US2391938A - Bag closure - Google Patents

Description

Jan. 1, 1946. N. BAKE R 2,391,938

BAG CLOSURE Filed Jan. 16, 1943 o ea was 0 6 BY 9y ATTORNEY Patented Jan. 1, 1946 UNITED STATES PATENT OFFICE 2,391,938 BAG cLos n'E Webster Noyes Baker, Baldwin, N. Y., assignor to Bagpak, Inc., a corporation of Delaware Application January 16, 1943, Serial No. 472,564

4 Claims. (Cl. 22962) v system involved in the present application, the

The present invention relates to the closing of bags and, more particularly, to the formation of the closure for paper bags of the so-called heavyduty type adapted to contain upwards of 100 pounds of material.

Paper bags, particularly of this large heavyduty type and in some instances of smaller types adapted to contain perhaps 5 pounds of material, have been closed by collapsing the mouth and securing the mouth walls together by formation of a line of stitching therein. The particular form of stitching and particular forms of thread used therein have varied in accordance with the manufacturer's design and with the desires of the users of such bags. In general, however, the stitching has been formed from cotton thread and has involved the use of a heavy-duty sewing head.

Some forms of stitching include cords or threads of unusual thickness or of a resilient nature and so arranged with relation to the other threads as to form a reenforced or cushioned stitch.

The principal demands to be met by closures of bags of this general type include unusual strength, freedom from'sifting of finely divided bag contents and freedom from contamination of the contents by the entry of foreign materials, moisture or gases into the bag.

Strength is always a necessary factor. Freedom from sifting must be related to the particular contents involved and in many instances a line of stitching of suflicient strength will hold the bag walls together with sufllcient tightness to avoid sifting of relatively coarse materials. when finer materials are encountered, it may be necessary to plug the needle holes or to cover the line of stitching, and when extremely fine contents are encountered, it may be necessary to provide some siftproof cover over the edges of the bag mouth lying beyond the line of stitching. These various conditions have heretofore been met by use of sewing machines, thread reenforcing cords and tape may be dispensed with.

It is an object of the present invention to provide a closure for paper bags which is molded or cast upon the bag at the time of closure.

It is another object of this invention to provide a closure for paper bags which is formed from a material which is a somewhat flexible or resilient solid at normal temperatures and which may be rendered substantially liquid by the application of elevated temperatures.

It is a further object of the present invention to provide a molded closure for paper bags which closure is molded upon the bag after the same has been filled. I

It is a further object of the present invention to provide a molded closure for bags which is strong and capable of withstanding strains which may be encountered in the handling and shipment thereof.

It is a further object of the present invention to provide a molded closure for bags which closure the application of reeni'orcing strips or tapes prior to the application of the stitching or by the application of a sealing tape over the line of stitch- I is made from a resilient tough homogeneous material capable of yielding upon the application of unusual stress whereby to distribute the stress over substantial areas of the bag to avoid rupture of the bag or breakage of the closure.

It is a further object of the present invention to provide a molded closure for paper bags which includes elements passing through apertures in juxtaposed walls of a bag mouth and elements for preventing escape of bag contents through the apertures through which such closure elements extend.

It is a further object of the present invention to form a strong siftproof and completely sealed closure for bags which closure is molded upon a bag mouth after the bag has been filled.

According to the present invention, a filled bag is collapsed in such a manner as to bring the portions of the walls thereof adjacent the mouth into face to face contact. The flatly closed bag mouth is then perforated in such a manner as to form a series of holes extending completely through the collapsed walls adjacent the mouth.

alternately, the bag may be -perforated during manufacture or prior to filling. If the bag is of eration and, of course, the intucked gussets will be 'perforated along with the other walls within the collapsed mouth. The perforated bag mouth is then brought between molding elements which are; adapted to engage withthe opposite faces and toforce a suitable moldable material through the perforations. The bag mouth may then be takenfrom the molding elements while holding the bag mouth in closed position and the holding of the mouth must be continued until the moldable material has set or solidified. When this operation is complete, the material extending through the perforations will form elongated strands, somewhat similar to stitches of thread or wire, which are capable of holding the mouth in a permanently closed position.

Preferably, the molding elements mentioned above should include suitable hollow portions aligned with the perforations of the bag mouth so as to form enlarged bodies of the moldable material on either side of the bag mouth which are integral with the opposite ends of the strands of moldable material forced through the perforations. According to one form of the present invention, there may be molded into each perforation in the bag mouth a body comprising two enlarged heads and a connecting strand. The connecting strand will, of course, assume the diameter of the bag wall perforations while the enlarged heads should be of somewhat greater diameter than these perforations. The resultant body thus resembles a double-headed rivet. Sultable spacing of the perforations of the bag mouth and the formation of a double-headed rivet by molding in situ in each of these perforations will form a closure of unusual strength when the moldable material is of a strong and preferably resilient nature.

According to another form of the present invention, continuous bands of moldable material may be formed throughout the width of each of the opposite faces of the bag mouth. These bands are formed integrally with the strands of material forced through the perforations and the resultant closure comprises a homogeneous ladderlike structure of molded material. The closure thus formed has even greater strength than that discussed in the preceding paragraph and is quite analogous to the form of stitched closure in which separate sealing or reenforcing tapes are used. The closure thus provided by the present invention is quite resistant to sifting of the bag contents and, except in the case of extremely finely divided material, is commercially satisfactory.

A still further form of the present invention embodies the strands forced through the bag mouth perforations and a continuous cap of molded material extending from the line of perforations on one side of the bag mouth over the exposed edges of the bag mouth and down to the line of perforations on the opposite sides thereof. In this form, the closure is completely proof against sifting and it is also completely proof against the entry of foreign material, moisture or ases to the bag.

Each of the forms of the present invention discussed above may be formed by suitably designed molding elements. The specific construction and characteristics of the molding elements will, of course, be varied with regard to the particular moldable compound selected.

Many moldable compounds or substances may be used. In general, those substances which are thermoplastic are easier to handle and when they are used the bag may be removed from the molding apparatus and conducted to suitable holding apparatus inwhich the thermoplastic material is allowed to cooland return to its original state. Thermosetting materials may also be used but, in such instances, it is necessary to maintain the bag mouth and the molding composition under heat and pressure for an extended period of time suitable for the particular thermosetting compound selected.

The general attributes which make a moldable composition suitable for use in the present invention are:

(1) It should fiow at temperatures not inconsistent with the characteristics of paper or other material from which the bag may be formed; (2) In the case of thermoplastic materials, they should be capable of returning to normal condition within a reasonably short period of time to avoid undue complications in the closure forming apparatus; (3) In the case of thermosetting materials, they should be of a liquid or fiowable character when introduced to the bag; (4) The material should be tough as distinguished from brittle whensubjected to the temperatures likely to be encountered by the closed bag; (5) Preferably, material should be yielding or even resilient at the temperatures encountered by the filled bag.

In general, thermoplastic materials, such as rubber, rubber derivatives, synthetic or artificial rubber or'modified latex materials; vinyl resins, preferably polyvinyl acetate, or polyvinyl chloride or vinylidene chloride; cellulose acetate, or cellulose acetate butyrate; and certain of the acrylic resins, such as the acrylate and methacrylate resins, are among those thermoplastic materials having characteristics suitable for use in the present invention. Other thermoplastic materials having equivalent or related characteristics may also be used. Of the thermosetting materials, phenol formaldehydes and urea or thiourea formaldehydes, which may be used in liquid or other nowable form, are suitable. Obviously, any of these materials may be modified by the addition of treating agents such as plasticizers to render them flexible and to impart other characteristics which may be desired.

Referring now to the drawings in which are illustrated preferredv but not necessarily the only forms of my invention:

Fig. 1 is a fragmentary elevation of a gusseted bag having perforations formed in the mouth thereof preparatory to closure in accordance with the present invention;

Fig. 2 is a fragmentary elevation of one form 50 of closure which may be applied to bags of the type illustrated in Fig. 1;

Fig. 2A is a section along the line 2A2A of Fig.

Fig. 3 is a fragmentary elevation of a 'diifer- 55 cut form of closure which may be formed upon the bag illustrated in Fig. 1;

Fig. 4 is a section along the line 4-4 of Fig. 3; Fig 5 is a fragmentary elevation of still another form of closure which may be formed upon 60 the bag illustrated in Fig. 1; and

Fig. 6 is a section along the line 8-5 of Fig. 5.

In the drawing, wherein similar characters of reference indicate similar parts throughout the several views, each of the sections have been 65 taken in the direction indicated by arrows associated with the respective section lines.

In Fig. 1, there is shown the end portion of a bag to which the present invention may be adapted. It will be understood that the portion 7 of the bag illustrated'in Fig. 1 may comprise the mouth portion of a filled bag and that the mouth portion has been partially collapsed toward closed position. In accordance with the present invention, the walls of the bag ID are perforated 75 to form apertures falling in alignment with one assaoss V another whereby to define continuous passageways from one face of the bag to the other. These perforations are illustrated in Fig. 1 at l2 and they may be formed in the bag mouth during manufacture of the bag or after the bag has been completed and flattened ready for shipment to a customer. If the bag is gusseted as indicated in Fig. l, the gusseted end walls l4 and ii of the bag will be perforated with holes I 8 formed during manufacture or after manufacture as described above.

The walls of the bag mouth may be perforated after the baghas been filled and it is ready to be closed. If this procedure is followed, any commercial bag may be used and the user of the bag needs only to provide himself with some form of perforating apparatus to prepare the filled bags for closure in accordance with the present invention. To this end, the collapsed mouths of filled bags may be passed through a station in which a rotary punch is arranged for successively forming the perforations l2 and I8 as the bag is passed thereth'rough. Alternatively, there may be provided a suitable gang punch adapted to form all of the perforations at a single operation. The particular manner of forming the perforations is a matter of choice, it only being necessary that the perforations extend all the way through the walls of the bag mouth and that they be aligned with sufilcient accuracy to permit the formation of continuous strands of moldable material extending therethrough for the purpose of securing the bag in a closed .position.

It will be understood that the bag illustrated in Fig. 1 maybe a single ply bag' or that it may comprise a plurality of plies. It may be formed from paper, textile material, plastic material or any combination of such materials. The present invention is particularly adapted for the closure of paper bags either of the single ply or multiply type. The greatest utility of the present invention is in connection with multiply paper or paper and asphaltdaminated bags of heavy-duty type adapted to contain upwards of 100 pounds of material.

In Fig. 2, there is illustrated a form of closure made in accordance with the present invention which is particularly adapted for closing containers whose contents are relatively coarse and not particularly likely to sift. The closure comprises a plurality of separate bodies molded or cast into the perforations l2'and it. These bodies comprise a strand having heads 22 and 24 integrally formed therewith on opposite faces of the bag walls. The heads 22 and 24 are of a diameter somewhat greater than that of the perforations and the strands 20 formed therein. Accordingly, the closure elements take the form of doubleheaded rivets cast or molded in situ. As shown in Fig. 2A, the closure elements serve to secure the walls 26 and 28 of a multiply paper bag in a securely closed position.

In Figs. .3 and 4, there is illustrated a modified form of closure formed in accordance with the presentinvention. As shown in these figures, strands 30 are molded or cast within each of the perforations i2 or it and the opposite ends of all of these strands are integral with bands 32 and 34 molded or cast completely across the width of the opposite faces of the bag mouth. As shown in Fig. 4, the bands 32 and 34 .together with the strands III serve to hold the walls 36 and 38 of a multiply paper bag in securely closed position. The modification illustrated in Figs. 3 and 4 is particularly adapted for materials which are likely to sift through relatively small openings. The bands 32 and 34 serve to prevent the sifting of contents through the perforation l2 and they also serve to hold the bag walls together whereby to reduce sifting of the contents through passageways between the strands 30. They also serve to reenforce the entire closure whereby to make itconsiderably stronger than the closure illustrated in Figs. 2 and 2A.

In Figs. 5 and 6, there is illustrated a further modification of the present invention. In these figures, the strands 40 formed within the perforations l2 are integral at their opposite ends with a continuous cap-like member 42. This caplike member extends along the full width of the bag mouth and serves to seal the perforations l2 and it also extends continuously over the top edges of the bag mouth to prevent escape of such material as might work its way between the strands 40. If so desired, a web 41 may be molded at each end of the cap 42 to insure tight closure of the corners of the bag mouth. As shown in Fig. 6, the cap 42 together with the strands 40 serve to secure the walls 44 and 46 of a multiply paper bag in tightly closed relationship and the cap 42 also extends over the edges 48 and 50 of the respective walls. 44 and 48. It will be understood that there is thus formed a completely sealed closure proof against sifting and proof against the ingress of moisture, dirt or contaminating gasestothe body of the bag. I

Any of the forms of closure illustrated and described in the preceding portion of this specification may be formed from suitable material which is flowable upon the application of elevated temperatures not inconsistent with the characteristics of the paper or other material from which the bag is formed and which solidifies into a tough somewhat yieldable and resilient body when normal temperatures are resumed. Many substances of the organic resin type are adaptable to the present invention. As set forth above, thermoplastic materials of the organic resin group or such thermoplastic materials as rubber may be used. Preferably, a. plasticized polyvinyl chloride or 'vinylidene chloride are used. Some of the thermosetting materials of the organic resin type may also be used provided they are available in liquid or semi-liquid form from which form they are adapted to be set into permanent shape by the application of heat and pressure compatible with the material from which the bag 'is made.

With any of the materials suggested above, the specific molding or casting apparatus maybe designed by those familiar with such apparatus and material. In general, the apparatus must include heating devices to make the material flowable or to cause it to set. There must also -be opposed dies adapted to be brought into pressure contact with the opposite faces of the collapsed bag mouth. Suitable passageways-must be provided for the flow of the flowable material into the dies and suitable pressure producing means must be employed to force the flowable material into the perforations I 2, l8 of the bag mouth.

The dies must also include suitable hollow portions shaped to form the heads 22, 24 of Figs.

variations in detail may be resorted to by those skilled in the art within the scope of the appended claims. 1

I claim:

1. A bag comprising a tubular body having fiexible walls and fastening means securing said walls together adjacent at least one end portion of the bag, said fastening means being molded in situ from a plastic material and comprising a pluralcludes the operations of flowing the material in a flowable or viscous condition into the proper shape and retaining it in such shape until it has cooled sufiiciently to retain such shape. In connection with thermosetting plastic materials, the word molding includes the operations of, flowin thev material in flowable condition into proper shape and maintaining it in such shape under heat and/ or pressure and/or other conditions necessary to cause condensation, polymerization or setting of the material whereby it will retain such shape. Thus, by the term molding I intend to include the shaping of a plastic material in flowable condition and the treatment of such material while retained in such shape to render it substantially non-fiowable whereby it will retain such shape with the particular characteristics, such as flexibility, toughness, resilience, etc., of the particular plastic material selected.

In the above description, emphasis has bee laid upon the closing of a filled bag. It is to be understood that the closures and methods herein disclosed are equally applicable to the bottoms or other seams which may occur in bags of various forms. Thus, inthe case of bags formed from blanks cut from continuous tubes, one end of each such blank may be closed by any of the closures herein defined to form a bottom. Thereafter, the bag may be opened, filled and closed in any suitable manner and of course the final closure may be one of thoseherein defined if so desired. Similarly, the closures herein defined are applicable, as bottoms or as final closures, to bags of the gusseted or non-gusseted type.

' The above detailed description has been made for the purpose of complying with the patent statutes and it is obvious that modifications and ity of strands extending completely through the walls of said bag and sealing strips on opposite faces of said =bag integral with said strands and extending throughout the width of said bag, said strands and said sealing strips consisting solely of said plastic material.

2. A bag comprising a tubular body having flexible walls and fastening means securing said walls together adjacent at least one end portion of the bag, said fastening means being molded in situ from a plastic material and comprising strands extending completely through the walls of said bag and a cap integrally united with each of said strands at each end thereof and extending over the end of said bag whereby to secure said walls and to seal the end of said bag.

3. A bag comprising a tubular body having flexible walls and fastening means securing said walls together adjacent at least one end portion of the bag, said fastening means being molded in situ from a plastic material and comprising strands extending completely through the walls of said bag and a cap integrally united with each of said strands at each end thereof and extending throughout the width of said bag and over the end thereof whereby to secure said walls and to seal the end of said bag.

4. A has comprising a tubular body having flexible walls and fastening means securing said walls together adjacent at least one end portion of the bag, said fastening means being molded in situ 'from a plastic material and comprising a plurality of strands extending completely through the walls of said bag and reinforcing means integral with and interconnecting a plurality of said strands. said strands and said reinforcing means consisting solely of said plastic material.

WEBSTER NOYES BAKER.

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