US3545347A - Web-feed arrangement for producing gusseted bags - Google Patents

Description

United States Patent inventors Appl. No.

Filed Patented Assignee John D. Sylvester Garden City, New York;

Johnl). Keenan, Jr., Caldwell, New Jersey 815,103

April 10, 1969 Dec. 8, 1970 Amsco Packaging Machinery, Inc.

a corporation of New York WEB-FEED ARRANGEMENT FOR PRODUCING GUSSETED BAGS 1 9 Claims, 6 Drawing Figs. W

U.S.Cl. ..93/84,93/1, 93/13, 93/20. 270/94 1 int. Cl. B3111 45/00, 1

B31d 5/04, 1331f 1/00 Field of Search 93/] (G),

References Cited UNlTED STATES PATENTS Harrison Beard McColgan Kugler Crawford Timms Primary ExaminerWayne A. Morse, Jr. Attorney-Breitenfeld & Levine ABSTRACT: Web of bagmaking sheet material is drawn over a sheet-folding device, including a pair of converging rods spaced apart at the delivery end of the device, to initiate longitudinal folding of the web into twooveriapping plies. Folded web bent around roller spaced in direction of web movement from delivery end of sheet-folding device. Guide finger projects into space between roller and delivery end of device to push central portion of web between two overlapping plies to initiate formation of a relatively narrow four-ply web portion which ultimately forms gusset at one end of each bag.

PATENTEU DEC 8 I970 SHEET 1 or z F. L M W ms .w 0mm E m m W5 I) O m i." mm v .v M u v 45 between each two successive advances of it.

WEB-FEED ARRANGEMENT FOR PRODUCING GUSSETED BAGS i This invention relates to the manufacture of bags from a web of sheet material, such as thermoplastic film, and more particularly to an arrangement for providing the web, as it is fed to a bagmaking machine, with three longitudinal fold lines defining two main overlapping plies of material and a two-ply pleat between them along one edge of the folded material. Such material, when sealed together along longitudinally spaced transverse lines forms a series of individual bags, the side edges of each bag being produced by two successive seals, one end of the bag being open to define a bag mouth, and the other end of the bag incorporating the pleat which serves as a gusset.

conventionally, one fold defining the two main overlapping plies is formed first, and at a subsequent point during the travel of the web, this first fold is pushed between the main plies forming the two additional folds and the pleat. It is usual to produce the first fold by drawing the web lengthwise over a sheet-folding device, often called a V-board, having two folding surfaces converging to an apex in the direction of movement of the web. The folding surfac'es may be the side edges of solid V-shaped board, or they; may be defined by a pair of rods mounted in a V formationLThe web is bent around the two folding surfaces simultaneously, and as it leaves the apex end a of the sheet-folding device it is folded longitudinally.

' After leaving the folding device, theweb is ordinarily "trained about suitable tensioning means, and the guided along the bed of the machine to'pair of feed rollers which intermittently advance it lengthwise. Beyond the feed rollers is a sealer, which may be a heat sealer if the web is of heat-sealable material, which produces a transverse seal in the folded web It is common practice to form the two additional folds, and hence the pleat, on the bed of the machine at a point between the tensioning means and the feed rollers. However, this practice presents a number of problems. First, it will be appreciated that as the web moves along the machine bed, the first folded edge, which is pushed between the main web plies, must move a greater distance than the remainder of the film, since this fold moves at an angle to the longitudinal center line of the machine whereas the remainder of the web moves parallel to this center line.'As-,a result, the web material is distorted causing little wrinkles which are ultimately scaled in, thereby producing an unsightly bag, as well as a bag whose two main walls, and/or whose gusset plies, do not lie flat against each other.

Furthermore, the force, applied to the first foldto push it between the main plies rename shift'theweb as a whole laterally on the machine bed. Such angling of the web causes ripples in the material which may become sealed in. Furthermore, any printing carried by the-material may not register properly with the sealer, and printed spots carriedby the material and intended to be sensed by electric eyes are shifted. Also, holes which are often punched in an extension, formed by. one main ply being wider than the other, become located where they are not intended to be. In addition, the lateral force applied to the first fold causes rolling of the material, which changes the size of both the extension andthe bag, and also adverselyaffects anyprinting'carried by the film and the holes punched in the extension.

It is an object of the present invention to overcome these problems by providing a web-feed-arrangement which forms all three longitudinal foldsin a geometricallycorrect fashion at the sheetfoldingdevice, or V-board, and thereby; avoids distorting the sheet material, machine bed. a

To accomplish this objective. the invention provides a sheet-folding device in which the folding surfaces terminate before reaching an apex, so that their ends at the delivery end or shifting it crosswise over the of the device are spaced apart. A member, such as a roller, is

spaced from the delivery end of the sheet-folding device, and presents a folding surface around which the folded web is bent in preparation for delivery to the bag making machine.

folding device is a guide for pushing the portion of the material traveling over the delivery end of the device between the two main plies to produce a pleat, or relatively narrow fourply web portion. The spacing between the folding surfaces at the delivery end of the sheet-folding device is adjustable to vary the depth of the pleat, and hence the depth of the ultimate gusset formed in each bag.

Additional features and advantages of the invention will be apparent from the following description in which reference is made to the accompanying drawings.

In the drawings: 1

FIG. 1 is a front elevational view of a web-feed arrangement according to this invention;

FIG. 2 is a vertical cross-sectional view taken on line 2-2 of FIG. 1;

FIG. 3 is a fragmentary perspective view, on an enlarged scale, of a portion of the arrangement shown in FIG. 1;

FIG. 4 is a fragmentary verticalcross-sectional view, on a still larger scale, taken through the lower portion of FIG. 3; and t a FIGS. 5 and 6 are cross-sectional views taken along lines 55 and 6-6, respectively, of FIG. 4.

The web-feed arrangement chosen to illustrate the present invention includes a stationary framework comprising a rectangular base 10, a pair of end uprights 11, mounted on the base, and an upper crossmember 12 extending horizontally between the uprights 11. The base is formed by a front angle member'l3, two side channels 14 fixed to the ends of the angle, and a rear tubular member 15 seated upon and extending between the channels 14. Projecting rearwardly from each upright 11, about midway up its length, is an arm 16, and a rod 17 extends between these arms. A supply roll 18 of bagmaking sheet material is rotatably supported on the rod 17. A guide rod 19 for the sheet material extends horizontally between the upper ends of the uprights ll.

A sheet-folding device carried by the: framework includes a pair of rods 23 arranged in an oblique plane and converging downwardly. The rods 23 do not meet at an apex, but instead their lower ends are spaced apart at the delivery end of the sheet-folding device. Located between the lower ends of the rods is a spacer block 24 having a rounded'lower end serving asa guide surface for the sheet material. The lower end of each rod 23 may be cut off at an angle, as shown in FIGS. 1 and 3, so that it fits squarely againstthe side of block 24.

Block 24 is secured to an adjustment block 25 extending between the. rods 23, the-end surfaces of block 25 being contoured to accommodate the arcuate exterior surfaces of the rods. Block 25 is fixed to the lower. edge of a support'plate 28, the upper edge of which is fixed to the crossmember 12 of the framework. Each end surface of block 25 is furnished with a series of internally threaded holes 26 spaced, for example onehalf inch apart, and the faceof the block may be provided with a series of markings to indicate the location of each hole. Each rod 23 is provided with a pair of through holes 27 spaced, for example three-quarters of an inch apart, each hole 27 being intended to accommodate a screw 29 adapted to be threaded alined to thereby fasten the rod to the block.

So that the spacing between the lower ends of the rods 23 I removed, the rod 23 is moved longitudinally up or down, while maintaining engagement with pin 30, one of the holes 27 is brought into alinement with a selected hole in the end surface of adjustment block 25, and the screw 29 replaced. Due to the difference in spacing between the holes 27 and the holes in the .block 25, the rods may be supported in any desired one'of a relatively large number of different positions. At the time of each change in spacing between the lower endsof the rods,

into any of the holes in the block 25 with which the hole 27 is the spacer block 24 is replaced with a different spacer block of appropriate width, or if desired the spacer block 24 may be eliminated.

Spaced beneath the delivery end of the sheet-folding device is a pair of nip rollers 33 and 34, the folded sheet material passing between these rollers and being bent around roller 33 on its way to the bag making machine. The rollers 33 and 34 are rotatably mounted between bearing supports 35, one of which is secured to tubular member 15, and the other being mounted on the angle member 13.

Also carried by the angle member 13 is a vertical standard 36 slidably accommodating a horizontal bar 37, the bar being maintained in any selected position of longitudinal adjustment by a setscrew 38. A pair of ears 39, projecting perpendicularly from the upper end of an L-shaped guide finger 40, straddle the inner end of bar 37 and are pivotally secured thereto. Two compression springs 41 seated between the beveled end face of bar 37, one on each side of the pivot axis for ears 39, and the upper end of guide finger 40 serve to resiliently maintain the position of the guide finger. The lower end of the finger 40 is formed with a blunt point (FIGS. and 6), and is located directly above the nip betweenrollers 33 and 34 and behind the face of the sheet-folding device over which the sheet material is drawn.

When the web-feed arrangement described above is in use, a web 43 of bag making material, which may be heat-scalable plastic film, is drawn from the supply roll 18 upwardly over guide rod 19, and then downwardly over the front face of sheet-folding device. The side edges of the web are then pulled downwardly over the folding surfaces of the device, defined by the rods 23, to bend the web at 44 (FIG. 1). It may be noted from FIG. 1 that the center of the roll 18 is preferably not alined with the center line of the sheet folding device. In this way, when the sheet is folded to produce two main overlapping plies 45 and 46 (FIGS. 3, 5, and 6) one of the plies, in this example lower ply 46, will be wider than upper ply 45 so that it presents a margin extending beyond the corresponding edge of the narrower ply. This'margin becomes a lip in each finished bag useful during the transporting and filling of the bags. a

The portion of the web 43 passing over the delivery end of the sheet-folding device, defined by the spacing between the lower ends of rods 23 and in this example the block 24, is tucked rearwardly by the guide finger 40 so that it forms a two-ply pleat 47 between the main plies 45 and 46. In this way, the web 43 is furnished along its folded edge with a relatively narrow four-ply portion which becomes the gusset of a bag formed between two successive transverse seals provided in the sheet material by the sealer of the bag making machine.

After bending the web at 44 around rods 23, and tucking the pleat-forming portion by the guide finger 40, the folds are formed in the web by drawing it around the folding surface defined by roller 33 on its way to the machine. Longitudinal advancement of the web, in the direction of the arrow in FIG. 3, is effected by the feed rollers not shown) of the machine I between which the folded web passes. In the present illustration, folding of the web is aided by provision of an additional roller 34 which, together with roller 33, forms a nip between which the web passes to be folded. Roller 34 is, however, not

' essential since folding would take place even if only roller 33 were present.

Should it be desired to vary the depth of the gussets being formed in the bags, i.e., vary the depth of pleat plies 47, the

length of rods 23 are altered, as described above, and the location of the pointed end of guide finger 40 is also changed by loosening setscrew 38 and adjusting the bar 37 longitudinally. The pointed end should, of course, extend behind the lower end of block 24 a distance aboutequal to onehalf the distance between the lower ends of rods 23. The resilient mounting of the guidefinger 40 allows the finger to yield as the web 43 passes over it so that the finger does not tear the web.

It will be seen that, with the present invention, the web 43 is while subjecting the web material to very little or no distortion. Furthermore, if the web material is plastic film, any slight distortion produced in the material vanishes by the time the material reaches the feed rollers of the machine due to the inherent resilience of the material. In addition, all folding takes place at the sheet-folding device, rather than on the machine bed, and hence there is no tendency for the web to be shifted crosswise of the bed.

The invention has been shown and described in preferred form only, and by way of example, and it is understood, therefore, that many variations may be made in the invention which will still be comprised within its spirit.

We claim:

l. A web-feed arrangement for a bagmaking machine, comprising:

a. a supply roll of bagmaking sheet material;

b. means rotatably supporting said roll;

c. a sheet-folding. device-over which a web of material is drawn lengthwise from said roll, said device having two folding surfaces converging in the direction of movement of the web but said surfaces terminating before reaching an apex so that said surfaces are spaced apart at the delivery end of said device, the web of material being bent around said folding surfaces to initiate the formation of two overlapping plies of the sheet material;

d. a member presenting a further folding surface spaced in the direction of movement of the web from the delivery end of said device, the overlapping plies of material being bent around said further folding surface preparatory .to delivery of the material to the bag making machine; and

e. a guide between said member and the deliveryend of said device for tucking the portion of the material traveling over said delivery end between the two overlapping plies to initiate formation of a relatively narrow four-ply web portion, whereby when the web plies are sealed alonglines transverse to their length to produce bags said fourply web portion forms a gusset at one end of each bag.

2. A web-feed arrangement as defined in claim 1 including means for adjusting the spacing between the folding surfaces at the delivery end of said sheet-folding device, so as to adjust the depth of the gusset-forming plies.

3. A web-feed arrangement as defined in claim 1 wherein the folding surfaces of said sheet-folding device are defined by a pair of rods arranged in converging relation.

4. A web-feed arrangement as defined in claim 3 wherein the length of each rod is adjustable, so as to vary the distance between their ends at the delivery end of said device, and including means for supporting said rods in any selected position of adjustment.

5. A web-feed arrangement as defined in claim 1 wherein said member (d) is a roller whose longitudinal axis is arranged in a plane substantially perpendicular to the plane containing the folding surfaces of said sheet-folding device.

6. A web-feed arrangement as defined in claim 5 including a second roller adjacent and parallel to said first-mentioned roller, said rollers defining a nip through which the sheet material passes subsequent to initiation of the four-ply web portion.

7. A web-feed arrangement as defined in claim 1 wherein said guide (e) is a finger extending in a plane substantially perpendicular to the plane containing the folding surfaces of said sheet-folding device, said finger extending behind the face of said device over which the web is drawn.

8. A web-feed arrangement as defined in claim 7 wherein the amount that said finger extends behind said face of said

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