US2615488A - Bag closure - Google Patents

Description

Oct. 28, 1952 c. v. BRADY ETAL 2,515,483

BAG CLOSURE Filed June 30, 1950 2 SHEETS-SHEET 1 FIGZ. H046 Oct. 28, 1952 c. v. BRADY grim 2,615,488

BAG CLOSURE Filed June 30, 1950 2 Sl'lEETS-SHEET 2 FIGS.

2,551,044, issued Patented Oct. 28, 1952 BAG CLOSURE Charles V. Brady and August Fl Qttinger, St.

Louis, Mo., assignors to Bemis Bro. Bag Company, St. Louis, Mo., a corporation of Missouri Application June 30, 1950, Serial No. 171,524 1 1 Claim. 1

This invention relates to a bag closure, and more particularly, to the construction and fabrication of draw closure bags.

- This application is a continuation-in-part of applicants copending United States Patent No. May 1, 1951 and entitled Bag Closure. I

Briefly, the invention comprises, a bag closure having a ravel-resistant textile tape formed from a relatively wide moving web of textile fabric which is slit into a plurality of narrow strips, adhesive being applied only to the longitudinal raw edges of the strips. The adhesive is applied to the longitudinal edges of the fabric by applicators having wiping surfaces which in engaging the edges of the fabric are generally normal to the plane of the tape. Thus, application of adhesive is restricted primarily to the edges of the fabric as contrasted with the surfaces of the fabric. 7

The bag closure of this invention is of particular construction in that the adhesive on the tape is primarily at the two outermost longitudinal yarns. It is contemplated that there may be adhesive on some of the other longitudinal yarns immediatelyadjacent the two outer most yarns, but the amount of such adhesive progressively diminishes in the longitudinal yarns away from theoutermost yarn. It is also contemplated that in one form of the invention, only the two outermost longitudinal yarns are adhesively secured to the transverse yarns of the fabric and the other longitudinal yarns aresubstantially free of adhesive. 7 g

The bag closure is relatively inexpensive as compared with tapes having woven selvages or with tapes having adhesive coatings over substantial portions of their areas. Other features will be in part apparent 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 claim.

In the accompanying drawings, in which several of various possible embodiments of the invention are illustrated,

Fig. l is a perspective view of apparatus particularly adapted for producing the tape of this invention;

Fig. 2 is an enlarged section taken on line 2-2 of Fig. 1;

Fig. 3 is an enlarged sectional view of portions of tape and of-rthe slitter illustrating certain features of the invention; q I

Fig. 4 is a section similar to that of Fig. 2 illustrating an alternative form of slitter;

Fig. .5 is a plan view of open-mesh material, showing the draw tape woven into the bag material; and,

Fig. 6 shows a segment of the web of Fig. 5 folded and seamed to form a bag.

Similar reference characters indicate corresponding parts throughout the several Views of the drawings.

It hasbeen found that tape-types of bag draw closures. possess certain advantages over cordtypes of draw closures. Among these advantages are the simplicity of manufacturing a bag having .a tape-type of draw closure, particularly in an- Reference is hereto made to the aforesaid copending United States patent. .Another approach to the problem is disclosed in Thomas M. Scruggs United States Patent 2,557,517, issued June 19,11951. .The principal-objection to the use of textile tape over cords for draw closures has been the expense, which necessarily is an 1 important item in the low-cost high-production bag art. A substantial part'of the increased expense of tape over that of cord is incurredin the attempt to prevent unraveling of textile tape at its raw edges. This invention-has as a main feature the reduction in the cost of manufacturing a ravel-resistant tape vto'a substantially nominal figure. v

Referring now to the drawing, there is shown in Fig. 1 apparatus for fabricating the tape. There is shown at I a supply roll of relatively wide textile sheet material. A relatively wide web3 of textile fabric is unwound from the supply roll I and fed to slitter apparatus, generally designated 5. In passing through. the slitter apparatus 5, the web 3 is longitudinally slit into a plurality of narrow stripsl, which are'wound into a corresponding number'of rolls '9 on a common axis. Suitable pay-off 'and'wind-up arbors II and I3 are shown for the rolls l and 9, respectively. It will be understood that at least the Wind-up arbor is drivenby suitable drive mechamsm.

The slitter apparatus has a plurality of cir-.- cular knives l5 on a transverse rotary shaft I! and has a transverse rotary back roller or anvil drum l9, which cooperates with the knives I5. Each knife I5 is generally in the form of a disc with a radially tapering periphery, thus providing a sharp V-shaped cutting edge 2|. As shown, the knives are ganged on the shaft ll so that the cutting edges 21 are axially spaced from one another or transversely spaced with respect to the longitudinal Web and strips of textile material. For convenience of upkeep and repair, it is preferred that each'knife (5 be a separate element slidable onto the shaft ll, though the knives may be formed integral with one another. The anvil drum I9 is formedwith a smooth cylindrical surface 23 adapted to engage or be closely adjacent the circular cutting edges of the knives I5. The knives and anvil drum are driven, in any conventional manner, with a peripheral speed substantially equal to the linear speed of the web 3.

Means is provided for applying liquid adhesive to the cutting edges 2| of the knives. This means may be a rotary pick-up roller 25 which rotates with the circular knives and is positioned to oooperate with the cutting edges thereof. A paste The pick-up closely adjacent the apexes of the V-shaped grooves 3| in the pick-up roller. A doctor blade 33 is adjustably mounted on the supply pot 2'! in a position so as to remove superfluous adhesive from the pick-up roller. This blade has a serrated edge 35 conforming with the peripheral surface of the pick-up roller. The doctor blade is adjusted so that only a light coating of adhesive is applied to the knives, as will be pointed out hereinafter.

The liquid adhesive used is one having fastsetting adhesive characteristics. Exemplary types of such adhesives are listed below:

Hot starch or dextrin mix Polyvinyl alcohol solution Polyvinyl acetate solution Polyvinyl chloride solution Cellulose nitrate solution Cellulose acetate solution Cellulose butyrate solution.

Additionally, the liquid adhesive should be thin or of light solid content so that it immediately strikes into the yarn and sets substantially instantaneously upon application to the fabric.

The textile fabric from which the tape is formed will depend upon the service to which the tape is put. Draw tapes for small, medium and large drawn closure bags may be formed from.

textile fabric as follows:

Small bags, 4.00 (yards/pounds) cotton sheeting Medium bags, Osnaburg fabric Large bags, 10 oz. burlap.

Operation is as follows: The supply roll I of textile sheet material is on the pay-off arbor l l. The web 3is unwound and threaded through the slitter, strips 1 being thereby formed which are wound up on the wind-up arbor l3. driving mechanism (not shown) causes rotation of the wind-up arbor, knives IS, the anvil drum Suitable i9 and the pick-up roller 25. The rotating pickup roller transfers a limited amount of liquid adhesive 29 to the rotating knives l5, which then apply the adhesive to the strips 1 as they are slit from the web 3. Liquid adhesive is thus applied to the raw edges formed in slitting the web into narrow strips.

As mentioned previously, only a limited quantity of adhesive is applied to the textile material by the slitting knives. Ideally, the quantity and location of adhesive 29 is such that of the longitudinal yarns 31 of the tape, only the two outermost 39 are adhesively secured to the transverse yarns M at their ends 43. In this connection it will be observed that the sharp knife edges 2 l inherently tend to restrict application of adhesive 29 to only these outermost longitudinal yarns 39 or conversely to only the two yarns immediately adjacent to and on opposite sides of any one knife edge during slitting (Fig. 3).' Each knife may be considered as an adhesive applicator having wiping surfaces 15 which engage the moving strips 7 on opposite sides thereof at their longitudinal raw edges and which are generally transverse to the planes of the strips 'i.

There is some tendency for the liquid adhesive to spread to the other longitudinal yarns'adjacent the outermost yarns 39, but this is restricted by limiting the quantity of adhesive on the knives by adjustment of the doctor blade and by employing a liquid adhesive of low solid content which strikes right into the yarn. These two factors will vary with the weight and weave of the textile fabric, but may be readily determined. In any event, outermost yarns 39 carry the greatest quantity of adhesive applied to the fabric and the quantity of adhesive on other longitudinal yarns adjacent the yarns 39 will progressively diminish away from the edges of the fabric.

The resultant tape wherein the two outermost longitudinal yarns 39 of the fabric carry most of the adhesive is advantageous for the purposes herein in that the expense of adhesive is held to a nominal figure and in that drying or setting problems are also minimized. Slitters commonly run at high speeds, thus necessitating fast drying in order to prevent the rolls 9 from being adhered together and to prevent the various layers built up in the rolls 9 from being adhered together. Moreover, the finished tape is superior to more heavily coated textile tapes in that it is flexible and easy to handle.

An alternative embodiment of the apparatus is shown in Fig. 4. The apparatus is similar to that of Figs. 1-3 except for the shape and action of the slitters. A shear type of slitter is employed here as contrasted with the pinch or cleave type shown heretofore. The construction of such a shear type of slitter is detailed in the copending United States patent application of Thomas M. Scruggs et a1. Serial No. 55,804, entitled slitting and Winding Apparatus and filed October 21, 1948.

As shown, a plurality of knives 41 are ganged upon a rotary shaft 49. Each knife comprises a central hub 5| and an annular knife-edged flange 53 extending outward at one end of the hub and raked back toward the other end of the hub so as to be of hollow conical form. Cooperating with the knives is a rotary anvil 55 comprising a pin-- rality of annular member 57, each having a hub 59 and a flange 6| extending outwardly at one end of the hub and raked toward the other end of the hub. The knives 47 and the anvil members 51 are assembled on their respective shafts 49 and 63 so as to rake toward one another with the circular edges 65 on the knives overlapping the cylindric rims 6! on the anvil members and providing shears.

Both the knives and anvil are rotated to slit a textile web passed therebetween. Otherwise, the construction and operation are as described heretofore in connection with the Figs. 1-3 em bodiment. Liquid adhesive is applied to the cutting edges 65 of the knives by means of a pick-up roller 69 and the knives transfer the adhesive to the longitudinal edges of the strips which are slit from the web of textile material. Application of adhesive i controlled so that the two outermost longitudinal yarns of the strips receive most of the adhesive.

Referring now to Fig. 5, there is shown a continuous web H of woven material from which the bag of this invention is manufactured. The material may be of close-weave or open-weave nature. At the time that the web H is woven, the tape 1 is woven in near its upper selvage 13. This weaving is preferably such that it passes over and under pluralities of open-mesh threads such as shown a1; 15 and 11. This gives the tape a certain looseness of weave that is desirable.

The bag web of Fig. 5 is then out into segments substantially twice the desired bag width. Each segment is then folded centrally so as to bring the side and bottom margins together and they are seamed as by stitching 19 at the bottom and stitching B! at the side, the latter being opposite the central fold. This stitching forms an anchor at 83 for the end portions of the tape which were formed by segmenting the bag Web. The bag thus formed may then be turned if desired. It will be understood that after the bag is filled, the bag mouth is closed by grasping the tape adjacent the folded side and withdrawing it, at the same time pushing in the bag mouth.

As is apparent, the flat ends of the interwoven tape are firmly secured by the side-seam stitching. The light adhesive coating at the edges of the tape prevents unravelling during initial handling, especially while the tape is being woven in the bag material. It is at this time that unravelling should especially be prevented. Once the tape is woven into the bag, unravelling is no longer a serious problem because the bag material itself tends to prevent excessively harmful 6 unravelling of the tape. Moreover, even if unravelling of the tape should occur during closing and opening of the bag mouth, the longitudinal strength and tension of the tape is not adversely aifected and the longitudinal yarns of the tape are retained in place by the bag fabric.

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

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 the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

We claim:

A bag composed of Woven material and having a draw-type closure comprising a length of rawedged flat fabric tape woven with the material of the bag, said length of tape encompassing the bag girthwise adjacent its mouth and being arranged fiatwise with respect to the bag body, stitching securing together the ends of the tape, the tape being of such width as readily to be secured by the stitching, and the tape being coated with adhesive only at its longitudinal raw edges, the greater portion of said adhesive being immediately adjacent the two outermost longitudinal yarns at the opposite edges of the tape and the other longitudinal yarns being substantially free of adhesive, the adhesive thereby being merely sufficient to prevent unravelling of the tape during initial handling and while the tape is woven into the bag.

CHARLES V. BRADY. AUGUST F. OTTINGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,320,634 Moller Nov. 4, 1919 1,368,933 Hutchingson Feb. 15, 1921 1,415,563 Hoffman May 9, 1922 1,960,647 Pelton May 29, 1934 2,104,237 Neidich -Jan. 4, 1938 2,319,019 Court May 11, 1943

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