US3051103A - Bag manufacture - Google Patents

Description

Aug. 28, 1962 R. J. WILLIAMS 3,051,103

BAG MANUFACTURE Filed April 10, 1958 e Sheets-Sheet 1 Aug. 28, 1962 R. J. WILLIAMS BAG MANUFACTURE 6 Sheets-Sheet 2 Filed April 10, 1958 Aug. 28, 1962 R. J. WILLIAMS BAG MANUFACTURE 6 Sheets-Sheet 3 Filed April 10, 1958 Aug. 28, 1962 R. J. WILLIAMS Bic?- MANUFACTURE 6 Sheets-Sheet 4 Filed April 10, 1958 Aug. 28, 1962 R. J. WILLIAMS BAG MANUFACTURE 6 Sheets-Sheet 5 Filed April 10, 1958 Aug. 28., 1962 R. .1. WILLIAMS BAG MANUFACTURE 6 Sheets-Sheet 6 Filed April 10, 1958 United States Patent 3,051,103 BAG MANUFACTURE Russell J. Williams, Clayton, Mo., assignor to Bemis Bro. Bag Company, St. Louis, Mo., a corporation of Missouri Filed Apr. 10, 1958, Ser. No. 727,564 6 Claims. (Cl. 112-40) This invention relates to bags, and more particularly to the manufacture of multi-ply paper bags.

This application is a continuation-in-part of my copending application Serial No. 416,281, filed March 15, 1954, for Bag, issued as Patent 2,854,186, September 30, 1958, and a continuation-in-part of my copending application Serial No. 573,853, filed March 26, 1956, for Bag, issued as Patent 2,869,772, January 20, 1959.

Multi-ply paper bags are conventionally formed with either stitched or folded and pasted closures. Bags with stitched bottom closures are usually provided with a stitched top closure. Bags with folded and pasted bottom closures (for example, self-opening square bottoms or diamond fold bottoms) may be provided either with a stitched top closure or a folded and pasted top closure. In the case of a stitched closure, the line of holes punched in the bag by the needle which drives the stitches through the bag weakens the bag at the closure. Under strain such as may occur when the filled bag is dropped, the stitches may cut through the paper. In the case of a pasted closure, the bag is weakened by the creasing and folding incident to the closure, particularly at crease intersections. Heretofore it has been regarded as necessary to offset the weakening eflfect of the closures by making the bags with enough plies to resist cutting the paper in the case of stitched closures and to resist tearing at the creases in the case of pasted closures. This means that one or more plies is useful only as regards its end portions at the closures, and that its intermediate portion between closures has no useful effect, representing a waste of paper. Almost all bags with stitched closures (sewn bags) are gusseted bags. Gusseted sewn bags made of relatively stiff paper (such as conventional plain kraft paper) are more apt to fail at the sewing line in the region between the gusset corners of the bags than elsewhere. I have found that gusseted sewn bags made of a flexible stretchable paper unexpectedly are more apt to fail at the sewing line in the regions of the gusset corners than in the region between the gusset corners.

Among the several objects of the invention may be noted the provision of a continuous-tubing method of economically manufacturing bags which are reinforced at their end closures in such manner as to offset the weakness otherwise caused by the stitching in the case of stitched closures or by the creases in the case of pasted closures, which eliminates any necessity for the use of one or more complete extra plies to offset the weakening effect of the closures, thereby effecting great saving of paper in quantity production; and the provision of gusseted sewn bags made by such method of flexible stretchable paper which are reinforced at their gusset corners. Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the methods hereinafter described, the scope of the invention being indicated in the following claims.

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

FIG. 1 is a semi-diagrammatic view in perspective illustrating procedure in the manufacture of gusseted stitchedbottom bags in accordance with this invention;

FIG. 1A is an enlarged continuation of FIG. 1 illustrating further steps in the procedure;

FIG. 2 is a view in perspective of a gusseted stitched- "ice bottom bag made in accordance with this invention as it appears from one side thereof, part of the outer ply of the bag being broken away;

FIG. 3 is a view in perspective showing the other side of the FIG. 2 bag, part of the outer ply of the bag being broken away;

FIG. 4 is an enlarged line cross-section taken on line 44 of FIG. 3;

FlG. 5 is a view similar to FIG. 3 showing a modification;

FIG. 6 is an enlarged line cross-section taken on line 66 of FIG. 5;

FIG. 7 is a semi-diagrammatic view in perspective similar to FIG. 1 illustrating a modified procedure in the manufacture of gusseted stitched-bottom bags in accordance with this invention;

FIG. 7A is an enlarged continuation of FIG. 7 illustrating further steps in the modified procedure;

FIG. 8 is a view in perspective of a gusseted stitchedbottom bag made pursuant to FIGS. 7 and 7A as it ap pears from one side thereof, part of the outer ply of the bag being broken away;

FIG. 9 is a view in perspective showing the other side of the FIG. 8 bag, part of the outer ply of the bag being broken away;

FIG. 10 is an enlarged cross-section taken on line 10- 10 of FIG. 7A;

FIG. 11 is a view similar to FIG. 8 illustrating a modification;

FIG. 12 is a view similar to FIG. 8 illustrating another modification;

FIG. 13 is a semi-diagrammatic view in perspective similar to FIGS. 1 and 7 illustrating a modified procedure in the manufacture from flexible stretchable paper of gusseted stitched-bottom bags in accordance with this invention;

FIG. 13A is an enlarged continuation of FIG. 13 illustrating further steps in the procedure of manufacturing the flexible stretchable paper bag;

FIG. 14 is a view in perspective of a gusseted stitched bottom flexible stretchable paper bag made pursuant to FIGS. 13 and 13A as it appears from one side thereof,

part of the outer ply of the bag being broken away;

FIG. 15 is a view in perspective showing the other side of the FIG. 14 bag, part of the outer ply of the bag being broken away; and

FIG. 16 is an enlarged cross-section taken on line 1616 of FIG. 15.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawmgs.

Referring to the drawings, 'FIGS. 14 illustrate th manufacture of gusseted multi-ply stitched bottom paper bags in accordance with this invention. To avoid complication of the disclosure, the manufacture of two-ply bags is shown, but it will be understood that the principles of the invention are applicable to the manufacture of bags with more than two plies. In accordance with this invention as it pertains to the manufacture of two-ply bags, \two webs of paper 1 and 3 are continuosly drawn from supply rolls 5 and 7, combined to form a two-ply web at a combining guide 9, and the two-ply web is continuously fed through a conventional tuber (not illustrated) to be formed into a tube. Guide 9 is shown as a roll. The webs 1 and 3 travel to the roll 9 in spaced paths, converging together at the roll to form a two-ply web. The web 1, which eventually becomes the inner ply of the tube, is shown as travelling from supply roll 5 over an upper guide roll 11 from which it leads downward to the .combining roll 9. The web 3, which eventually becomes the outer ply of the tube, is shown as travelling from supply roll 7 around a lower guide roll 13, from jthe webs.

which it travels upward to a guide roll 15, thence forward to a guide roll 17, and thence forward and downward to the combining roll 9. The bite of webs 1 and 3 (i.e., the transverse line on which they come into engagement) is indicated at B. The webs 1 and 3 are combined in laterally offset relation, as is conventional in the manufacture of multi-ply paper bags.

As the webs -1 and 3 are combined at the combining roll 9, reinforcing patches or bands 21 (which may also be referred to as pieces) are fed in between the webs and pasted in between them, the patches or bands being spaced at bag length intervals along the length of the composite two-ply web formed at the combining roll. The patches or bands 21 are severed from a continuous web 23 of materal drawn from a supply roll 25. This material may be paper, cloth or any other suitable reinforcing material. As shown in FIG. 1, the width of web 23 is preferably somewhat less than the width of webs 1 and 3. The web 23 is drawn from the supply roll 25 at a speed less than the speed of webs 1 and 3 by a pair of draw rolls 27. It -is fed by the draw rolls in a preferably downwardly inclined path through a cutter 29 and between the converging webs 1 and 3 into the bite B of The cutter 29, as shown, may comprise an anvil roll 31 and a double-blade cutter 33, and is adapted .to sever the web 23 into patches which are of an appropriate dimension in the longitudinal direction of the webs 1 and 3. What the appropriate longitudinal dimension is will be later made clear in reference to the finished bags. The line on which the cutter cuts web 23 is preferably spaced from the bite B of webs 1 and 3 a distance corresponding generally to the desired longitudinal dimension for the patch. The timing of the cutter is such that it severs the web 23 to form a patch substantially at the instant that the end of the web 23 is caught in the bite of webs 1 and 3, and the severed patch is thereupon drawn in between the webs 1 and 3 at the speed at which webs 1 and -3 are travelling. The patch is 'Pulled away from the freshly cut end of web 23 since web 23 is fed by the draw rolls 27 at a speed lower than the speed of the webs 1 and 3, and the patches drawn in between the webs 1 and 2 are spaced along the length of the webs 1 and 3 at equal intervals. The speed of web 23 in relation to the speed of webs 1 and 3 is made such that the spacing of the patches corresponds to the desired length of the bags to be manufactured.

The patches or bands 21 are shown as being adhered between the webs 1 and 3 by applying a pattern of adhesive (paste) to the inside surface of the web 3 as it travels toward the combining roll 9. As illustrated, this is accomplished by means of a spot paster 35 adapted to apply a pair of rows of spots 37b and 371 across the width of the web 3, the two rows of the pair being spaced longitudinally of the web a distance somewhat less than the longitudinal dimension of the patches 21, and with successively ap-plied pairs spaced at bag length intervals along the length of the web. The timing of the paster is such that each pair of rows of paste spots 37b and 37 t registers with a patch 21 as the patch is drawn in between the webs '1 and 3, with the two rows 37b and 37t lying on opposite sides of the transverse center line C-C of the patch and closely adjacent those edges of the patch which extend transversely of the webs.

Thus, there issues from the combining roll 9 the composite web 39 consisting of the webs or plies 1 and 3 with the patches or hands 21 pasted in between the plies at bag length intervals along the length of the composite web. In accordance with the invention as illustrated in FIG. 1, the patches extend from near one side margin of the composite web 39 to near the other. The composite web travels around a guide roll 41 and thence to a tuber (not illustrated) where it is formed in conventional manner into a gusseted tube 43 with generally I central longitudinal tube seams 45 and 47 for its inner and outer plies 1 and 3. The gussets are designated 49.

As a result of the previously described operations, the tube 43 is a two-ply tube and has the patches 21 pasted in between its plies spaced at bag length intervals along the length of the tube, as shown in FIG. 1A. The patches extend substantially completely girthwise of the tube from near one side of the seamed region of the tube to near the other side thereof. Here it will be understood that the width of the patch-forming web 23 and hence the transverse dimension of the patches is preferably somewhat less than the width of the ply-forming webs 1 and 3 so that the patches do not extend into the ply seams, otherwise the tube (and bags to be formed therefrom) would be unduly thickened at the seam.

The tube 43 is severed into individual bag lengths 51 substantially on the transverse center lines C-C of the patches or hands 21 (see FIG. 1A). This divides each individual patch or band 21 into two patches or bands 21b and 21t (which may also be referred to as parts. 21b and 21t), and results in each bag length 51 having a patch or band 21b at one end and a patch or band 211. at the other. The patch 21b of each bag length is pasted in betweenthe two plies 1 and 3 of the bag length by the row of spots 37b, and the patch 21t is pasted in between the plies by the row of spots 371. Rows 37b and 371, having originally been located adjacent the transverse edges of patches 21, are spaced from the respective ends of the bag length. Each bag length is bottomed by stitching together its front and back walls adjacent one end of the bag length (the end including patch 21b) as indicated at 53 in FIGS. 2 and 3. The stitches extend through the patch 21b and also through the gussets 49. The line of stitching is located outward from (below) the row of paste spots 37b. This is important in order that the stitches not be driven through pasted areas, and accounts for the disposition of the rows 37b (and 372) adjacent the transverse edges of the patches 21. Here it will be observed that the dimension of patch 21b heightwise of the bag (longitudinally of plies 1 and 3) need be only sufficient to account for the spacing of the stitching above the bottom of the bag (standard spacing being one-half inch) plus enough space for the paste spots, and it will be clear that the appropriate longitudinal dimension for each patch 21 is twice this. Each bag length is also ultimately closed at its top by a line of stitching like stitching 53, with the top stitches extending through the patch 21; above the row of paste spots 37!. It will be understood that the top closure may be formed either after filling, or after the formation of a valve and before filling.

In the filled bag provided with the stitched bottom and top closures, the patches or bands 21b and 21t act as reinforcement to prevent the stitches from cutting through the bag. plies under strain such as is incurred when the bag is dropped. This reinforcement results from the patches being pasted in between the bag plies, whereby they are locked against moving outward from between the plies. Each patch provides two extra thicknesses of paper for reinforcement, except in the region of the ply seams, but here there are two extra thicknesses irrespective of the patches in view of the overlapping of the margins of the plies. Hence, the absence of patch material in the region of the ply seams is not detrimental to the strength of the bag.

similar to the paster 35. l

The bags may be manufactured with more than two plies simply by combining additional webs with webs 1 and 3 at the combining roll 9, as will be readily understood. It is also contemplated that bags which have more than two plies may have more than one patch at each end. For example, a three-ply bag may have two patches at each end, one pasted in between the inner ply and intermedia-e ply, and the other pasted in between the intermediate ply and the outer ply.

It will be observed that the stitched closure for a gusseted bag is inherently reinforced where it traverses the gussets and where it crosses the longitudinal ply seams, in view of the extra thicknesses of paper present in these regions. This reinforcing eifect of the gussets and ply seams may be availed of in some cases, particularly in the case of bags made from relatively stiff paper such as Kraft paper, to reduce the girthwise extent of the patches further to save paper, and FIGS. and 6 illustrate a modification to this efiect. The bag shown in FIGS. 5 and 6 is in all respects like that shown in FIGS. 24 except in respect to the girthwise extent of the patches or bands, which are designated 61b and 61! to distinguish them from patches 21b and 212. Each of patches 61b and 61! is pasted in between the plies of the front wall (the unseamed wall) of the bag, the bottom edge of the bottom patch 6111 being coincident with the bottom edges of the plies, the top edge of the top patch 611 being coincident with the top edges of the plies. The transverse dimensions of the patches and their position are such that their side edges are approximately coincident with the inner creases 63 of the gussets. Thus, the patches reinforce the stitching in the two-ply region of the front wall of the bag between the gussets. Outward of the side edges of the patches, the gussets provide reinforcement. In the back wall of the bag, the longitudinal ply seams provide reinforcement. It will be understood that bags of the type shown in FIGS. 5 and 6 may be manufactured in the same manner as illustrated in FIGS. 1 and 1A, using a relatively narrow patchforming web.

It will be understood that the method is applicable to the manufacture of bags with folded and pasted closures, the procedure being the same except that each individual bag length, instead of being provided with a stitched closure or closures, is provided with a pasted closure or closures in conventional and well-known manner. As to the manufacture of bags with pasted closures, the dimension of the patch or band 211) heightwise of the bag will be suflicient that the patch or band extends at least past the creases in the bag which define the width of the closure (i.e., the creases made by folding over the front and back flaps of the closure), so that it will reinforce the corners of the filled bag. Also, the patches should be pasted to both of the plies between which they lie to develop full strength, and this pasting should preferably be near the end of the bag.

FIGS. 7-40 illustrate a possible alternative method of this invention for manufacturing gusseted multi-ply stitched bottom paper bags. Again to avoid complication of the disclosure, the manufacture of two-ply bags is shown, but it will be understood that the principles of the FIG. 7 method are applicable to the manufacture of bags with more than two plies. As shown in FIG. 7, two webs of paper 111 and 3a (corresponding to Webs 1 and 3 of FIG. 1) are continuously drawn from supply rolls 5a and 7a (corresponding to rolls 5 and 7 of FIG. 1), combined to form a two-ply web at the combining guide 9, and the two-ply web is continuously fed through a conventional tuber (not illustrated) to be formed into a tube as in FIG. 1. The webs 1a and 3a travel to the roll 9 in spaced paths, converging together at the roll to form a two-ply web. The web 1a, which eventually becomes the inner ply of the tube, is shown as travelling from supply roll 5a over the upper guide roll 11 from which it leads downward to the combining roll 9. The web 3a, which eventually becomes the outer ply of the tube, is shown as travelling from supply roll 7a around the lower guide roll 13, from which it travels upward to the guide 6 roll 15, thence forward to the guide roll 17, and thence forward and downward to the combining roll 9. The bite of webs 1a and 3a (i.e., the transverse line on which they come into engagement) is indicated at B. The Webs 1a and 3a are combined in laterally offset relation, as is conventional in the manufacture of multi-ply paper bags.

As the webs 1a and 3a are combined at the combining roll 9, rows R of reinforcing pieces or patches 121 are fed in between the webs and pasted in between them, the rows R being spaced at bag length intervals along the length of the composite two-ply web formed at the combining roll. Each row R is shown as having six patches 121 arranged side-by-side with the side edges of adjacent patches abutting one another. The six patches 121 are severed from six continuous strips 8-1 to 5-6 of patch material drawn from six supply rolls SR-l to SR-6. For utmost economy, the strips 8-1 to S-6 may be strips of paper resulting from trimming operations in the bag factory otherwise disposed of as scrap. As shown in FIG. 7, the total width of the six strips is somewhat less than the width of webs 1a and 3a. The strips 5-1 to S-6 are drawn from the supply rolls SR-1 to SR-6 at a speed less than the speed of webs 1a and 3a by the pair of draw rolls 27. They are fed by the draw rolls in a downwardly inclined path through the cutter 29 and between the converging webs 1a and 3a into the bite B of the webs. The cutter 29 is the same as shown in FIG. 1 and is adapted to sever the strips into patches which are of the appropriate dimension in the longitudinal direction of the webs 1a and 3a. What the appropriate longitudinal dimension is will be later made clear in reference to the finished bags. The line on which the cutter cuts the strips is spaced from the bite B of webs 1a and 3a a distance corresponding generally to the desired longitudinal dimension for the patches. The timing of the cutter is such that it severs the strips to form a row of patches substantially at the instant that the ends of the strips are caught in the bite of webs 1a and 3a, and the severed patches are thereupon drawn in between the webs 1a and 3a at the speed at which webs 1a and 3a are travelling. The patches are pulled away from the freshly cut ends of the strips since the strips are fed by the draw rolls 27 at a speed lower than the speed of the webs 1a and 3a, and the rows of patches drawn in between the webs 1a and 3a are spaced along the length of the webs 1a and 34 at equal intervals. Since the strips 8-1 to S 6 are simultaneously severed by the cutter 33, the edges of the patches 121 in each row R which extend transversely of the webs 1a and 3a are aligned. The speed of the strips in relation to the speed of webs 1a and 3a is made such that the spacing of the rows of patches corresponds to the desired length of the bags to be manufactured.

The rows R of patches 121 are shown as being pasted in between the webs 1a and 3a by applying a pattern of paste to the inside surface of the web So as it travels toward the combining roll 9. As illustrated, this is accomplished by means of the spot paster 35 adapted to apply the pair of parallel lines or rows of spots 37b and 371 across the width of the web 3a, the two rows of the pair being spaced longitudinally of the web a distance somewhat less than the longitudinal dimension of the rows of patches 121, and with successively applied pairs spaced at bag length intervals along the length of the web. The timing of the paster is such that each pair of rows of paste spots 37b and 371 registers with a row R of patches 121 as the row of patches is drawn in between the webs 1a and 3a, with the two rows 37b and 372 lying on opposite sides of the transverse center line CC of the row of patches and closely adjacent those edges of the row which extend transversely of the webs.

Thus, as shown in FIG. 7, there issues from the combining roll 9 the composite web 139 consisting of the webs or plies 1a and 3a with the rows R of patches 121 pasted in between the plies at bag length intervals along the length of the composite web. In accordance with the invention roll 41 and thence to a tuber (not illustrated) where it is formed in conventional manner into a gusseted tube 143 with generally central longitudinal tube seams 145 and 147 for its inner and outer plies 1a and 3a. The gussets are designated 149. As a result of the previously described operations, the tube 143 is a two-ply tube and has the rows R of patches 121 pasted in between its plies spaced at bag length intervals along the length of the tube, as shown in FIG. 7A. The rows of patches extend substantially completely girthwise of the tube from near one side of the seamed region of the tube to near the other side thereof. Here it will be understood that the combined width of the six patch-forming strips 8-1 to 5-6 and hence the transverse dimension of the row of patches 121 is somewhat less than the width of the plystorming webs 1a and 3a so that the rows of patches do not extend into the ply seams, otherwise the tube (and bags to be formed therefrom) would be unduly thickened at the seams.

The tube 143 is severed into individual bag lengths 151 on the transverse center lines C-C of the rows R of patches 121 (see FIG. 7A). This divides each individual row R into two rows Rb and Rt and each patch 121 into two patches or parts 121b and 1211. It results in each bag length 151 having a row Rb of patches 121b at one end and a row Rt of patches 121t at the other. The transverse edges of the patches 12111 at said one end of the bag length are aligned and coincident with said one end. The transverse edges of the patches 121b away from said one end are aligned. The transverse edges of the patches 12113 at said other end of the bag length are aligned and coincident with said other end. The transverse edges of the patches 121t away from said other end are aligned. The patches 121b of each bag length are pasted in between the two plies 1a and 3a of the bag length by the row of spots 37b, and the patches 121x are pasted in between the plies by the row of spots 37t. The rows of spots 37b and 371, having originally been located adjacent the transverse edges of rows R of patches 121, are located on transverse lines adjacent the inner edges of the patches spaced from the respective ends of the bag length.

Each bag length is bottomed by stitching together its front and back walls adjacent one end of the bag length (the end including patches 121b) as indicated at 153 in FIGS. 8 and 9. The stitches extend through the patches 121b and also through the gussets 149. The line of stitching is offset from the row of paste spots 37 b, being located outward from (below) spots 37b. As before, this is important in order that the stitches not be driven through pasted areas, and accounts for the disposition of the rows 37b (and 371) adjacent the transverse edges of the rows R of patches 121. Here it will be observed that the dimension of patch 121b heightwise of the bag (longitudinally of plies 1 and 3) need be only sufiicient to account for the spacing of the stitching above the bottom of the bag (standard spacing being one-half inch) plus enough space for the paste spots, and it will be clear that the appropriate longitudinal dimension for each patch 121 is twice this. Each bag length is also ultimately closed at its top by a line of stitching like stitching 153, with the top stitches extending through the patches 121t above the row of paste spots 37 t. It will be understood that the top closure may be formed either after filling, or after the formation of a valve and before filling.

In the filled bag provided with the stitched bottom and top closures, the rows Rb and R1 of patches 121b and 1211 act as reinforcement to prevent the stitches from cutting through the bag plies under strain such as is incurred when the bag is dropped. This reinforcement results from the patches being pasted in between the bag plies, whereby they are locked against moving outward from between the plies. Each row Rb and Rt of patches provides two extra thicknesses of paper for reinforcemeint, except in the region of the ply seams, but here there are two extra thicknesses irrespective of the patches in view of the overlapping of the margins of the plies. Hence, the absence of p t rial in the regi n f the ply e ms i n detrimental to h str ngth of the b g.

As to bas sold ith p months. i is d sirabl to have the patches at the mouth pasted to both plies so that the plies are secured together at the mouth. In some cases it may be desirable to have the patches at both top and ot m pa ted o th P es m s u y o lo hem in be een th P s. Th m y b P i y sirable where the patch material is of considerably higher strength than the bag ply material and additional pasting is needed to utilize the full strength of the patch material. Under these circumstances, paste may be applied to Web In, as well as to web 3a, by a. paster similar to the paster 35.

The bags may be manufactured with more than two plies simply by combining additional webs with webs 1a and 3a at the combining roll 9, as will be readily understood. It is also contemplated that bags which have more than two plies may have more than one row of patches at each end. For example, a three-ply bag may have two rows of patches at each end, one row pasted in between the inner ply and intermediate ply, and the other row pasted in between the intermediate ply and the outer ply.

As above described, the patches 121 and hence the patches 1211b and 1211 into which the patches 121 are divided are arranged side-by-side with the side edges of adjacent patches abutting one another. It will be understood, however, that precise abutment of the side edges of adjacent patches is not essential. The side edges of adjacent patches may be only substantially in abutment, either overlapping each other to some extent or being spaced from each other to some extent. Hereinafter, when reference is made to the side edges of adjacent patches as being substantially in abutmen it will be understood that this includes overlapping or spacing of the side edges to some extent as well as precise abutment of the side edges.

It is contemplated that the rows Rb and Rt of patches 121b and 1212. may be pasted in between the plies of the bag on the outside of the lines of stitching as well as on the inside of the lines of stitching. As shown in FIG. 11, row Rb of patches 121b is pasted in between the plies by a row of paste spots 38b located outward of the line of stitching 153 as well as by the row of paste spots 37b located inward of the line of stitching. Row Rt of patches 121t is pasted in between the plies by a row of paste spots 38t spaced from the row of paste spots 37! toward the top edge of the bag so thatthe line of stitching for closing the top of the bag may be driven between the rows 37t and 381.

It is also contemplated that the rows Rb and Rt of patches 121b and 1211 may be pasted in between the plies only on the outside of the lines of stitching. As shown in FIG. 12, row Rb of patches 1211) is pasted in between the plies only by the row of paste spots 38b located outward of the line of stitching 153. Row Rt of patches 1211 is pasted in between the plies only by the row of paste spots 38 located adjacent the top edge of the bag so that the =line of stitching for closing the top of the bag may be driven inward of (below) the row 38t.

FIGS. 13 and 13A illustrate still another method of this invention for manufacturing gusseted multi-ply stitched bottom paper bags from flexible stretchable paper, such as creped paper. This method is similar to the methods previously described, except that instead of feeding in the single web 23 or the plurality of strips 8-1 to S6, t'wo continuous strips T-1 and T-2 are fed in between the webs which are to form the bag plies. These webs are designated 1b and 3b and the supply rolls from which they are drawn are designated b and 7b to distinguish them from the webs previously designated 1 and 3, 1a and 3a, and the supply rolls previously designatcd 5 and 7, 5a and 7a. Each of these Webs 1b and 3b is a flexible stretchable paper web, such as, for example, creped kraft paper in which the lines of creping extend transversely of the web so that the web is longitudinally stretchable. The strips T-1 and T-2 are preferably of the same material as the webs 1b and 3b. They are drawn from supply rolls TR-l and TR-2 which are lined up in such relation to the webs 1b and 317 that the strips T-i and T-2 are fed in between the webs 1b and 3b substantially centered in respect to the gussets to be subsequently formed. Each strip T1 and T2 has a width greater than the gusset width, and as shown, only slightly greater than the gusset width, for utmost economy in regard to the quantity of paper used.

The strips T-l and T-2 are simultaneously severed into pieces or patches P-1 and P2 by the cutter 29, and these patches P1 and P-2 are fed in between the webs and pasted in between them in the same manner as previously described for the bands 21 and patches 121. Thus there issues from the combining roll 9 the composite web 239 consisting of the webs or plies 1b and 3b with groups of two patches P-1 and P2 pasted in between them at bag length intervals along thelength of the composite web. As to each group, the two patches P-1 and P-2 are transversely spaced apart, their longitudinal center lines being spaced a distance equal to the desired bag width plus the width of one gusset (twice the gusset depth). For example, assuming that the bag is to be fifteen inches wide with a three inch gusset width (one and one-half inch gusset depth), the patches would have their longitudinal center lines spaced eighteen inches. Each patch would be, for example, three and one-half inches wide to allow a onequarter inch lap beyond the gusset.

The longitudinal dimension for the patches P-1 and P2 corresponds to that of the bands 21 and patches 121, and is preferably such that the patches extend far enough inward to reinforce the corners of the filled bag. The patches P-1 and P-2 are pasted in between the webs in the same manner as bands 21 and patches 121, that is, by means of the spot paster 235 applying parallel lines or rows of spots 2371) and 2371 across the width of the strips T-l and T-2 lying on opposite sides of the transverse center line C-C of the pair of patches P-1 and P-2 and closely adjacent those edges of the patches which extend transversely of the webs.

As shown in FIG. 13, the composite web 239 travels around the guide roll 41 and thence to the tuber (not illustrated) where it is formed in conventional manner into a gusseted tube 243 with generally central longitudinal tube seams 245 and 247 for its inner and outer plies 1b and 3b. The gussets are designated 249. The tube 243 is a two-ply tube and has the pairs of patches P-'1 and P-2 pasted in between its plies spaced at bag length intervals along the length of the tube, as shown in FIG. 13A. As to each pair of patches, one patch lies within and spans the gusset 249 at one side of the tube, extending slightly into the seamed and unseamed walls of the tube, and the other lies within and spans the gusset 249 at the other side of the tube, also extending slightly into the seamed and unseamed walls of the tube.

The tube 243 is severed into individual bag lengths 251 on the transverse center lines C-C of the pairs of patches P1and P-2 (see FIG. 13A). This divides patch P-l into two parts or patches P1b and P1r and patch P-2 into two parts or patches P-2b and P-2z. It results in each bag length 251 having patches P41) and P-Zb at the corners at one end of the bag length, and patches P-lt and P-2t at the corners at the other end of the bag length. The transverse edges of the patches P-lb and P2b at said one end of the bag length are aligned and coincident with said one end. The transverse edges of the patches P-1t and P-Zt at said other end of the bag length are aligned and coincident with said other end. The patches P-1b and P-2b it of each bag length are pasted in between the two plies 1b and 3b of the bag length by the row of spots 237b, and the patches P-lt and P-2t are pasted in between the plies by the row of spots 237t. The rows of spots 237k and 237t, having originally been located adjacent the transverse edges of the patches, are located on transverse lines adjacent the inner edges of the patches spaced from the respective ends of the bag length.

As shown in FIGS. 14 and 15, each bag length 251 is bottomed by stitching together its front and back walls adjacent one end thereof (the end including patches P-lb and P-2b) as indicated at 253. The stitches extend through the patches 12112 and also through the gussets 249. The line of stitching is offset from the row of paste spots 237b, being located outward from (below) spots 23717. As before, this is important in order that the stitches not be driven through pasted areas, and accounts for the disposition of the rows 2371) (and 237t) adjacent the transverse edges of the patches. Each bag length is also ultimately closed at its top by a line of stitching like stitching 253, with the top stitches extending through the patches P1t and P2t above the row of paste spots 237t. It will be understood that the top closure may be formed either after filling, or after the formation of a valve and before filling.

In the filled bag provided with the stitched bottom and top closures, the corner patches P1b, P2b, P-lt and P2t act as reinforcement to prevent the stitches at the gusset corners from cutting through the bag plies under strain such as is incurred when the bag is dropped. The bag being made of flexible stretchable paper, reinforcement along the stitching line is not needed between the gussets.

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

As various changes could be made in the above methods without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. The method of manufacturing multi-ply paper bags comprising continuously feeding a plurality of paper webs in a predetermined path at a predetermined speed and combining the webs to form a multi-ply web, continuously feeding at least one continuous strip of reinforcing material in a path between said paper webs in the same direction as said paper webs and at a predetermined speed less than that of said paper webs, segmenting said strip of reinforcing material transversely into pieces, accelerating said pieces up to the speed of said paper webs and feeding them in between said paper webs, the difference between the speed of said paper webs and the speed of said strip being such that said pieces are spaced at bag length intervals along the length of the multi-ply web, applying adhesive for adhering the pieces between the paper webs, continuously forming the multiply web with said pieces therein into a flattened tube, segmenting the flattened tube into individual flattened multi-ply bag lengths, each of which is open at both ends, on lines extending transversely of the tube and intersecting said pieces so that each piece is divided into two parts and each of said open-ended bag lengths has one of said parts adhered between its plies at each end, and thereafter forming each bag length at least at one end with a bottom closure with the said part at said one end included in the bottom closure.

2. The method of manufacturing multi-ply paper bags comprising continuously feeding a plurality of paper webs in a predetermined path at a predetermined speed and combining the webs to form a multi-ply web, continuously feeding at least one continuous strip of reinforcing material in a path between said paper webs in the same direction as said paper webs and at a predetermined speed less than that of said paper webs, segmenting said strip of reinforcing material transversely into pieces, accelerating said pieces up to the speed ofsaid paper'webs and feeding them in between said paper webs, the difference between the speed of said paper webs and the speed of said strip being such that said pieces are spaced at bag length intervals along the length of the multi-ply web, applying adhesive for adhering the pieces between the paper webs on opposite sides of the transverse center line of each piece and spaced from the cen ter line, continuously forming the multi-ply web with said pieces therein into a flattened tube, segmenting the flattened tube into individual flattened multi-ply bag lengths, each of which is open at both ends, on lines extending transversely of the tube and intersecting said pieces substantially on the transverse center line of each piece so that each piece is divided into two parts and each of said open-ended bag lengths has one of said parts adhered between its plies at each end, and thereafter stitching at least one end of each bag length along a line offset from the adhesive which adheres the said part between the plies of said bag length at said one end with the stitches extending through this said part.

3. The method of manufacturing multi-ply paper bags comprising continuously feeding a plurality of paper webs in a predetermined path at a predetermined speed and combining the webs to form a multi-ply web, continuously feeding at least one continuous strip of reinforcing material in a path between said paper webs in the same direction as said paper webs and at a predetermined speed less than that of said paper webs, segmenting said strip of reinforcing material transversely into pieces, accelerating said pieces up to the speed of said paper webs and feeding them in between said paper webs, the difference between the speed of said paper webs and the speed of said strip being such that said pieces are spaced at bag length intervals along the length of the multi-ply web, applying rows of spots of adhesive for adhering the pieces between the paper webs adjacent the edges of said pieces which extend transversely of said paper webs and on opposite sides of the transverse center line of each piece, continuously forming the multi-ply web with said pieces herein into a flattened tube, segmenting the flattened tube into individual flattened multiply bag lengths, each of which is open at both ends, on lines extending transversely of the tube and intersecting said pieces substantially on the transverse center line of each piece between said rows so that each piece is divided into two parts and each of said open-ended bag lengths has one of said parts adhered between its plies at each end by a row of spots of adhesive spaced from the respective end of the bag length, and thereafter stitching at least one end of each bag length along a line located between the said one end of the bag length and the adjacent row of spots of adhesive with the stitches extending through the said part at said one end.

4. The method of manufacturing multi-ply paper bags comprising continuously feeding a plurality of paper webs in a predetermined path at a predetermined speed and combining the webs to form a multi-ply web, continuously feeding at least one continuous strip of reinforcing material having a width somewhat less than the width of said paper webs in a path between said paper webs in the same direction as said paper webs and at a predetermined speed less than that of said paper webs, with the side edges of said strip spaced inward from the side edges of said multi-ply web, segmenting said strip of reinforcing material transversely into pieces, accelerating said pieces up to the speed of said paper webs and feeding them in between said paper webs with each piece extending from near one side of the multi-ply web to near its other side, the difference between the speed of said paper webs and the speed of said strip being such that said pieces are spaced at bag length intervals along the length of the multi-ply web, applying adhesive for adhering the pieces between the paper webs, continuously forming the multi-ply web with said pieces therein into a flattened tube with pasted longitudinal ply seams, se'gmenting the flattened tube into individual flattened .multi-ply bag lengths, each of which is'open at both ends, on lines extending transversely of the tube and intersecting said pieces so that each piece is divided into two parts and each of said open-ended bag lengths has one of said parts adhered between its plies at each end, each part extending substantially completely girthwise of the bag length from near one side of the seamed region of the bag length to near the other side of the seamed region, and thereafter stitching at least one end of each bag length along a line offset from the adhesive which adheres the said part between the plies of said bag length at said one end with the stitches extending through this said part.

5. The method of manufacturing multi-ply paper bags comprising continuously feeding a plurality of paper Webs in a predetermined path at a predetermined speed and combining the webs to form a multi-ply web, continuously feeding a plurality of strips of reinforcing material in a path between said paper webs in the same direction as said paper webs and at a predetermined speed less than that of said paper webs, segmenting each of said strips of reinforcing material transversely into pieces, accelerating each of said pieces up to the speed of said paper webs and feeding them in between said paper webs, the difference between the speed of said paper webs and the speed of said strips being such that said pieces are spaced at bag length intervals along the length of the multi-ply web, applying adhesive for adhering the pieces between the paper webs on opposite sides of the transverse center line of each piece and spaced from the center line, continuously forming the multi-ply web with said pieces therein into a flattened tube, segmenting the flattened tube into individual flattened multi-ply bag lengths, each of which is open at both ends, on lines extending transversely of the tube and intersecting said pieces substantially on the transverse cen ter line of each piece so that each piece is divided into two parts and each of said open-ended bag lengths has a number of said parts adhered between its plies at each end, and thereafter stitching at least one end of each bag length along a line offset from the adhesive which adheres the said parts between the plies of said bag length at said one end with the stitches extending through these said parts.

6. The method of manufacturing multi-ply paper bags comprising continuously feeding a plurality of paper webs in a predetermined path at a predetermined speed and combining the webs to form .a multi-ply web, continuously feeding two strips of reinforcing material in a path between said paper webs in the same direction as said paper webs and at a predetermined speed less than that of said paper webs, said strips being transversely spaced in said path, segmenting each of said strips of reinforcing material transversely into pieces, accelerating each of said pieces up to the speed of said paper webs and feeding them in between said paper webs, the difierence between the speed of said paper webs and the speed of said strips being such that said pieces are spaced at bag length intervals along the length of the multiply web, applying adhesive for adhering the pieces between the paper webs on opposite sides of the transverse center line of each piece and spaced from the center line, continuously forming the multi-ply web with said pieces therein into a flattened gusseted tube, said strips being so transversely spaced and so located relative to said path that said pieces are located within the gussets of said tube, segmenting the flattened tube into individual flattened multi-ply bag lengths, each of which is open at both ends, on lines extending transversely of the tube and intersecting said pieces substantially on the transverse center line of each piece so that each piece is divided into two parts and 13 14 each of said open-ended bag lengths has two of said parts References Cited in the file of this patent adhered between its plies at each end within the gussets, UNITED STATES PATENTS and thereafter stitching at least one end of each bag length 1, 5 B 1 19, 1927 along a line oflfset from the adhesive which adheres the 332 3 gf g, 10, 1938 two said parts between the plies of said bag length at said 5 2,220,374 Waters 5 1940 one end with the stitches extending through these said 2,311,733 Bushman Feb. 23, 1943 two parts. 2,330,015 Stokes Sept. 21, 1943

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