US3739543A - Envelope opening apparatus and method - Google Patents

Abstract

Envelopes are opened through frictional engagement and a resultant tension action along preweakened edges. An envelope is driven onto a moving belt and the envelope is detected in its path by a photocell. A time delay circuit allows the envelope to be moved to a predetermined station where shoes contact the envelope. The shoes move through an envelope plane intersecting path to frictionally engage the envelope only once. The shoe normal force in combination with the moving belt force cause the envelope to burst open at the preweakened edges after which it passes under a pair of rollers.

Description

United States Patent 1 [111 3,739,543 Harris June 19, 1973 ENVELOPE OPENING APPARATUS AN METHOD Primary Examiner-Travis S. McGehee Assistant Examiner-John Sipos 75 I t: RlndG.H Hdd f'ld,N.J. nven or 0 8 a on 1e Attorney-Allan Ratner and Maleson, Klrnmelman & [73] Assignee: Automated Mail Systems, Inc., Ratn Cherry Hill, NJ.

[22] Filed: June 21, 1971 [57} ABSTRACT [21] A L No; 154,827 Envelopes are opened through frictional engagement and a resultant tension action along preweakened edges. An envelope is driven onto a moving belt and [52] :LS. Cll. 53/3, 55/118312: the envelope is detected in its path by a photocell A [51] f 3 time delay circuit allows the envelope to be moved to [58] 1e 0 care 5 a predetermined station where shoes contact the enve- 225/]01 106 lope. The shoes move through an envelope plane intersecting path to frictionally engage the envelope only [56] References cued once. The shoe normal force in combination with the UNITED STATES PATENTS moving belt force cause the envelope to burst open at 3,060,075 10/1962 Kincaid 53/28 the preweakened edges after which it passes under a 2,618,336 11/1952 Davidson pair of rollers. 3,529,756 9/1970 Smith 225/100 34 Claims, 10 Drawing Figures PAIENIEB 9 SNEEI 1 BF 5 IN VE' N T 0!? ROLAND 6. HARRIS WWmrrQawu/u ATTORNEYS PATENIEDJIINWE?! 3.139.543

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SHEEI & 0f 5 IN VENTOR ROL A ND 6. HARRIS A TTOR/VEYS ENVELOPE OPENING APPARATUS AND METHOD BACKGROUND OF THE INVENTION A. Field of the Invention This invention pertains to the field of bursting machines. In particular, this invention relates to the field of preweakened envelope opening apparatus to frictionally engage and open the envelope along weakened edges.

B. Prior Art A number of apparatus and methods of opening preweakened envelopes are known in the art. However, most of the prior mechanisms rely on opening envelopes by cutting or burning the envelope edges or by engagement of the envelope between rollers operating at different rotational speeds.

In those prior mechanisms which burst the envelopes by cutting a portion of one or more edges from the closed envelope, content placement has been found to be a critical factor. These machines have been found to be insensitive in distinguishing content edges from envelope edges with the result that in some cases the contents have been destroyed.

Other apparatus provide for burning of envelope edges as the primary feature in the opening process; however, in these machines the envelope burning rates are found to be critical in the process. In these cases, it has been found that where the contents lie contiguous to the burning edges, they also may be burned. Such mutilation of the contents cannot be tolerated in instances where the contents include computer data cards or other sensitive material.

Many of the prior mechanisms rely on opening the envelopes by engagement between rollers operating at different rotational speeds to provide a tearing action on the weakened edges of the envelope. This does not provide for different combined thickness of envelopes and contents which often leads to jamming of the envelopes between the rollers. In these machines, there is continued contact throughout the entire length of the envelope during bursting. This tends to promote jamming and tearing of the panels in unwanted areas since continuing contact tends to produce unpredictable tearing forces. As a further deficiency, in most prior methods, the tearing forces were not applied only along the preweakened edge.

SUMMARY OF THE INVENTION A preweakened envelope has an upper and a lower panel and a force is applied within the plane of the envelope to the lower panel. In this manner, the lower panel is moved while the upper panel is engaged through a force substantially normal to the envelope plane. The combination of these forces is effective to burst open the preweakened envelope.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a top view of the envelope opening appara tus;

FIG. 2 is an elevational view of the envelope opening apparatus;

FIG. 3 is a perspective view of a portion of the opening mechanism acting in conjunction with the path guidance mechanism;

FIG. 4 is a perspective illustration of a preweakened envelope usable in the envelope opening apparatus;

FIG. 5 is an elevational view of the predetermined location of a heavy stock envelope when contact is made by the opening mechanism;

FIG. 6 is an elevational view of the predetermined location of a low weight stock envelope at initialization of contact by the opening mechanism;

FIGS. 7-9 are elevational views of the envelope taken sequentially after opening and showing retraction of the opening mechanism; and,

FIG. 10 is a system block diagram detailing the actuation time delay circuit for movement of the opening mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1 and 2, there is shown burst ing machine or envelope opening apparatus 10 for automatically opening preweakened envelopes 12, shown in FIG. 4. In general operation, apparatus 10 provides for the application of a force to envelope 12 on lower panel 14 or 16 coincident or tangent with the plane of envelope 12 in order to cause linear motion in a predetermined direction. At a predetermined point in the travel direction, envelope 12 upper pannel 14 or 16 is engaged with a force substantially normal to the plane of envelope 12. The combination of normal and tangential forces with respect to the envelope plane serves to burst open preweakened envelope 12.

Although not part of the inventive concept as herein defined, a description of envelope l2 follows in order to provide a clear understanding of apparatus 10 and the method steps employed in the opening operation. As shown, envelope 12 includes opposing panels or faces 14 and 16 forming a closed internal volume body through attachment at peripheral edges 18, 20, 22 and 24. Although either face 14 or 16 may serve as the lower panel of envelope 12, for purposes of clarity the lower panel will be that face which is driven by a force substantially in the plane of motion of envelope 12 while the opposing face will be referred to as the upper panel. Edges 18, 20 and 22 are provided with perforations, scoring, sanded or some like weakening means in order to achieve a weaker bond between faces 14 and 16 at these edges than is found at peripheral edge 24. In a manner to. be discussed fully, machine 10 engages envelope 12 in a particular manner to separate opposing panels 14, 16 from each other along perforations 26, thereby opening envelope l2 and exposing the contents contained therein.

Apparatus 10 structurally comprises frame or housing member 28, path guidance or transporting mechanism 30, opening or contacting mechanism 32, envelope detection means 34 and stacker 36. Housing 28 provides a stationary platform attached to a base surface through verticallyextending legs 38 shown in FIG. 2. Additionally, frame 28 provides the necessary horizontal and vertical mounting walls permitting apparatus 10 to be an inclusively unitary structure where all major opening mechanisms are affixed.

Envelope guidance or translating mechanism 30 transports envelope 12 within a predetermined plane of motion defined by the upper surfaces 44, 46 of a pair of endless belts 40, 42 shown in FIGS. 2 and 3. Guidance drive motor 48 actuates pulley mechanism 50 where the combination is rigidly mounted to horizontal cross-bar 52, in turn secured to opposing vertically eX- tended legs 38. Pulley 54 is rotatably driven about an axis substantially normal to the axis of rotation of motor 48 where the rotation plane change is provided by a combination bevel/spur gear arrangement or some like standard mechanism not important to the inventive concept.

Inclined drive belt 56 passes over and is driven by lower pulley 54 in order to promote a rotational driving mechanism for pulley system 58. System 58 as is shown in FIG. 1 is rotatably mounted to vertical wall member 60 of housing 28. Rotatable cylinder 62 of system 58 passes transverse to the longitudinal travel direction of envelope 12 when it is in linear motion on belts 40, 42. Transversely displaced belts 40, 42 passing over cylinder 62 are frictionally driven by the corresponding rotation to provide a substantially horizontal planar movement for envelopes 12 on upper surfaces 44, 46. It is therefore seen that in operation, rotation of pulley 54 acting through belt 56 defines a corresponding coplanar rotation of pulley 64 which is rigidly mounted to, and commands a similar rotation of cylinder 62 which in turn provides the basic driving mechanism for belts 40, 42.

As shown clearly in FIG. 2, each of belts 40, 42 have substantially identical contour paths defined by driving cylinder 62, second driven cylinder 66 and tension rollers 68. Driving and driven cylinders 62, 66 respectively are longitudinally displaced but are positioned vertically in a manner so as to permit upper surfaces 44, 46 of belts 40, 42 to lie in a substantially horizontal plane throughout the displaced longitudinal distance. Driven cylinder 66 is rotatably attached to wall 60 of housing 28 and is free to rotate about a transverse axis with respect to the defined longitudinal direction. Freely rotating tension rollers 68 are transversely attached to housing 28 on a lower surface thereof to permit proper tensioning of belts 40, 42 on opposing cylinders 62, 66.

ln the manner described, path guidance mechanism 30 operates to provide a transporting medium for envelopes 12 in a plane defined by upper surfaces 44, 46 of belts 40, 42. Motor 48 actuation in combination with the aforementioned pulley mechanism drives the upper surfaces of belts 40, 42 in substantially linear motion. Envelopes 12 passing from stacking apparatus 36 are deposited on surfaces 44, 46 with one of opposing panels or faces 14 or 16 contiguous with surfaces 44, 46. Belts 40, 42 are longitudinally moveable and frictionally grip panel 14 or 16 thereby providing longitudinal path guidance for envelope 12 during travel through opening mechanism 32.

Opening mechanism 32 performs the envelope opening operation by moveably engaging envelope 12 in a path which intersects the plane of movement defined by upper surfaces 44, 46 of endless belts 40, 42. In operation, boots or shoes 72, 74 contact one of opposing panels 14 or 16 of envelope 12 as it is being guided in a longitudinal direction on belts 40, 42. Shoes 72, 74 apply a force substantially normal to the envelope travel path.

The normal force applied to upper panel 14 or 16 of envelope 12 is applied for a small increment of time only once to produce a singular contact for each of envelopes 12 being opened. This contact force is applied by the impact of shoes 72, 74 to envelope 12 along substantial portions of opposing transverse edges 20, 22. Singular contact of envelopes 12 by shoes 72, 74 essentially produces a single impact on every envelope at a predetermined point in the envelope travel direction.

The panel of envelope l2 continguous with belts 40, 42 continues to have a frictional driving force applied coincident with the plane of motion due to the movement of belts 40, 42. The combined normal and frictionally horizontal forces provide frictional engagement of envelope 12 at a predetermined station on upper surfaces 44, 46, the location of which will be detailed in follow ing paragraphs. The continuous longitudinal force provided to envelope 12 provides the necessary force to disengage panels l4, 16 along scored or perforated edges 18, 20, 22.

In detail, opening mechanism 32 includes a pair of pivoting arms 76, 78 transversely displaced with respect to each other on opposing belts 40, 42. Arms 76, 78, shown clearly in FIG. 3, are pivoted about respective pivoting rods 80, 82 which are rotationally journaled to vertical wall member 60 of frame 28. Rotation of pivoting arms 76, 78 and consequently boots or shoes 72, 74 is, therefore, limited to a plane substantially perpendicular to the plane of motion of envelopes l2.

Tension spring 84, attached on opposing ends to pivoting arm 76 and tension member 86 respectively, provides a constant downward force on arm 76, as shown in FIG. 2. Tension member 86 provides a relatively stable platform being rigidly mounted to vertical wall member 60. The compressive force of spring 84 applied to arm 76 permits shoes 72, 74 to be maintained in an open or displaced position with respect to surfaces 44, 46. Since spring 84 and boots 72, 74 are longitudinally displaced from each other on opposing sides of pivoting rods 80, 82, a normally downward force by spring 84 causes a resulting upward or disengaging displacement at a point where boots 72, 74 are located.

Transverse mounting bar 88 is rigidly secured through bolts 90 or some like means to opposing pivoting arms 76, 78 as shown in FIG. 3. Shoes 72, 74 are securely fastened to transverse mounting bar 88 through mounting bolts 92. Vertical rod members 94 extend vertically at an upper end from mounting bar 88 to a pair of lower cylindrical disks 96 at the lower opposing ends. Rubber disks 98 are attached to lower cylindrical disks 96 on each of boots 72, 74. Disks 98 provide a relatively resilient engagement surface for envelope 12 when shoes 72, 74 are actuated to an engaging or contacting position.

Friction member 89 is rigidly attached to and vertically extending from transverse mounting bar 88. Member 89 is located substantially midway with respect to the transverse direction between endless belts 40, 42. The lowermost edge of friction member 89 is vertically displaced from the plane defining upper surfaces 44, 46 by an amount approximately l/32 inch. By composition, member 89 is resilient in nature and constructed of a hardened rubber or some like material. Resilient friction member 89 functions as an aid in folding back upper panel 14 or 16 as envelope l2 longitudinally passes through the predetermined station on belts 40, 42.

Actuation of the path movement to an engaged position is provided by solenoid mechanism 100 shown in FIG. 2. Mechanism 100 is structurally mounted to frame 28 of apparatus 10 in a fixed position. Moveable rod 102 extends between solenoid 100 and pivoting point 101 of arm 76. Rod 102 is rotationally mounted to arm 76 to permit a free upward and downward path movement of boots 72, 74 when actuation takes place.

Actuation of solenoid 100 to a closed or engaged posi tion is dependent on envelope detection mechanism 34 in combination with a time delay circuit to be described in following paragraphs.

In the manner described, spring 84 compressively holds boots 72, 74 in an open or non-touching displacement with respect to the plane upon which envelope 12 is longitudinally traveling. Upon detection of envelope 12 by detection mechanism 34, solenoid mechanism 100 acting through a time delay circuit pulls moveable rod 102 downward. Shoes or boots 72, 74 are directed in a curvilinear intersecting path with respect to longi tudinally directed envelope 12. Disks 98 then contact one of opposing panels 14, 16. The singular momentary contact provides a frictional force to be applied to envelope 12 and thus causes a ripping or tearing action along perforations 26.

Cantilever arms 104, shown in FIG. 3, are transversely aligned and displaced on belts 40, 42. Arms 104 comprise cantilever rods S rigidly secured to frame 28 on one end and rotatably mounted to rollers 106 on an opposing end. Rollers 106 are provided to flatten envelope 12 to the belt after engagement and opening by boots 72, 74 and to further prevent a forward end of moved envelope 12 from curling in an upward direc* tion. In this manner, rollers 106 have the purpose of restraining opened envelope 12 to a plane contiguous with belts 40, 42. As is seen, rollers 106 are transversely displaced from each other to prevent blockage in retrieving envelopes in the event of improper opening of envelopes 12 and possibly resultant jamming under shoes 72, 74 and rollers 106. However, in order to increase the structural integrity of cantilever arms 104 and associated rollers 106, a structural rod element may be connected to opposing arms 104 transversely to present a unitary structure. If such a structural member were added, it may be formed into a transverse bridge to permit access to any envelopes 12 which have jammed under rollers 106. Under operating conditions, rollers 106 maintain substantially rolling contact with opposing edges 20, 22 in an overlapping manner.

Of importance, and shown clearly in FIGS. 1 and 3, disks 98 apply an engaging force on substantial portions of opposing transverse edges 20, 22 of envelope 12. Disks 98 engage upper panel 14 or 16 in a transverse discontinuous manner within envelope 12 boundary edges. Although disks 98 overlap edges 20, 22, contact is only made on upper panel 14 or 16 since disks 98 are transversely tapered in an upward manner. The tapering of disks 98 permits internal envelope boundary engagement, but does not permit additional engagement of moving belts 40, 42.

Contact made by disks 98 substantially near weakened edges 20, 22 provides the largest tearing forces to be applied on perforations 26. In addition, where contact is not made on edges 20, 22, there is a possible tendency for upper panel 14 or 16 to form a transverse 22. The opening of envelope 12 in this way provides a smooth opening procedure to prevent any possible envelope jamming that may occur.

Platform roller 108 is attached to central shaft 110 which is rotatably'mounted to vertical wall members 60 on opposing transverse sides. Roller 108 is positioned below and maintained substantially contiguous with the lower surfaces of belts 40, 42. Due to the rotational capability of roller 108, the linear longitudinal movement of belts 40, 42 present a rolling contact relative drive to roller 108. Further, boots or shoes 72, 74 are vertically aligned with roller 108 when in a closed or contacting position on belts 40, 42. Roller 108 provides a relatively rigid platform upon which disks 98 may impinge when contacting envelope 12.

Envelope detection mechanism 34 includes a standard photoelectric cell 116 comprising light source 112 and appropriate circuitry shown in FIG. 10. Emitter 112 is positioned vertically above the plane of longitudinal transport for envelope 12. Emitter 112 generates a beam of light or electromagnetic radiation continubridge or warping effect. This warping may culminate in eventual jamming of envelope 12 when passing from shoes 72, 74 into rollers 106.

In order to provide a sequential tearing along perforations 26, it is preferred that the land to sea ratio of ously through the longitudinal opening 114 between belts 40, 42. Detector 116 positioned below belts 40, 42 is vertically aligned with emitter 112 to continuously receive the emitted light beam. When envelope 12 passes longitudinally on upper surfaces 44, 46 of belts 40, 42 and intersects the light beam, a time delay circuit, shown in FIG. 10, electrically connected to the cell is actuated to operate solenoid in the manner previously described.

Once the leading edge of envelope 12 has interrupted the light signal, an electronic time delay is initiated which is variable substantially between 0.001 to 0.5 seconds. This delay in solenoid 100 actuation permits envelope 12 to longitudinally continue to a predetermined station before contacting boots 72, 74. The predetermined envelope station may be defined as a positional transverse across belts 40, 42 which is coincident with leading edge 18 at the time of contact of shoes 72, 74 with upper panel 14 or 16. The station, therefore, defines the longitudinal positioning of envelope 12 on belts 40, 42 at the time bursting contact occurs. Precise position control may be accomplished by adjusting a time delay control 154 located on vertical wall 60 of frame 28. When this preset position in time is reached, a single shot pulse is directed to solenoid 100, thus applying the downward force through boots 72, 74 required to burst preweakened edges 18, 20, 22. The actuation time delay circuit and associated flow diagram between detection mechanism 34 and solenoid 100 is shown in FIG. 10 and is detailed in the following paragraphs.

Interruption of the light signal between emitter 112 I and cell 116 produces a signal from differential amplifier 146. The signal from amplifier 146 sets first flip/- flop 148 thereby applying a pulse to one-shot or time delay circuit 150. The duration of the quasi-stable state of circuit 150 may be adjusted by potentiometer 154 as well known in the art. The signal from circuit 150 branches at nodal point 156 into two paths: (1) into amplifier 158 and counter 160 to count the number of envelopes 12 being opened and (2) into a path for actuation of solenoids 100.

The signal passes through nodal point 162 and resets switch 148 as well as being applied to flip/flop 164 which activates one-shot circuit 166. The pulse output signal from circuit 166 is applied through a pair of am plifier drivers 168, 170 which activate a pair of solenoids 100 to move boots 72, 74 through a path intersecting the plane of envelope 12 on belts 40, 42. Additionally, the signal recursively passes into second flip/- flop 164 to provide reset for the next successive envelope application.

Envelope stacker 36 provides an initial placement medium for preweakened envelopes 12 as well as a mechanism to insure singular displacement of individual envelopes 12 into path guidance mechanism 30. Stacker 36 includes hopper 118 of standard construction being geometrically defined by inclined and longitudinally extended base surface 119 and normally displaced side walls or adjustable guide members 142. As shown in FIG. 2, envelope stack 138 is initially maintained in substantially vertical alignment with respect to inclined base surface 119 before entry onto belts 40, 42. In order to provide proper positioning during the opening process, envelopes 12 are stacked in hopper 118 having opposing panels 14 or 16 contiguous each other with perforated edges 18 transversely interfacing with base surface 119.

Stacker drive motor 120 is rigidly mounted to crossbar 124 of frame 28. Motor 120 independently provides rotary drive actuation to stacker drive pulley 122.

Endless rotary belt 126 is frictionally driven by drive pulley 122 as shown in FIG. 2, passing over and frictionally engaging pulley 128 in an actuating drive mode of operation. Rotationally moveable transverse rod 130 is fastened to, and driven by pulley 128. Rod 130, in turn, is connected to rear transverse rod 134 through pulley belt system 132. A pair of rear disk members 136 which are rigidly secured to rear rod 134, contact envelope stack 138 on one panel 14 or 16 of individual envelopes 12. Disks 136 are transversely displaced with respect to each other and contact a forwardly positioned envelope 12 near edges 20, 22. Additionally, members 136 are located in fixed relation above base surface 119 of hopper 118 to permit individual envelopes 12 to be moved under and forward disks 136.

Clockwise rotation of disks 136 (as viewed in FIG. 2) bends a forwardly stacked envelope 12 under disks 136 and drives envelope 12 in a forward direction into contiguous contact with base surface 119. Resilient cylinder 140, rotationally driven by transverse rod 130 is positioned substantially mid-point the transverse direction of hopper 118. Cylinder 140 releasably contacts an upper surface 14 or 16 of envelope 12 and provides a longitudinal displacement to envelope 12 onto belts 40, 42. Adjustable guide members 142 may be adjustably moved on base surface 119 to provide an adjustable wall guide path for envelope stack 138 before contact with disk members 136. Members 142, therefore, permit disks 136 to contact individual envelopes 12 in substantially the same transverse positions thus providing a high degree of repeatability success during the opening operation.

In the manner described, envelope stack 138 within shoes 72, 74 during the opening operation. The time delay herein described allows envelope 12 to continuously move on upper surfaces 44, 46 to the predetermined station necessary for proper bursting of edges 18, 20, 22. Proper longitudinal positioning is further complicated by the fact that the contact station is not only a function of belts 40, 42 speed but is also a function of the stock of the envelope panel construction as well as the contents contained therein. Where a lower weight stock envelope is used or the contents are flimsy such as scanning paper, it has been found that leading edge 18 should be contiguous with rollers 106 when initial contact by boots 72, 74 is made. In such a case, the predetermined station is located under a leading edge of rollers 106. The contents and lower panel 14 or 16 are continually driven longitudinally under rollers 106, but the upper panel is restrained by the force exerted b/ shoes 72, 74. As shown in FIGS. 6-9, the upper panel may be nominally forced in a rearward direction due to the frictional contact of disks 98 with the upper panel surface, thus resulting in a continuous flow of opened envelope 12 through rollers 106 in a flattened condition. If the predetermined station defined initial contact being made when edge 18 was substantially rearward of rollers 106, the combined shoe forces and tangential belt forces would tend to cause edge 18 to move rearward before tearing occurs. Since edge 18 is still constrained by the closed envelope 12 edges, the only freedom of motion is in an upward direction. This tends to curl envelope 12 out of the plane of belts 40, 42 which may cause a transverse crease on the still closed envelope. The now creased envelope, no longer lying contiguous with belts 40, 42 may, therefore, jam under rollers 106 thus disrupting the envelope opening operation. I

In order to provide a clearer understanding of the nature of the frictional engagement and bursting action of the opening operation, FIGS. 6-9 present a sequential time action operation for the low stock weight envelope as hereinbefore described. As shown in FIG. 6, initial contact is made by rubber disks 98 of shoes 72, 74 on upper panel 14 when leading edge 18 has moved substantially under rollers 106. FIG. 7 describes the initialization of the retraction process of shoes 72, 74 after bursting has taken place wherein disks 98 remain in contact with panel 14 to provide a continued rearward force thereby lifting panel 14 away from face 16. It is also seen from FIG. 7 that rollers 106 flatten face 16 to prevent any curling action that may occur. Continued retraction of shoes 72, 74 is shown in FIG. 8' wherein the curvilinear retraction path becomes apparent. The arcuate path travel in both contact and retraction phases is clearly shown to result from the restrained rotary motion of boots 72, 74 about pivoting rods 80, 82. This arcuate retraction does permit disks 98 to continue in frictional contact with surface 14 for an increased time interval, thereby ensuring a proper opening and passage under rollers 106. FIG. 9 illustrates the final phase in the opening of envelope 12 wherein disks 98 are retracted from contact with panel 14, and it passes under rollers 106.

Where a heavier stock envelope is used for paneling or where the internal contents are more rigid such as is the case when the computer cards are contained therein the time delay must be shortened. The shortening of the actuation time delay results in initial contact as shown in FIG. 5. In this case, it is seen that disks 98 contact envelope 12 at leading edge 18 and then sequentially follows the operation through substantially in the'same manner as described in FIGS. 7-9. The contact station for this type envelope 12 as shown, prevents any nicking of the internally placed card and allows lower panel 16 plus contents to move smoothly under rollers 1116. The varying positional relation of envelope 12 with respect to shoes 72, 74 as a positional function of time may be adjusted by changing the time delay as described in previous paragraphs. Empirically derived positions may further be accommodated through analysis of the contents as well as envelope paper stock weight for particular applications of the user.

Bursting machine or envelope opening apparatus 19 as herein described presents a machine permitting a vast increase in quality control associated with the opening of preweakened envelopes 12.

The method of opening preweakened envelopes 12 in broadest definition as herein described includes applying a force within the plane of envelope 12 to lower panel 14 or 16 to move envelope 12 to a predetermined station on path guidance mechanism 30. At the predetermined station, opening mechanism 32 frictionally engages upper panel 14 or 16 through a force substantially normal to the envelope plane. The force, applied by mechanism 30, in combination with the normal force generated by opening mechanism 32 provides a tearing of envelope 12 along perforations 26, thus opening the contents of envelope 12.

In the operating sequence of events, envelope stack 138 is inserted within stacker 36 with edges 18 contiguous to base surface 119 of the inclined plane as shown in FIG. 2. Individual envelopes 12 are removed from stack 138 by frictional contacting rear disk member 136. Envelopes 12 are forced into a plane coincident with the plane defined by base surface 119 and are fed into the substantially horizontal plane defined by endless belts or transporting means 40, 42 under frictional engagement of resilient cylinder 140. Transversely displaced belts or transporting means 40, 42 provide longitudinal aperture 114 spanned by envelope 12 transverse to the direction of motion imparted by belts 40, 42. Emitter and detector 112, 116 pass a continuous light beam vertically through aperture 114 and is interrupted by incursion of frontal edge 26 of envelope 12 into the continuous path. Interruption of the light beam initiates a time delay circuit to permit envelope edge 18 to move into a predetermined station on upper surfaces 44, 46 before contact is made by opening mechanism 32 on panels 14 or 16. The predetermined station, as has been previously defined, is a transverse line on belts 41), 42 which leading edge 18 has reached when contact is made by rubber disks 98. The station is adjustable in the longitudinal or direction of motion of envelope 12 to permit optimum positioning of different weight and stock envelopes l2 and contents. The positioning contact station is clearly shown, for different envelope stocks, in FIGS. and 6. When envelope 12 has moved to the proper station, upper panel 14 or 16 is engaged through a force substantially normal to the envelope plane which bursts open envelope 12 along perforations 26. The engagement by disks 98 includes a con tacting of panel 14 or 16 in a substantially planar interface. Since disks 98 are separate entities, the contacting is, therefore, transversely discontinuous with respect to the movement of envelope 12 in the longitudinal direction.

The engaging force applied by opening mechanism 32 through disks 98 includes application over a substantial area of envelope 12. Shoes or boots 72, 74 are transversely positioned such that disks 98 move toward and in contact with envelope 12 to apply the engaging force over substantial portions of opposing transverse edges 20, 22 within the contour boundaries of envelope 12. Since the lower surfaces of disks 98 may overlap the envelope boundaries, it has been found preferable to taper disks 98 along a line substantially coincident with edges 20, 22 in an upward and outward manner to avoid contacting both envelope 12 and belts 40, 42 during the engagement step. Contacting by disks 98 substantially near edges 20, 22 permits the largest tension forces to be applied at the weakest envelope edges to allow a clean tear at perforations 26. In addition, where the contacting force is not applied substantially on the preweakened edges, it has been found that a transverse warping may occur causing the envelope 12 upper panel to be arched in a transverse direction. Such warping or arching may then cause jamming under rollers 106 thus disrupting the continued flow of envelopes.

Additionally, boots 72, 74 normally contact upper panel 14 or 16 for a small increment of time when the envelope 12 has reached the predetermined station thus producing singular contact as has been described. As necessarily follows, engagement occurs during only a portion of the time that envelope 12 passes entirely through the station. At no time for any envelope 12 will disks 98 touch the upper panel 14 or 16 for the entire duration of the time the envelope 12 passes through the station. The momentary contact reduces the possibility of content mutilation due to continued contact of the envelopes 12 by the impacting force which may cause content movement within the envelope and subsequent bending, warping or mutilation.

The bursting open of envelope 12 is followed by the step of flattening envelope 12 to maintain panels 14, 16 contiguous with belts 40, 42. In this final step, opened envelope 12 is engaged in rolling contact with transversely displaced cantilever rollers 106. The roller heads extend across edges 20, 22 to restrain warping or other undesirable effects and thus expose the contents of envelope 12.

In a modification of the invention, it may be preferred to accommodate varying transverse length envelopes 12. To accomplish this adjustable envelope length opening, transverse mounting bar 88 may have incorporated therein a transverse slot having a width substantially larger than vertical rod members 94 but smaller than mounting bolts 92. A particular sized envelope 12 is measured, and bolts 92 are loosened to permit repositioning of boots 72, 74. Once located, bolts 92 are tightened and apparatus 10 has been reset to a new transverse envelope length. In a similar manner, pivoting arms 78 may include a transverse screw arrangement, operated by an external handwheel,

which bears against shoes 72, 74 to provide the necessary transverse shoe moving force. Turning of the handwheel then transversely positions shoes 72, 74 to the proper length. In this manner, shoes 72, 74 may be manually or otherwise adjusted in the transverse direction to properly contact varying size envelope panels 14 or 16.

What is claimed is: w

l. The method for opening a preweakened envelope having an upper and lower panel, including the steps of a. applying a force within the plane of said envelope to said lower panel thereof moving said lower panel,

b. engaging said upper panel of said envelope through a force substantially normal to said envelope plane for bursting open said preweakened envelope and c. moving said upper panel about said lower panel until said upper panel lies in substantially the same plane as said lower panel.

2. The method of claim 1 in which the engaging step includes applying said normal force in a direction toward said envelope plane and frictionally engaging said upper panel whereby said normal force in combination with said force within the envelope plane provides said bursting open of said preweakened envelope along three edges thereof.

3. The method as recited in claim 1 wherein the step of applying a force to said lower panel of said envelope includes the step of transporting said envelope to a predetermined station on a substantially planar path for said envelope.

4. The method as recited in claim 1 wherein the step of engaging said upper panel includes engaging said upper panel in a substantially planar interface.

5. The method as recited in claim 1 wherein the step of engaging said upper panel includes engaging said upper panel in a transversely discontinuous manner with respect to said envelope movement.

6. The method as recited in claim 4 wherein the step of contacting said upper panel includes the step of applying an engaging force on substantial portions of opposing transverse edges of said envelope.

7. The method as recited in claim 1 wherein the step of engaging said upper panel of said envelope is immediately followed by the step of flattening said opened envelope to be coincident with said envelope plane.

8. The method as recited in claim 7 wherein the step of flattening said opened envelope comprises restraining by cantilevered rollers opposed transverse edges of said envelope. g

9. Apparatus for opening a preweakened envelope comprising:

a. means for guiding said envelope in a predetermined plane, said envelope having a first panel contiguous to said guidance means,

b. opening means moveable in a path intersecting said predetermined plane for contacting and frictionally engaging a second panel of said envelope for bursting open said preweakened envelope and moving said second panel about said first panel, and I means for flattening said second panel contiguous to said guidance means until said second panel lies in substantially the same plane as said first panel.

10. The apparatus as recited in claim 9 including positioning means for actuating said opening means for contacting said second envelope panel when a leading edge of said envelope reaches a predetermined station on said guidance means.

11. The apparatus as recited in claim 10 wherein said predetermined station is located on a transverse line of said guidance means wherein a forward edge of said opening means path with respect to said envelope movement, intersects said predetermined plane.

12. The apparatus as recited in claim 10 in which there is provided flattening roller means positioned forward of said opening means in the direction of travel of said envelope and in which said predetermined station is located on a transverse line of said guidance means adjacent said roller means.

13. The apparatus as recited in claim 12 wherein said predetermined station for said envelope located adjacent said roller means is vertically positioned beneath said roller means.

14. The apparatus as recited in claim 9 wherein said opening means includes means for singularly engaging said envelope when said envelope reaches a predeter mined station, said engaging means for contacting said envelope during only a portion of the time of passage of said envelope through said predetermined station.

15. The apparatus as recited in claim 9 including roller means for flattening said opened envelope on said guidance means after said opening means has contacted said second panel of said envelope, said roller means positioned forward said opening means with respect to the direction of travel of said envelope and contiguous to said guidance means.

16. A method for opening a preweakened envelope having an upper and a lower panel including the steps of: I i

a. transporting said envelope in a predetermined direction with a plane of motion,

b. singularly engaging and contacting said envelope at a predetermined station during only a portion of the time that said envelope passes entirely through said station for bursting open said preweakened envelope and c. moving said upper panel about said lower panel until said upper panel lies in substantially the same plane as said lower panel to form a single panel.

17. The method as recited in claim 16 wherein the step of transporting said envelope includes the step of moving said envelope to a predetermined station on an envelope guidance means through frictional engagement between said guidance means and a lower panel of said envelope.

18. The method as recited in claim 16 wherein the step of engaging and contacting said envelope includes the step of forming a frictional restraint for said envelope between an opening means moveable in a path intersecting said envelope plane of motion to contact an upper panel of said envelope and a path guidance means interfacing with a lower panel of said envelope.

19. The method as recited in claim 18 wherein the step of forming said frictional restraint includes the step of impacting said upper panel of said envelope by said opening means with a substantially normal force 22. The method as recited in claim 16 wherein the step of singularly engaging and contacting said envelope includes the step of hitting said envelope on op posing transverse edges of said envelope.

23. The method as recited in claim 22 wherein the step of hitting said envelope includes the step of covering a substantial linear length of said opposing transverse edges when said contact is made.

24. The method as recited in claim 16 wherein said engaging and contacting step is followed by the step of maintaining said opened envelope in planar contact with a path guidance means.

25. An apparatus for opening a preweakened envelope having a first and second panel comprising:

a. means for transporting said envelope in a predetermined direction,

b. opening means for contacting and frictionally engaging said second panel of said envelope in substantially planar contact, said engagement being transversely discontinuous with respect to said predetermined direction, said opening means bursting open said envelope and moving said second panel about said first panel, and

means for flattening said second panel until said second panel lies in substantially the same plane as said first panel.

26. The apparatus as recited in claim 25 wherein said contacting means engages said envelope when a frontal edge of said envelope has moved to an adjustable predetermined station on said transporting means.

27. The apparatus as recited in claim 25 wherein said contacting means is moveable in a path intersecting a plane of motion of said envelope for contacting and frictionally engaging an upper panel of said envelope substantially simultaneous with, but not before said envelope reaches a predetermined station on said transporting means.

28. The apparatus as recited in claim 27 wherein said contacting means engages said upper panel of said envelope through a force substantially normal to a plane of motion of said envelope defined by said motion of said envelope in contact with said transporting means.

29. The apparatus as recited in claim 28 wherein said means for contacting said envelope includes engage ment of said envelope upper panel at said predetermined station during only a part of the time that said envelope passes entirely through said station.

30. The apparatus as recited in claim 25 wherein said contacting means engages said envelope on an upper panel thereof when said envelope has moved to a pre' determined station on said transporting means, said contacting means for engaging said envelope on substantial portions of opposing transverse edges thereof.

31. An apparatus for opening a preweakened envelope having a first and a second pane] comprising:

a. means for linearly translating said envelope in a predetermined direction,

b. opening means for contacting and frictionally engaging said second panel of said envelope on substantial portions of opposing transverse edges of said envelope to burst open said preweakened envelope and moving said second panel about said first panel, and

c. flattening said second panel until said second panel lies in substantially the same plane as said first panel.

32. The apparatus as recited in. claim 29 wherein said contacting means frictionally engages said envelope on an upper panel thereof when said envelope has moved to a predetermined station on said translating means, said envelope having a lower panel being contiguous to said translating means.

33. The apparatus as recited in claim 32 wherein said contacting means engages said envelope in substantially planar contact, said engagement being transversely discontinuous with respect to said predetermined direction. 1

34. The apparatus as recited in claim 31 including cantilever roller means positioned forward of said contacting means with respect to said translating direction of said envelope, said cantilever roller means for flattening said opened envelope contiguous to said translating means.

Claims (34)

1. The method for opening a preweakened envelope having an upper and lower panel, including the steps of a. applying a force within the plane of said envelope to said lower panel thereof moving said lower panel, b. engaging said upper panel of said envelope through a force substantially normal to said envelope plane for bursting open said preweakened envelope and c. moving said upper panel about said lower panel until said upper panel lies in substantially the same plane as said lower panel.

2. The method of claim 1 in which the engaging step includes applying said normal force in a direction toward said envelope plane and frictionally engaging said upper panel whereby said normal force in combination with said force within the envelope plane provides said bursting open of said preweakened envelope along three edges thereof.

3. The method as recited in claim 1 wherein the step of applying a force to said lower panel of said envelope includes the step of transporting said envelope to a predetermined station on a substantially planar path for said envelope.

4. The method as recited in claim 1 wherein the step of engaging said upper panel includes engaging said upper panel in a substantially planar interface.

5. The method as recited in claim 1 wherein the step of engaging said upper panel includes engaging said upper panel in a transversely discontinuous manner with respect to said envelope movement.

6. The method as recited in claim 4 wherein the step of contacting said upper panel includes the step of applying an engaging force on substantial portions of opposing transverse edges of said envelope.

7. The method as recited in claim 1 wherein the step of engaging said upper panel of said envelope is immediately followed by the step of flattening said opened envelope to be coincident with said envelope plane.

8. The method as recited in claim 7 wherein the step of flattening said opened envelope comprises restraining by cantilevered rollers opposed transverse edges of said envelope.

9. Apparatus for opening a preweakened envelope comprising: a. means for guiding said envelope in a predetermined plane, said envelope having a first panel contiguous to said guidance means, b. opening means moveable in a path intersecting said predetermined plane for contacting and frictionally engaging a second panel of said envelope for bursting open said preweakened envelope and moving said second panel about said first panel, and c. means for flattening said second panel contiguous to said guidance means until said second panel lies in substantially the same plane as said first panel.

10. The apparatus as recited in claim 9 including positioning means for actuating said opening means for contacting said second envelope panel when a leading edge of said envelope reaches a predetermined station on said guidance means.

11. The apparatus as recited in claim 10 wherein said predetermined station is located on a transverse line of said guidance means wherein a forward edge of said opening means path with respect to said envelope movement, intersects said predetermined plane.

12. The apparatus as recited in claim 10 in which there is provided flattening roller means positioned forward of said opening means in the direction of travel of said envelope and in which said predetermined station is located on a transverse line of said guidance means adjacent said roller means.

13. The apparatus as recited in claim 12 wherein said predetermined station for said envelope located adjacent said roller means is vertically positioned beneath said roller means.

14. The apparatus as recited in claim 9 wherein said opening means includes means for singularly engaging said envelope when said envelope reaches a predetermined station, said engaging means for contacting said envelope during only a portion of the time of passage of said envelope through said predetermined station.

15. The apparatus as recited in claim 9 including roller means for flattening said opened envelope on said guidance means after said opening means has contacted said second panel of said envelope, said roller means positioned forward said opening means with respect to the direction of travel of said envelope and contiguous to said guidance means.

16. A method for opening a preweakened envelope having an upper and a lower panel including the steps of: a. transporting said envelope in a predetermined direction with a plane of motion, b. singularly engaging and contacting said envelope at a predetermined station during only a portion of the time that said envelope passes entirely through said station for bursting open said preweakened envelope and c. moving said upper panel about said lower panel until said upper panel lies in substantially the same Plane as said lower panel to form a single panel.

17. The method as recited in claim 16 wherein the step of transporting said envelope includes the step of moving said envelope to a predetermined station on an envelope guidance means through frictional engagement between said guidance means and a lower panel of said envelope.

18. The method as recited in claim 16 wherein the step of engaging and contacting said envelope includes the step of forming a frictional restraint for said envelope between an opening means moveable in a path intersecting said envelope plane of motion to contact an upper panel of said envelope and a path guidance means interfacing with a lower panel of said envelope.

19. The method as recited in claim 18 wherein the step of forming said frictional restraint includes the step of impacting said upper panel of said envelope by said opening means with a substantially normal force with respect to said plane of motion of said envelope.

20. The method as recited in claim 19 wherein the step of forming said frictional restraint includes the step of engaging said upper panel of said envelope in substantially planar contact, said contact being coincident with said plane of motion of said envelope.

21. The method as recited in claim 20 wherein the step of engaging said upper panel of said envelope includes the step of contacting said envelope discontinuously transverse with respect to said predetermined direction.

22. The method as recited in claim 16 wherein the step of singularly engaging and contacting said envelope includes the step of hitting said envelope on opposing transverse edges of said envelope.

23. The method as recited in claim 22 wherein the step of hitting said envelope includes the step of covering a substantial linear length of said opposing transverse edges when said contact is made.

24. The method as recited in claim 16 wherein said engaging and contacting step is followed by the step of maintaining said opened envelope in planar contact with a path guidance means.

25. An apparatus for opening a preweakened envelope having a first and second panel comprising: a. means for transporting said envelope in a predetermined direction, b. opening means for contacting and frictionally engaging said second panel of said envelope in substantially planar contact, said engagement being transversely discontinuous with respect to said predetermined direction, said opening means bursting open said envelope and moving said second panel about said first panel, and c. means for flattening said second panel until said second panel lies in substantially the same plane as said first panel.

26. The apparatus as recited in claim 25 wherein said contacting means engages said envelope when a frontal edge of said envelope has moved to an adjustable predetermined station on said transporting means.

27. The apparatus as recited in claim 25 wherein said contacting means is moveable in a path intersecting a plane of motion of said envelope for contacting and frictionally engaging an upper panel of said envelope substantially simultaneous with, but not before said envelope reaches a predetermined station on said transporting means.

28. The apparatus as recited in claim 27 wherein said contacting means engages said upper panel of said envelope through a force substantially normal to a plane of motion of said envelope defined by said motion of said envelope in contact with said transporting means.

29. The apparatus as recited in claim 28 wherein said means for contacting said envelope includes engagement of said envelope upper panel at said predetermined station during only a part of the time that said envelope passes entirely through said station.

30. The apparatus as recited in claim 25 wherein said contacting means engages said envelope on an upper panel thereof when said envelope has moved to a predetermined station on said transporting means, said contacting means for engaging said envelope on substantial porTions of opposing transverse edges thereof.

31. An apparatus for opening a preweakened envelope having a first and a second panel comprising: a. means for linearly translating said envelope in a predetermined direction, b. opening means for contacting and frictionally engaging said second panel of said envelope on substantial portions of opposing transverse edges of said envelope to burst open said preweakened envelope and moving said second panel about said first panel, and c. flattening said second panel until said second panel lies in substantially the same plane as said first panel.

32. The apparatus as recited in claim 29 wherein said contacting means frictionally engages said envelope on an upper panel thereof when said envelope has moved to a predetermined station on said translating means, said envelope having a lower panel being contiguous to said translating means.

33. The apparatus as recited in claim 32 wherein said contacting means engages said envelope in substantially planar contact, said engagement being transversely discontinuous with respect to said predetermined direction.

34. The apparatus as recited in claim 31 including cantilever roller means positioned forward of said contacting means with respect to said translating direction of said envelope, said cantilever roller means for flattening said opened envelope contiguous to said translating means.

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