Gusseted zipper bag

Abstract: A zipper bag (10) contains interlocking profiles (30,32) on the front and rear walls (14,16) of the bag. The bag further has gusseted side walls (18) that include portions (36) aligned with the interlocking profiles (30,32) that are relatively thin as compared with the remainder of the bag walls. The thinned sections may be profile-free portions of a carrier web (24) for the profiles (30,32). Windows (36) are cut out of the sidewalls (18) and covered by the profile free sections of the carrier web (24). These thin portions (36) are then captured between the profiles (30,32) when the bag is closed.

Description: The present invention relates to gusseted reclosable plastic bags and, in particular to zipper bags made of barrier films, wherein the gusset can be fully opened and the zipper can fully close the bag Heretofore reclosable plastic bags have been provided with gusseted sides. Advantages of such gusseted bags is that they may be opened more fully to facilitate filling and emptying, and the gusset may be inverted to form a pouring spout. In previous concepts for such bags, the profiles of the zipper had to be sufficiently large to capture a double thickness of the bag film in order to accommodate the gussets. This results in a construction that was generally not acceptable in applications where barrier films were required. The problem becomes more acute the more complex the film and hence, the thicker the bag walls. Such a gusseted reclosable bag is known from EP-A-1 020 369, in accordance with the preamble of claim 1. In accordance with the present invention a bag is provided having front and rear walls and gusseted side walls. Mating zipper profiles are provided on the front and rear walls respectively and a thinned wall section is provided in the gusset portions aligned with the zipper profiles. The thinned gusset wall portions may be provided in different manners. The portions of the bag film material forming the gussets may be physically thinned in the areas aligned with the profiles. Alternatively, windows may be cut in the plastic film material of the gussets in the areas aligned with the profiles, with the windows, in turn, being covered by thin film segments. The gusset windows may be covered by separate strips of thin film which is free of profiles. Alternatively, the zipper profiles may be provided on a thin carrier strip wherein segments of profiles are separated from each other by a distance equal to that of the length of the windows. The carrier strip may then be attached to the bag wall, with the profile free portions of the strip covering the window openings. The gussets may be open at both opposite ends of the bag or may be sealed together at one end to provide a spout at the opposite end. A particular embodiment in accordance with this invention will now be described with reference to the accompanying drawings; in which:- Fig. 1 is a perspective view of a gusseted bag in accordance with the present invention; Fig. 2 is a top plan view of a partially zippered carrier strip used in forming the bag of Fig. 1; Fig. 3 is a side elevation view of the bag of Fig. I with the gusseted area open; Fig. 4 is a sectional view taken along reference lines 4-4 of Fig. 3; Fig. 5 is a side elevation view of the bag of Fig. 1 with the gusseted area closed; Fig. 6 is a sectional view taken along reference lines 6-6 of Fig. 5; Fig. 7 is a fragmentary perspective view of the bag of the present invention with a side gusset partially closed; and, Fig. 8 is a perspective view of the gusset bag of the present invention wherein the top of one of the gusseted sides is sealed and the opposite side is inverted to form a pouring spout. Reference is now made the drawings and to Fig. 1 in particular wherein a gusseted bag 10 in accordance with the present invention is depicted comprising a bottom 12 (which may or may not be gusseted), a front wall 14, rear wall 16 and gusseted side walls 18 and 20. The top end 22 of the bag is open and closed by a zipper 24. A peel seal 26 may be provided below (or above) the zipper to provide pilfer evidence and/or to permit hermetic sealing. Zipper sections 24 are attached on a carrier web whose construction is depicted in Fig. 2 and consists of a carrier web 28 upon which sections of zipper with profiles 30, 32 are laid out between profile-free zones 34. The profiles 30, 32 may be male and female profiles or both may be unisex. What is important is that profile section 30 be capable of interlocking with profile section 32. The carrier web 28 is formed of plastic film that is relatively thin with respect to the walls of the bag so as to enable the profile-free zones to be readily captured between portions of the profiles 30, 32 when interlocked. Reference is now made to Figs. 3 and 4 wherein the zipper and carrier web 28 is depicted in position on the bag body. Referring to Fig. 3, a side 18 of the bag 10 is depicted with the gusset fully open. As can be seen, a window 36 is cut in each of the side walls extending from edge to edge of the respective sides. The edges 38, 40 of the zipper and carrier web 28 are sealed about the bag so that window 36 of one side wall is covered by one zipper profile free portion 34 of the carrier web 28 and the opposite side wall is covered by the next profile-free portion 34. The top and bottom marginal portions 38, 40 of the carrier web 28 are also sealed to the front and rear walls of the bag so that one of the zippers with profile portions 30 of the zipper carrier web extends along the interior of the front wall and the other of the zippers with profile portions 32 of the zipper carrier web extends across the rear wall. The zipper profile free portions 34 of the carrier web extend across the gusset side walls 18, 20 in line with the profiles and cover the windows 36 and 40 cut outs of the gusset side walls. Referring to Figs. 5, 6 and 7 it can be seen that as the gusseted side walls are closed, by folding the gussets inward about the gusset folds 50, 52, the profile free portions 34 of the carrier web are captured between the zipper profiles 30, 32 at their ends 42, 44 and 46, 48. Since the carrier web is relatively thin with respect to the remainder of the bag walls, the gusseted sides are accommodated within the interlocked profiles with relative ease. If desired, after capturing one of the profile free areas of the carrier strip within the associated profiles, as discussed above, the front 14 and rear 16 walls of the bag may be sealed to one another through the profiles and profile free area of the gusset side wall 20 at a side seal 53. The gusset at the other side 18 may then be fully opened and inverted, as shown in Fig. 8 to form a convenient pour spout 54 for the bag.

Claims: A reclosable plastic bag (10) comprising: a front wall (14); a rear wall (16); and gusseted walls (18,20) on opposite sides of said bag interconnecting said front (14) and rear (16) walls; first and second interlocking zipper profiles (30,32) extending between said side walls (18,20) respectively positioned below the tops of said front (14) and rear (16) walls; characterized in that each of said gusseted side walls (18,20) comprises a major section having a first thickness substantially the same as that of said front and rear walls (14,16) and a minor section having a thickness less than said first thickness, said minor sections extending on said side walls between said front and rear walls (14,16) and being aligned with said interlocking profiles (30,32) whereby when said gussets are collapsed, portions of said minor sections of the gusseted walls (18,20) are captured between said interlocking profiles (30, 32). A bag according to claim 1, wherein portions of said bag side walls (18, 20) are cut out to form window openings (36) extending between said front and rear walls (14,16), said window openings (36) being covered by a carrier web (28) of film material, said film material defining said minor sections of said gusseted walls. A bag according to claim 2, wherein said carrier web (28) further includes sections attached to said bag front and rear walls (14,16) and said first and second profiles (30,32) are affixed respectively to said carrier web portions affixed to said front and rear walls (14,16). A bag according to any one of the preceding claims, further comprising a peel seal (26) joining said bag front and rear walls (14,16). A bag according to claim 4, wherein said peel seal (26) is positioned below said interlocking profiles (30,32). A bag according to any one of the preceding claims, wherein at one side of said bag (10) said front and rear walls (14,16) are further sealed to one another through said interlocking profiles (30,32). A bag according to any one of claims 1 to 5, wherein at one side of said bag said front and rear walls (14,16) are further sealed to one another adjacent said interlocking profiles (30,32).

Inventors: AUSNIT STEVEN, AUSNIT, STEVEN
Applicants: ILLINOIS TOOL WORKS, ILLINOIS TOOL WORKS INC.
Application year: 2001
Main classification: B65D33
IPC codes: B65D33, B65D30