US3318511A

US3318511A - Pasted valve bag with flexible elastic insert

Info

Publication number: US3318511A
Application number: US568607A
Authority: US
Inventors: Howard J Winegard
Original assignee: Union Camp Corp
Current assignee: Union Camp Corp
Priority date: 1966-07-28
Filing date: 1966-07-28
Publication date: 1967-05-09
Anticipated expiration: 1984-05-09

Description

y 1967 H. J. WINEGARD 3,318,511

PASTED VALVE BAG WITH FLEXIBLE ELASTIC INSERT Filed July 28, 1966 FIGI 2 Sheets-Sheet l May 9, 1967 H. J. WINEGARD 3,

PASTED VALVE BAG WITH FLEXiBLE ELASTIC INSERT Filed July 28, 1966 2 Sheets-Sheet 2 FIG? INVENTOR HOWARD J. WINEGARD ATTORNEY United States Patent 3,318,511 PASTED VALVE BAG WITH FLEXIBLE ELASTIC INSERT Howard J. Winegard, Trenton, N.J., assignor to Un on Camp Corporation, New York, N.Y., a corporation of Virginia Filed July 28, 1966, Ser. No. 568,607 9 Claims. (Cl. 229-625) This invention relates to valve bags which are closed by pasting at both ends except for a filling valve in one corner, and more particularly to a type of bag having a flexible insert in the valve corner through which the bag is filled.

Paper bags having valved filling openings are in common use for packaging bulk material, such as chemicals, cement, fertilizer, grain, feed, flour and the like. Such bags are made of a tough and strong paper or other fibrous material, and usually have walls comprising multi-ply layers of paper to increase their strength. Such bags are filled by inserting a spout through the filling opening and blowing the bulk material therein. When the bag has been filled, the spout is withdrawn and the valve is automatically closed by the pressure of the material in the bag against the valve. Since such valves have a tendency to leak and sift material, sleeves of flexible or limp paper have been inserted in the valve to make a tighter closure of the filling opening and prevent material from sifting through the valve. Such valve sleeves are usually made of a single sheet of paper folded to form a tube with the opposite sides adhesively secured to the bag. Although such sleeves extending into the valve are an improvement from the standpoint of leakage, the leakage is not entirely prevented. Consequently when more expensive materials are packaged in the bags, the sleeve is made longer and extends outward from the valve. After the bag has been filled, the free or outer end of the sleeve is folded and tucked in between the overlying flaps to provide an additional closure to prevent the material in the bag from seeping out. It is diflicu-lt to securely tuck in the end of the sleeve so that it will not be released during the transit of the filled bag. Consequently such tuck-in sleeves have to be carefully and manually tucked in by the workman who operates the filling machine, all of which substantially reduces the speed and increases the cost of filling the bags.

In order to provide a bag having the required strength to resist rupture during handling, many bags are being made with multi-ply walls. Such a bag comprises a plurality of separate sheets positioned one inside the other and may have as many as six plies or layers of paper or a combination of paper and plastic. The multi-ply Walls have a substantial thickness that greatly reduces its flexibility. Furthermore, when the ends of the bag are folded to form closure flaps, the overlapping folds still further increase the thickness and decrease the ability of the wall to flex, as well as forming irregular surfaces which are to be adhesively secured to each other. The difliculty of sealing the overlapping flaps of such bags increases as the thickness of the wall increases, which further reduces the flexibility of the wall and increases the irregularity of the overlying surfaces to be pasted. As a result, a bag having a multi-ply wall and a multi-ply valve is more apt to sift material therefrom and the probability of leakage increases as the wall thickness increases.

An object of the present invention is to provide an improved construction in a bag which insures a more perfect seal between the surfaces of the overlapping flaps.

Another object is to provide a bag which has a valve that does not appreciably increase the thickness of the wall and does not decrease the walls flexibility.

"ice

Another object is to provide a bag which has a standardized valve insert that flexes to accept filling spouts of varying dimension.

Another object is to provide a bag which has a flexible valve insert that does away with uneven bottom dimen- SlOIl.

Another object is to provide a bag which has a flexible valve insert that returns to its original size upon removal of the filling nozzle.

Another object is to provide a bag which has a flexible valve insert that provides a seal around the filling nozzle.

Another object is to provide a bag which has a flexible valve insert made of elastic sheet material, such as rubber latex, milled rubber, polyvinylchloride, polyurethane, styrene-butadiene copolymer, or similar material.

Another object is to provide a bag which has a flexible valve insert which is of simple and compact construction, economical to manufacture, and reliable in operation.

Another object is to provide a bag which has a flexible valve insert that allows squaring out of the bag to use less paper.

Still another object is to provide a bag which has a flexible valve insert that is especially effective in preventing fine materials from sifting from the bag.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises an article of manufacture possessing the features, properties, and the relation of elements which will be exemplified in the article hereinafter described and the scope of the invention which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawing, in which:

FIG. 1 is a perspective view of a bag with the flexible valve insert in position.

FIG. 2 is a plan view of the flexible valve insert.

FIG. 3 is a side view of the flexible valve insert.

FIG. 4 is a cutaway view of the flexible valve insert in place.

FIG. 5 is a cut-away view of the flexible valve in a bag being filled.

FIG. 6 is a plan view of a modified flexible valve insert made from a laminated sheet.

FIG. 7 is a cutaway view of the insert of FIG. 6 in place in the valve.

Referring to FIG. 1 of the drawings, there is shown a bag 10, preferably formed of a heavy grade of kraft paper. It can also be constructed from heavier or lighter material, depending on the requirements of the bag. As shown, the bag has

side walls

12 and 13, portions of which are folded inwardly to form an overlying end of conventional design having an inturned va-lve corner flap 11. The valve is indicated at 14 in FIG. 1 and the insert is shown in greater detail in FIGS. 2 and 3 before its insertion in the valve corner.

As shown in FIGS. 2 and 3, the flexible valve 14 comprises a rectangular sheet of paper 15 having secured to its upper surface intermediate its ends at A, one end of a substantially rectangular section of rubber latex sheet 16. The latex sheet 16 is secured on its opposite end to the bottom surface of a second paper sheet 17 at B, the second kraft sheet 17 substantially overlapping the latex sheet 16 and the first paper sheet 15. Latex sheet 16 is as wide as or wider than

paper sheets

15 and 17 in order to prevent leakage between the valve and the valve opening of the bag. Intermediate the secured ends of latex sheet 16 is an opening which may be a slit 18 having non-tearing ends 19, as illustrated, or an opening having a curvilinear contour, such as a circle or oval. While in my presheet to handle it during insertion in the valve.

, size of the spout.

ferred embodiment I have utilized a rubber latex sh'eet,

Iany mate-rial that is strong enough to withstand tearing when the filling spout is inserted in slit 18 and sufiiciently -stretchable to have relatively full recovery to its original size when the spout is removed can be utilized. In my preferred embodiment, I have found that a rubber latex sheet of approximately five mils thick has the necessary attributes. Other materials having the extensibility and recovery of latex rubber will work equally well.

Paper sheet 15 is secured along its free overlapping end 7 to the top of corner flap 11, and latex sheet 16 is folded 4 tended 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.

back 180 along opening 18. This places sheet 17 in the position shown in FIG. 4. The end closure is formed by folding the end portions of

side walls

12 and 13 on opposite sides of the bag inwardly toward each other and securing them by glue to the upper surface of sheet 17, thereby positioning the valve in the bag as shown in FIGS. 1 and 4.

s In operation, as shown in FIG. 5, a filling spout 20 is.

inserted between

sheets

15 and 17 and through stretchable opening 18 in the elastic sheet 16. Material is passed through spout 20 which is in communication with the.

inside of bag 10. When the bag is fill'ed arid the filling spout is removed, the stretchable valve opening 18 reinsertion of the elastic sheet in the valve and to hold such sheet after it is inserted. It would be quite difficult because of the softness and limpness of the elastic ever, if that problem could be overcome, the elastic sheet alone would sufiice. Accordingly, a modification is shown in FIGS. 6 and 7, which allows easy handling of the elastic sheet and saves the cost of combining the elastic sheets and the sheets of paper as heretofore described FIG. 6 shows the elastic sheet 21 lightly laminated or coated to a paper sheet 22. This laminated sheet has a fold line 23 in the center for centering the stretchable opening 18 in the .valve. The laminated sheet is inserted in the valve opening and secured at one end to the top of corner'fl-ap 11 and at the otherend to the folded end portions of the

side walls

12 and 13. When the filling spout 20 is inserted in the stretchable opening 18 the paper will tear but the elastic sheet will stretch to the After the spout is removed the opening 18 returns to its original dimension, as described in connection with the other construction described above.

Since certain changes may be made in the'a'bove article, and ditferent embodiments of the invention could be made without departing from the scope thereof, it is in- It is also to be understood that the following claims are intended to cover all of the generic and specific fea- V tures of the invention herein described, and all statements of the scope of the invention which, as a matter of Ian g-uage, might be said to fall therebetween. 7

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1.'A pasted valve bag having 'side walls and an in- 'turned corner flap, aportion of said side Walls :being.

folded inwardly and overlapping said corner flap to form a valve opening in one corner, an elastic valve insert 'secured to and extending inwardly between said overlap ping side walls and said corner flap, said elastic valve insert having a stretchable opening in communication with the interior of said bag for receiving a filling spout.

2. A pasted valve bag in accordance with claim 1, in which the elastic valve insert comprises a first sheet of paper secured to said corner flap, a second paper sheet secured to said overlapping side walls, a sheet of elastic material at least as wide as the bag opening having a relatively small opening intermediate its ends, said elas tic material having one end secured along the width of the upper surface of said first paper sheet and its oppo-' site end secured along the width of the lower surface of said second paper sheet, whereby said opening communie cates with the interior of said bag.

7 3. A pasted valve bag in accordance with claim 1 in 7 which the elastic material is rubber latex.

4. A pasted valve bag in accordance with claim 1 in lwhich the elastic valve insert comprises styrene-butadiene out that the

sheets

15 and 17 primarily serve to permit Howcopolymer mounted on a paper sheet.

-5. A pasted valve bag in accordance with claim 1 in which the opening in theelastic material has a curvilinear contour.

6. A pasted valve bag in accordance with claim 1 in' which the elastic valve insert is secured to said bag 'by an adhesive.

7. A pasted valve bag in accordance with claim 2 which the sheet of elastic material is secured to said paper sheets by a fusion bond.

8. A pasted valve bag in accordance with claim 1 in overlapping side walls and said corner flap.

References Cited by the Examiner V UNITED STATES PATENTS 946,318 1/1910 Bates 229 62.s 1,476,560 12/1923 Witmer 229-625 2,338,254

1/1944 Miller 22962.S

JOSEPH R. LECLAIR, Primary Examiner. D. BOCKENEK, Assistant Examiner,

Claims

1. A PASTED VALVE BAG HAVING SIDE ALLS AND AN INTURNED CORNER FLAP, A PORTION OF SAID SIDE WALLS BEING FOLDED INWARDLY AND OVERLAPPING SAID CORNER FLAP TO FORM A VALVE OPENING IN ONE CORNER, AN ELASTIC VALVE INSERT SECURED TO AND EXTENDING INWARDLY BETWEEN SAID OVERLAPPING SIDE WALLS AND SAID CORNER FLAP, SAID ELASTIC VALVE INSERT HAVING A STRETCHABLE OPENING IN COMMUNICATION WITH THE INTERIOR OF SAID BAG FOR RECEIVING A FILLING SPOUT.