US2983430A

US2983430A - Multi-wall bag and the like

Info

Publication number: US2983430A
Application number: US647688A
Authority: US
Inventors: Donald B Taylor
Original assignee: Hudson Pulp and Paper Corp
Current assignee: Georgia Pacific LLC
Priority date: 1957-03-21
Filing date: 1957-03-21
Publication date: 1961-05-09
Anticipated expiration: 1978-05-09

Description

y 1961 D. B. TAYLOR 2,983,430

MULTI-WALL BAG AND THE LIKE Filed March 21, 1957 2 Sheets-Sheet 1 Z4 FIG. 2. m i ;My M I W INVENTOR DONALD E. TAYL 0/? I BY 3 4411;, MM; Ida/$14.

ATTORNEY$ y 9, 1961 D. B. TAYLOR 2,983,430

MULTI-WALL BAG AND THE LIKE Filed March 21, 1957 2 Sheets-Sheet 2 FIG. 4.

INVENTOR DONALD E. 77010,?

BY 60122;, MWrfa/yod ATTORNEY9 MULTI-WALL BAG AND THE LIKE Donald B. Taylor, West Englewood, NJ., asslgnor to Hudson Pulp 8: Paper Corp., New York, N.Y., a corporation of Maine Filed Mar. 21, 1951, Ser. No. 647,688

Claims. Cl. 229-66) This invention relates to paper bags and the like, and more in particular to arrangements for easily and quickly opening multiwall bags.

An object of this invention is to facilitate the intentional tearing open of a strong paper bag which has a stitched end and is filled with a product such as cement, fertilizer, or bulkchemicals. A further object is to ensure that each such bag may be easily opened in such a way that it is always torn neatly along the line of the stitches which close the bag. It is a further object to provide closed bags of such uniform charcteristics in every respect that they may be opened and dumped in a routine manner, with no substantial deviation in the mode of opening and handling, and in the attendant and resultant actions. A further object is to provide a bag with an easy-opening arrangement which is simple and inexpensive, but which nonetheless does not harmfully weaken a bag or allow its contents to spill out accidentally. These and other objects will be in part obvious in part pointed out below.

Paper bags, made of one or a number of layers or plys of strong kraft paper formed into tubes and then stitched closed along their ends, are widely used at the present time for packaging materials such as flour, sugar, cement, fertilizer, etc. Ideally, a bag filled with a large quantity of loose pulverized material should be impervious enough to prevent spillage or seepage of material out of it, and its walls, particularly in the vicinity of an edge of the bag where stress is likely to be concentrated, should be sufiiciently strong to resist normal abuse, such as dropping. Heavy kraft paper has many characteristics, including high strength and imperviousness, which make it an excellent material for such bags. At the present time, therefore, most if not all bags for packaging particular kinds of pulverized, powdered and other materials are made of kraft paper.

Where both economy and strength are important, large paper bags are fabricated from single or multilayer tubes whose ends are stitched generally inthe way illustrated in US. Patent 1,668,542, for example. Usually, to allow the bag to expand when filled, re-entrant folds are provided along the parallel side edges of the bag. At each corner of such bags which are stitched closed, there is a double thickness of material that adds to the strength of the bag at these zones. a

In opening a stitched paper bag of this kind, it is desirable that it open along a straight line which: is as close as possible to one of the bag ends. That facilitates pouring and dumping, and some of the material may be stored in the bag when that is desired. Perhaps-more importantly with some products where a large number of bags are dumped one after another, it is preferable to be able to open each bag along one particular end and to dump the contents of each bag with a uniform set of acts or movements without any spilling and without any bag tearing non-uniformly or requiring special attention.

One way of opening such abag along one of its stitched ends is by cutting it with a knife or scissors; But, apart United States Patent expansion folds 14,

2,983,430 Patented May 9, 1961 ice from the serious disadvantage of requiring the use of a sharp instrument, that is slow and involves considerable effort with no certain guarantee that the cut made will be exactly in the right place and with uniformity of results, such as, a minimum amount of the bag removed and a clean edge along the cut. Another way of opening a stitched end of a bag is by removing the stitches which hold it closed, but that causes difficulties, and it requires a special form of stitching which is not entirely satisfactory from many standpoints, namely, as to strength, dustsealing or sift-proof ability, and proper functioning.

.tear the bag open along the end, the wall of the bag is apt to tear imperfectly, and not along the line of stitching. The paper wall of the bag will often rip or tear unevenly toward the other end of the bag so that the material in the bag spills out, and the shifting of the weight of this material often tended to tear the bag wall further.

It is an object of the invention to overcome the prior difficulties in a way which is thoroughly practical, simple and inexpensive, and which can be used with any type of stitched-end paper bag without harmfully weakening it and without objectionable sifting of the material from the bag.

In the illustrative embodiments of the present invention, a multiple-ply tubular wall paper bag having stitched ends is provided with a short row of incisions in the form of needle holes positioned at one corner of the bag just inside the adjacent line of stitches, that is, toward the main portion of the bag from the row of stitches. These needle holes are made quickly and simply with mechanism which projects a small needle or awl through the bag after the bag end has been closed. These holes are extremely small and are effectively self-sealing, so that, when the bag is later filled, the product does not sift through them. Furthermore, these holes do not weaken the bag in such a way as to interfere in any way with the normal and expected use of the bag. However, these holes insure that the portion of the bag above the line of stitching can be torn away, and that the tearing will be uniform, thus leaving a substantially straight-edged bar opening. In practice, the person desiring to open a filled bag grasps the tap at the corner adjacent the incisions or needle holes, and gives the tab a sudden pull or yank. This causes the top of the bag to tear at the first incision, and thence along the line of stitching. A steady pull then removes the entire strip from the top of the bag.

A better understanding of the invention, together with a fuller appreciation of its many advantages will best be gained from a study of the following description given in connection with the accompanying drawings in which:

Figure l is a perspective view of a stitched-end paper needle holes provided in accordance with the invention; 7

Figure 3 is a cross-sectional view on the line 3-3 of Figure 2; I

Figure 4 is a view similar to Figure 2 but showing the corner after a tear has been started; and

Figures 5 and 6 are similar to Figure 2 but show other bags having different arrangement of needle holes provided in accordance with the invention.

Multi-wall bag 10 is a tubular body 12 with re-entrant and is filled with a loose bulk material. The bag is formed by cutting a multi-wall tube into lengths with right-angle cuts, and then sewing the ends of the tube at the respective lines of stitching 16 and 18, with there being a valved filling opening at one corner.

Prior to the sewing operations, the tube or bag ends are covered by folded

sealing strips

20 and 22, respectively (see also Figure 3). The faces of these sealing strips which contact the bag are coated with glue to give a dusttight seal. Each of these sewing operations is performed through its strip and the bag at -a predetermined distance from the end edges of the bag walls.

Referring to Figure 2, which shows the upper left-hand corner 24 of the bag of Figure l, the line of stitches 16 comprises multiple strands 26 of thread, some of which are cotton and pass through the respective needle holes 30 to 35, etc., and others of which are filler threads which seal the needle holes. The walls of the bag are tightly held together by this line of stitches, and at the corner 24 the re-entrant fold results in double thickness so that the structure is very strong, and the other corners are similarly strong. The end of the-sealing strip 20' and the line of stitching 26 extend beyond the corner 24 of the bag and form a tab 40- which can be grasped readily.

As shown best in Figure l, the bag wall at corner 24 terminates in two side edges 41, each of which is formed by the wall being folded back upon itself to give two double wall thicknesses at the line of stitches 16. This makes it particularly difiicult to open the bag by tearing it along the line of stitches, because both of these side edges are extremely strong.

Positioned slightly below the line of stitches 16 is a row of evenly spaced incisions or

needle holes

43, 44 and 45 which extend through all of the layers or plys of the walls adjacent the edges 41. Hole 43 is a predetermined distance from the extreme side edge, and the spacing between the three holes is slightly greater than one half the distance between stitch holes 30 to 35. The line of

holes

43, 44 and 45 is inclined at an angle toward the line of the stitches 16.

During the stitching operation, it is not feasible to attempt to start the stitching operation at a predetermined distance from the side edge of the bag, and the first needle hole may be substantially at the edge or at any distance therefrom up to substantially the distance between a stitch. In the illustrative embodiment, hole 32 is a substantial distance from the edge of the bag, and the holes at the left thereof 31, 30, etc. do not extend through the bag walls, but merely extend through the two layers of sealing strip 26 to form the tab 40. It has been pointed out above, that it would normally be very difiicult to open the bag by merely pulling on the tab 40. However, with the constructions shown, a sharp pull or yank upwardly upon tab 40 causes the stitches at

holes

32, 33 and 34 to transmit substantial forces to the areas of the bag walls above the row of

holes

43, 44 and 45. This sudden application of force causes the bag walls to tear between hole 43 and the edges 41, and the tear then continues to hole 44, and thence upwardly to the stitch hole 32. Continued, or further pulling causes the tear thus started to continue along the line of stitches 16. The entire top of the bag above the line of stitches is therefore easily removed by the initial sharp pulling, followed by a relatively light or easily continued pull. The bag is fully opened, and the top edge is substantially even. Under some circumstances, it is desirable to open the bag only adjacent the corner 24, in which case the tearing is not continued, and the opening provides a pouring spout.

In Figures 1 to 4, the first hole in the bag 32 is above and slightly to the left of hole 44 It should be noted, however, that the spacing and arrangement of

holes

43, 44 and 45 insures that a relatively simple and uniform sudden pull will start the tearing operation, regardless of the distance between the first stitch hole and the edge.

Under some circumstances, the normal variation in operating conditions may misplace the line of stitches 16 either nearer to or farther from the top or upper end of the bag. However, the angular pushing of the line of

holes

43, 44 and 45 insures the desired uniform opening action, even though .the line of stitches 16 is displaced from the ideal position shown in the drawing. For example, if the line of stitches is below that shown, there will be a shorter distance between

holes

43, 44 and 45 and the nearest stitch holes; even if the line of stitches is substantially not in line with hole 43, there is no serious result. Similarly, if the line of stitches 16 is above the position shown, the line of tear may then follow from hole 44 to hole 45 before it moves upwardly to the line of stitches. As a practical matter, it has been found that very excellent results are obtained with'the operating conditions which have been encountered by providing three

holes

43, 44 and 45. However, additional holes may be provided, and they may be spaced closer together, as shown at 50 in Figure 5. Also, the line of holes may be closer to and parallel to the line of stitches. Satisfactory results for some conditions of operation have also been obtained by providing other incisions positioned difierently, for example, as in Figure 6, where two holes 52 are positioned in a line extending transversely of the line of stitches 16. The

holes

43, 44 and 45' are produced by projecting square needles through the tube at the time that the tube is cut into lengths to form the bags. The positioning of these holes can therefore be controlled very accurately, both with respect to the side edge of the bag and with respect to the adjacent edges. The holes are self-sealing, and they do not weaken the bag walls sufficiently to interfere with normal usage.

The holes shown are formed by needles or pins, size .O92"-.095", with square taper end spaced about 7 center to center. In the drawings, a three-ply kraft paper bag is shown, and an identical arrangement of the holes is also useful for two-ply bags. With two or three-ply sewn open-month bags, hole 43 is placed a distance from the edge 41 of plus or minus ,4, but itis desirable to maintain the lesser range of this distance. With fourply sewn open mouth bags, two, three or four-Zone valve bags, five-ply zone open moutlroifset gusset bags, and five-ply flat-tube open mouth bags, it is desirable to hold the distance to A or less, but a maximum distance of 7 is permissible. With all of the types of bags just referred to, hole 43 should be W from the edges of the end of the bag, with a minimum distance of /2". With five and six-ply bags, the gusset is offset so that the edges 41 are slightly out of alignment. The tab 40 in the illustrative embodiment extends 1 /2" beyond the edge 41 of the bag. This is of sufficient length to permit grabbing and screw holding for the opening operation. In the illustrative embodiment, the angle 48 between the lines of

holes

43, 44 and 45 and a line parallel to the line of stitches 16 is 7. Under circumstances where wider tolerances of manufacturing are necessary, this angle may be increased.

It has been found that

holes

43, 44 and 45 produce an insignificant weakening of the bag, but they effectively insure the opening of the bag with a relatively simple and uniform action. It has been indicated above that the uniformity of action is quite important where an operator works for a period of time opening a large number of bags, so that he may become accustomed to the exact amount of force required to start the tearing and to complete the opening. The bags are not torn other than along the line of stitches, and there is no danger of the product becoming contaminated with pieces of the bag. The invention is applicable to different types of bags, and the bags may be used for various products. The row of

holes

43, 44 and 45 or the other incisions to facilitate opening of the bag may be positioned at either a top or bottom corner and, in commercial practice, this comer is marked so that it may be readily identified. The hole 43 or other incision should be placed closer to the side edge of the bag 41 when the bag is of heavier weight paper, or is of a greater number of plys. In any event, the incision may be placed as close to the edge as is permissible, consistent with maintaining the necessary bag strength.

This application is a continuation-in-part of application 7 Serial No. 466,568, filed November 3, 1954, now abandoned, and application Serial No. 516,087, filed June 17, 1955, now abandoned.

I claim:

1. In a bag structure of the character described, a

tubular bag having two ends and comprising a plurality of layers of kraft paper, and a stitched closure sealing one end of said tubular wall, said closure comprising a line of thread stitches uniting and firmly holding together a the opposite walls of said bag near the end thereof along a generally straight line, said stitches passing through relatively small and widely spaced stitching needle holes, said bag wall including structure to ensure that the end of said bag may be intentionally torn open and will tear along said line of stitches and which comprises a plurality of starting incisions adjacent one end of said line of stitches at the side of said line toward the main portion of the bag, one of said incisions being spaced from one side edge of said wall a distance less than the distance between said stitching holes, and one of said incisions being spaced from one of said stitching holes a distance less than the distance between adjacent stitching holes, whereby a sudden pull upon the corner bag portion separated'from the main portion of the bag by said end of said line of stitches starts a tear from said side edge of the bag to said incision and thence to and along said line of stitches.

2. The bag structure as described in claim 1, wherein there are a plurality of said incisions in the form of holes positioned in a line which is inclined toward said line of stitches, a spacing between the incisions being substantially less than the spacing between the holes formed by the stitching.

3. The bag as described in claim 1, wherein said bag wall comprises a plurality of layers of heavy kraft paper, the sides of said wall being creased into re-entrant folds to allow for expansion, a corner of the stitched edge of said bag being of double thickness with its layers held firmly united by said stitches and wherein said incisions are small needle or pin hole punctures through every layer of said bag wall at said corner.

4. An easy-open high-strength bag, said bag comprising a heavy paper tubular wall having a plurality of layers and having two ends, one of said ends being termed the upper end and being sealed closed by a narrow flexible strip doubled over said bag end on each side thereof and united to' said wall by a line of stitches through said strip and wall, said strip and stitches extending beyond one corner of said wall a short distance to provide a tab which can be manually pulled to rip said strip off of said bag along said line of stitches, said bag wall adjacent said one corner and beneath said strip being provided with an extended line of incision which leaves at least the outer layer of said wall substantially sealed to contain the contents of said bag, said line of incision starting below said strip closer to a side edge of said bag wall than the spacing between said stitches and extending a short distance to a point closer to saidline of stitches than the spacing therebetween, whereby a sharp pull on said tab will cause said bag wall to start to tear open immediately adjacent said line of stitches and to continue to tear smoothly therealong.

5. A bag as described in claim 4 wherein the side edges of said bag wall are creased into re-entrant folds to allow for expansion, each corner of the stitched edge of said bag being of double thickness with its layers united by said stitches.

References Cited in the file of this patent UNITED STATES PATENTS 1,155,740 Lacroix et al. Oct. 5, 1915 1,157,568 Mills Oct. 19, 1915 1,217,818 Peterson Feb. 27, 1917 1,668,542 Bates et a1. May 8, 1928 2,323,779 Kennedy July 6, 1943 2,447,096 Schneider Aug. 17, 1948 2,549,199 Hodska Apr. 17, 1951 2,699,285 Bell et a1. Jan. 11, 1955 2,790,592 Doyle et a1. Apr. 30, 1957 FOREIGN PATENTS 63,588 Switzerland Mar. 20, 1913 481,327 Canada Feb. 26, 1952 709,750 Great Britain June 2, 1954 865,561 France Mar. 3, 1941