WO1996003272A1

WO1996003272A1 - Method and apparatus for manufacturing stand-up plastic bags

Info

Publication number: WO1996003272A1
Application number: PCT/US1995/009351
Authority: WO
Inventors: Larry W. Crabtree; Jerome J. Kennedy; Kenneth H. Kirby; Ronald L. Ramsay
Original assignee: Lin Pac Inc
Current assignee: Lin Pac Inc
Priority date: 1994-07-25
Filing date: 1995-07-25
Publication date: 1996-02-08
Anticipated expiration: 1997-01-25
Also published as: AU3144595A

Abstract

A method and apparatus (F) for manufacturing a stand-up plastic bag. The apparatus includes a section for supplying a continuous length of heat-sealable material (A), and a bag assembly section (B, C, D, E) connected to the supply section for producing a bag from the heat-sealable material having close sides, a closed bottom and an open mouth. The apparatus also includes a section for receiving the bag (F) after it is assembled and shaping the bag into a stand-up plastic bag. The bag shaping section includes a series of stations including: a first station for forming opposed faces, opposed sides, and a substantially flat bottom; a second station for creasing at least the bottom of the bag, so that the bottom folds inwardly and does not obstruct the front and back display surfaces of the bag; and a third station for unloading the bag.

Description

METHOD AND APPARATUS FOR MANUFACTURING STAND-UP PLASTIC BAGS BACKGROUND OF THE INVENTION

The present invention relates to a stand-up plastic bag. More particularly, the present invention pertains to a method and apparatus for making a plastic bag that is capable of standing up by itself, when the bag is opened, and also capable of fully exposing the front or back display surfaces of the bag, when the bag is folded.

The advantages of stand-up, free standing or self- standing plastic bags are well known. Conventional methods of manufacturing such bags often times produce bags that are too limp to stand up or too complicated to manufacture. Also, conventional manufacturing methods typically avoid applying a crease across the bottom in an attempt to preserve the integrity of the bottom surface of the bag. When folding such bags, the flat bottom surface is folded along a crease on the side of the bag, in which case the bottom surface obstructs either the front or back display surface of the bag.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to the method and apparatus for manufacturing a stand-up plastic bag that substantially obviates one or more of the limitations of the related art.

To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described, the apparatus of the present invention comprises supply means for providing a continuous length of heat sealable material, and bag assembly means connected to the supply means for producing a bag from the heat sealable material having closed sides, a closed bottom, and an open mouth. The apparatus also includes means for receiving the bag from the bag assembly means and shaping the bag into a stand-up plastic bag. The bag shaping means includes a series of stations including: a first station for forming opposed faces, opposed sides, and a substantially flat bottom; a second station for creasing at least the bottom of the bag, so that the bottom folds inwardly and does not obstruct the front and back display surfaces of the bag; and a third station for unloading the bag.

In a preferred embodiment, the bag shaping means includes at least one rotatable turret assembly for positioning the bag at each of the stations. The turret assembly includes means for holding the bag as the turret assembly is rotated. Preferably, the holding means includes a collapsible frame that is positioned within the bag when the frame is at least partially collapsed. The frame is expanded and collapsed during processing at the various stations before the bag is unloaded for collection and stacking.

In addition, the present invention comprises a method of manufacturing a stand-up plastic bag. The method includes unwinding a roll of heat sealable material and conveying the material through an arrangement of rollers. The material is folded to form top and bottom sheets, which are intermittently sealed along a seal line extending transverse to the direction of travel of the material when it is sealed. The method also includes cutting the material along the seal line to form individual bags having a closed bottom and an open mouth. The bags are then loaded onto a frame for shaping the bags interiorly to correspond essentially to the frame, so that when the bag is opened the bag has a substantially planar bottom surface and support columns, such as vertical folds, extending from the bottom surface. The method also includes creasing a fold line along at least the bottom surface of the bag for folding each of the bags inwardly along the fold line so that neither the front nor back display surfaces is obstructed by the bottom surface when the bag is folded. Preferably, the method includes the step of providing lateral support to prevent the bag from collapsing inwardly when the bag is opened. In a preferred embodiment, the lateral support includes cuffing a top portion of the bag. The method also may include applying tape along a top portion of the bag, for example, along the cuff.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide an explanation of the invention as claimed. The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention, and, together with their description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the layout of the apparatus for making a stand-up plastic bag in accordance with the present invention.

FIG. 2a is a side elevation view of an unwind section of the present invention.

FIG. 2b is a perspective view of the details of the unwind section of the present invention.

FIG. 3a is a side elevation view of a cuffer section of the present invention.

FIG. 3b is a perspective view of the details of the cuffer section of the present invention.

FIG. 3c is a perspective view of a scoring assembly in the cuffer section of the present invention.

FIG. 3d is a perspective view of a lower roll bar in the cuffer section of the present invention.

FIG. 3e is a perspective view of an upper roll bar in the cuffer section of the present invention.

FIG. 3f is a side elevation view of a tie bar mechanism in the cuffer section of the present invention. FIG. 3g is a rear perspective view of the tie bar mechanism shown in FIG. 3f.

FIG. 4a is a rear elevation view of a bag folding section of the present invention featuring an alternative arrangement of scoring assemblies.

FIG. 4b is a side elevation view of the bag folding section shown in FIG. 4a except the alternative embodiment is not shown.

FIG. 4c is a perspective view of the bag folding section shown in FIGS. 4a and 4b except the alternative embodiment is not shown.

FIG. 5 is a side elevation view of the bag seal and cut section of the present invention.

FIG. 6a is a schematic diagram of stations in a turret assembly of the present invention.

FIG. 6b is a top view of the turret assembly of the present invention.

FIG. 6c is a side view of a fully opened, collapsible frame in the turret assembly of the present invention.

FIG. 6d is a side view of a partially collapsed frame in the turret assembly of the present invention.

FIG. 6e is a side view of a fully collapsed frame in the turret assembly of the present invention.

FIG. 6f is a top view of a flap sealing station in the turret assembly of the present invention.

FIG. 6g is a front elevation view of a bag mounted on the fully opened, collapsible frame in the turret assembly of the present invention, and showing a flap of additional material adjacent the bottom surface of the bag.

FIG. 6h is a top view of a gusset-forming station in the turret assembly of the present invention.

FIG. 6i is a side, sectional view of a creaser bar of the present invention taken along lines "6i-6i" in FIG. 6h. FIG. 6j is a front elevation view showing side, gusset-forming creaser bars of the present invention disposed beneath the collapsible frame.

FIG. 6k is a front elevation of the embodiment in FIG. 6h, except a gusset-forming creaser bar disposed along the bottom of the bag is not shown.

FIG. 61 is a front elevation view of a bag mounted on a partially collapsed, collapsible frame with side, gusset-forming creaser bars engaging the sides of the bag, in accordance with the present invention.

FIG. 7a is a perspective view of a fully opened, stand-up plastic bag of the present invention.

FIG. 7b is a perspective view of a partially opened, stand-up plastic bag of the present invention.

FIG. 7c is a perspective view of a fully opened, stand-up plastic bag of the present invention with the flap secured to the side of the bag.

FIG. 7d is a perspective view of a substantially closed, stand-up plastic bag of the present invention.

FIG. 7e is a perspective view illustrating details of a top portion of the stand-up plastic bag of the present invention.

FIG. 7f is a cross-section of the bag taken along lines "7f-7f" in FIG. 7e.

FIG. 7g is a perspective view of a fully opened, stand-up plastic bag of the present invention with the flap secured in an inner pocket formed between the sides and bottom of the bag.

DETAILED DESCRIPTION

The present invention relates to a method and apparatus for manufacturing a collapsible, stand-up plastic bag comprising a substantially planar bottom surface when the bag is opened, and support columns extending upward from the bottom surface for holding the bag upright. The support columns define front, back, and side surfaces of the bag. The bag also includes a substantially continuous seam along the bottom and side surfaces for folding the bottom and side surfaces inward when collapsing the bag, so that the front and back surfaces of the bag are substantially, fully exposed when the bag is folded.

Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings.

An exemplary schematic diagram of the method and apparatus for manufacturing stand-up plastic bags in accordance with the present invention is shown in FIG. 1. As embodied herein, the apparatus of the present invention includes an unwind section, which is identified in FIG. 1 by reference character A. The apparatus also includes a cuffer section B, a handle forming section C, a bag folding section D, and a bag seal and cut section E, where individual bags are assembled. The individual bags are then conveyed to one or more turrets, which are generally designated by reference character F. The turrets include stations for shaping and gusseting the bags, which are then off-loaded, collected, and stacked.

In accordance with the present invention, the apparatus for manufacturing a stand-up plastic bag includes an unwind section for supplying a continuous length of heat sealable material. As shown generally in FIGS. 2a and 2b, the unwind section A includes a feed roll 10 having a continuous web of plastic sheet material 12 and an arrangement of rollers, generally referred to as an accumulator or dancer assembly 14. The sheet material 12 is drawn from the feed roll 10 and fed through the dancer assembly 14, which enables uniform tension to be maintained on the sheet material 12 as it is fed to the cuffer section B of the apparatus.

In accordance with the present invention, the cuffer section includes a scoring assembly spaced from an edge of the length of heat sealable material for scoring the material along a score line a predetermined distance from the edge to form a cuff . As embodied herein and shown principally in FIGS. 3a-3g, the cuffer section B preferably includes a pair of scoring assemblies 16, 16' that are adjustably positioned along a crossbar 20 extending parallel to a scoring roller 22. The sheet material 12 is fed over the scoring roller 22, and the scoring assemblies 16, 16' are aligned along opposite sides 24, 24' of the sheet material 12 (see FIG. 4c) for scoring the sides 24, 24' to form cuffs.

The structure and operation of the scoring assemblies 16, 16' are essentially identical. Therefore, reference will be made to only one of the scoring units 16, though it will be appreciated that both units 16, 16' function similarly and contain similar elements that form cuffs along opposite sides 24, 24' of the same sheet material 12.

As shown in FIG. 3c, the scoring assembly 16 comprises outer and inner scorers 26a, 26b. The scorers 26a, 26b have individual scoring discs 28a, 28b mounted on a bracket 30 depending from a housing 32 mounted on the crossbar 20. The housing 32 contains a spring assembly (not shown) for applying tension to each scoring disc 28a, 28b. Each spring or arrangement of springs is operated by a control knob 36 for adjustably controlling the tension applied to the scoring disc 28a, 28b.

As embodied herein, the scoring discs 28a, 28b have knife-like edges 38 for scoring a pair of parallel creases on the side 24 of the sheet material 12. As shown in FIG. 3d, The outer scoring disc 28a applies a first crease 40 that forms a first cuff 42. Like the outer scoring disc 28a, the inner scoring disc 28b breaks the memory of the sheet material 12, thereby applying a second crease 44 to form a second or double cuff 46. The scorers 28a, 28b form first and second creases 40, 44 by applying either continuous or intermittent force to the sheet material 12 as the sheet material 12 is conveyed over scoring roller 22. In accordance with the present invention, means are provided for folding the material along the creases . As embodied herein and shown principally in FIGS. 3a and 3d, the cuffer section preferably includes one or more rollers, such as lower rollers 48a, b and c and upper rollers 50a, b, for folding the side 24 along the creases 40, 44 to form cuffs 42, 46, as the sheet is drawn through the rollers. As shown in FIG. 3d, the side 24 of the sheet material 12 is folded along the first crease 40, thereby forming first cuff 42 as the sheet material passes over the first lower roller 48a and the first upper roller 50a.

In accordance with the present invention, the second upper roller 50b may be sized to be narrower than the sheet material 12 and slightly narrower than the distance between the second creases 44 on opposite sides 24, 24' of the sheet material 12. For example, as shown in FIG. 3e, an end 52 of the second upper roller 50b preferably is aligned a slight distance inside of the second crease 4 . This alignment enables the unsupported side 24 of the sheet material 12 to begin to fold along the second crease 44, as the sheet material is drawn over the second upper roller 50b. Thus, the formation of the second cuff 46 commences as the sheet material is passed over the second upper roller 50b.

As embodied herein and shown generally in FIG. 3a, the sheet material 12 passes from upper rollers 50a, 50b to lower rollers 48b, 48c before exiting the cuffer section B. Substantially adjacent the lower roller 48b is an arrangement of fixed bars, referred to as a tie bar mechanism 53. As shown in FIGS. 3f and 3g, the side 24 of the sheet material 12 passes through the tie bar mechanism 53, which preferably comprises three fixed bars 53a-c. The tie bar mechanism 53 forces the first and second cuffs 42, 46 together and reinforces the fold along first and second crease lines 40, 44. The sheet material 12 passes around lower rollers 48b, 48c, and exits the cuffer section B. Reference has been made to a single scoring assembly and formation of a double cuff along one edge of sheet material 12. As noted, a similar scoring assembly 16' and corresponding rollers and tie bar mechanisms are used to form cuffs on both sides 24, 24' of the sheet material 12 passing through the cuffer section B. The scoring assemblies and corresponding rollers and tie bar mechanisms can be adjusted to accommodate sheet material of varying widths and thicknesses.

Preferably, after the sheet material 12 leaves the cuffer section B, the sheet material 12 is conveyed to a handle forming section C, where handles 54 are attached to the opposite edges 24 of the sheet material 12. Alternatively, handles may be stamped or punched into the sheet material 12 to provide a means for grasping the bag when formed.

In accordance with the present invention, sheet material leaving the cuffer section B or the handle forming section C is conveyed to a section of the apparatus in which the sheet material is folded. As embodied herein and shown principally in FIGS. 4a-4c, the folding section D includes a pair of friction rollers 56a, 56b for drawing sheet material 12 into the folding section D, and a tension bar 58 for applying tension to the sheet material 12. The folding section D also includes a spring-operated scoring assembly 60 similar to the scoring assembly 16, 16' described with respect to the cuffer section B, except the scoring assembly 60 comprises a single scoring disc 62. The scoring assembly 60 is adjustably mounted above a scoring bar 64 over which the sheet material 12 passes. The scoring assembly 60 is aligned so that the scoring bar 64 applies a bottom crease 66 along a midpoint between opposite edges 24 of the sheet material 12.

The bottom crease 66 allows the bag 84 to keep the top of the bag in line from front to back. Due to buildup of gauge created by the cuffs, the material is much tighter and will prevent one cuff from running over the other. As such, the center bottom crease 66 locks the sheet material 12 in position, so that the top and bottom surfaces of the sheet material do not slide relative to each other.

In an alternative embodiment, as shown in FIG. 4a, the scoring assembly 60 may include additional scoring assemblies 61, 61' that provide side creases 67, 67' along either side of the bottom crease 66. The side creases 67, 67' correspond to the side edges for the bottom of the bag when it is eventually formed in the bag shaping assembly F. The side creases 67, 67' provide reinforcement and stability for the bag when it is used.

As embodied herein and shown principally in FIG. 4c, after the bottom crease 66 is formed (and side creases 67, 67' , if desired) , the sheet material 12 is drawn over an upside down A-frame 68 positioned above a nip roll 70 formed by a pair of opposing rollers 72a, 72b. The A-frame 68 is angled downwardly and has steeply angled sides 68a, 68b that lead to a common end point 68c aligned with the bottom crease 66 of the sheet material 12. When drawn over the A-frame 68, the sheet material folds along the bottom crease 66, and the top and bottom surfaces of the sheet material are drawn through the nip roll 70 beneath the A-frame 68. The folded sheet material 12 is then lead from the bag folding section D through one or more rollers (not shown) .

In accordance with the invention, the folded sheet material is passed to a section of the apparatus for sealing and cutting the folded sheet material to form individual bags. As embodied herein and shown in FIG. 5, the bag seal and cut section E includes a feed roll 74 for drawing the folded sheet material 12 from the bag folding section D. This section also includes an arrangement of rollers 76 that act as an accumulator for taking up slack in the folded sheet material before it is cut into individual bags.

Preferably, after the folded sheet material 12 leaves the accumulator rolls 76, a registration device 78, such as an electronic eye, assesses whether the sheet material 12 is in registration, i.e., in alignment. The registration device is particularly important when the sheet material features a design. The seal and cut section E also may include a preheater 80 for warming the edges 24 of the sheet material where cuffs have been formed so that the edges 24 are easier to seal and cut.

As embodied herein and shown in FIG. 5, the apparatus includes a conventional seal and cut unit 82 for sealing and cutting the sheet material at spaced intervals to form individual bags. The seal and cut unit 82 may seal and cut adjoining bags simultaneously or in sequence (i.e., first seal, then cut), as long as individual, flattened bags 84 are formed having closed sides and an open mouth. In a preferred embodiment the individual bags 84 are pulled from seal and cut unit 82 by a conventional rope conveyor 85 for transfer to the bag shaping section F.

In accordance with the present invention, the apparatus includes a bag shaping section comprising a conveyor for transferring individual bags from the bag seal and cut section to one or more turrets having stations for shaping and creasing each of the bags. As embodied herein and shown schematically in FIGS. 1 and 6a, the bag shaping section F includes a conveyor 86 for receiving bag 84 formed by the bag seal and cut section E. The bags 84 are deposited on the conveyor 86 one at a time so that the mouth 88 of each bag 84 faces the side of the conveyor 86 passing closest to the turrets 90. Once the bag 84 reaches the designated turret 90, the bag 84 is loaded on the turret 90 for processing. Each of the turrets 90 include the same processing stations.

As shown in FIG. 6a, a turret 90 includes a bag loading station I, a flap sealing station II, a gusset forming station III, a bag unloading station IV, and a vacant station V that has no designated processing function. The turrets 90 comprise a turntable or turnstile 92 supporting five collapsible frames 94 that are indexed from one station to the next. At the bag loading station I, one of the collapsible frames 94 will receive a bag 84 when the frame 94 is partially or fully collapsed. The turret 90 will rotate to the flap sealing station II and the frame 94 expands within the bag 84 to form side walls 96, a bottom surface 98, and a flap 100 of additional material adjacent to the bottom surface 98. See FIGS. 6b and 7a. Immediately after the flap 100 is formed, a sealing assembly 102 secures the flap 100 to the bag 84. Once this occurs, the turnstile 92 rotates and the frame 94 at flap sealing station II will go to gusset forming station III. Likewise, the other frames 94 will be rotated to the next succeeding station, i.e., I to II, III to IV, IV to V, and then V goes back to I. At gusset forming station III, the side walls 96 and the bottom surface 98 of the bag 84 are creased forming a gusset enabling the bag to fold inwardly along the crease. After the bottom and sides of the bag are gusseted, the bag is delivered to an unload station IV, where the bags are collected and eventually stacked. The vacant station V has no designated function. However, it may be used to load bags manually.

As previously described, the bags 84 formed in the bag seal and cut section E are transferred to the turrets 90 for processing. As embodied herein, the bags 84 are conveyed to a gate 104 adjacent a designated turret 90 with the mouth 88 of the bag facing the turret for loading the bags on a collapsible frame 94. Preferably, suction cups (not shown) grip the top and bottom of the bag 84, as the gate 104 urges the open bag 84 over the collapsed or partially collapsed frame 94, as shown in FIGS. 6d and 6e. The frame 94 acts as a self-centering mechanism, when expanded, enabling the sides and bottom of the bag to be shaped properly, even if the bag is loaded onto the frame 94 so that one of the side seams of the bag is higher than the other, for example. As embodied herein, the collapsible frame 94 includes upper and lower rectangular plates 106, 108 that are interconnected by a hinge mechanism 110. The upper and lower plates 106, 108 are opened (FIG. 6c) and closed (FIG. 6d and 6e) by the hinge mechanism 110, in response to oscillating movement of a drive shaft 112 which is pivotally connected to the hinge mechanism 110. The drive shaft 112 is actuated by an hydraulic system or other conventional means mounted on the turntable 92 and generally designated by reference numeral 114.

As embodied herein and shown generally in FIG. 6a, once a bag is positioned over the upper and lower plates 106, 108, the turret assembly rotates the bag from the loading station I to the flap sealing station II, as shown in FIG. 6f, and the frame 94 is expanded to a fully open state. In accordance with the present invention, the frame 94 is expanded rapidly forming a bag 84 having side walls 96, a bottom surface 98, and a flap 100 of additional material adjacent to the bottom surface 98, as shown in FIG. 6g. Preferably, the force in which the frame 94 is expanded is sufficient to crease the bag along side and bottom edges 116, 116a of the frame 94 shown in FIG. 6f. The frame 94 provides the square bottom configuration, and the creasing defines vertical and horizontal support columns that enable the bag to stand upright once formed.

As embodied herein and shown in FIG. 6f, the flap sealing station II also may include a creasing pads 117 mounted on fixed or movable side frames 117a. The creasing pads 117 engage the bag 84 along the side edges of upper and lower plates 106, 108, thereby reinforcing the creases formed along the sides of the bag when the frame 94 is expanded. The creasing pads 117, which preferably are formed of silicone rubber, may have a planar configuration, or may be a wedge or a disc. The creasing pads 117 also may be heated. As embodied herein and shown generally in FIG. 6f, a sealing assembly is provided for securing to the bag the flap of additional material, which ordinarily forms adjacent the bottom surface, as shown in FIG. 3g, when the frame 94 is expanded. As embodied herein, the flap sealing station II includes an exterior flap sealing unit 118 and an interior flap sealing unit 120, which are mounted on a support structure (not shown) that does not obstruct rotation of the turnstile 92 and its associated equipment, particularly the collapsible frame 94. The exterior flap sealing unit II comprises an exterior sealing pad 122 located adjacent to the periphery of the bag when the collapsible frame 94 is rotated to the flap sealing station II. The sealing pad 122 is pivotally mounted on a housing 124 that contains a heating element 126. A similar exterior flap sealing unit is located adjacent the other flap 100 along the bottom of the bag 84. When the bag 84 arrives at the flap sealing station II, the housing 124 pivots so that the sealing pad 122 engages the flap 100, which is created when the frame is expanded within the tubular material. The flap 100, which typically takes on a triangular configuration, is urged by the sealing pad 122 into contact with the bottom 98 of the bag.

In accordance with the present invention, the interior sealing unit 120 comprises a sealing pad 128 mounted on a retractable arm 130 that is removably inserted through the mouth 88 of the bag 84 and between upper and lower plates 106, 108. The sealing pad 128 is positioned so that it contacts the bottom interior portion 131 of the bag 84, thereby clamping the bottom of the bag 84 and the flap 100 between the interior seal pad 128 and exterior seal pad 122. The interior seal pad 128 may include a heating element for heat sealing the 100 to the bag 84 along the bottom interior portion 131.

While the exterior and interior seal units 118, 120 are shown to heat seal the flap to the bottom surface 98 of the bag, other conventional seals may be provided. For example, it should be readily appreciated that an adhesive (not shown) may be applied to the flap 100 by a separate mechanism before the flap 100 is secured to the bag 84 by the exterior and/or interior sealing units 118, 120. In addition, the seal units 118, 120 may be adapted to sew the flap to the bag. Further, the exterior flap sealing unit 118 may be aligned to secure the flap 100 along the side 96 of the bag 84, as shown in FIG. 7c, or the top portion of the bottom of the bag, as shown in Figure 7g.

In accordance with the present invention, once the flap 100 is sealed to the bag 84, the turret assembly rotates the bag 84 from the flap seal station II to the gusset forming station III. When the turret assembly is rotated to position the bag at the gusset forming station III, the collapsible frame 94 is in the expanded position, as shown in FIG. 6g.

As embodied herein and shown in FIGS. 6b and 6h, the gusset forming station includes a creaser assembly for forming fold lines along the side walls and the bottom surface of the bag enabling the bag to flatten along the fold lines. The creaser assembly, which is generally designated by reference numeral 132, preferably includes an arrangement of creaser bars 134, 136, and 138, as shown in FIG. 6h that are adapted to be disposed around the periphery of the expanded bag. Preferably, the creaser assembly 132 is mounted on a support structure (not shown) that does not obstruct rotation of the turnstile 92 or its associated equipment. For example, the creaser assembly 132 may be positioned lower than the lower plate 108 of the frame 94, when it is fully expanded, as shown in FIG. 6j . After the expanded frame 94 and bag 84 are rotated from the flap sealing station II to the gusset forming station III, the creaser assembly 132 may be raised and positioned so that the creaser bars 134, 136, and 138 are disposed around the periphery of the bag. Preferably, the creaser bars 134, 136 and 138 are raised to a height corresponding to a midpoint 140 between upper and lower plates 106, 108, as shown in FIG. 6k.

As embodied herein and shown in FIGS. 6i, and 61, the creaser bars 134, 136 and 138 are mounted on retractable support arms 142 that enable the creaser bars 134, 136, and 138 to be inserted between the upper and lower plates 106, 108. The creaser bars 134, 136, and 138 are inserted simultaneously or at different times, as desired. Once inserted, the creaser bars 134, 136, and 138 form a seam along the sides and bottom of the bag, while the frame 94 collapses to a partially closed position about the inserted creaser bars 134, 136, and 138. Preferably, the creaser bars 134, which may be heated, form a substantially continuous fold line 144 along the side and bottom surfaces 96, 98 of the bag 84. See FIG. 7a.

As embodied herein, the gusset forming station III also includes holding means for preventing the bag from shifting when the frame 94 is collapsed. The holding means may include upper and lower holding bars 146, 148, as shown in FIGS. 6b and 6i. The present invention also may include a creasing mechanism for further creasing the bag along the periphery 116 of the frame 94.

In accordance with the present invention, after the creasing bars 134, 136, and 138 are withdrawn and lowered, the gusset forming operation is completed. At this point, the collapsible frame 94 is rotated to the unloading station and the bag is taken off the collapsed frame 94 by a suction mechanism (not shown) and an engagement mechanism (not shown), which engage a top portion of the bag 84, and open and slide the gusseted bag 84 off the frame 94. The bag 84 is deposited in a bin (not shown) for stacking. The collapsible frame 94 is then rotated to a fifth station, that is vacant, before returning to the loading station for receiving a new bag. In operation, a substantially flat bag 84 (with or without a handle) having close bottom and open mouth (with or without a handle) is produced by the bag seal and cut section E. The bag 84 is deposited on a conveyor 86 for transfer to a turret 90. Preferably, one or more turrets 90 are aligned along the conveyor, whereby the bag is presented to each turret 90 with the open mouth 88 facing the turret 90. The first bag is stopped by a gate 104 adjacent to the first turret 90 and the first bag is loaded under the first turret 90. Meanwhile, the second and third bags are sent to the second and third turrets 90, respectfully. Thereafter, the fourth bag is sent to the first turret, and the fifth and sixth bags are sent to the second and third turrets, and so forth. When the fourth bag is loaded on to the first turret assembly, the first bag is at the flap seal station.

It is intended that every collapsible frame assembly will be indexed so that it is capable of accommodating a bag. The turret assembly is designed to rotate so that each turret generates approximately 20 bags per minutes. If there is a malfunction or a gate fails to engage and load a bag on the turret assembly, the missed bag would be deposited in a holding area at the end of the conveyor 86, as shown in FIG. 1. The bags can then be loaded on the collapsible frame 94 at the auxiliary or vacant station to avoid any waste.

In accordance with the present invention, the network of components of the present invention perform a number of different functions that are integrally connected and synchronized by software that controls the timing of all the different processing functions. For example, the operation of the gates 104 is controlled so that the gates 104 corresponding to each respective turret 90 load the correct bag in sequence.

The method and apparatus of the present invention, as herein described, produces a collapsible, stand-up plastic bag. With reference primarily to FIG. 7a, the bag includes a substantially planar bottom surface 98 when the bag is open. The bag also includes longitudinal support columns or folds 150 and lateral support columns 151 formed by the expanded frame 94. The longitudinal or vertical support columns 150 extend upward from the bottom surface 98 and hold the bag upright when the bag is opened, as shown in FIGS. 7a-7c. The vertical support columns 150 define and side walls 96 that include front and back surfaces 152, 154 of the bag 84.

The gusset forming station III forms a substantially continuous seam 144 along the bottom and side surfaces 98, 96, of the bag. The substantially continuous seam 144 enables the bag to fold inwardly along the bottom and side surfaces 98, 96, so that the front and back surfaces 152, 154 are substantially fully exposed when the bag is folded. Preferably the seam 144 bisects the bottom and side surfaces 98, 96, enabling the bottom and side surfaces 98, 96 to be substantially concealed when the bag is folded, as shown in FIG. 7d. In a preferred embodiment, the flap 100 is secured to the bottom surface 98 of the bag 84 and provides reinforcement for the bottom surface when the bag is opened.

In accordance with the invention, the stand-up plastic also includes lateral beam support along an upper portion of the bag for preventing it from collapsing inwardly when the bag is opened. As embodied herein and shown in FIGS. 7e and 7f, the lateral beam support includes cuffs 42, 44, formed along the top portion of the bag. The lateral beam support may also include tape 156 securing the cuffs 42, 46 to the interior 158 of the bag. The cuffs 42, 44 may include apertures 160 enabling the tape to be secured through the apertures along the interior wall 158 of bag.

It is desirable to have bags with designs along the front and back surfaces 152, 154. In accordance with the present invention, the bags are designed to fold inwardly along seam 144, thereby allowing the sides and bottom 96, 98 to be substantially concealed, whereas the front and back surfaces 152, 154 are fully visible when folded. As such, any displays or designs on the front or back surfaces 152, 154 are not obstructed by the folding arrangement of the bag.

It will be apparent to those skilled in the art that various modifications and variations can be made in the structure and methodology of the present invention without departing from the spirit or scope of the invention. For example, the flap sealing station II and the gusset forming station III may be consolidated into a single station. Thus, it is intended that the present invention cover modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims

20WHAT IS CLAIMED IS:

1. A process for manufacturing a stand-up plastic bag from a heat sealable material comprising: unwinding a roll of the heat sealable material; conveying the material through an arrangement of rollers; folding the material to form top and bottom sheets; intermittently sealing said top and bottom sheets along a seal line extending transversely relative to a direction of travel of the material when sealed; cutting the material along said seal line to form individual bags having a closed bottom and an open mouth; loading each of said bags on an expandable frame; and shaping said bags interiorly with said frame.

2. The process as defined in claim 1, wherein said shaping step also includes forming a substantially planar bottom surface and support columns extending from said bottom surface.

3. The process as defined in claim 2, also including creasing a fold line along at least said bottom surface for folding each of said bags inwardly along said fold line for stacking each of said bags.

4. The process as defined in claim 1, also including the step of cuffing a top portion of said bag.

5. The process as defined in claim 4, also including the step of forming a handle along said top portion.

6. The process as defined in claim 1, wherein said folding step also includes applying a crease line to the material and folding the material along said crease line.

7. The process as defined in claim 4, also including the step of preheating said top portion before sealing and cutting said top portion.

8. The process as defined in claim l, also including the step of evaluating whether the material is aligned before said sealing and cutting steps.

9. The process as defined in claim 1, wherein said shaping step also includes forming a flap of excess material adjacent said bottom surface, and securing said flap to said bags.

10. An apparatus for manufacturing a stand-up plastic bag comprising: supply means for providing a continuous length of heat sealable material; bag assembly means connected to said supply means for producing a bag from said heat sealable material, said bag having closed sides, a closed bottom and an open mouth; and bag shaping means for receiving said bag from said bag assembly means and having a series of stations for shaping said bag, including: a first station for forming opposed faces, opposed sides and a substantially flat bottom; a second station for creasing at least said bottom, so that said bottom folds inwardly to flatten said bag when stacking two or more of said bags; and a third station for unloading said bag.

11. The apparatus as defined in claim 10, wherein said bag shaping means includes at least one rotatable turret assembly for positioning said bag at each of said series of stations.

12. The apparatus as defined in claim 11, wherein said turret assembly includes means for holding said bag while said turret assembly is rotated to said series of stations.

13. The apparatus as defined in claim 12, wherein said holding means includes a collapsible plate inserted within said bag when said plate is at least partially collapsed, said plate being expanded and collapsed at said series of stations before releasing said bag at said third station.

14. An apparatus for producing a stand-up plastic bag from a length of tubular material having a closed bottom and an open mouth, said apparatus comprising: a shaping assembly for receiving the tubular material and having a series of stations for shaping a bag from the tubular material, said series of stations including: a first station for forming opposed faces, opposed sides and a substantially flat bottom; a second station for creasing at least said bottom so that said bottom folds inwardly to flatten said bag when stacking two or more of said bags; and a third station for unloading said bag.

15. The apparatus as defined in claim 14, wherein said shaping assembly includes at least one rotatable turret assembly for positioning said bag at each of said series of stations.

16. The apparatus as defined in claim 14, wherein said turret assembly includes means for holding said bag while said turret assembly is rotated to said series of stations.

17. The apparatus as defined in claim 16, wherein said holding means includes a collapsible plate inserted within said bag when said plate is at least partially collapsed, said plate being expanded and collapsed at said series of stations before releasing said bag at said third station.

18. An apparatus for producing a stand-up plastic bag from a length of heat-sealable tubular material having a closed bottom and an open mouth, said apparatus comprising: a collapsible frame expanded within the tubular material to define a bag having side walls, a bottom surface, and a flap of additional material adjacent said bottom surface; a sealing assembly for securing said flap to said bag; and a creaser for forming fold lines along said side walls and said bottom surface so that said bag flattens along said fold lines.

19. The apparatus as defined in claim 18, wherein said frame includes a pair of hingedly connected, parallel mounted plates.

20. The apparatus as defined in claim 18, wherein said frame includes a pair of rectangular plates.

21. The apparatus as defined in claim 18, wherein said frame is rapidly expanded under force sufficient to form creases along said side walls and said bottom surface.

22. The apparatus as defined in claim 18, wherein said sealing assembly includes an exterior seal pad movably positioned to urge said flap into contact with said bag.

23. The apparatus as defined in claim 22, wherein said sealing assembly also includes an interior seal pad aligned with said exterior seal pad for clamping said flap therebetween.

24. The apparatus as defined in claim 22, wherein said exterior seal pad includes a heating element for applying a heat seal to secure said flap to said bag.

25. The apparatus as defined in claim 23, wherein said interior seal pad includes a heating element for applying a heat seal to secure said flap to said bag.

26. The apparatus as defined in claim 23, wherein said interior seal pad is mounted on a rectangular arm.

27. The apparatus as defined in claim 18, wherein said flap is triangular.

28. The apparatus as defined in claim 18, wherein said flap is secured to said bottom surface.

29. The apparatus as defined in claim 18, wherein said flap is secured to said side surface.

30. The apparatus as defined in claim 18, wherein said creaser includes creasing bars disposed along said side walls and said bottom surface, said creasing bars being timed to form said fold lines along said side walls and said bottom surface simultaneously.

31. The apparatus as defined in claim 18, wherein said creaser includes creasing bars disposed outside of said bag adjacent said side walls and said bottom surface, said creasing bars being directed into engagement with said bag as said frame is collapsed.

32. The apparatus as defined in claim 18, wherein said frame and said creaser cooperate to form gussets along said side and said bottom surfaces of said bag.

33. The apparatus as defined in claim 18, wherein said creaser includes heated creasing bars.

34. The apparatus as defined in claim 18, wherein said fold lines extend along a center of said side walls and said bottom surface, so that when said bag folds, front and back surfaces of said bag are fully exposed for display.

35. A collapsible, stand-up plastic bag comprising: a substantially planar bottom surface when said bag is opened; support columns extending upward from said bottom surface for holding said bag upright when said bag is opened, said support columns defining front, back and side surfaces of said bag; and a substantially continuous seam along said bottom and side surfaces for folding said bottom and side surfaces inwardly so that said front and back surfaces are substantially fully exposed when said bag is folded.

36. The collapsible, stand-up plastic bag as defined in claim 35, wherein said seam bisects said bottom and side surfaces, so that said bottom and side surfaces are substantially concealed when said bag is folded.

37. The collapsible, stand-up plastic bag as defined in claim 35, wherein said bottom surface is substantially rectangular.

38. The collapsible, stand-up plastic bag as defined in claim 35, also including a reinforcement flap secured to said bottom surface.

39. The collapsible, stand-up plastic bag as defined in claim 35, wherein said support columns include folds extending along a periphery of said front, back and side surfaces of said bag.

40. The collapsible, stand-up plastic bag as defined in claim 35, also including a lateral support member for preventing said bag from collapsing inwardly when said bag is opened.

41. The collapsible, stand-up plastic bag as defined in claim 40, wherein said lateral support member includes a cuff along a top portion of said bag.

42. The collapsible, stand-up plastic bag as defined in claim 40, wherein said lateral support member includes tape secured along a top portion of said bag.

43. The collapsible, stand-up plastic bag as defined in claim 40, wherein said lateral support member includes a cuff and tape combination, whereby said tape secures said cuff to a wall of said bag.

44. The collapsible, stand-up plastic bag as defined in claim 42, also including a handle secured to said bag by said tape.

45. The collapsible, stand-up plastic bag as defined in claim 43, wherein said cuff includes at least one aperture and wherein said tape is secured to said wall of said bag along said aperture.

46. An apparatus for providing a cuff on a continuous length of flexible material used to form a bag, said apparatus comprising: a scoring assembly spaced from an edge of the length of the material for applying at least one score line to the material a predetermined distance from said edge; and means for folding the material along said score line to form the cuff.

47. The apparatus as defined in claim 46, wherein said scoring assembly includes a rotatable knife edge and a scoring bar, wherein the material is passed between said knife edge and said scoring bar.

48. The apparatus as defined in claim 46, wherein sia scoring assembly includes spring means for applying tension to the material along said score line.

49. The apparatus as defined in claim 48, wherein said scoring assembly includes adjustment means for adjusting the tension applied to the material.

50. The apparatus as defined in claim 46, wherein said folding means includes an arrangement of roll bars.

51. The apparatus as defined in claim 46, wherein said folding means includes an arrangement of fixed and rotatable bars.