.

Figure 10 is an enlarged plan View of a portion of the forming plate.

' Figure 11 is a partial sectional View taken along the line ll-l l of Figure 9.

Figure 12 is a partial transverse sectional view of the end ofthe first section of the machine and the beginning of the second section, taken along the line l2-l2 of Figure l.

Figure 13 is a partial longitudinal section of the machine at the entering end of the second section taken along the line |3-i3 of Figure l.

Figure 14 is a sectional View showing the mode of supporting the Vanes on the air supply pipes, and is taken along the line M-lli of Figure 13.

Figure 15 is a partial sectional view illustrative of the mode of mounting the air supply pipes and is taken along the line I5-I5 of Figure 13.

Figure 16 is a partial sectional view showing in elevation the elements of an end sealer for bag tubes, the View being taken along the line lli-i6 of Figure 1.

Figure 17 is a sectional view through the belt elements employed in the mechanism of Figure 16, along the line l'I-l'l in that figure.

Figure 18 is a sectional view of mechanism employed in connection with the end sealer, and is taken along the line l-l of Figure 16.

Figure 19 is an elevational View of a pressure element employed in connection with the mechanism of Figure 16.

Figure 20 is a partial plan view of an alternative form of sealing apparatus employable both in connection with the formation of longitudinal seams and in end sealing.

Figure 21 is an elevational view thereof with parts in section, taken along the line 2I--2l of Figure 20.

Figure 22 is a partial transverse section of the apparatus taken along the line 22-22 of Figure 21.

Figure 23 is a transverse sectional view of a sealing shell and torch assembly taken along the line 23--23 of Figure 21.

Figure 24 is a plan View 4of the sealing shell element.

Figure 25 is an elevational view of the sealing shell element and torch mounting apparatus.

Figure 26 is a partial elevational View of end' lil i sealing apparatus employing a sealing shell and torch.

Figure 27 is a sectional View showing torch operating mechanism, and is taken along the line 27 21 of Figure 26.

Figure 28 is a partial sectional view showing the use of a movable torch and a shield for the torch flame.

In the sealing of polyethylene films by heat, there is a spread of only about 5 degrees between a condition of the material toc solid to weld together and a condition of the material too soft to maintain its integrity when handled on conventional sealing apparatus. This has hitherto rendered the continuous or automatic sealing of polyethylene lms impracticable.

Briefly, in the practice of our invention, we have found that successful and entirely dependable heat-welded seams may be formed in such films as polyethylene which are very readily fusible if mechanism is employed such as hereinafter described. In one aspect of this mechanism and procedure, the film is pulled over a former, and the lapped portions are supported from beneath by moving means. A heat conducting element is caused to travel with lapped portions of the lm over theV area of seam formation, heat is applied through the heat conducting element by a heating means of narrower effective width and arranged to apply the heat intermediate the edges of the traveling member so that a heat gradient is established in the traveling member and in the lapped portions of the film, and the welded seam is allowed to travel with the moving members until the fused parts have congealed or hardened before separationtherefroin. By means and a method such as have just been briefly characterized, we can continu-- ously and perfectly form welded seams in polyethylene lm materials without the use of protective paper strips or other extraneous elements'. We shall now proceed to a more particular description ofthe mechanism and method by which this is accomplished.

Referring to Figures 1 and 2 we have shown a machine having a general frame 30. A polyethylene or other readily fusible film material 3l; is withdrawn from a supply roll journaled between supports on the machine frame, is carried over a reversing roll 32 and downwardly beneath a forming plate 33, having an upturned front end, about which plate the film is to be tubed.

The forming plate is shown as supported by a post. at one end, engaged by a bracket 35 on a shaft or rod 36, which in turn is held by a bracket 3'! on a shaft 38 extending across be tween the machine supports 39 and d8, and by other shafts and supports as may be required. The forming plate and the material extending beneath may be supported from below by a series of rolls lil, d2, 43, journaled in any suitable: way in connection with the machine frame, and: driven if desired. The driving of these rolls, whilev not usually necessary, assists in the passage of the lm through the machine.

The lm material 3l is folded about the forming plate 33 as is usual in bag tubing operations, by folding fingers dll and rollers l5 mounted in suitable brackets on the shaft or rod 36. Our forming plate 33 is unusual in that it is preferably formed, in an area underlying the area of seam formation, with a plurality of small transverse rollers, one of which is shown at. i6 in Figure 8, acting at the top surface of the forming plate to form a moving support for the lapped material *1i/4 of an inch Wide.

aecomo A thereon While it lis being Weldedtogether. The Vj rollers-are small in diameter-pand they and their imountings preferably do not significantly-increase the effective thickness of the forming plate. There are many ways of mounting such rollers. @ne `Way is illustrated 'in Figures 6 and l0 Where the forming plate A33 "is cutaway `as at 4l, and `the jseveralsmall y rollers i6 are jour-naled at the lapices of their tapered ends in bars 2418 and'49. These bars have bifurcated ends, e. Aguita `which, as most clear-ly shown in -Fig-ures 10V-and `11, engage and `clamp edge por-tions of the forming plate 3-3 adjacent the cutout 4l. Enlargement of the cutout as at 33a permits the insertion -of the bars 4t and '49 andthe assembly of the rollers 45 thereto. The clamping -maybe accomplished by screws 50 engaging Athe l-bif-urcated `ends ofthe bars.

As Will be clear from Figure Y6, the lrollers 46 form arnoving support for the lapped portions `of the folded 3| beneath the area of seam formation. The small individual rollers may be made lof steel or other metal. In the mode of rmo-untii-ig these rollers illustrated in our ldrawings, they serve to conduct heat from the seam `so that it maybe absorbed and dissipated vby the forming plate. Tlieir -primary purpose, however, is to hold the fi-lin layers up into contact with an overhead metal belt which will subsequently be described. They `play an important part in the sealing for this reason, particularly inasmuch as `they provide support practically 4free from frictional resistance. When irregularities in the formation or position of the overhead belt are likely'to be encountered, we prefer to rho-unt the rollers resiliently or to provide resilience in the surfaces of the rollers themselves. The latter may be accomplished, as shown in Figures 8 Aand ll, by reducing somewhat the -midsection of the rollers, as 'at 4ta, and `placing over them -a sleeve 4Gb of rubber or other resilient material.

Also, `weprefer to form a groove (33t in Figures l and l1) Vin the former extendingA forwardly of the place at which the rollers 46 are mounted. This slot or groove, underlying the lapped edges of the film material in the area of seam formation, serves as a vent and also as a clearance for the film while the material in the seam is still softened.

Figure 6 also illustrates one Inode of applying heet te lapped, perbene ef the .1i- 1m i0 effect e veel@ er ,Seem in` aeeerdenee with eur invention Pireetly there enel .in Contact with the lapped portions of the lm 3|, we have shown in section in this figure a traveling metallic belt 5l having seed heat conductivity- Above the belt there is located an ,electric er other heater 52 havingia nose or heat .applying means 53. in contact with. the belt 5l` centrally thereof, and substantially narrower than the belt. The heater 5 2. if electric, Will preferably be supplied with thermcsatic control. means (not illustra-ted), and as shown in Figure 5, the power supply circuit 543 being provided with a variableresistance 155 or other reactor for the purpose of accurate heat control. B y Way of example, yin our practice We are successfully employing asthe moving member A5| anendless steel belt .008 inch in thickness and TheV contacting Anose 53 of the heating element 52 is only 1/8 inch in width. These dimensions arelexemplary'merely, andmay bevwidely varied not only for the same material, but in connection with changesV in the thickness of the film, the desired widthof actual fusion fin the seam, the vheat transmitivity of `the sub.-

stance of Athe belt 5| and the like.

ylit will '-be noted that the heat ltransmitting nose 53 does not `contact the edges of the .beltl 5|, but serves to heat only the central portion .of the belt. Heat sufficient to fuse the substance :of the lapped portions `of the -lm is 'transmitted `.only through the central portion of the belt 5|, and a temperature gradient is established 'by the belt due to the loss of heat .at Athe edges thereof by radiation and conduction. The edges of the belt .are therefore substantially cooler than the longitudinal central portion of the belt over the welding area and in particular the `edges of the belt are maintained below the'temperature required to :soften the material of the film to `Welding or fusion consistency. This condition is one easily attained with the apparatus and in the method .described herein. Where a heating element of xed Wi th and uniform temperature is applied toV the films, difficulties vare had, as Valready explained, with excess fusion of the film substance, and these -difficulties are greatest along the side edges of the heating element. Our procedure and apparatus entirely obviate these difficulties and result in the application of heat to the lapped portions of the film in accordance with a gradient curve indicating a gradual lowering of temperature -from a Welding heat adjacent the center of the belt to temperatures `outwardly therefrom at both sides which temperatures are well below the fusion temperature of the material.

Since it is driven at the same speed as the moving llm, the element 5|, traveling with the lapped portions of the nlm, does not tend to disrupt them by physical interference, but rather to maintain the softened portions of the lm in position during the Welding operation. As will hereinafter be explained, -cooling may be applied to the welded seam through the belt element 5| beyond the welding zone so as to cause the welded parts to har-den or congeal fully prior to their separation from the belt. Thus the development of stickiness in the lm material :adjacent the under surface of the belt the Welding zone is not of consequence, and does not lead to the disruption of the film. The small rollers 45 are highly important in the seam` forming operation since they exert no frictional resistance on the softened lm portions,

have minimum contact therewith, and continu- A ously presentfresh, cool surfaces to the film.

The traveling member 5|, the heating means and the cooling means are preferably mounted as a unit in such fashion that they can be brought into contact with the work and removed from conta-ct therewith at will. In Figures 4 and 5 we have shown the belt element 5| passing over sheaves 56 and 5l which are. mounted on stub shafts 58 and 59 on a bar or frame element 60, a preferred shape of which is most clearly shown in lFigure 1. This bar or frame element, hereinafter simply called the bar 60, is freely pivoted at one end on a shaft 6| which extends across the machine and is journaled in brackets 62 and 63 (see Figure 1) on the machine frame. The mounting of the bar 60 on the shaft -6I provides for a downward swinging of the upper sealing apparatus into contact with the work on the forming plate 33', or an upward swinging of the apparatus out of contact with 'the work, the swinging from position to position being controlled as later described.

The belt 5| will be driven, and to this end we have shown, most clearly in Figures 4, and 7, a sprocket 64 attached to the sheave `5`| and mounted on the stub shaft 6|. This sprocket is connected by a chain 65 to a sprocket 6-6 fixed on the shaft 6|. As shown in Figure 1, the shaft 6| may bear another sprocket 61 connected by a chain `68 to a sprocket 69 on a main drive shaft '10.

The heater 52 may be mounted directly -upon a stud on the bar 60 if desired. However, we have found it p-referable to provide a means whereby the pressure of the nose of the heating element can be regulated against the belt 5|, and whereby the heater can be moved out of contact with the belt where this may be desired. To this end, as more particularly illustrated in Figure 6, we mount the heater :52 on a yoke which in turn is mounted on a stud 'I2 on a lever arm 13. The lever arm is pivotally mounted on the stub shaft 59 which holds the sheave 51, either directly or adjusta-bly by means of a guide 14, the lever arm 'I3 being slotted, as shown, to permit movement with respect to the guide.

The yoke has opstanding ears Ha and 'Hb engaging the stud |2. The ear 'Hb is provided with a vertically elongated slot through which the stud 12 passes, and a compression spring i5 engages between the lever arm 'i3 and the ear. This construction permits an up-and-down movement of the right-hand end of the yoke i as illustrated in Figure 6, the result of which will be a tilting of the heater 52 and hence a lateral adjustment of the position of its nose 53 with respect to the moving belt 5|.

a laterally extending ear Hc on the yoke which is engaged from beneath by a set screw '|53 threaded in a bracket 'il' on the lever arm '13.

rlhe opposite end of the lever arm 'I3 may be connected by means of a tension spring 'I8 (Figure 5) to an arm 'I9 on a bar or angle iron d@ extending across the machine. A bar 8|, also attached to the angle iron S9, has pivoted to its lower ends a lever arm 82 having a downwardly depending, bifurcated end, within which is mounted a roller` 83 bearing against the lefthand end of the lever arm '53. An upwardly turned portion of the lever 92 may be engaged for adjustment by a thumb nut 81 or the like on an eye -bolt 85 engaging the bar 9|. A spring 86 may be interposed between elements 52 and 8|, as shown. By means of the thumb nut the position of the lever -82 may be adjusted so as to regulate the pressure of the heater 52 against the belt l5|, and to lift it entirely from the belt, in the lower position of the mounting bar 60. When the mounting bar `6G is swung to its upraised position, the roller S3, mounted as described on the stationary angle iron 9|), will act to raise the lever arm 13, removing the heater 52 from contact with the belt 5|.

The lever arm 13 is provided with a lower extension 13a, underlying the shaft 6|, by means of which the heater may be raised out of contact with the belt 5| by mechanism hereinafter described.

The sealing of readily fusible films is a very delicate operation, and it has been found that during stoppages of the machine, the bare removal of the nose l53 of the heater a short distance from the belt 5| may not be suflicient to prevent 4building up of heat in the belt. As a consequence, we prefer to provide a shield which,

This f, adjustment may be accomplished by providing when the heater 52 is raised :as hereinafter described, will automatically swing into position between the heater and the belt and which will likewise be automatically removed from shielding position when the heater is lowered to operating position. To this end we provide a shield element 8l attached to a bar or lever 88 which is pivoted as at 89 to an extension or crossbrace of the mounting bar 60. A tension spring 190 (Figure 1) engages the bar 88 and tends to urge it to a position in which the shield is oil-side.

Referring to Figure 1, we have shown a sliding element 9| mounted on the shaft 6|. This sliding element is connected by a link to one arm of a three-arm bell-crank 93 pivoted in a bracket on the machine frame. Another arm of the bell crank is connected by a link 94 with the operating lever 95 of a clutch mechanism 96 interposed between the shaft and a. drive pulley 91 which may be belted to a prime mover (not shown).

The sliding element 9| is connected to the shield lever 88 by a link 9&3. Also the sliding element 9| is provided with a conical nose 99 capable of engaging the lower extension 13a of the heater-bearing arm 73.

The arrangement is such that when the clutch operating lever 95 is swung to the o position, (a) the clutch 96 is disengaged and the machine stops, (b) the element 9| is slid along the shaft il until the nose 99 contacts and depresses the extension 13a of the lever arm T3, thus raising the heater 52 away from the belt 5|, and (c) the lever 88 is swung so as to interpose the shield 8l between the heater and the belt. A reversal of these operations occurs automatically when the clutch operating lever is moved to the on position.

In Figures 4 and 5, I represents a cooling shoe engaging the belt 5|. It may be in the forni of a hollow body having flexible conduits |9| and |92 for connection with a source of cooling fluid such as water, and with a drain. It may be mounted by bracket means H33 on studs ll and |95 on the bar or frame 6|), the bracket means being provided with springs and adjustment screws |66 as shown to regulate the pressure of the shoe I against the belt. The cooling capacity of the shoe, where employed, will be suicient to lower al1 parts of the belt 5| passing beneath it to a temperature well below the weldingr temperature of the film.

For the adjustment of the tension of the belt 5| we may provide a screw-type adjustment means |91 in the bar or frame 69 engaging the stub shaft 58.

To assist in the removal of the formed seam from the belt 5|, we may if desired provide an air blast device comprising a nozzle IB (Figure 2) with a delivery end directed into the pinch between the belt and the seam at the exit side of the apparatus. This nozzle may be held in a bracket |69 on the bar 6|) and provided with a flexible hose connection IIB to a source of air under pressure.

Apparatus such as that hereinabove described will dependably produce longitudinal seams in difficulty weldable material such as polyethylene or other films which are readily fusible. For machine threading purposes it is desirable to .provide means for the removal of the whole upper sealing apparatus from proximity to the lrn, so that the disposition of the film on the former 33 can be adjusted. One way of accomplishing this is illustrated in Figures 1 and 2. Here an upstanding post suitably mounted on the machine carries adjustably a laterally extending arm H2, which is slotted to receive a handleA ||3 pivoted to the right-hand end of the mounting bar Sii. The handle is notched at its upper end, a detent H4 is provided on the arm H2, a spring latch ||5 is provided, cooperating with the detent, so that when .the sealing mechanism is swung downwardly to operating position, it will be held there through the illustrated engagement of the handle element. A screw adjustment means llt is provided on the post 9!) for the positioning of the arm I l2A thereon, so that the pressure of the sealing mechanism against the work can be accurately controlled. Usually the adjustment is made in such fashion that less than the full weight of the sealing mech-- anism is imposed on the work,

The sealing mechanism is counterbalanced in some suitable fashion. We have shown a cable Ill attached to the handle ||3, passing over a pulley H8 on the arm ||2 and another pulley ||9 on a bracket on` the machine frame, and bearing at its lower end a weight element |20 somewhat heavier than the effective weight of the 'sealing apparatus and itsr associated parts. Consequently, if the handle |13 be released, the sealing mechanism will be swung upwardly into inoperative position.

The tubed nlm is drawn through the machine by a pair of pinch rolls |2| and |22, one or both of which is driven. As the former bag tube is fed forwardly'by the pinch rolls, it is cut into desired lengths for bags in any suitable way, as by a' fly knife device |23, and delivered to a conveyor |24 having an upper pressure belt E25. The bag tube lengths may then be associated with cartons, if desired, in known ways, or othern wise employed as finished bag tubes.

Figure 9 is a cross-sectional illustration of a weld formed as at |26 in the lm element 3| where its edges are lapped.

This is most conveniently accomplished by pro- :s:

viding an angularly related machine section havinga frame |29, as in Figure 1. The transfer of the tubes from one machine section to the other, however, involves a serious problem by 'reason of the Aflimsiness of the nlm material f1 and the bag tubes lformed therefrom. In pre; viding angularly related` sections `on ordinary carton making machines, or on bag making vmaf-` chines yvir-here'the'material of thebagtubes isV relatively stiff and self-sustaining, it isv sufficient to Ifeed the structures forwardly against a stop so that they overlie a second conveyor operatingV in the` new direction. This,lhoweve,r, `cannot be done/simply with the extremely iiexible bag tubes to which this invention is primarily addressed', i .especially where such tubes `are made inlarge sizes. AAs a consequence, we have had, to `device special .transfer mechanism which will now .bev

described. As will be evident from Figures l and 2, the

` conveyor elementsil and l2", receiving the bag tubes from the ny knife `mechanisr'n |23,r"eed `thetubesin an upwardly directicn'for transier purposes. At 'the `end of these conveyors, `we

preferto provide a pinch roll feeder, indicated 1.0 most clearlyA in Figure 12 at |30; and |13 A second, or angularly related,` conveyor is provided in the second machine section, and isshown as, comprising av pair of chains |32- and |33 passingr over suitably driven sprockets. An end stop or guide against which the bag tubes may be fed is indicated at |314. But unless some additional mechanism were provided to carry the bag tubes across the initial conveyor inthe second section of the machine, they could not be broughtV to rest against the stop |34 so as to be engaged by the pins on the chains H32 and |33. Furthermore, the engagement of the pins with the extremely fleXi-. ble bag tubes, so as to produce a sudden change in the direction of their motion, would tend tor fold and distort them or cock them in various directions, so that a perfect end seal could not be made. In order tio; give to the bag tubes an initial tendency to follow the new direction of motion, the conveyor elements |32 and |33 are slanted downwardly in the new direction of me..-` tion, as will be best appreciated from Figure 13. To carry the tubes across the conveyor elements so that they may be positioned against the stop |34, we provide a gas blast mechanism, which tends to float the tubes across and also to assist in moving them against the stop i3d. This mechanism comprises a series of air tubes |35 extending longitudinally of the conveyor formed by the elements |32 and 33 and having openings throughout their eifective length, which openf ings are generally upwardly directed, .as will be apparent from FigureV 13. In connection with these tubes, we employ a series of vanes |36, one for each tube, which vanes are mounted on the tubes, extend generally in the same direction, and can be tilted `on the tubes, being adjustably mounted thereon by'releasable clamp means it?V Til . to the handling of bag tubes of various (see Figure 14). The vanes, as will be apparent from Figure 12,` are tilted upwardly in the direction of motion of the bag tubes as delivered by the first section of the machine, and they serve to direct the air blasts in the direction of motion of the tubes as so delivered. It will be readily understood from the above description that a flow of gas upwardly off the edge .of each of the vanes tends to noat the bag tubes across until they can be brought into contact with the stop device |34, whileat the same time the tubes are not raised so high as to be out of contact with the pins on the conveyor elements |32 and |33.

The air tubes |35 may, as will be seen from Figures 13 land 15, be mounted upon cross elements or channels |38 and |39 on the machine by means of clips or brackets -iliil which permit rotary adjustment of the tubes and hence'the positioning of the orifices therein. We prefer, as shown in Figure l, to connect the tubes |35 by individual vconduits lai and through individual valves |42 to `a manifold Iii3, which in turn is connected through a pressure regulating valve lati to a source of air or other gas under pressure, such as a pressure tankf. A conditioning unit Erie may be interposed in this connection so as to control the temperature'or the humidity of the ir, or both; to the end of minimizing the effect of static in the bag tubes. The individual valves iii? permit the regulation of pressurev independently foreach of the tubes |33, as may be `desired for accommodating the transfer mechanism sizes and various weights of material. i v

. The downward sloping initial `conveyor |32, 133 of the second section ofthe machinemerges with vunder controlled pressure.

il a horizontal conveyor comprising chains |41 and |43 shown in Figures 1 and 13. By the time the bag tubes, indicated in the latter gure at ii, reach the conveyor section 141, 148, they will be traveling in the required direction and at the proper orientation transverse the path of travel.

To sustain the bag tubes intermediate th chain elements 1111 and 148, we may provide a table S or in lieu thereof a traveling belt element intermediate the chains. It is also within the scope of our invention to provide hold-down or moving clamping means in connection with the conveyor 1M', 148 or with a traveling belt element forming a part thereof. By any of these means, the tubes, moving in succession in a direction transverse their length, may be carried through end sealing means, certain forms of which will now be described.

' As in forming the longitudinal seam of a bag tube, it is quite possible in forming end closure seams to support the material on one side by means of a series of small spaced rollers while applying the seam forming heat to the opposite side through a metallic belt. But due to the eX- tremely iiimsy and nexible nature of the individual bag tubes, we prefer to engage them between concurrently traveling belts. To this end, as shown in Figure 16, we provide spaced sheaves and 151 mounted in bearings adjustable in supports 152 and 153, and provide an upper belt element traversing these sheaves. The beltV element is preferably metallic, as at 152i, but in order to even the pressure, the metallic element .may be faced with rubber or other resilient material 155. This construction is most clearly shown in Figure 1'7.

On the same standards or supports, we journal sheaves 156 and 151 for a belt 15e which is the belt through which the seam forming heat will be applied. The arrangement is such that an .rf

end of the bag tubes passing through this section of the machine (one of the tubes being indicated at 159) will be caught between the two belts. The sheaves and 151 also have adjustable bearings preferably, and the entire standard or support 153 may be made longitudinally adjustable as at 160 on the bed 161 Yof the machine.

In orderV to hold the lower night of the belt element 154, 155 down into contact with the end of the bag tube 59, we provide a series of small rollers |62. These rollers, as shown in Figures 16 and 19, are mounted in bifurcated elements 153 to which upwardly extending rods or shafts [5% are attached. These shafts pass through opposite sides of hollow bodies and 165; they bear abutment means 161; and compression springs H58 (see Figure 18) surround the shafts Y or rods '18a engaging between the upper sides of the bodies 55 and ii and the abutments 1%'1 on the rods. Thus the rollers are urged downwardly In order to prevent cookingr .or the rollers, the biiurcated elements |53 may be provided Ywith non-circular bosses 163e which engage in non-circular recesses in the bottom elements of the bodies 155 and i. Other means of preventing cooking may .be adopted, as will be evident. 'v

The bodies 165 and iet may be adjustably mounted as shown by means of threaded rods and nuts on brackets 56S and lli? attached to a machine frame element 1 i 1 end portion of the bag tube les.

belts. The lower belt is provided with a heating element |13 similar to the heating element 52 described in connection with Figure 6, having a similar nose for contacting the belt and resiliently mounted on a bracket 111% by means of rods and compression springs, as will be clear from Figures 16 and 18. There is also provided in connection with the belt 153 a fluid cooling shoe V55. This may be resiliently mounted on the machine frame by bracket means lle similar to the bracket means 1G32 hereinabove described.

The sheaves 155 and i are driven in synchronism so that the belts move together in that flight in which they simultaneously engage the This may be accomplished in various ways. We have shown the sheaves provided with sprockets 111 and V13, engaged and driven by a common chain H3 which will be understood as engaging a drive sprocket (not shown) affixed to one oi the power shafts of the machine.

In the formation of end closure seams, it is as necessary as in the formation oi longitudinal seams toY provide a means whereby the heating element may be automatically withdrawn from the belt 15S when the machine is stopped for any reason. There are various ways in which this may be accomplished. We have illustrated one suitable mechanism in which the bracket element 1113, which mounts the heating shoe 113, is in turn pivotally mounted to one end of a lever arm 13d, as shown in Figure 18. The other end of the lever arm is pivoted to an element 181 slidable on a bracket E82 on the machine frame. Intermediate its ends, the lever arm 18@ is pivoted to a link 1183 which in turn is pivoted to the bracket 1&2. The arrangement is such that if the sliding element 131 is moved to the left in Figure 18, the link 133 will tend to swing the lever arm 1851 downwardly, as shown in the dotted lines in that ligure. Similarly, when the sliding element 181 is moved to the right in the gure, the link 183 will move the lever arm upwardly. An adjustable abutment is provided comprising a stop member ist, threaded into an ear 131i on the bracket 182 and provided .with a locking nut. This abutment serves to limit the upward movement of the lever arm 189 to bring the heating shoe |13 to rest against the belt 153.

The sliding element 13| is arranged to be actuated in accordance with the clutch lever 95 controlling the main drive of the machine. In Figure 1 we have shown a third arm of the bell crank 93 connected by a link |86 with a bell crank |81, which in turn is connected by a link 1853 to a bell crank 189. The last mentioned bell crank is connected by a link 193 to the sliding'element 181. The elements 18B to 198, inclusive, as will readily be understood, simply form atransmission between the power control for vthe machine andthe means Vfor moving the heating sho-e 1 '13, and other transmissions may be substituted if desired. Y

In the making both of longitudinal welded seams and of transverse end closure seams, the application of heat for the purpose is a delicate operation. The heat has to be limited and controlled so as to prevent an unwanted fusion or softening of the lm substance .beyond the desired area of seam formation. At the same time, if the heat should be appreciably diminished by sporadic conditions, there will be insuicient to accomplish the welding, and the seam will be characterized by skips. The belts 5i and |53, through which the heat is transmitted to the nlm,

mustvbe carefully andA accuratelymada VVariations in thickness of the belts, such as mayoccur aitfwcldedibends in them, lmay be productiveof skips; butl it is: readily .possible by suitable grind; ingfand ldressing techniques to provide belts of constant andluniform thickness. In our initial wormwhen skips l,were encountered inthe seam, it-was 'at first believed.' thatthey might' .be dueto failure of the.supnorting` means `to `hold therfllm elements in `accurate contact nwith the surfaces of theibelts. ItvW'as later found, however, that the small rubber covered'rollers '4G of Figure, 8:' and elements such as the lrubber :covered belt |54, |55 suitably backed by spaced rollers |62 acted 'suf'- fieiently to maintain contact between the belts andthe nlm portions. Where skips were encountered with carefully `made belts of constant thickness, it was found that the difliculty lay rather in-'a lack of flatnesslin the belts theinselves. Belts may become kinked. 'or may acm quire-:rl-permanentV non-planar set in use. Such orrbends, passing throughthe welding zone, tendtoy displace the-heating shoes and, there fore, interfere withv the uniform Aeaznplicationv of hea-t `to the lm portions.

We have'developed` a mode and mechanism of applying heatto the sealing belts independently o'fbelt displacement; as willJno-w be described. Pursuant to this development, we do not employ 'a=` inet'alllc heating shoe' with aV n'os'e pressed againstwthe belt,l but'l instead, heat the belts yby aiiarnefso that the beltsbecome uniformlyk heated.` irrespectiveof minor deviations of the belts frox'nvtheir truepaths `of' travel.

'Apparatus of thisV kind is illustrated in Figures. 2Std' 27` inclusive: We' provide a` trough'- like element I9! which, as shown innig-ure 23, is 'Vefshape'di:v in transverse vertical'v section. As showniniA this lgure andin Figure 24, the lower endfof the trough. is open in such manner'asto fornita slot`l`'i2 which isnarrower than.` the belt 2193. Thebelt |931 is t'he metallic belt through which heat-will beapplied to 'the 'fllnl portions,- 'and itmay beeither the4 belt 5| of Figures or thebelt-|`581of Figure 1,6. Cine: portion. 'of the slot, i'. e.rthat portion` whererthe flame from' a torch presently to be described impinges. on the belt |93, may be. made somewhat wider, as` at Y |5924! inv Figure 24.1 The' hollow wall'soi the- V1- shaped ltrough are'lledlwith" a cooling fluid. |194 which: is circulated'. Trough element FSL rides uponv the belt |92 in ay manner similar ftoffthe noses of the heat shoes hereinabove described; But it' Iwill be vseen that the.` lower.` edge portions of the vtrouglnriding againstithe outer. .marginal portions of the belt, serve to` cool thesefport-ions by conduction, while heat isv appliedt tothe belt `centrally* through the-slot |92.v In Figure 23 we have shown ay bracket.'nleans` |95- for mounting thevtrough, and a-troug-helement |195 for lapplying lthe flame. The troughl element may ,bie mounted` on the trough EASI- or bracket |95 if desired, and the entire structure substituted. for the heating shoes 52 and. |13 of the various fige ures hereinabove described, flexible tubing ypro-v vided for ythe torch gases andthe cooling fluid |913, and these heating4 elements may be actuated in the same. way `and by the. same mechanisms already set forth. i However, We prefer to mount the. torchin a movable. fashion on an` external support so that upon stoppage 'of thegmaohine, the torch tip may -be swung 'out ofthe trough ele-:mentv |Sl to some position. it cannot applyheat to the belt.. When. thisiis done, thecontinuous 14 passage of"cooling fluid -through :the-trough element |9| will make it unnecessary to remove this element from the belt.V

As shown inFigure 22, the mountingwbracket |95 may be supported gimbalwise in the forked endfof'a lever arm |97 pivoted centrally on'a support |98 attached to the machine frame. The otherend of the levert-arm may be connected by a tension spring |99 toanadjustment means-29e on asupport; andan adjustable-stop meansrmay be provided to fix: the lower. portion of?? they trough element Isl., as shown in thisiig-ure-at 28|.y The trough elementlel, having arcurved' end tonenterthe trough :in vthe relationship showninFigure 23, may be mounted upon anrelement Zdwhich is adapted to rotate. This element; as most clearly shown linFgure 20,' is U-slrlapedaory Eeshaped and is affixed to =a shaft 42da rotatively mountedfina bearing 2M onthe machine- It will be' evident. that. as t'ie shaft; 2&3V is causedto rotate, the torchmaybe swungfrom that 'pusietion indicated in Figure 2l (corresponding to the operative. positionV described in` connection with Figures23andz24) to the position: shown in Figure 2,5. Forrotating the shaft, wev affix to it a toothed :pinion 235 which mesheswiththe teeth of. a' segment element. 2l|i=mounted so-as to rock` upon the shaft .of a sprocket `2.57! carry.- ing the. belt |33, there being: a spacedisproeket 2&3" for the return of this belt:A

In the particular embodiment of Figuresv20xt`o 26: inclusive', thebeltvv |932 is:- illustrat'ed as*` the upper belt ofan. end sealingdevice,` therebeing` a lower belt 2de provided;withrsupporting rollers and shown in Figure 26. The upper belt element |33 may also beprovided with-a coolingj shoe- 2=|0` mounted as hereinaboveolescriberhr It will' be understood' that the upperl beltand its ap*- purtenancesmay be employedl in= lieu ofthe belt 52 and its appurtenances for* the formation vof longitudinal seams'in the apparatus 'ofv Figures 1 and-2` The sheave 243i? is'pr'ovidedwith'A a sprocket '245|' connected by a:k driving: chain Z122 to a:'spi'focketV 2id on a Shaft ZMS. Forv opt-:ratingV the torch; especial-ly where theapparatus of' Figures1 26 and 2-'1 is employed for the-'formation Vof longitudinal seams, wemayA provide an extension '21e ad` justable with respect to the segment ZS and bearing a4 cam followingzroller 216" at its end; A11

'element 2121', slidable upon the shaft 2"|`4"and'.

havinga 'tapered' nosezl'ia, is analogous to the'. elements 91, 99 hereinabove described in connection with Figure 1;,and the sliding element the machine including such` temporary stoppages` asmay b elreauired 'for adjustment. Asafconser quenoe, they torch is swung to the inopera.-

time position, wepreier torprovide ashield against whielfl. its flame may impi-nge.- For simplicity,A suchv a shield-has not been iliustrated in Fig-rires 20: to7 25|;l but Figure 28V shows the torchV '|96 in upraised' position 4 with its. name yirnpi'ngingfA against `a lshield element 2|-8,faced. at 2;t9,

'15 with asbestos or other heating resistant refractory.

Flexible connections for the supply and withdrawal of coolant fluid to the cooling shoe 2m and to the trough-shaped element lS have been shown in various of the figures, but do not require special description.

For operating the torch when our sealing mechanism is employed for the formation of end closure seams, a modined form of operating apparatus may be found desirable, and is illustrated in Figure 27. Here the torch |96 is mounted on the torch holding element 2%2 as before, and this, in turn, is mounted on the shaft 2&3. The pinion Z on this shaft meshes with a pinion 22d on a shaft 221 suitably journaled in bearing elements, not shown. The shaft 22| in this instance bears a cam element 222 having a helical cam groove of such pitch that the shaft may be rotated by a cam follower engaged in the groove and moved parallel tothe axis of the shaft 22S. Such a cam follower, illustrated as a roller 223, is mounted directly upon the slider iti hereinabove described, which slider may be connected through the transmission to the clutch operating lever 95.

The torch itself may be of any known form for the burning of a gaseous fuel in a jet of desired dimensions and producing a desired degree of heat. The natureV of the gaseous fuel and whether it is burned in admixture with air or with a more strongly oxidizing gas, such as oxygen, do not constitute limitations on our invention. By Way of example, we may use acetylene or natural gas as the fuel, with or without oxygen. The torch will have those features of adjustment conventional in known torches so that the size and shape of the jet and the amount of heat produced can be varied in accordance with specilic requirements. It will be understood that the quantity of heat produced per unit of time by the flame will be proportioned to the degree of heat required for specific sealing operations and the speed of travel of the material being sealed through the machine.

We have, however, found it readily possible to effect seam formation positively, continuously and without skips by applying heat to the lm materials through a metallic band from a torch or flame essentially conned, except for a narrow line of contact with the belt in a iluid cooledhousing as described; and the flame, used as herein taught, serves to heat the belt or band uniformly so as to effect Welding without skips inspite of sporadic displacements of the band, f

Such as may be due to kinks or bends therein, providing` the supporting means used opposite the band serves to keep the nlm materials inY contact therewith.

Modifications may be made in our invention without departing from the spirit of it. Having thus described our invention in an exemplary embodiment, What we claim as new and desire to secure by Letters Patent is:

1. In seaming apparatus for seaming lapped lm portions, an elongated forming plate about which nlm is drawn and tubed, said forming plate having a longitudinally extending opening therein, a series of transversely disposed rollers rotatively mounted in said opening, said rollersv acting at the top surface of said forming plate to provide'a moving support for the lapped lmportions, a moving belt extending along said forming plate` and overlying said rollers, and heating means located above said rollers 16 and juxtaposed to said belt to apply heat to said belt.

2. In seaming apparatus for seaming lapped lapped film portions, an elongated forming plate about which nlm is drawn and tubed, said forming plate having a longitudinally extending opening therein, a series of transversely disposed rollers rotatively mounted in said opening, said rollers acting at the top surface of said forming plate to provide a moving support for the lapped lm portions, a moving belt extending along'said forming plate and overlying said rollers, and heating means located above said rollers and juxtaposed to said belt to apply heat to said belt, said heating means being juxtaposed only to the central portion of said belt so as to establish a temperature gradient between the center and edge portions of said belt.

3. In seaming apparatus for seaming lapped lm portions, an elongated forming plate about which lm is drawn and tubed, said forming plate having a longitudinally extending opening therein, a series of transversely disposed rollers rotatively mounted in said opening, said rollers acting at the top surface of said forming plate to provide a moving support for the lapped film portions, a moving belt extending along said forming plate and overlying said rollers, and heating means located above said rollers and juxtaposed to said belt to apply heat to said belt, said heating means being juxtaposed only to the central portion of said belt so as to establish a temperature gradient between the center and edge portions of said belt, and a cooler located beyond said heating means in the direction of travel of said belt, said cooler being juxtaposed to said belt.

4. In seaming apparatus for seaming lapped lm portions, an elongated forming plate about which nlm is drawn and tubed,` said forming plate havingV a longitudinally extending opening therein, a series of transversely disposed rollers rotatively mounted in said opening, said rollers acting as the top surface of said forming plate to provide a moving support for the lapped nlm portions, a moving belt extending along said forming plate and overlying said rollers, heating means located above said rollers and juxtaposed to said belt to apply heat to said belt, said heating means comprising a torch and shield, said shield comprising a trough-shaped element adapted to be brought against said belt and presenting a slot thereagainst through which Y a flame can be directed against said belt, the

walls of said trough-shaped element being hollow and fluid cooled.

5. In Yseaming apparatus for seaming lapped film portions, an elongated forming plate about which nlm is drawn and tubed, said forming plate having a longitudinally extending opening therein, a series of transversely disposed rollers rotatively mounted in said opening, said rollers acting as the top surface of said forming plate to provide a moving support for the lapped nlm portions, a moving belt extending along said forming plate and overlying said rollers, heating means located above said rollers and juxtaposed to said belt to apply heat to said belt, said heating means comprising a torch and a shield, said shield comprising a trough-shaped-.eleinent adapted to be brought against said belt' and presenting a slotV thereagainst Vthrough which a name can be directed againsts'aid belt, the walls of said trough-shaped-element being hollow and fluid cooled and means for moving said torch from a position in which said flame plays against said belt through said slot, to another position in which said flame is directed away from said slot.

6. In apparatus for the purposes described, a rst seaming section comprising an elongated forming plate about which a lm is drawn and tubed, said forming plate having a longitudinally extending opening therein, a series of transversely disposed rollers rotatively mounted in said opening, said rollers acting at the top surface of said forming plate to provide a moving support for the lapped film portions, a moving belt extending along said forming plate and overlying said rollers, heating means located above said rollers and juxtaposed to said belt to apply heat thereto, cooling means located beyond said heating means in the direction of travel of said belt, said cooling means being juxtaposed to said belt, pinch roll means for withdrawing the formed tube from said forming plate, cutting means for severing the formed tube into bag tube lengths, a rst conveyor for moving the bag tube lengths longitudinally, a second conveyor at an angle to said first conveyor for moving the bag tube lengths transversely through a second seaming section, transfer means for transferring said bag tube lengths to said second conveyor, said transfer means comprising means for directing an air blast against the under sides of said bag lengths during said transfer, said last mentioned means including air tubes extending in the direction of said second conveyor and carrying adjustable vanes tiltable to a position in which the air blast is directed in the direction of motion of the bag tubes as they leave the said rst conveyor, and seaming means in the second seaming section for seaming the ends of the bag tube lengths.

7. In combination for the purposes described, an elongated forming plate about which a web of material is drawn and tubed, said forming plate having a longitudinally extending opening therein, a series of transversely disposed rollers rotatively mounted in said opening, said rollers acting at the top surface of said forming plate to provide a moving support for the tubed web of material, and means for drawing the web material about said forming plate.

8. In combination for the purposes described, an elongated forming plate about which a web of material is drawn and tubed, said forming plate having a longitudinally extending opening therein, a series of transversely disposed rollers rotatively mounted in said opening, said rollers acting at the top surface of said forming plate to provide a moving support for the tubed web 18 of material, said rollers having a diameter substantially equal to the thickness of said forming plate, and means for drawing .the web material about said forming plate.

9. A process of forming continuous seams by heat fusion in readily fusible lms which comprises continuously moving the lm in a path, juxtaposing film portions for seam formation by tubing the film, bringing the juxtaposed film portions against a band element traveling with the tubed lm, applying heat to the juxtaposed lm portions through said band under conditions of a temperature gradient such that the central portion of the band is at fusion temperature of the material of the lm while laterally outlying portions of the band are below the fusion temperature, and movingly supporting the lapped seam portions internally of the tube during contact with the band.

10. A process of forming continuous seams by heat fusion in readily fusible i'llms which comprises continuously moving the lrn in a path, juxtaposing lm portions for seam formation by tubing the film, bringing the juxtaposed iilm portions against a band element traveling with the tubed lm, applying heat to the juxtaposed film portions through said band under conditions of a temperature gradient such that the central portion of the band is at fusion temperature of the material of the lm while laterally outlying portions of the band are below the fusion temperature, and movingly supporting the lapped seam portions internally of the tube during contact with the band, and thereafter cooling said band to bring the central portion thereof below the said fusion temperature during continued joint movement of tubed material and the belt.

WALTER HAAS. FRANK D. BERGSTEIN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,258,820 Sill Mar. 12, 1918 '1,453,852 Mahoney May 1, 1923 1,625,786 Blackmon Apr. 26, 1927 2,390,171 Ratay Dec. 4, 1945 2,444,685 Waters July 6, 1948 2,449,526 Dunne Sept. 14, 1948 2,459,235 Hewitt Jan. 18, 1949 2,474,917 Schenk July 5, 1949 2,504,500 Collins Apr. 18, 1950 2,516,280 Welch July 25, 1950 2,522,346 Carson Sept. 12, 1950 2,542,901 Chaffee Feb. 20, 1951

Images