MXPA00002003A - Thermoplastic bag with offset fastener - Google Patents

Abstract

A reclosable thermoplastic bag (10) having an offset fastener. The bag includes first and second sidewalls (11, 12), each having a top (23a, 23b), a bottom (25a, 25b) and two opposing side edges (16, 17), the first and second sidewalls being attached together along the respective bottom and side edges;and inwardly folded top pleat (13) positioned across the first sidewall (11);a reclosable fastener (14) having at least two cooperating closure members, one closure member being positioned proximate to the top of the first sidewall above the pleat, the other closure member being positioned proximate to the top of the second sidewall, such that when the bag is filled and closed, the reclosable fastener is offset.

Description

OP THIN BAG WITH DISPLACED BRA TECHNICAL FIELD The present invention relates to a resealable thermo-plastic bag. TECHNICAL BACKGROUND Re-closed thermoplastic bags have a wide variety of applications, most notably in the food industry. The bags typically comprise two opposite side walls joined together along side edges and the bottom to form the sides and bottom of the bag. The bags also include a reclosable fastener along the top portions of the side walls, or the mouth of the bag. Sometimes there is a fold at the bottom of the bag that helps to expand the volume available for storage. Typically, the reclosable fastener extends along the center line of the mouth of the bag. That is, when viewed from the top of the bag, the reclosable fastener would be placed directly through the center. However, when the bag is filled and closed, the reclosable fastener along the center line of the mouth tends to catch up by passing the side edges of the bag. This presents a problem when the bag is inserted into a secondary container such as a box, since the stator is too tight on the outside, so that the bag does not fit easily into the fitted container. Modifications have been made in order to make the bags more convenient as linings. For example, U.S. Patent No. 34,317, issued to Van Erden et al., Describes a bag having oblique seals at the four corners of the bag, so that the four corners do not interact with the bag. Easy reception and the packaging of the bag fits in a very narrow fit cardboard. Another example is U.S. Patent No. 5,275,491, issued to Kuge et al, which describes a bag having inward bends that extend vertically downward along the side edges of the bag. Moreover, U.S. Patent No. 5,080,253 issued to Zie e discloses a cropped or oblique upper section of the bag as well as folds along the sides of the bag. One problem with these modifications for the fastener is that when the mouth of the bag is open, the available area is restricted, it being relatively difficult to fill the bags. In the resealable bags mentioned above, the reclosable fastener is disposed along the center line of the mouth of the bag. The problem with these fasteners disposed along the centerline is that when the bag is filled, the fasteners protrude from the sides of the bag, making undesirable bags like liners for narrow fitting containers. That is, in order to use these bags as container liners, the containers must be larger than necessary to allow the fastener to fit inside the containers, thus wasting space inside the container. Also, if the clip is cut so that it does not protrude, then the bag may become difficult to fill because the opening of the mouth is restricted. It would be a breakthrough in the technique of reclosable thermoplastic bags to provide a bag that is conveniently used as a liner for a narrow fit container and at the same time have a relatively unrestricted mouth opening when the bag is opened. COMPENDIUM OF THE INVENTION The present invention provides an alternative to prior art bags. In one aspect, the present invention is a reclosable thermoplastic bag comprising first and second side walls, each having an upper part, a lower part and two opposite side edges, the first and second side walls being joined together along the side edges and approximately to the bottom; a top fold from one side inward positioned through the first side wall; a reclosable fastener having at least two cooperating lock members, a lock member positioned near the top of the first side wall above the fold, and the other lock member positioned near the top of the second side wall, so that when the bag is filled and closed, the reclosable fastener is displaced. In a second aspect, the present invention is a reclosable thermoplastic bag comprising two side walls, each having an upper edge, a lower edge and two opposite side edges, the side walls being joined together as length of the lateral edges and approximate to the bottom; an upper fold bent inwardly extending laterally between the side edges in one of the side walls; a reclosable fastener placed near the top to the side walls above the fold, so that when the bag is filled and the reclosable fastener is closed, the reclosable fastener It is displaced. An important advantage of the bag of the present invention is that the reclosable fastener is offset, so that it extends along the perimeter of the bag instead of along the center line. As a result, the reclosable fastener does not snap off the sides of the bag and does not need to be cut to fit inside a narrow fit container. This allows a better use of the bag as a liner, while still maintaining the entire area of the mouth opening to be available to fill the bag. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a filled bag of the present invention in an extended condition. Figure 2 is a front plan view of a bag of the present invention. Figure 3 is a cross-sectional view of a bag in a collapsed state taken along line 3-3 of Figure 2, showing the upper and lower pleats forming the present invention. Figure 4A and 4B are top views of bags embodying the present invention. BEST WAY TO CARRY OUT THE INVENTION Figure 1 shows a thermoplastic bag B of the present invention. The bag 10 includes the opposite side walls 11 and 12, an inwardly folded upper fold 13, and a reclosable fastener 14. In the embodiment shown, the bag 10 also includes a lower fold 15.

The bag 10 may be made of any thermoplastic film such as, for example, low density polyethylene, linear low density polyethylene, substantially linear copolymers of ethylene and an α-olefin with 3 to 8 carbon atoms, polypropylene, polyvinylidene, mixtures of two or more of these polymers, or mixtures of one or more of these polymers with another thermoplastic polymer. The thermoplastic film can have any desired thickness. Preferably the thickness of the film is greater than about 0.0127 millimeters, more preferably greater than about 0.019 millimeters, and more preferably greater than about 0.0254 millimeters. Preferably, the thickness of the film is less than about 0.254 millimeters, more preferably greater than about 0.19 millimeters, and more preferably less than about 0.127 millimeters. Each side wall 11 and 12 has an upper part 23a, 23b, a lower part 25a, 25b, and two edges of opposite sides. The upper parts of the side walls form a mouth 27 of the bag 10. The side edges of the side walls are common and are sealed together to form common side seals 16 and 17. The side seals can be formed by any desired means, such as, for example, pulse bonding, hot wire sealing, hot knife sealing, bending, using an adhesive, or any other desired means. The side walls 11 and 12 also adjoin one another along the bottom 25 of the bag 10 by any desired means such as, for example, impulse sealing, hot wire sealing, hot knife sealing, bending, using an adhesive, or any other desired medium. An important feature of the present invention is the upper fold 13 which is placed laterally together with the width of at least one of the side walls 11. Preferably, the upper fold 13 is placed close to the top of the side wall 11. " Near the top "of the upper part is defined herein as being closer to the upper part 23a of the side wall 11 than to the lower part 25. The upper fold 13 is simply an inward fold extending laterally across the width of the side wall 11. The upper fold 13 is an inward fold as opposed to an outward fold, which means that it forms a bag inside the side wall 11, as opposed to a flange that would exceed the side wall when in collapsed condition, illustrated in Figure 3. The upper fold 13 allows the side wall 11 to effectively extend in relation to the wall l 12 and thereby extend outwardly further than the side wall 11 would extend without bending as illustrated in Figures 1, 4a and 4b. In this way, when the bag is filled and the fold 13 extends, the inner fold 13a of the upper fold 13 becomes the center line C of the bag, as opposed to the fastener 14. In this way, the fastener that can be reclosing 14 shifts from its initial center position illustrated in Figure 3 when bag 10 collapses to a displaced position illustrated in Figures 1, 4a and 4b when the bag is filled and extended, as opposed to being disposed of. along the center line of the mouth of the bag when it is full. Figures 4A and 4B illustrate top views of the displaced fasteners of the present invention. The dotted lines in Figures 4A and 4B represent what is defined herein as the center line C of the mouth of the bag. As shown, the reclosable fastener 14 does not extend along the center line C of the mouth of the bag; instead, the reclosable fastener 14 is displaced, so that it is positioned along the perimeter of the bag when the bag fills and arches away from the wall 11 towards the wall 12. The fold Top 13 can have any desired depth. The depth of the upper fold 13, d? _, is defined herein as the distance between the lower part of the reclosable fastener 14 and the fold. Advantageously, d ^ is a maximum of 1/4 times the width of the bag, w. The width of the bag, w, is defined herein as the distance from a side seal 16 of the bag to the other side seal 17. By varying the depth, d of the top fold 13 will chathe shape of the filled bag. For example, a relatively deep fold having a depth dj will result in an elliptical bag when viewed from the top, as in Figure 4A. On the other hand, a relatively shallow fold having a depth dj will result in a long, rectangular shape when viewed from above, as in Figure 4B. In this way, the selection of the appropriate d ^ depends on the desired shape of the final use of the bag. Advantageously, when a lower fold 15 is incorporated in the bag, the depth of the lower fold 15, d2 is equal to dj. In this way, the shape of the bag will be uniform from top to bottom. The bag can be cylindrical so that it is an effective storage bag for bread and the like; or the bag may have square corners so as to be an effective liner for a cereal box and the like. The reclosable fastener 14 is placed along the width of the bag 10 near the top of the bag 10. The reclosable fastener is placed closer to the top 23 of the bag. bag that to the upper ply 13, so that the reclosable fastener is placed between the upper ply 13 and the upper part 23 of the pouch when the pouch is flat as in Figure 2. The fastener that can be returned to close 14 may be any desired type of fastener having sealable, resealable fastening members or elements 31, 32 carried by the walls 11, 12 of the bag 10 adjacent to the top 23 thereof, such as, for example, a plastic zipper, a plastic zipper with a slider, an adhesive fastener, VELCRO, snaps, or any other type of fastener that can be reclosed. Preferably, the resealable fastener 14 is a plastic zipper having cooperating lock elements, such as, for example, rib and groove elements as described in U.S. Patent No. 5,140,727, rolling action lock as described in U.S. Patent No. 5,007,143, or U-shaped lock elements with interlocking hooks as described in U.S. Patent No. 4,747,702. Moreover, if desired, the fastener may include a slider that runs along the fastener and is adapted to open or close the fastener, such as, for example, those described in United States Patent No. 5,070,583 and U.S. Patent No. 5,007,142. The reclosable fastener 14 can be extruded separately and attached to the side walls 11 and 12 of the bag or can be integrally extruded with the side walls of the bag. The side walls and reclosable fastener of the present invention can be made using methods well known in the art such as, for example, blown or mold extrusion. The bag of the present invention can be made using a sheet or film with a reclosable fastener disposed along the width of the sheet or film. Preferably, the sheet or film is bent to form two layers of film with the reclosable fastener placed at one end of the layers of the film. The bag of the present invention is preferably made by bending inward a portion of one of the film layers near the fastener to form a top fold; sealing the two layers of film together transversely to the upper fold to form a first side seal; sealing the two layers of film together transversely to the upper fold at a distance w from the first side seal. Preferably, the method also includes bending inward at least one of the layers near the lower edge 25 to form a lower fold 15.ou.

Both upper and lower folds can be formed using methods such as those described in U.S. Patent Nos. 5,246,416; ,186,707; 5,083,999; 5,147,278, incorporated herein by reference. EXAMPLE A 45-centimeter film is formed using standard cast film equipment. The film includes a rib-and-groove type plastic zipper such that the rib element is at one end of the film and the groove element is at the other end of the film. The film is folded in half so that the two layers of films are formed, one layer having the rib element at the mouth end of the layer, and the other layer having the groove element at the end of the mouth . The rib and groove elements are positioned so that they can interlock with one another. The fold between the two layers is the bottom edge of the bag. An upper fold is formed by folding one of the layers in to a length d of 6.35 centimeters. A lower fold is then formed by bending inward at the lower edge to a depth d2 of 6.35 centimeters. The two layers are urged sealed together transversely to the rib and slot lock elements at a distance of 25.4 centimeters.

INDUSTRIAL APPLICABILITY Bags are useful for storing bulky items in a reclosable bag.

Claims (10)

1. A thermoplastic storage bag (10) comprising: a pair of opposite walls (11, 12) made of thermoplastic material bonded along a common bottom edge (25) and joined by common side seals (16, 17) as along common side edges thereof and having adjacent upper edges (23a, 23b) providing a mouth of said bag; and a reclosable fastening member (14) adjacent to the upper edges (23a, 23b) and extending laterally between the side seals (16, 17) of a bag, the fastening member (14) being selectively united to close the mouth of the bag; characterized by at least one first of the side walls (11) having an expandable upper fold section folded inwardly (13) adjacent to the upper edge thereof provided by a double overlap of said first wall (11) which is bent inwardly against said wall when said bag (10) is in a collapsed condition, the upper expandable crease section (13) extending laterally through that first wall (11) and having the opposite edges thereof joined to the walls by means of the common side seals (16, 17), the upper fold section (13) is not restricted between the side seals and is selectively extensible so that the first wall (11) is effectively lengthened relative to the other (12) of the walls and thereby move the clamping member that can be closed from an initial position centrally between the walls (11, 12) when the bag is in the condition n collapsed to a displaced position when the bag is in the extended condition and in which the reclosable fastening member (14) arcs outwardly away from the first wall (11) toward the other wall (12) . The pouch of claim 1, wherein the top ply (13) forms a pouch in the first wall when the pouch is in the collapsed condition having an interior fold along the bottom of the ply (13), being the fold along the center line of the bag (10) between the midline between the walls (11, 12) when the bag is in the extended condition. 3. The bag of claim 2 wherein the reclosable fastener (14) extends along a perimeter of the bag (10) in a spaced relation to the center line of the bag when the bag is in the extended condition. The bag of claim 1 wherein the top ply (13) has a predetermined depth dj that is a maximum of 1/4 times a predetermined width w of the pouch. The bag of claim 4 wherein at least one of the walls (11, 12) includes an inwardly folded lower fold (15) extending laterally between the side seals (16, 17) of the walls having a depth d2 equal to the depth dl of the upper fold. The bag of claim 1 wherein at least one of the walls (11, 12) includes an inwardly folded bottom fold (15) extending laterally between the side seals (16, 17) of the walls. The bag of claim 1 wherein the reclosable fastening member (14) comprises a plastic zipper having cooperating lock elements (31, 32). 8. The bag of claim 7 wherein the zipper includes a slider. The bag of claim 1 wherein the upper fold section (13) is attached to the first wall in the region between the side seals (16, 17). The bag of claim 1 wherein the upper fold section (13) has wall portions extending inwardly of the first wall (11) when the wall is in a collapsed condition provided by an extension bent inwardly of the wall. first wall, the wall portions joined by a lower fold of the upper fold section and being otherwise not joined to the first wall and to each other in the region between the side seals (16, 17).