US3927825A

US3927825A - Bag

Info

Publication number: US3927825A
Application number: US436131A
Authority: US
Inventors: Robert J Stearley
Original assignee: Great Plains Bag Corp
Current assignee: Great Plains Bag Corp
Priority date: 1972-02-22
Filing date: 1974-01-24
Publication date: 1975-12-23
Anticipated expiration: 1992-12-23

Abstract

A bag having improved leak resistant characteristics is disclosed herein. The bag comprises an inner ply of tubular paper and an outer ply of tubular paper coextensive with the outer surface of the inner ply. A moisture impervious means such as a plastic liner or plastic coated paper is coextensive with the inner surface of the inner ply and has a length substantially the same as the inner ply. The forward panel of the outer ply has its lower edge normally dwelling above the lower edges of the inner ply and the rearward panel of the outer ply when the plies are in an unfolded flattened condition. A single straight fold is imposed on the inner ply, moisture impervious means, and the rearward panel of the outer ply at a level below the lower edge of the forward panel of the outer ply to form a single straight flap means. The moisture impervious means is joined at its lower end within the flap. Adhesive means joins to the lower outer end of the forward panel of the outer ply the portion of the flap means comprising the lower inner surface of the rearward panel of the outer ply and the lower outer surface of the foward panel of the inner ply. The method of forming the bag and sealing the same is also disclosed.

Description

United States Patent [191 Stearley Dec. 23, 1975 BAG [75] Inventor: Robert J. Stearley, Des Moines,

Iowa

[73] Assignee: Great Plains Bag Corporation, Des

Moines, Iowa [22] Filed: Jan. 24, 1974 [21] Appl. No.: 436,131

Related US. Application Data [63] Continuation-impart of Ser. No. 227,821, Feb. 22,

1972, abandoned.

Primary Examiner-William Price Assistant Examiner-Stephen P. Garbe Attorney, Agent, or Firm-Zarley, McKee, Thomte & Voorhees [57] ABSTRACT A bag having improved leak resistant characteristics is disclosed herein. The bag comprises an inner ply of tubular paper and an outer ply of tubular paper coextensive with the outer surface of the inner ply. A moisture impervious means such as a plastic liner or plastic coated paper is coextensive with the inner surface of the inner ply and has a length substantially the same as the inner ply. The forward panel of the outer ply has its lower edge normally dwelling above the lower edges of the inner ply and the rearward panel of the outer ply when the plies are in an unfolded flattened condition. A single straight fold is imposed on the inner ply, moisture impervious means, and the rearward panel of the outer ply at a level below the lower edge of the forward panel of the outer ply to form a single straight flap means. The moisture impervious means is joined at its lower end within the flap. Adhesive means joins to the lower outer end of the forward panel of the outer ply the portion of the flap means comprising the lower inner surface of the rearward panel of the outer ply and the lower outer surface of the foward panel of the inner ply. The method of forming the bag and sealing the same is also disclosed.

3 Claims, 6 Drawing Figures All US. Patent Dec. 23, 1975 JII Sheet 1 of 2 BAG This is a continuation-in-part of co-pending application Ser. No. 227,821, filed Feb. 22, 1972 now abancloned.

Products such as meat and the like are frequently placed in paper bags and then frozen for storage and/or shipment. The paper material is frequently lined with a plastic liner or the like to prevent the paper from absorbing the moisture from the product. A problem is encountered in closing and sealing the bag, especially the bottom, since the closure must be strong and leak proof. Bags with gusset sides have been used for this purpose but have not been altogether satisfactory since sealing problems are associated therewith. In certain other bags, the edge of the paper material is exposed in the closure within the bag and wicking occurs even though a plastic liner is employed.

Therefore, it is a principal object of this invention to provide an improved bag and the method of manufacturing the same. i

A further object of this invention is to provide a leak resistant bag.

A further object of this invention is to provide a leak resistant bag having an improved seal at its closure end.

A further object of this invention is to provide a paper bag wherein wicking is eliminated.

A further object of this invention is to provide a multi-ply bag including a moisture impervious means coextensive with the inside surface of the inner ply.

A further object of this invention is to provide a multi-ply bag which has superior strength characteristics.

A further object of this invention is to provide a bag which is economical of manufacture, durable in use and refined in appearance.

These and other objects will be apparent. to those skilled in the art.

This invention consists in the construction, arrangements and combination of the various parts of the device, whereby the objects contemplated are attained as hereinafter more fully set forth, specifically pointed out in the claims, and illustrated in the accompanying drawings, in which:

FIG. 1 is a perspective view of the bag;

FIG. 2 is a partial perspective view of the lower end of the bag prior to folding the same;

FIG. 3tis a partial plan view of the bag with layers cut away to more fully illustrate the construction thereof;

FIG. 4 is a sectional view taken on lines 44 of FIG.

FIG. 5 is an enlarged sectional view taken on lines 55 of FIG. 1; and

FIG. 6 is an enlarged sectional view taken along lines 66 of FIG. 1.

The bag of this invention is referred to generally by the reference numeral 10 and includes an upper end 12 and a lower end 14. For purposes of description, the bag 10 will be described as having rearward and forward sides 16 and 18 respectively. Bag 10 has an inner ply 20 of tubular paper having forward and

rearward panels

22 and 24 respectively. Bag 10 also has an intermediate ply 26 of tubular paper having forward and

rearward panels

28 and 30 respectively and outer ply 32 of tubular paper having forward and

rearward panels

34 and 36 respectively.

Bag 10 is referred to in the art as a tube sack or bag. It should be distinguished from gusset walled bags 2 which have folds or gussets running vertically along the lateral edges. Bag 10 has no folds or gussets running longitudinally, but instead is formed from tubular plies which are folded over on the ends thereof.

The numeral 38 refers to a moisture impervious means such as a polyethylene liner which is coextensive with the inner surface of the inner ply 20 and which has substantially the same length as the ply 20. Moisture impervious means 38 may be comprised of a seamless tubular polyethylene liner as shown or a thermoplastic coated kraft paper material (polyvinyl chloride, polyethylene, etc.). The thermoplastic coating may be provided on the inner surface of the inner ply 20 if desired. Liner 38 comprises a forward panel 40 and a rearward panel 42 having their lower ends terminating in the same plane as the inner ply 20.

FIG. 6 illustrates the manner in which the plies are formed into their tubular shape. The preferred form for inner ply 28 is that of a seamless tube. Seamless plastic liners have previously been utilized in other types of bags, but they have not heretofore been utilized in a pinch type bag which does not have gusset walls.

As seen in FIG. 6, the side edges of outer ply 32 are overlapped and sealed by suitable adhesive. The intermediate and

inner plies

26 and 20 are also overlapped and sealed in an offset relationship with respect to the overlapped edges of outer ply 32.

FIg. 2 illustrates the bottom of the bag 10 prior to the folding thereof. As seen in FIG. 2, the forward panel 34 of the outer ply 32 has its lower edge normally dwelling above the lower edges of the forward panel 28 of intermediate ply 26, the inner ply 20, rearward panel 30 of intermediate ply 26 and the rearward panel 36 of outer ply 32.

Preferably, the lower end of the liner 38 is heat sealedprior toany folding operation thereof. The numeral 48 refers to the area of the inner ply 20 upon which the heat is imposed to seal the lower end of the liner 38.

The inside surface of rearward panel 36 of outer ply 32 is spot pasted to the outer surface of rearward panel 30 of intermediate ply 26 at 50. The lower inside surface of panel 36 is provided with a suitable adhesive 52 thereon which is located below the lower end of panel 30. The inside surface of panel 30 is spot pasted at 54 to the outer surface of panel 24 of inner ply 20. The lower inside surface of panel 30 is also provided with three beads or rows of adhesive 56, 58 and 60 which are located below the lower end of panel 24. The lower outside surface of panel 22 is also provided with an adhesive 61 thereon.

The outer surface of panel 22 is spot pasted at 62 to the inner surface of panel 28. The outer surface of panel 28 is spot pasted at 64 to the inner surface of panel 34. Suitable spot paste and adhesive materials are contact cement, latex base adhesive, starch base adhesive, hot melt thermoplastic adhesive, etc.

The numeral 66 refers to the area wherein a single straight fold is imposed in the bag to close and seal the bottom end thereof.

Panels

36, 30, 24, 42, 40 and 22 are folded forwardly and upwardly from the position of FIG. 4 to the position of FIG. 5. In FIG. 5, it can be seen that the adhesive 52 joins the inner surface of panel 36 to the outer surface of panel 34 and that

adhesive rows

56, 58 and 60 join the inside surface of panel 30 to the outer surface of panel 34. Adhesive 50 joins the

panels

30 and 36 as shown. Adhesive 61 joins the outer surface of panel 22 to the outer surface of panel 28 and to the outer surface of panel 34.

Thus it can be seen that an extremely effective seal has been provided to close the lower end of the bag which positively prevents any leakage from the bag. The seal is not only leakproof but it is extremely strong. The arrangement of the lower ends of the various panels with respect to the plastic liner 38 and the seamless structure of liner 38 assure that wicking will not occur within the bag since there are no exposed paper edges. The preferred method of heat sealing the lower end of the plastic liner 38 prior to the folding of the same further aids in providing a positive seal through which moisture cannot pass.

As can be seen in FIG. 5,

panels

22, 24 of inner ply protect liner 38 along the fold line from engagement with the lower edge of panel 28. This is important because it prevents the lower edge of panel 28 from puncturing plastic liner 38 when the bag is being filled. Any such puncture could result in wicking of moisture into the contents of the bag.

It should be noted that additional plies may be provided in the bag if additional strength is required. If additional plies are employed, the additional plies would have the same length as the inner ply 20. It should also be noted that the bag could be constructed without the intermediate ply being employed. How ever, the preferred embodiment does employ the inner, intermediate and outer plies.

Thus it can be seen that the bag accomplishes at least all of its stated objectives.

1 claim:

1. A bag comprising a tubular container having forward and rearward walls comprised of at least an inner plastic ply and first, second and outer paper plies; each of said plies having front and rear panels with upper and lower edges;

said lower edges of said front and rear panels of said inner and first plies being coincident with one another;

said lower edge of said second ply front panel being spaced above said lower edges of said inner and first plies;

' said lower edge of said outer ply front panel being spaced above said lower edge of said second ply front panel;

said lower edge of said second ply rear panel being below said lower edges of said inner and first plies when said plies are in an unfolded condition;

said lower edge of said outer ply rear panel being below said lower edge of said second ply rear panel when said plies are in an unfolded condition; said bag being folded along a single straight fold imposed at a level below said lower edges of said second and outer ply forward panels and above said lower edges of said inner and first plies, said front first ply panel being in facing engagement with said front panel of said second ply and said rear panel of said outer ply being in facing engagement with said front panel of said outer ply, said rear panel of said second ply being in facing engagement with said front panel of said outer ply,

an adhesive material joining said folded over portions of said first ply front panel and said outer ply rear panel to said second ply front panel and said outer ply front panel respectively, said adhesive material also joining said folded over portion of said second ply rear panel to said outer ply front panel.

2. A bag container according to claim 1 wherein said layer of moisture impervious material comprises a seamless flexible plastic tube having open upper and lower ends.

3. A bag according to claim 1 wherein said lower edge of said second ply rear panel is folded over into engagement with said front panel of said outer ply, said adhesive material joining said folded over portion of said second ply rear panel to said outer ply front panel.

Claims

1. A bag comprising a tubular container having forward and rearward walls comprised of at least an inner plastic ply and first, second and outer paper plies; each of said plies having front and rear panels with upper and lower edges; said lower edges of said front and rear panels of said inner and first plies being coincident with one another; said lower edge of said second ply front panel being spaced above said lower edges of said inner and first plies; said lower edge of said outer ply front panel being spaced above said lower edge of said second ply front panel; said lower edge of said second ply rear panel being below said lower edges of said inner and first plies when said plies are in an unfolded condition; said lower edge of said outer ply rear panel being below said lower edge of said second ply rear panel when said plies are in an unfolded condition; said bag being folded along a single straight fold imposed at a level below said lower edges of said second and outer ply forward panels and above said lower edges of said inner and first plies, said front first ply panel being in facing engagement with said front panel of said second ply and said rear panel of said outer ply being in facing engagement with said front panel of said outer ply, said rear panel of said second ply being in facing engagement with said front panel of said outer ply, an adhesive material joining said folded over portions of said first ply front panel and said outer ply rear panel to said second ply front panel and said outer ply front panel respectively, said adhesive material also joining said folded over portion of said second ply rear panel to said outer ply front panel.