US3187984A - Valve bag - Google Patents

Description

June 8, 1965 c. R. HoLLls ETAL 3,137,984

VALVE BAG' Filed NOV. 30, 1962 y@ m6' 'Ilmm- K l cgmrmv e. Hou/s FIG. 8 9 BY if/05H27 o. /aAxrfa rme/vsy United States Patent O s,1s7,ss4 VALVE BAG- Clinton R. Hollis and Robert 0. Baxter, Camden, Ark., assignors to International Paper Company, New York, NY., a corporation of New York Fired Nov. 30, 1962, ser. No. 241,231 1 Claim. (Cl. 229-625) This invention relates to bags and, more particularly, to a dual sleeve for valve bags which are `lilled by means of a filling spout received in the valve and which adapts rsuch bags to be self-closing.

The invention in a preferred embodiment thereof cornprises a dual sleeve for a sewn valve bag. This is a gusseted type bag, with both the top and bottom sewn and taped in the bag factory. By means of special folding, one corner is left open, forming a valve or orifice through which granular material or the like is introduced into the bag.

The valves of such bags are closed by the pressure of the contents of the filled bag when the latter is inverted. However, due to the stiffness of the material from which the bag is formed, the walls of the valve are often not pressed into sufficiently tight contact one with the other to prevent the material from seeping through the valve. In an effort to prevent such leakage, it has been common practice to provide the valve with a supplemental ciosure or single-ply sleeve of exible material, such as soft paper, which is more completely crushed by the contents of the bag than is the valve itself. Y

While such sleeves have reduced leakage, they have not eliminated it entirely, particularly when the material with which the bag is loaded is of a finely divided character such as wheat flour. Further, then insertion of the singleply sleeve requires an additional, and usually a manual operation and, because of the flexible nature of the sleeve, it has been found that existing bag machinery cannot effectively insert it.

lt is therefore a primary object of this invention to provide a bag having a dual or two ply sleeve which effectively eliminates leakage or shifting of the contents of the bag through the valve.

Another object of the invention is to provide a dual sleeve which, although serni-exible in character, can be inserted mechanically by existing machines.

Other objects and advantages will appear from the following specification and drawings in which:

FG. 1 is a fragmentary plan view showing the valve corner of a sewn valve bag having the duel sleeve of this invention;

FIG. 2 is a sectional View (with partsbroken away) taken substantially along line 2-2 of FIG.` 1;

FIG. 3 is a sectional side view taken along line 3-3 of FlG. 2;

FIG. 4 is a sectional end view taken along line 441 of FIG. 2;

FIG. 5 is a plan view of the unfolded outer part of the dual sleeve of the present invention;

FIG. 6 is a plan view of the unfolded inner part of the dual sleeve which is combined with the outer part of FIG. 5;

FiG. 7 is a plan view -showing a modified form of the unfolded outer part of the dual sleeve and a fragmentary plan view of .a like outer part showing how it can be cut or stamped out of the sheet material from which it is formed without loss of material; and,

FIG. 8 is a plan view of the unfolded inner part of the dual sleeve which is combined or used with the unfolded outer part of FIG. 7.

Referring to FiG. 2 of the drawings, there is shown the valve corner of a gusseted bag B, preferably formed of a heavy grade of kraft paper. It can also be con- 3,183,934 Patented June 8, 1965 ICC structed from heavier or lighter material, depending on the requirements of the bag. As shown, the bag has single ply side walls 11 and 12, portions of which are folded inwardly to form a conventional valve 13. It is to be understood that the basic principle of the invention are also applicable to a bag having a number of plies, i.e., a multi-wall bag.

At 14 is shown a dual sleeve of the present invention which is secured to and projects from the valve 13 into the bag. The sleeve 14 consists of an inner layer or part 15 of thermoplastic material having blocking characteristics, such as polyethylene and an outer layer or part 16 of paper secured thereto. It is inserted during the manufacture of the bag by automatic machinery, such as shown in the U.S. Patents 2,809,569, issued October 15, 1957, and 3,002,747, issued October 3, 1961, to C. R. Hollis, in a manner further to be described. After the sleeve is inserted and the sleeving operation is completed, the bag is fed to a sewing section where it is provided with a conventional closure 17 which consists of a reinforcing tape 18 folded over the ends of the bag and a sewed seam 19 which passes through the walls of the bag and the tape to complete the formaion of the bag.

The unfolded inner part 15 of the dual sleeve, as shown in FIG. 6, is cut from a supply roll of thermoplastic material and is substantially rectangular in form. The preferred material for the inner part is polyethylene, but any iiexibie type of material will do as long as it has effective blocking characteristics; that is, any material that has a tendency to cling to itself.

The unfolded outer part 16 of the dual sleeve, as shown in FIG. 5, is cut or stamped from a supply roll of paper in a manner well known in the art. As shown in FIG. 7, a like outer layer 16a of the dual sleeve can be cut or stamped out of the same paper supply roll without loss of paper since the elliptical cuts 22 in the first or leading outer sleeve part 16 form the tabs 2? inthe following outer sleeve part 16a in the cutting operation.

The unfolded inner and outer parts 15 and 16 are secured together by glue applied to the side edges of unfolded outer part 16, as shown by the shaded area in FIG. 5, thereby completing the formation of the dual sleeve 14.

Means are provided to secure the dual sleeve 14 to the valve 13, preferably in the form of tabs 2) at the outer marginal edge Z1 of the outer part 16 of the sleeve. Means are also provided to expose portions of the inner part 1S of the dual sleeve, for a purpose further to be described, preferably in the form of elliptical cuts 22 at the inner marginal edge 23 of the outer part 16 of the sleeve.

rl`he dual sleeve 14 is folded along its bottom center and positioned on the valve 13 as shown in FIG. 2 and secured thereto by zones of glue on the tabs 20 of the outer part 16 of the sleeve, and if desired, by glue on the outer marginal portions of the inner part 15 of the sleeve. The tabs 2G provide a greater surface area for gluing the dual sleeve on the valve and render the structure stronger.

As has been stated, the dual sleeve is adapted to be inserted and positioned on the valve during the bag forming operation by existing automatic equipment. Since the outer layer of the dual sleeve is made of paper, the dual sleeve has the required stiffness to be handled by this equipment which could not insert a non-rigid plastic sleeve because it would not be stiff enough; i.e., it is too pliable.

The bag may also be filled by conventional automatic equipment such as a valve packer in which the filling spout by which the filling of the bag is effected sae/,eea

for paper part 16 of dual sleeve serves as a guide to in,

crease the eihciency of the operation. v

The inner or thermoplastic part 15 of the dual sleeve i acts as a choke arrangement to close the valve opening of the bag after it is lled. When a bag is packed on a valve packer, there is a certain amount of trapped air that ows into the bag with the material and as the bag isbeing taken from the spout, after lling, the trapped air has a tendency to blow back out the valve. Due to the fact that a thermoplastic material, such as a low mil polyethylene, has a natural tendency to cling to itself, such will happen when the bag begins to fall from the lling spout and the trapped air will then force the polyethylene or inner part of the dual sleeve to cling even tighter. As the bag continues to fall backward on its back edge, the material in the bag will rush forward and close the polyethylene part even tighter against the top of the bag. In other words, immediately after filling two actions take place; the polyethylene part clings to itself in the vertical position, as shown at 26 in FIG. 3, with the assistance of the trapped air forcing the polyethylene part to cling tightly, and as the bag falls on its side the material rushes forward and forces it together in the horizontal position. Such action thus reduces the valve opening in a choke fa-shion.

The elliptical cuts 22 in the paper part 16 of the dual sleeve provide a surface opening for air to be forced against the polyethylene part thus causing the action described above. The paper part t6 of the dual sleeve also acts as a sure-.close feature when the material is thrust forward as the bags falls off the filling spout since it forces the polyethylene part 15 against the top edge of the bag, thus tightly closing it.

In certain applications, depending on the type of material to be packed, it is desirable to provide the dual `sleeve of this invention with slits along its bottom center. A modied form of the dual sleeve having these slits is shown in FIGS. 7 and 8; the slits 27 and 2S in the outer and inner parts 16 and 15, respectively, extending inwardly from the inner edges 23 and 29 `of these parts to a point spaced inwardly from the outer edges 2l and 3i? of these parts. properly, the inner and outer parts are secured together not only at their sideY edges but also by glue applied to bottom center of the outer layer 16 as shown by the shaded area in FIG. 8. Otherwise, the slit dual sleeve is identical to the dual sleeve 14 shown in FIG. 2.

What is claimed is:

A bag having side walls, portions of said walls being folded inwardly to forni a valve, a dual sleeve positioned on said valve and projecting inwardly into said bag, said sleeve consisting of an inner part and an outer part, said inner part of said sleeve being formed of a thermoplastic material having blocking characteristics and said outer part of said sleeve being formed of paper, said inner part and said outer part of Said sleeve being secured together along their side edges by zones of glue, means to secure said sleeve to said valve including tabs formed at the outer marginal edge of said outer part of said sleeve, said sleeve being secured to the inner marginal edge of said valve by Zones of Vglue on said tabs and means to expose portions of said inner part of said sleeve including elliptical cuts at the inner marginal edge of said outer part of said sleeve.

References Cited by the Examiner UNITED STATES PATENTS 2,275,565 3/42 vCrawford 229-625 2,884,182 4/59 Woodward 229-525 3,065,899 11/62 Means et al. 229-625 FOREIGN PATENTS 565,770 12/32 Germany.

FRANKLIN T. GARRETT, Primary Exwminer.

EARLE I. DRUMMOND, Examiner.

To enable the dual sleeve to be slit Y

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