US2373010A

US2373010A - Bag closure

Info

Publication number: US2373010A
Application number: US444284A
Authority: US
Inventors: Charles V Brady
Original assignee: Bemis Brothers Bag Co
Current assignee: Bemis Brothers Bag Co
Priority date: 1942-05-23
Filing date: 1942-05-23
Publication date: 1945-04-03
Anticipated expiration: 1962-04-03

Description

April 3, .1945. v BRADY 2,373,010

BAG CLOSURE Fil ed May 25, 1942 FIGIQ Patented Apr. 3, 1945 UNITED STATES PATENT OFFICE .(lharles V. Brady, Webster Groves, Mo... or

to Bcrnis Bro. Bag corration of 1.

@ompamy, St. llrouls, Me, a

Application 3 23, 1942, Serial No. dddfldd d llla.

This invention relates tobag closures, and with regardto certain more specific features to clo sures for bags which are to contain hygroscopic or like materials.

Among the several objects of the inventionmay be noted the provision of a moisture-proofing seal in and around needle-holes, which under all temperature conditions avoids a sticw or tacky characteristic on the bag exterior although the sealing material retains the usual tacky orlike characteristics which go with a desired permanent flexibility in the closure; the provision of a seal of the class described in which optimum placement and distribution of sealing material is obtained for more effective sealing in and around is often intended that this, of has contain material which should be kept dry d which may take up moisture (is hygroscopic) these bags heretofore have had their taped and sewn ends dipped into a low melting point was which substantially covered the outside of the tape and the stitched thread. This was intended to enter the needle holes from the outside, thus to plug the holes against entry of moisture.

This procedure has had several disadvantages,

the first of which was that in the of a clo-,

' sure for a filled the bag needed to be turned the needle holes; and the provision of a seal of' this class which is simple and economical to carry out in practice, Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described. and the scope of the application of which will be indicated in the following claims.

In the accompanying drawing, in which is illustrated one of various possible embodiments of the Similar referencecharacters indicate corresponding parts throughout the several views of the drawing.

It has been common practice to close bags, in-

cluding paper bags by bringing together-the opposite sides of the bag mouth, app a V: shaped covering tape, and sewing through the opfilling, and for bag tops, atterfilllng. This operation has involved punching needle holes through the tape and through the has material, which holes although partially filled with thread or twine, are not hygroscopically tight. Since it posite sides of the tape and bag. For bag bot-- toms, the operation has been performed prior to upside down in order to apply the wax, since spraying or brushing was not satisfactory. sides, the clipping was dimcult, and particularly so with heavy materals and large bs. The contained materials tended to deform the h end when the bag was inverted and made more cult a dipping operation.

Another disadvantage of the former method was that the war: only entered the needle holes superficially from the outside, and in addition the tacky wax was located on the outside of the bag ends where subsequently it caused culties'.

The present invention avoids all of the above troubles and produces a much more water-tight seal throughout the whole interior of the closure. Referring now more particularly to Fig 1, there is shown at numeral i a four-ply, gusseted bag, but it is to be understood that the invention is equally applicable to non= and single-ply bags, both oi the tubular and. l varieties. and also to valved bass.

The front and rear sides or t of the bag are shown at t and t. The ii-shaped coverin tape is shown generally at l, the same ha opposite sides t and ii folded tow one another and enclosing the mouth. its indicated in Fig. 4, where bags have alr been filled, it is the practice to brine together the ends of the faces g and t, the filled bag being on a movable belt I beneath a running supply of the tam l which is turned into a V- which, in conjunction with the w the sewing machine, draw the e through the sewing machine. It is to be imde 1 r that after passing through the draw rolls it the continuous sewn mm is out between When the closure forms a bottom, the bag is of course flat when the closure is e, which is necessarily prior to filling.

Prior to fillin The successive filled bass are brought or covering with tape and sewing, each bag, according to the present invention, has its open end dipped into melted, low

melting point wax, the results of which on a multi-ply bag are indicated in Fig. 2. The dipping is carried out, for example, to a depth of about one inch into the wax. that is to say, beyond the point at which the sewing is to take place. At room temperature, the wax solidifies but retains enough tackiness to flex with the bag material. Sewing is ordinarily accomplished at a distance of about five-eighths to three-quarters of an inch from the end of the bag. As indicated in Fig. 2, the wax under these conditions is deposited on both faces of the bag mouth and also on all faces and inter faces of each ply. Thus all faces of all plies are provided with a wax surface or coating which at room temperature, before sewing, solidifies more or less. without becoming hard. The wax is shown-by stippled-dots in the drawing, and is provided with the index character 23. It may be composed, for example, of paramn, thinned with enough petrolatum to maintain tackiness or stickiness and to prevent cracking upon solidification. The temperature for melting to a flowing liquid may be around 150 F.

Either or both ends of the bag may be treated as above indicated, and the tape is then sewn on, but in the case of the top, the bag is fil ed prior to applying the tape.

Assuming that we are dealing with a bag top. the bag is filled after dipping and hardening but before applying tape if. It is then advanced toward the sewing machine I? and the supply of tape i. The opposite ends oi? the faces 5 and '43 are suitably brought together by hand. as indicated at the right in Fig. i. The tape 9, which in the present example is made of paper, is then folded in the folder '5 and applied over the bag end. The assembly then proceeds to the sewing machine 971. It is to he understood that the folded tape is not covered with wax, but is dry paper so that the presser foot of the sewing machine I? operates on a. dry surface. How ever, the presser foot squeezes the wax inside of the tape. The needle 2? of the sewing machine reciprocates through the opposite sides of the tape 9 and through the bag plies, including the wax, and performs its sewing operation as usual.

The dry tape strips clean the needle as it recip rocates.

The proper operation of the stitching is not interfered with, because the wax is not in a running condition. being more or less solidified though tacky at ordinary room temperatures.

After leaving the sewingmachine H, the sewn tape is subjected to heat, as indicated by the infra red lamps 29, which serve again to melt e wax so that it proceeds to infill the needle hol s aro1md the thread passing through said holes, thus sealing them from the inside. In addition, the squeezing draw (rolls l9 may be kept warm by means of additional lamps 31. The squeezing action of these rolls 19, as also the squeezing of the presser foot at Il aids in forcing the wax into sealing position. Either or both sets of

lamps

29 or 3| may be made to provide the heating step, or other heating means may be used. The heat should only be enough to melt the wax without damaging the bag or tape material, such as paper or waterproof fabric.

It is to be understood that when the invention is applied to providing a similar closure at the other end of the bag to form its bottom, the

bottom closure is made prior to filling the bag on suitable machinery for the purpose.

From the above, it will be seen that, instead of a superficial closure of the needle holes, there is an interior closure or plugging of the same. In addition, instead of a large area. of wax being exposed on the exterior of the bag, none is exposed because the exterior surface of the cover tape 1 has no wax on it, and the exterior loops of the thread entirely cover the outer ends of the needle holes, substantially preventing outfiow of wax. Thus the bag mouths are exteriorly dry, even when warmed, and they do not tend to stick to adjacent bags or articles. In addition, the appearance of the bag is much neater, since there is no dipping mark of wax on the exterior.

The distribution of wax is much better because it flows inside and outside of the bag plies as well as between the piles, and therefore makes a better distribution for eflective sealing.

It will be seen that dipping is the best manner of applying the substance to the bag end, particularly in the case of a 'multiply paper bag wherein the dipping operation at once covers all oi the faces and inter faces at the ply ends. In the case of gusseted bags, the distribution of material into the gussets is also made easier to accomplish by dipping. For example, it is difficult to brush or spray material between plies or in gussets. However, some of the advantages of the invention may be obtained by applying the wax by other methods when this is effective and possible, as for example on non-gusseted, single-ply bag bottoms.

The invention is most useful in the case of paper bags, or bags lined with treated paper or similar waterproofing. substances. Paper is a class example of materials which protect against -m0isture when properly treated. Thus, if the bags are made of cloth suitably treated to close the interstitial spaces, such bags could advantathat the substance to which it applies may be made liquid at a. temperature low enough that a bag treated therewith will not w deteriorated by the temperature required for melting. Wax is exemplary of any material which is properly amorphous, waterproof and of low melting point. The intention is to cover broadly sealing materials which retain their properties of sealing against moisture when located upon a flexible base such as the materialof the bag, cover tape, and stitching. Low melting point asphalt would be an exemplary equivalent for wax for certain uses.

The term tubular bag" as used herein is intended to cover bags having (broadly) tubular bodies whether seamed. unseamed, gusseted, multiply, valved, or not, unless otherwise qualified.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in A the accompanying drawing shall be interpreted ingpoint flexible sealing substance covering all iaces and inter i'aces or said plies near the bee oi the into low melting point flexible sealing substance in such a manner that'the faces and inter faces of the multi-ply portions are entirely covered tor a predetermined distance from said ends, allowing said substance to solidify, bringing the bag ends adjacent to one another, applying an enclosing cover tape over the bag end, said tape being free of adhesive prior to application to the bag end. the width of the tape on each side being such as to cover the entire treated area, stitching through the tape and the bag end within said area while the substance is solid, and

' thereafter heating the bag through the tape to render said substance temporarily liquid interiorly to plug the holes caused by sewing substantially without exuding to the outside of the tape.

3. 4 bag closure comprising adiacently located bag end portions, a layer of low melting point sealing substance covering the outer laces and interiaces of said end portions, a v-shaped cover tape encl said has end and a thereto by the sealing was on the outside 0! the outer laces. stitching passing through the tape and said bag end portions. the holes formed by said stitching in the bag end portions beins completely penetrated from two sides and sealed by said substance, but the holes through the tape being merely backed by said substance without substantial penetration to the exterior, whereby a closure is provided with all internal stitching openings completely closed from two sides by the sealing substance which is substantially confined to locations inside the tape, the outside oi the tape being substantially free of said sealing substance.

4. A bag closure comprising adiacently located multi-ply bag end portions, a layer of low melting point fusible sealing substance covering adjacent bands on all faces and inter-faces of said plies. a v-shaped cover tape enclosing said bag end and attached thereto by the sealing substance on the outside of the outer plies, stitching passing through the tape and said bag end, the holes in all plies formed by said stitching being completely penetrated from two sides and sealed by said substance, but the holes through the tape being merely backed by said substance without substantial penetration to the etxerior, whereby a closure is provided with allinternal stitching openings completely closed from two sides by the sealing substance which is substantially confined to locations inside the tape, the outside of the tape being substantially tree oi said sealing substance.

CHARLES V. BRADY. v