Flexible bags – Bag having means to facilitate opening it by severing bag... – Including a separate tearing element which is gripped and...
Reexamination Certificate
1999-12-06
2001-10-09
Pascua, Jes F. (Department: 3727)
Flexible bags
Bag having means to facilitate opening it by severing bag...
Including a separate tearing element which is gripped and...
C383S086000, C383S203000, C383S211000
Reexamination Certificate
active
06299355
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates generally to industrial bags and, more particularly, the invention relates to an easy-open industrial bag and tabs for use therewith.
DESCRIPTION OF THE RELATED ART
Industrial bags, often made from multi-ply kraft paper, synthetic sheets, and combinations thereof, are closed in numerous ways. A common closure is referred to as a pinch bottom where a flap of one wall of the bag is folded over and glued, sewn or otherwise secured to another wall of the bag. The pinch bottom closure is commonly used in gusseted bags and flat tube bags.
Once closed it becomes necessary at some point to open the bag. In bags that were sewn shut, it is possible to open the bag by undoing the stitching. Sewing generally requires substantial additional processing equipment and processing expense, and thus is no longer a preferred closure method. Providing a glued closure for a pinch bottom bag provides for an easily automated process that is inexpensive and yields a secure sift resistant closure. However, glued closures are difficult to open without cutting the bag, or substantially tearing the walls of the bag. The walls of the bag, of course, are designed to resist tearing, which further makes opening of the bag difficult, and cutting requires having a cutting tool to be handy.
In U.S. Pat. No. 4,480,752 there is disclosed a feature for a pinch bottom bag that facilitates the opening of the bag. The feature includes a tab which is bonded inside the bag within one of the side wall gusset folds. A portion of the tab extends out of the interior of the bag and as the bag is folded closed, remains exposed to the exterior of the bag. By pulling on the tab, the pinch bottom closure is opened in an area surrounding the tab.
In commonly-assigned U.S. Pat. application Ser. No. 08/768,389, the disclosure of which is hereby expressly incorporated herein by reference, an easy opening feature for industrial bags is also described. A tab is bonded into the bag with a portion extending outwardly from the bag, and the side walls of the bag are formed to include at least one tear line to cause localized tearing of the bag during opening as well as to reduce the effort required to open the bag. In particular embodiments of the bag, tear lines may be formed in both the front and back walls of the bag and arranged so as to align and overlap in a double fold closure.
Disposing the tab within the bag may cause difficulty when the bag is used for particular contents materials. For example, if the bag is to contain pet food, the pet food will typically have some fat content. Unless the tab is specially treated, such as coated with silicone or formed from synthetic materials, over time the tab will wick fatty oils from the pet food to the exterior of the bag. The fatty oils make the tab difficult to grasp hindering opening of the bag, may weaken the tab causing it to fail as the bag is opened, may distort printing disposed on the bag and/or the tab, and may further attract insects and rodents. Using silicone coated tabs and or synthetic materials to form the tab presents problems in effectively gluing the bag closed.
Many times it is desirable to reclose the bag after it has been opened. This is often the case where not all of the contents of the bag will be distributed. Reclosing a bag either sewn closed or glued closed is generally not possible without the use of tape or a clip to keep the bag closed. Frequently neither tape nor a clip is available and the bag is simply folded over in the hope that it will remain closed and that its contents will not spill.
SUMMARY OF THE INVENTION
The invention provides an easy open feature for an industrial bag utilizing a tab disposed on the exterior of the bag in combination with a uniquely glued closure.
In accordance with a preferred embodiment of the invention, a bag includes a front wall, a back wall, first and second side walls interconnecting the front wall and the back wall, and an enclosed end defining an interior portion and an exterior portion of the bag. The enclosed end includes a flap formed integral with the back wall that is folded over and bonded to the front wall using adhesive. A tab is secured to the front wall on the exterior of the bag and is disposed between the flap and the front wall. The tab is detachably secured to the front wall and the adhesive is disposed between the front wall and the flap in a pattern defining an adhesive void adjacent an opening edge of the bag.
In accordance with another aspect of the invention, a tab useful in opening the bag is further useful for reclosing the bag. The tab may include a peel-free adhesive that permits the tab to be repeatably reattached to an outer surface of the bag. A opening flap of the bag may then be folded over to close the opening and the tab used to keep the bag in the closed condition.
Alternatively, the tab may include a segmented backing material. Removing successive portions of the segmented backing material exposes adhesive. The bag may be folded closed and the exposed adhesive used to keep the bag closed. As the exposed portion of adhesive becomes less effective for keeping the bag closed, another segment of the backing material may be removed exposing fresh adhesive.
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Marshall Gerstein & Borun
Pascua Jes F.
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