Stand up bag and method of manufacturing the same

Abstract

A method for manufacturing a stand up bag having an indented bottom wall includes the steps of forming a tube of material and sealing the end of the tube. The sealed end is then moved up with respect to the sidewall to form a downwardly-extending rim. Portions of the rim are then welded to hold the bottom wall in this position.

Description

BACKGROUND OF THE INVENTION

[0002] 1. Technical Field

[0003] The present invention generally relates to storage containers in the field of flexible bags and, more particularly, to stand-up bags having indented bottom walls. Specifically, the present invention relates to stand-up bags that are fabricated from a flexible material wherein the bottom wall of the bag is reformed into an indented cup with a welded downwardly-projecting rim.

[0004] b 2. Background Information

[0005] Various products such as snack foods are sold to consumers in thin-walled flexible bags fabricated from a polymer material. These bags are typically formed from a tube of material that is sealed with spaced flanges. The storage compartment between the flanges is filled with the product.

[0006] An undesirable aspect with these bags is that the lower sealed flange prevents the bag from standing in an upright position. The bag thus tips over on its side after it has been opened. The users of these bags desire a bag configuration that will stand on end after the bag is opened.

[0007] Different types of stand up bags are known in the art. One type of stand up bag is fabricated from a relatively thick foil material with protruding flanges extending from opposed sides of the bag. Such bags have gained acceptance for certain products but are generally undesirable because the thick material cannot be used for snack food bags without undesirably increasing the cost of the bag. The art thus desires a stand up bag structure and a method for manufacturing the stand up bag wherein the bag may be formed from a relatively inexpensive, thin material.

BRIEF SUMMARY OF THE INVENTION

[0008] One embodiment of the invention provides a stand up bag having an indented, cup-shaped bottom wall that allows the bag to stand up. A lower rim is formed between the bottom wall and the sidewall. Portions of the rim are welded so that the bottom wall is held in its indented position. The invention provides numerous different weld patterns for the lower rim.

[0009] Another embodiment of the invention provides a method for manufacturing a stand up bag having an indented bottom wall. The method includes the steps of forming a tube of material and sealing the end of the tube. The sealed end is then moved up with respect to the sidewall to form a downwardly-extending rim. Portions of the rim are then welded to hold the bottom wall in this position.

[0010] A further embodiment of the invention provides an apparatus for forming a stand up bag having an indented bottom wall. The invention provides three embodiments of the apparatus for reforming the bottom wall into the indented cup. Each embodiment of the apparatus generally includes a bottom former, an inside dome former, and a reform welder that cooperate to reform the bottom wall and to weld the lower rim to hold the bottom wall in place.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0011] FIG. 1 is a perspective view of the stand up bag of the present invention.

[0012] FIG. 2 is a front view of FIG. 1.

[0013] FIG. 3 is a side view of FIG. 1.

[0014] FIG. 4 is a bottom view of FIG. 1.

[0015] FIG. 5 is a section view taken along line 5-5 of FIG. 4.

[0016] FIGS. 6A-6D shown four different exemplary shapes for the bag of the invention.

[0017] FIGS. 7A-7D show four different exemplary weld patterns for an oval-shaped bag.

[0018] FIG. 8 is a front view of the first embodiment of the apparatus for forming the stand up bag of the invention.

[0019] FIG. 9 is another front view of the apparatus for the stand up bag of the invention.

[0020] FIG. 10 is a top view of a portion of the apparatus.

[0021] FIG. 11 is a perspective view of the reform collar used to form the rim of the bag.

[0022] FIG. 12 is a front view showing the first step of the first embodiment of the method of the invention.

[0023] FIG. 13 is a front view showing the second step of the first embodiment of the method of the invention.

[0024] FIG. 14 is a front view showing the third step of the first embodiment of the method of the invention.

[0025] FIG. 15 is a front view showing the fourth step of the first embodiment of the method of the invention.

[0026] FIG. 16 is a front view of the second embodiment of the apparatus for forming the stand up bag of the invention.

[0027] FIG. 17 is a front view showing the first step of the second embodiment of the method of the invention.

[0028] FIG. 18 is a front view showing the second step of the second embodiment of the method of the invention.

[0029] FIG. 19 is a front view showing the third step of the second embodiment of the method of the invention.

[0030] FIG. 20 is a front view showing the fourth step of the second embodiment of the method of the invention.

[0031] FIG. 21 is a front view showing the first step of the third embodiment of the method of the invention.

[0032] FIG. 22 is a front view showing the second step of the third embodiment of the method of the invention.

[0033] FIG. 23 is a front view showing the third step of the third embodiment of the method of the invention.

[0034] FIG. 24 is a front view showing the fourth step of the third embodiment of the method of the invention.

[0035] Similar numbers refer to similar parts throughout the specification.

DETAILED DESCRIPTION OF THE INVENTION

[0036] A first embodiment of the stand up bag according to the present invention is indicated generally by the numeral 10 in the accompanying drawings. Bag 10 includes a continuous sidewall 12 and an indented bottom wall 14 that cooperate to define a storage compartment for holding items. As shown in FIG. 5, bottom wall 14 is disposed transverse to sidewall 12 and may be substantially perpendicular to the portions of sidewall 12 adjacent bottom wall 14. The structure of bottom wall 14 allows bag 10 to stand in an upright configuration without tipping over. Bag 10 may have any of a variety of shapes such as the exemplary oval shape shown in the drawings. In other embodiments, the cross section (looking down along the longitudinal axis of the bag) of bag 10 may be rectangular, diamond, or round as shown in FIGS. 6A-6D. Other bag shapes are also within the scope of the invention.

[0037] A downwardly projecting rim 16 is formed between sidewall 12 and bottom wall 14. Rim 16 is welded with a plurality of welds 18 that hold the shape of rim 16 and indented bottom wall 14 while bag 10 is in use. Welds 18 also keep bottom wall 14 disposed substantially perpendicular to sidewall 12. In one embodiment of the invention, bottom wall 14 is indented 1 ½ inches with respect to sidewall 12 as indicated by dimension line 20 in FIG. 5. The 1 ½ inch indentation dimension (20) has been found to function well with medium, large, and oversize snack food bags. Other indentation dimensions will also function with bag 10. For instance, the indentation dimension may be as short as ¼ inch and as tall as 2½ inch.

[0038] Bag 10 may be provided in a wide variety of shapes and rim 16 may be welded in a wide variety of weld configurations. FIGS. 6A-6D show bottom views of different shapes of bag 10. FIG. 6A shows oval. FIG. 6B shows rectangular. FIG. 6C shows diamond and FIG. 6D shows a round bag. In each of these drawings, the thick line along rim 16 represents the location of weld 18 with each drawing representing one of the variety of possible weld patterns that may be used to hold rim 16 in position. FIGS. 7A-7D show four weld patterns used with an oval bag. Each of these weld patterns may be used with each of the shapes depicted in FIGS. 6A-6D and any bag shapes known to those skilled in the art. In the exemplary embodiment, the ratio of the total weld lengths to the perimeter of rim 16 should be about 75 percent. In other embodiments of the invention, the ratio may be as small as 5% and as large as 95%. Small pinch welds may be used that are not long in length.

[0039] Bag 10 further includes a top closure seam 30 and a bottom closure seam 32. Seams 30 and 32 may be positioned with respect to welds 18 as shown in the drawings or turned at any of a variety of angles with respect to welds 18.

[0040] Bag 10 may thus stand on rim 16 or bottom wall 14. Sidewall 12 is formed from a continuous tube or a tube formed with a longitudinal overlap seam so that sidewall 12 does not have any protruding flanges. Bag 10 may be fabricated from any of the weldable materials known in the art of manufacturing snack food bags. The structure of the invention allows stand up bag 10 to be manufactured from a thin, flexible chip-bag material.

[0041] A first embodiment of the apparatus 100 for manufacturing bag 10 is depicted generally in FIGS. 8-11 for the purpose of introducing some of its elements. FIGS. 8 and 9 depicts a front view of apparatus 100 with some elements depicted in section and other elements exploded for clarity. Apparatus 100 generally includes a collar 102 that extends down from the end of a former 104. Former 104 is used to form a tube 106 (see for example FIG. 12) of material that is used to form the walls of bag 10. The use of former 104 and the process of making tube 106 is known to those skilled in the art and will not be described here in detail. Collar 102 has a cross section that generally matches the shape of former 104 and thus generally matches the shape of the cross section of bag 10. In the exemplary embodiment of the invention depicted in FIGS. 8-11, collar 102 is round and is used to form round bags 10 as shown in FIG. 6D.

[0042] Collar 102 is used to form rim 16 by bending the material of bag 10 over collar 102. The upper portion 110 of collar 102 is connected to former 104 with the lower portion 112 of collar 102 extending down free of former 104 so that the material of tube 106 may be wrapped around lower portion 112. The body of lower portion 112 defines a plurality of weld openings 114 positioned at the locations where welds 18 will be formed in rim 16. Openings 114 allow welders 120 to weld the desired areas of rim 16 during the process of forming bag 10.

[0043] Welders 120 are carried by a first base member 118. Base member 118 may include several elements as shown in the drawings. For instance, base member 118 may include the lower plate and an outer ring. Base 118 is divided into halves that move apart to allow bag 10 to pass through base 118 as described in more detail below. In other embodiments of the invention, base 118 may be divided into other numbers of elements such as three, four, five, etc. The structure and operation of welders 120 are known to those skilled in the art. Welders 120 are generally configured to melt the material of bag 10 without burning and without melting a hole in the material. Welds 18 thus do not break the integrity of bag 10 such that bag 10 remains hermetically sealed.

[0044] In the exemplary embodiment of apparatus 100, each welder 120 is movable between a resting position and a welding position with welder 120 being biased toward the resting position. Welder 120 may be biased with a spring or other mechanism known to those skilled in the art.

[0045] A guide 122 (FIG. 12) is associated with each welder 120. Each guide 122 is mounted to first base 118. Base 118 may include blocks or define an opening that defines a slide path for guide 122. Each guide 122 is movable between first and second positions within the slide path defined by base 118. When guide 122 is in the first position, welder 120 is in the resting position. As guide 122 moves to the second position, welder 120 is moved inwardly to the welding position. In the exemplary embodiment of the invention, each guide 122 includes an angled surface 124 that engages a corresponding angled surface 126 defined by a portion of welder 120. The engagement of angled surfaces 124 and 126 as guide 122 moves upwardly cause welder 120 to move inwardly. This configuration allows the movement and positioning of welders 120 to be precisely controlled and adjusted. The movement of guides 122 may be controlled by any of a variety of actuators (not shown) and linkages as are needed. For instance, an actuator may be associated with each guide 122 or a suitable linkage may be provided that links each guide 122 to a single actuator. In other embodiments, guides 122 may be removed and the movement of welders 120 may be achieved directly with actuators.

[0046] Apparatus 100 further includes a dome former 130 that helps form bottom wall 14 during the reform process. Dome former 130 may be mounted to base 118. Former 130 is aligned with collar 102 and may be concentric with collar 102 so that they may cooperate during the reform process described below. Dome former 130 includes a sidewall 132 having a straight lower portion and a curved portion that merges with a relatively flat upper wall 134. Sidewall 132 is aligned with welders 120 so that portions of rim 16 may be pinched between or pinched adjacent sidewall 132 and welder 120 to form welds 18. The thickness of dome former 130 is substantially equal to the height of bottom wall 14 as indicted by dimension 20 in FIG. 5.

[0047] Dome former 130 is divided into the same number of pieces as base 118 so that former 130 may be moved out of the way as described below. In the exemplary embodiment, dome former 130 is divided into two pieces.

[0048] Apparatus 100 further includes a set of upper seal welding jaws 140 and a set of bottom seal welding jaws 142. Jaws 140 and 142 include opposed members that are adapted to cooperate to form seals 30 and 32. Upper seal welding jaws 140 are used to form seal 32 while bottom seal welding jaws 142 are used to form seal 30. Jaws 140 and 142 may also be used to sever the material of tube 106. The structure and operation of jaws 140 and 142 are known to those skilled in the bag forming art.

[0049] In apparatus 100, base 118 is configured to be moved upwardly toward collar 102 with actuators 150 such as the air cylinders depicted in the drawings. Base 118 rides on guides 154 between the disengaged position depicted in FIGS. 12, 14, and 15 and the engaged position depicted in FIG. 13. In the engaged position, collar 102 is disposed adjacent wall 132 where welders 120 may be moved inwardly to the welding position where the inner end of welder 120 is disposed adjacent wall 132. Welders 120 and dome former 130 move with base 118 between these positions.

[0050] A first method for forming bag 10 is depicted in FIGS. 12-15 and is performed with apparatus 100. In FIG. 12, a finished bag 10 is depicted at the bottom of the drawing with the lower portion of another bag beginning to be formed. At this point, bottom seal welding jaws 142 have just cut bag 10 away from tube 106 so that the next bag may be formed.

[0051] In this position, welders 120 and dome former 130 are spaced from collar 102 in the disengaged position. Tube 106 has been drawn over former 104 and collar 102 with a portion of tube 106 being positioned between jaws 140 and 142. Jaws 140 and 142 clamp together to form seals 30 and 32 and to sever tube 106 between seals 30 and 32. After tube 106 is cut to form bag 10 at the bottom of the page, jaws 140 and 142 are opened slightly (such as ⅛th inch) to allow the lower bag to drop from apparatus 100.

[0052] At this point, the material 160 that is being placed into bags 10 starts filling the bag being formed through former 104 and collar 102. Actuators 150 then start moving dome former 130 and welders 120 up toward the engaged position depicted in FIG. 13. Dome former 130 bends tube 106 around the lower edge of collar 102 to form rim 16. Welders 120 are then moved to the welding position to form welds 18.

[0053] After welds 18 are formed, welders 120 and jaws 140/142 move down to the disengaged position while moving to an open position as depicted in FIG. 14. Tube 106 continues to move down through these open elements while material 160 continues to be dispensed. Tube 106 moves down until an appropriate amount of material 160 has been dispensed. Tube 106 then continues to move to provide slack for jaws 140 and 142. Once enough slack is provided, jaws 140 and 142 move inwardly to form seals 30 and 32 and to cut the finished bag 10 from tube 106 as depicted in FIG. 15.

[0054] The second embodiment of the apparatus of the present invention is indicated generally by the numeral 200 in FIGS. 16-20. Apparatus 200 includes many of the same elements as apparatus 100 and the same reference numbers are used to identify these elements. Apparatus 200 differs from apparatus 100 in that welders 120 and dome former 130 do not move up and down and actuators 150 and guides 154 have been removed. In apparatus 200, collar 102 and former 104 move down from the disengaged position of FIG. 17 to the engaged position of FIG. 18 to form welds 18.

[0055] A second method for forming bag 10 is depicted in FIGS. 17-20 and is performed with apparatus 200. In FIG. 17, a finished bag 10 is depicted at the bottom of the drawing with the lower portion of another bag beginning to be formed. At this point, bottom seal welding jaws 142 have just cut bag 10 away from tube 106 so that the next bag may be formed.

[0056] In this position, welders 120 and dome former 130 are spaced from collar 102 with collar 102 in the disengaged position. Tube 106 has been drawn over former 104 and collar 102 with a portion of tube 106 being positioned between jaws 140 and 142. Jaws 140 and 142 clamp together to form seals 30 and 32 and to sever tube 106 between seals 30 and 32. After tube 106 is cut to form bag 10 at the bottom of the page, jaws 140 and 142 are opened slightly to allow the lower bag to drop from apparatus 100.

[0057] At this point, the material 160 that is being placed into bags 10 may start entering the bag through former 104. An actuator (not shown) then starts moving collar 102 and former 104 down from the disengaged position to the engaged position depicted in FIG. 18. Dome former 130 bends tube 106 around the lower edge of collar 102 to form rim 16. Welders 120 are then moved to the welding position to form welds 18.

[0058] After welds 18 are formed, collar 102 and former 104 moves up to the disengaged position while jaws 140 and 142 and welders 120 move to an open position as depicted in FIG. 19. Tube 106 continues to move down while material 160 continues to be dispensed. Tube 106 continues to move down until an appropriate amount of material 160 has been dispensed. Tube 106 then continues to move to provide slack for jaws 140 and 142. Once enough slack is provided, jaws 140 and 142 move inwardly to form seals 30 and 32 and to cut the finished bag 10 from tube 106 as depicted in FIG. 20.

[0059] The second embodiment of the apparatus of the present invention is indicated generally by the numeral 300 in FIGS. 21-24. Apparatus 300 includes many of the same elements as apparatus 100 and the same reference numbers are used to identify these elements. Apparatus 300 differs from apparatus 100 and 200 in that both welders 120 and dome former 130 move up with collar 102 and former 104 moving down.

[0060] A third method for forming bag 10 is depicted in FIGS. 21-24 and is performed with apparatus 300. In FIG. 21, a finished bag 10 is depicted at the bottom of the drawing with the lower portion of another bag beginning to be formed. At this point, bottom seal welding jaws 142 have just cut bag 10 away from tube 106 so that the next bag may be formed.

[0061] In this position, welders 120 and dome former 130 are spaced from collar 102 with collar 102 in the disengaged position. Tube 106 has been drawn over former 104 and collar 102 with a portion of tube 106 being positioned between jaws 140 and 142. Jaws 140 and 142 clamp together to form seals 30 and 32 and to sever tube 106 between seals 30 and 32. After tube 106 is cut to form bag 10 at the bottom of the page, jaws 140 and 142 are opened slightly to allow the lower bag to drop from apparatus 100.

[0062] At this point, the material 160 that is being placed into bags 10 may start entering the bag through former 104. An actuator (not shown) then starts moving collar 102 and former 104 down from the disengaged position to the engaged position depicted in FIG. 22. At the same time, actuators 150 move dome former 130 and welders 120 up toward the engaged position depicted in FIG. 22. Dome former 130 bends tube 106 around the lower edge of collar 102 to form rim 16. Welders 120 are then moved to the welding position to form welds 18.

[0063] After welds 18 are formed, collar 102 and former 104 move up to the disengaged position while jaws 140 and 142 and welders 120 move to an open position as depicted in FIG. 23. Tube 106 continues to move down while material 160 continues to be dispensed. Tube 106 continues to move down until an appropriate amount of material 160 has been dispensed. Tube 106 then continues to move to provide slack for jaws 140 and 142. Once enough slack is provided, jaws 140 and 142 move inwardly to form seals 30 and 32 and to cut the finished bag 10 from tube 106 as depicted in FIG. 20.

[0064] Each of these methods forms bags at a rate that is only slightly slower than—or the same as—prior art bag manufacturing processes. The methods allow rim 16 to be formed while the bag is being filled with material 160 so that extra time is not needed for the welding step.

[0065] In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed.

[0066] Moreover, the description and illustration of the invention is an example and the invention is not limited to the exact details shown or described.

Claims

1. A method of forming a bag comprising the steps of: (a) providing a tube of material that will be used to form the body of the bag; (b) closing a portion of the tube to form the bottom closure seam of the bag; (c) indenting the bottom closure seam of the bag with respect to the tube to define a rim and a bottom wall; and (d) welding at least one portion of the rim.

2. The method of claim 1, further comprising the step of filling the tube with material after step (b).

3. The method of claim 2, further comprising the step of filling the tube with material during step (c).

4. The method of claim 2, further comprising the step of filling the tube with material during step (d).

5. The method of claim 1, wherein step (d) includes the step of welding a plurality of spaced locations about the rim.

6. The method of claim 1, wherein step (c) includes the steps of: providing a bottom former; and moving the bottom former up into the tube.

7. The method of claim 1, wherein step (c) includes the steps of: providing a bottom former; and moving the tube down onto the bottom former.

8. The method of claim 1, wherein step (c) includes the steps of: providing a bottom former; and simultaneously moving the tube down onto the bottom former and moving the bottom former up into the tube.

9. The method of claim 1, further comprising the steps of: providing a former that performs step (c); and passing the filled tube through the former after step (d).

10. The method of claim 1, further comprising the steps of: passing the tube of material over a collar that defines a plurality of weld openings; and welding the rim portions at the weld openings of the collar.

11. A method of forming a bag comprising the steps of: (a) forming a tube of weldable material having a leading end; (b) sealing the leading end to itself to form the bottom closure seam of the bag; (c) filling the tube with material to provide a filled tube; (d) indenting the bottom closure seam with respect to the tube of material to define a rim and a bottom wall of the bag; (e) welding a plurality of rim portions to create a plurality of spaced welds along the rim; and (f) sealing another portion of the tube of material to form the top closure seam of the bag and a sealed filled bag.

12. The method of claim 11, wherein step (d) occurs during step (c).

13. The method of claim 11, wherein step (f) of one bag simultaneously performs step (b) for the next bag to be formed.

14. The method of claim 11, further comprising the steps of: sealing the leading end of the tube of material with a welding jaws; and passing the filled tube through the welding jaws after step (d).

15. The method of claim 11, further comprising the steps of: passing the tube of material over a collar that defines a plurality of weld openings; and welding the rim portions at the weld openings of the collar.

16. The method of claim 15, further comprising the steps of: providing a welder for each weld; and moving the welder during step (e) in a direction substantially transverse to the longitudinal direction of the tube of material.

17. The method of claim 11, further comprising the steps of: providing a former that performs step (d); and passing the filled tube through the former after step (d).

18. The method of claim 11, wherein step (d) includes the steps of: providing a bottom former; and moving the bottom former up into the tube.

19. The method of claim 11, wherein step (d) includes the steps of: providing a bottom former; and moving the tube down onto the bottom former.

20. The method of claim 11, wherein step (d) includes the steps of: providing a bottom former; and simultaneously moving the tube down onto the bottom former and moving the bottom former up into the tube.