The present invention relates to thermoplastic bag structures which are characterized by having a pair of carrying handles which are formed integrally with the bag walls, and extend upwardly from the open mouth portion of the bag. The configuration of the individual bag handles is such that there is reduced tendency for that portion of the handle which is in the user's palm, when such bags are loaded are carried, to curl into a small cross sectional area, commonly known as roping. Additionally, the individual bags are constructed so that when the bags are loaded and being carried by the user, the stress points around the bag mouth are distributed to areas which are less likely to rupture and tear as a result of stress concentration.

Patent
   RE34019
Priority
Mar 23 1978
Filed
Aug 16 1991
Issued
Aug 04 1992
Expiry
Aug 04 2009
Assg.orig
Entity
unknown
8
17
EXPIRED
1. A thermoplastic bag structure comprising a front and rear bag wall and an open mouth top portion, said open mouth portion being characterized by having handles which are located on opposite ends of said open mouth portion, said handles being integral extensions of said front and rear bag walls, said bag being further characterized in that the upper portion of each of said handles is substantially wider than the lower portion of said bag handles said lower portions being located adjacent opposite ends of said bag mouth; said bag mouth being further characterized by having stress relief notches positioned at opposite ends of said mouth, the upper edges of said mouth extending above said stress relief notches.
3. A handle bag comprising a front and rear bag wall and an open mouth top portion, said open mouth portion being characterized by having handles which are located on opposite ends of said open mouth portion, said handles being integral extensions of said front and rear bag wall, said bag being further characterized in that the upper portion of each of said handles is substantially wider than the lower portion of said bag handles, said lower portions being located adjacent opposite ends of said bag mouth; said bag mouth being further characterized by having arcuate areas positioned at opposite ends of said mouth and adjacent the lower portions of said handles, said handles extending upwardly and inwardly from said arcuate areas, and the upper edges of said mouth extending above said arcuate areas and being located closer to the lower portion of said handles than to said upper portion of said handles. 4. In a bag structure comprising front and rear bag walls joined together to form a bag bottom, an open mouth top portion opposite to said bottom, said top portion characterized by having handles which are integral extensions of said front and rear walls, said handles having lower portions located at opposite ends of said open mouth and having upper portions located farther away from said bottom than is said open mouth; the improvement which comprises, said bag mouth being further characterized by having arcuate areas positioned at opposite ends of said mouth and adjacent the lower portions of said handles, said handles extending upwardly from one end of said arcuate areas, said bag mouth extending above said arcuate areas and having upper edges which are located closer to said lower portions of the handles than to said upper portions of said handles.
2. A bag structure in accordance with claim 1 wherein said front and rear walls are joined together by an integral pleat portion.

12, whose function is described in detail hereinafter.

It will be noted that in the bag structure of the present invention a means is provided to reduce the roping of the handles in thin gauge thermoplastic handle bags. When the handles of typical prior art handle bags are subjected to heavy bag loads and, when carried, are additionally subjected to a rolling of the handles across the palm of the hand of the carrier, there is a tendency for the film in the handle region to assume a minimum cross-sectional area, thus, to form a round cross-section with a small diameter.

This configuration is referred to hereinafter as a "rope". The undesirable effects of such a roping tendency resides primarily in the fact that the weight of the loaded bag is then supported over the relatively small diameter of the ropes and thus approximates point loadings across the palm of the hand of the carrier. This roping tendency increases proportionally as the gauge of the thermoplastic material in the handle portion of the bag is reduced. For obvious economic reasons it is preferred to prepare such disposable thermoplastic handle bags with as little resinous material as is possible, i.e. the thinnest gauge possible consistent with satisfactory performance.

In accordance with one aspect of the present invention, means are provided to add more cross-sectional bulk in the handle region to compensate for the reduction in bulk attendant to gauge reduction and reduced rope diameter as a result of such gauge reduction. As particularly shown in FIGS. 1, 2, and 3 of the accompanying drawings the increase in bulk in accordance with the present invention is accomplished by making the upper portions of handle members 11 wider in the regions where the palm of the hand would typically be placed to carry the loaded bag. It will be noted that in FIGS. 1 through 3 the inside portions of handle members 11 in the areas generally designated as 18 and 19 are tapered inwardly towards the side edges 15 of the bag structures. Such inward tapering provides a means for increasing the width of the upper portion of handle elements 11 while maintaining a sufficient width of bag opening at the base of handle members 11 to permit ease of loading of products through the open bag mouth.

It will be noted that the difference in structure between the bag illustrated in FIG. 1 and that illustrated in FIG. 3 resides solely in the design of the taper on the inside of bag handle 11. In the case of FIG. 3 this taper is uniform and continuous from the top of the handle 11 to the base thereof adjacent the radius stress relief notch 12 whereas in the case of the handles shown in FIG. 1 the taper is provided by an abrupt radius curvature at point 18 flowing into stress relief notch 12.

Accompanying FIG. 8 sets forth in graphic form the effects of varying gauge on the rope diameter assumed by handle elements 11 when a loaded bag is manually transported. The following formula has been found to be an accurate means of calculating the effect of the rope diameter on gauge variation, the diameter being computed as follows: ##EQU1## with:

D=equivalent diameter of the "rope" (in.)

W=Handle width (in.)

G=gauge (in.)

As shown in accompanying FIG. 8 as the gauge of thermoplastic material, in the present instance low density polyethylene, is reduced the rope diameter decreases. However, as the width of the upper portion of handle 11 is increased the pronounced reduction in rope diameter, as the gauge is reduced, is not as severe whereby the concentrated palm pressure exerted by the handles of a loaded bag is proportionally reduced.

As shown in FIGS. 6 and 6-A, prior art bag structures which have been assembled into unitized packs and retained in pack form utilizing a detachable tab 21 which was joined to the main bag body by a perforated area 23-A, located immediately adjacent the bag mouth, when removed from such a pack were characterized by having nicks or small tears along the mouth portion of the bag as a result of having been perforated in that area. As particularly illustrated in FIG. 6-A, when such bags were loaded and subjected to the normal carrying stresses and forces encountered along the perimeter of the bag mouth, there is a pronounced tendency for such forces to concentrate at a stress point S. Since, in this area of the prior art bags, an initial tear in the form of a nick caused by the perforation operation is already present, such prior art bag structures were particularly prone to rupture and tear.

Conversely, in accordance with the bag structures of the present invention, as illustrated in FIGS. 7 and 7-A, by reason of the presence of a stress relief notch 12 and also by virtue of the fact that the perforated mouth area is restricted to a confined location, i.e., attached to upwardly extending attached tab 24, when normal stresses, e.g., as a result of being loaded and carried, are applied to the loaded bag structures of the present invention, the stresses tend to concentrate in area S'. Since in this area S' there are no nicks or slight tears as a result of the perforation operation, there is a pronouncedly reduced tendency of the present bag structures to tear during normal loading and carrying operations.

Although the present invention has been described with preferred embodiments, it is to be understood that modifications and variations may be resorted to, without departing from the spirit and scope of this invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the appended claims.

Kuklies, Milton C., Orem, William G.

Patent Priority Assignee Title
5348399, Dec 23 1992 Plastic bags with waveform edge configurations
5465846, Mar 08 1994 Atlantic Packaging Products Ltd. Bag dispensing system
5566873, Dec 15 1993 , Dispenser for flexible webbing
6558764, Mar 05 1999 SABIC INNOVATIVE PLASTICS IP B V Single layered polypropylene containers and their use
7255271, Oct 08 2004 Target Brands, Inc.; TARGET BRANDS, INC Check-out counter systems and methods
7578440, Oct 08 2004 Target Brands, Inc. Check-out counter systems and methods
7753588, Sep 15 2003 SUPERBAG CORP Bag, bag pack, and bag dispensing system
D353761, Apr 12 1993 Bag
Patent Priority Assignee Title
1808375,
2019197,
3180557,
3298416,
3312339,
3352411,
3358904,
3774837,
4062170, Mar 17 1977 Mobil Oil Corporation Apparatus for loading bags
4085822, Dec 04 1975 Mobil Oil Corporation Bag assembly and method and apparatus for loading individual bags
4136723, Jun 28 1976 Norsk Hydro A.S. Flexible container for transportation and storage of bulk material
CH405057,
DD61848,
DE1844267,
FR1496589,
JP4730024,
JP4740984,
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Executed onAssignorAssigneeConveyanceFrameReelDoc
Aug 16 1991Mobil Oil Corporation(assignment on the face of the patent)
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