US2345434A - Siftproof bag - Google Patents

Description

/rl l BY mE/w@ March 28, 1944. A. J. STERLING SIFT-PROOF BAG Filed OCf..V 25, 1941 Patented Mar. 1944 SIFTPROOF BAG Albert il. Sterling, Brooklyn, N.. Y.: VSarah M. Sterling execntrix o! said Albert J. Sterling, de-

ceased Application October 25, 1941.; Serial No. 416,472

(Cl. 22B-62) 1 Claim.

invention relates to bags and has vparticu- 'in wn in the art as sift-proof bags.

siti.

.An object of the invention is to provide a newl ,.fnetl'lod of making `sift-prooi closures for bags which is simpler than any prior method of the reference improvements in what are kind and whici'i is, nevertheless, more eifective "for the purpose intended than mostof them.

Yanother object is toprovide a sift-proof closure efficient closure and which is at the same time strong enough to withstand even severe abuse in handling.

The improved method and the product involves the use only of material forming a part of the bag proper instead of tapes, liller cords and so on in effecting the closure. Where stitched seams are used the new construction provides a reinforcement for the stitch to prevent the stitches from tearing through and in addition, the needle punctures made in doing the stitching are sealed from both sides to prevent fine contents from sifting out through the punctures.

The invention is applicable to bags of either single or the multi-wall type and may be used with equal facility for the bags of either type.

With the foregoing and other objects in view the invention comprises a novel method of maklng a sealed bag closure and a novel product; that is, a sift-proof closure having new and valuable characteristics. An illustrative embodiment of the sift-proof closure is illustrated in the accompanying drawing and the method of making it as hereinafter described in detail, with the novel features of both the product and the method being set forth in the claim appended hereto.

In said drawing:

Fig. 1 ls a view of a bag to which one form of the invention is applied, the figure illustrating particularly the flap employed in making the closure. Fig. 2 shows the bag with the flap folded over the bag mouth to close the mouth and one side of a row of stitches through the iiap and the bag walls at the mouth of the bag.

Fig. 3 is the same as Fig. 2, but shows the opposite side of the stitched seam. I

Figs. 4, 5 and 6 illustrate successive steps in completing the sealed closure. l

Fig. 7 is the same as Fig. 6, except that the former illustrates the invention applied to a multi-wall bag.`

'Ihe invention is shown in the drawing as it would appear when applied to a gussetedbag. Extending from and preferably integral with one wall of the bag is a long flap Ill. This ilap is long enough to provide three sections for the purpose hereinafter set forth. It is shown in the figures as havingfold or crease lines li, but this is partly tosimplify the explanation.

` While such fold or craselines l maylbe used fnl fil

they are not absolutely essential.

After the bag has been illled adhesive is ap plied either to the upper part I2 Aof the bag Wall or to the portion I3 of the flap, orto both; and the flap is then drawn tightly over the mouth of the bag, as illustrated in Fig. 2. The adhesive will hold the flap and the bag wall in that position. In some instances it maypot be necessary to use adhesive on the surfaces I2 and I3, but that procedure is preferred.

After the flap has been drawn over the mouth of the bag it is stitched through the flap and through the walls of the bag. Any form of stitch on the single thread side.

may be employed which is strong enough and otherwise adapted to the purpose. In the drawing,y the stitch is shown as a loop stitch; that is, a stitch having a series of loops I4 along one side of the seam, with the loops being connected as illustrated. The bight of one loop passes around the base of the next loop so that the loops not only give a reinforcing for the stitch ing along one side but the connection between the loops affords a preventive against sifting of the contents through the needle punctures. The other side of the seam has only a. single thread as shown at I5 and if a seam tears when such a loop stitch is used the tear usually begins The seam is prefer--` ably sewed in such a way that the single thread side of the seam is on the side which includes the portion' I3 of the flap. This gives extra bag .material on the Weak side of the seam so as to reinforce the seam along that side.

After the stitching is completed, adhesive is applied and the remainder of the ilap folded back over the portion I3 and top of the bag and down over the other side so as to cover the loops Il. The adhesive may be applied to the portions of the preliminary closure which includes the sides Il and I5 of the stitched seam and the flap then further folded as described, but itis preferred to apply the adhesive to the portions I6 and I1 of the nap before the flap is folded to final position. It is advisable to use plenty of a good strong adv heslve and in some cases it may be advisable tc. apply adhesive to all of the surfaces which will be brought into contact by the final fold so that there will be a double amount of adhesive included in the nal fold. l

As shown in Fig. 4 in making this iinal fold the flap is turned up so that the portion I6 is folded on a line I8 below the single threads I5 of the stitched seam and then, as illustrated in Figs. 5 and 6, the remainder of the iiap is brought down over the loop side Il of the stitch. Sealing pressure may then be applied wherever it is thoughtto be required.

The adhesive may be any of the usual glues, although for some uses it may be advisable to use plioiilm or similar material which is softened by heat and simultaneously pressed to effect a sealing operation.

The final closure oi a single wall bag is shown in cross-section in Fig. 6. Als will there be seen, the stitch is' reinforced by an extra thickness of the paper on the weak side of the seam and the stitches are covered from both sides by the flap. Adhesive between the contacting parts of the nap and the bag walls and between the contacting parts of the iiap after it is folded vholds all of the material in its intended position and also affords a very effective seal of the needle punctures against sifting through the punctures of the bag contents.

The multi-wall construction is illustrated in Fig. 1. It is, except for the number of plies, the same in every substantial respect as the single ply structure.-

From all of the foregoing it is clear that there is provided a very eilicient and simple sift-proof closure and that in its making there is a new process or method involved which is in itself a very simple one. One advantage of the method is that it can readily be carried out by simple automatic machinery and with a very considerable saving in material and time of operators.

While an embodiment of the new closure and a preferred method of making it have been described somewhat in detail, it is apparent that changes or variations might be made and it is not the desire to be limited by anything hereinabove contained, except to the extent indicated in the claim which follows.

What is claimed is:

A paper bag having a sift-proof closure for its mouth comprising a flap, which is at least as wide as the mouth of the bag, extending from v and integral with the bag wall at one side of the mouth, said flap having transversely 'extending fold lines defining three panels arranged to be folded over the mouth of said bag and reversely upon themselves along one of the fold lines, stitching extending entirely across the mouth of the bag and comprising stitches extending through the bag walls' and the panel adjacent thereto, and adhesive on the inner side of said stitched panel and on the inner side of the remaining two panels, said adhesive covering the entire inner face of each of said panels and being in an amount on the inner face of each outer panel to completely cover and seal the holes produced by said stitches.

ALBERT J. STERLING

Images