IE20020756A1 - Gusseted paper bag production process - Google Patents

Abstract

The invention relates to the manufacture of gusseted paper bags having a handle. A web of paper (21) is delivered from a Station 1, through rollers to a printing station (2), where the web of paper (21) is printed. Then the web (21) is led to an edge gluing station (3), where a thin line of adhesive is placed on the paper. The web paper (21) is then fed to a tube folding station (4), where arcuate guide bars bend the paper (21) to form an open unsealed tube. The unsealed tube is led over plates between idler wheels (33), which gradually cause a gusseted side to be formed. The tube is then flattened by rollers to form a gusseted flat tube, which is delivered, to a cutting station (7) where it is cut into lengths. The lengths of tube are delivered onto a conveyor belt where an air sucker grips the top sheet of the tube. As the conveyor draws the tube forwards, the air sucker peels back the top sheet to form an open mouth. The tube is then sent between folding plates, and is folded along a central line and the upstanding sides are folded inwards and downwards. The flattened tube is delivered to a gluing station (10) and then to folding stations (11,12,13), for folding and securing together glued edges of the tube to form the base of a bag. Then the bags are delivered to the stacking station (14). Each bag is then delivered through apparatus for forming a handle on a bag.

Description

“Gusseted paper bag production process” Introduction The present invention relates to a the manufacture of gusseted paper bags and is particular to gusseted bags having a handle.

It is well known to produce a paper bag from paper, such as described in my GB Patent Specification No. 2269560. There is, however, a major problem with paper bags which has led to the replacement of paper bags by bags of plastics materials. The problem relates to the carrying of large quantities, or indeed the carrying of the bags at all because the bags generally do not have handles. Where handles have been cut in the material of the bag, such handles have proved relatively ineffective tending to tear and break when the bag is carried. Ideally what is required is a paper bag that could carry reasonably substantial loads or quantities of material and which would have a handle to allow the bag to be carried safely.

The ideal construction of such a bag is a bag having what is effectively a base and upstanding sides of a rectangular configuration when opened out fully and also 0 having a handle attached thereto. Such bags generally have gusseted side walls to allow the bag to be folded neatly prior to use. Such bags are often referred to as gusseted paper bags. These bags are relatively efficient in use, however, they are relatively difficult to manufacture efficiently. Firstly, it can be difficult to manufacture the gusseted side wall in an efficient manner and secondly it can be difficult to fold and glue the base of the bag with any reasonable accuracy. On the face of it, gusseting the side of the bag is relatively simple. Firstly, a tube is formed and glued into position on the tube and then the gusset is formed. Generally, this is carried out by leading what is effectively a loose elongate tube around a pair of vertically spaced-apart plates inclined towards each other in the direction of travel of the tube. Then, the sides of the tube are pushed inwards between the plates to form a tube having two gusseted sides. Unfortunately, very often, the gussets are inaccurately formed. The tube tends to get pushed sideways, adhesion does not occur and in all, a considerable amount of the semi-formed bags have to be rejected. On the face of it, forming the gusset is relatively simple. However, it is - 2 IE020756 the source of considerable problems. Very often, the tube gets grumbled, the tube gets misaligned between the plates or the paper tears.

Again, the placing of handles on the bag can be difficult and time consuming such that many paper bags have reinforced portions of cardboard or the like adjacent the mouth thereof through which handles formed from cord and the like flexible material are mounted. Again, this is costly and while it produces an efficient handle, it is, as remarked, costly and time consuming to produce.

As the amount of plastics materials being used is causing severe environmental problems, governments have been imposing taxes or charges on plastics bags. For example in Ireland, the government has placed a charge of €0.15 per plastics bag supplied by shops. Thus, more and more customers are bringing shopping bags, baskets and carriers generally to shops when they wish to purchase goods. However, this does not deal with a considerable amount of purchases where people who have no suitable carrier bag are forced to buy plastics bags, the cost of which far exceeds the actual cost of their production. Therefore, in many establishments you see people leaving the shop clutching purchases because they do not wish to buy the costly plastic bags or they feel that purchasing the plastic bags, while convenient, is not environmentally friendly.

Thus, both the shopkeeper and the customer require a paper bag which has a greater capacity than the conventional small handle-less paper bag such as described in U.K. Patent Specification No. 2269560. Such a bag should also have handles and finally should be sufficiently robust as to take a relatively heavy load compared to the more conventional paper bag. While it is possible to produce such a paper bag, the problem is to produce such a paper bag in sufficient quantities with sufficient efficiency as to make the production and provision of such paper bags an economic possibility that would not impose too great a cost burden on the shopkeeper to supply.

IE 02 07 5 6 - 3 Statements of Invention According to the invention, there is provided a method of producing a gusseted bag of the type having, in use a rectangular base and four upstanding sides comprising:leading a flat web of paper off a roll; applying adhesive adjacent one edge thereof; folding the web to form a loose elongate tube; leading the elongate tube around a pair of vertically spaced apart plates, namely, a substantially horizontally arranged bottom plate and a narrower top plate, one of the exposed side edges of each plate initially coinciding with the top plate and inclining downwardly and across the bottom plate in the direction of travel of the tube side so that the other side edges coincide; pressing the sides inwards by two opposed sets of converging opposed idler wheels, the idler wheels being of decreasing thickness and diameter in the direction of travel of the tube and rotatable about an axis orthogonal to the tube; and simultaneously pressing the tube down on the uppermost of the plates by rollers to seal the adhesive and to retain the tube during formation of the sides; cutting the tube into discrete lengths to form exposed end edges; holding the top sheet of each length tube while moving the bottom sheet away from the top sheet to fold the top sheet back on itself about a central transverse fold line while holding the top sheet; IE 02 07 5 β - 4 flattening the top sheet back on itself; applying adhesives to the exposed surfaces of the tube expose by the folding; folding the top sheet forwardly over itself about another transverse fold line between its exposed adjacent end edge and the central fold line to cause contact with some of the adhesive; folding the bottom sheet back over itself and the top sheet about another fold line between its adjacent exposed end edge and the central fold line to cause contact with the reminder of the adhesive; flattening the bag so formed; and attaching a pair of handles thereto.

The use of the narrower top plate in forming the tube and then the gusset affords some surprising advantages. Initially, the sides of the tube are accurately guided to overlap and ensure adhesion occurs while the fact that the top plate is narrower than the bottom plate accommodates the web of paper so that it is not too tightly held when the plates are far apart. Minor realignments of the web appears to be accommodated and the tube is easily sealed. This means that the sealing can be done in conjunction with the web forming which is advantageous because it ensures that the seal portion can now be fairly tightly held when the first part of the web is being formed and there is some force being exerted on the adhesive. As the gussets are being formed, the narrow upper plate allows a certain amount of lateral movement of the tube preventing crumpling and tearing of the paper and consequent downtime.

Ideally, the method comprises:leading the cut tube onto a rotating conveyor drum having mounted IE 02 07 5 8 - 5 above it a plurality of transversely arranged spaced apart bars and drive chains; engaging the bottom sheet at its exposed edge by hook to retain it on the drum; applying a vacuum to the top sheet; releasing the vacuum when the top sheet is folded about the central line; after applying the adhesive, folding the top sheet forwardly by moving the drive chains faster than the drum to impinge against the top sheet to fold down against the adhesive; pushing the bottom sheet by a rotating arm and then across and against the top sheet; and pressing the sheets together by a roller proud of the conveyor.

In another embodiment of the invention, the web is folded to form the elongate tube by feeding the web onto a plate having opposed upstanding arcuate guide arms, the free ends of which project across the plate to guide the web back onto itself with the portion on which the adhesive is applied uppermost.

In a further embodiment of the invention, as the tube is being folded about the central fold line, the tube is simultaneously folded inwardly transversely to the direction of travel to lie about the two fold lines in line with the outermost side edges of the tube.

Ideally, the web is printed prior to the application of adhesive for the formation of the elongate tube.

In a further embodiment, the method comprises:IE 0 2 ο 7 5 6 - 6 leading a flat web of paper off a pair of rolls; applying adhesive adjacent one edge thereof of each web; folding each web to form an elongate tube; flattening each tube; cutting each tube into discrete lengths; folding each length of tube about a pair of spaced apart incline fold lines to form a handle having a central handle grip portion and a pair of opposed orthogonally projecting legs; feeding a bag and a pair of handles, one above and the other below the bag, towards each other; applying adhesive to part of the leg of each handle; and pressing the legs of each handle onto the bag.

Description of Invention The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which:Fig. 1 is a perspective view of portion of a plant for carrying out a process according to the invention, Fig. 2 is a side view of the plant illustrated in Fig. 1, ¢0207 5 8 Fig.3 is a perspective diagrammatic view showing details of various stations in the production of a bag without handles according to the invention, Figs. 4, 5 and 6 are enlarged perspective views of portions of Fig. 1, Figs. 7,8 and 9 are enlarged side views of the plant as illustrated in Fig. 2, Fig. 10 is a sectional diagrammatic view of portion of the plant, Fig. 11 is a diagrammatic view of portion of the plant in operation, Fig. 12 is another diagrammatic view showing the plant in operation, Fig. 13 is a perspective exploded view of a handle forming and fixing plant according to the invention, Fig. 14 is a side view of the handle forming and fixing plant, and Fig. 15 is a view similar to Fig. 3 showing how a handle is formed.

It should be noted in the drawings that in many instances various details are removed so that the operation of the invention can be clearly understood. This is particularly with support structures.

Referring to Figs. 1 and 2 there is illustrated portion of the plant for carrying out the present invention. The various stations, as listed below, are each identified generally by a reference numeral.

Further, Fig. 3 illustrates the principal operation carried out at most of these stations or stations which again are identified for ease with the same reference numeral. Essentially the stations in operation are synonymous.

To form the gusseted bag prior to attaching a handle thereto, if such is required, the following stations and operations are carried out. - 8 IE 02 07 5 6 Station 1: Feeding A web of paper is led off a roll in this station Station 2: Printing Any printing required on the bag is carried out here.

Station 3: Edge gluing Here one edge of the web paper is glued.

Station 4: Tube folding In this station the paper is folded to start to form a tube.

Station 5: Tube formation Here the tube is formed and once it is formed, the next station takes place.

Station 6: Gusseted side formation In this operation rollers are used to form the gussets.

Station 7: Cutting In this station the gusseted tube is formed into discrete lengths.

Station 8: Base folding In this station the top sheet of the tube formed is folded back on itself to start the formation of the base.

Station 9: Flattening of base Station 10: Base adhesive application In this station, adhesive is applied to the flattened open end of the tube.

Station 11: First folding of the base The top sheet, that has previously been folded back to form the base, is now folded back on itself against the adhesive. - 9 IE 02 ο7 5 6 Station 12: Second folding of the base.

In this station the bottom sheet of the tube is folded back in itself to complete the formation of the base.

Station 13: Flattening The form bag is flattened and the base totally formed.

Station 14: Stacking In this station the bags are stacked.

Referring now more specifically to the drawings and initially to Figs. 4 and 7 where there is illustrated stations No.1, No. 2 and No. 3, namely the feeding, printing and edge gluing stations. There is provided a paper roll support 20 on which is mounted a web of paper 21 which feeds through a plurality of rollers 22, printing head 23 which in turn feeds by further rollers 22 back from the printing head 23 the web 21 to the station 3 namely the edge gluing station. There is provided a gluing mechanism 25 feeding a glue head 26. The web of paper is transferred by further rollers 22 to a longitudinal crease former 27.

Referring now to Figs. 5 and 8, there is provided arcuate guide arms 30 on either side of a plate 31 across which the web is led to a pair of arcuate guide plates 32. There are side mounted idler wheels 33, mounted on the plate 31. The idler wheels 33 comprise an upward disk 34 and a lower disk 35, the idler wheels 33 can be seen in Fig. 11.) The idler wheels 33 are mounted above and between two plates, namely an upper plate 36 and a lower plate 37. Further, top pressing rollers 38 are provided (Fig. 8). It will be noted from Fig. 10 that the plates 36 and 37 not only converge in the direction of travel of the web which is now actually forming a tube and is identified by the reference numeral 21, however now with subscript (a).

Referring now to Figs. 5, 6 and 9, the remainder of the stations are now illustrated. In station No. 7 there is provided a cutter 40 which feeds on a conveyor 41 through a take off mechanism 42 which in turn feeds a conveyor drum 50 formed from a conveyor belt 51 and rollers 52. Above the drum 50 there is provided a pair of drive ^020756 chains 53 carrying therebetween transverse bars 54 spaced apart from the belt 51. The conveyor belt 51 mounts a plurality of spaced apart hooks 55. On either side of the conveyor belt 51, there is mounted a pair of accurate folding plates 57 and an upper control guide 58. Further, mounted above the adjacent drum 50 is a pneumatic suction device 56.

A rotary glue head 60 fed with glue from a hopper 61 is mounted adjacent the conveyor drum 50 as is a rotating arm 62 carrying outwardly directly radially arranged pushers arms 63. A pushing device 64 is mounted beyond the rotating arm 62. A take off conveyor 66 is provided adjacent a stacking device 67. Suitable drives for the conveyor drum 50 and the drive chain 53 are provided.

In use, a web 21 of paper is fed from the Station No.1, namely feeding, through the rollers to the second station, namely printing station, where the necessary printing on the web of paper 21 is carried out. Then the web 21 is led to station 3, namely the edge gluing station where a thin line of adhesive is placed on the paper. The web of paper, still identified by the reference numeral 21 is fed to station No. 4, namely tube folding, where the arcuate guide bars 32 start to bend the paper 21 to form an open unsealed tube 21(a) as illustrated in Fig. 12. The unsealed tube 21(a) is then led over the plates between the idler wheels 33 and the idler wheels 33 gradually cause the gusseted side to be formed in the tube which is now identified by the reference numeral 21 (b). This can be clearly seen from Figs. 10(a) to 10(d) and from Fig. 11.

The tube 21 (a) which has been flattened by the rollers 38 is now a gusseted flat tube 21(b) which is delivered then to the cutting station 7 where it is cut into discrete lengths. The discrete lengths of tube 21 (c) are then delivered onto the conveyor belt 51 where the air sucker 56 anchors the top sheet of the tube 21 (c) while the hook 55 engages river the lower sheet of the tube 21 (c). As the tube 21 (c) is drawn forwards by the conveyor 50, the effect is to pull out the tube and to form an open mouth of the tube. The tube 21 (c) is then sent between folding plates 57 and the central guide 58, thus firstly the tube 21 (c) is folded along a central line identified by the letter a in Fig. 3 and then led between the plates 57 and under the guide 58 where the upstanding sides as shown are then folded inwards and downwards to a position illustrated again in Fig. 3. - 11 IE0207 58 Then the flattened tube, now identified by the reference numeral 21 (d) is delivered to the gluing station No. 10, namely the base adhesive application, and then in station No. 11, one of the bars 54 knocks the top sheet forward to fold down against the adhesive.' Then the tube 51 (d) is delivered to station No. 12, namely the secondly folding of the base, where the rotating arm 62 causes the pusher arms 63 to push the bottom sheet of the tube 21(d) rearwards and against the top sheet. Then the partially formed tube bag still identified by the reference numeral 21 (d) proceeds to station No. 13 where the base of the bag is firmly formed and then the bags, now identified by the reference numeral 21 (e) are delivered to the stacking station number 14.

Referring to Figs. 13 to 15 there is illustrated the formation of a handle and the attachment of a handle to a bag, such as a bag 21 (e) as formed in accordance with the invention.

Referring initially to Fig. 15 it can be seen how the eventual shape of a handle is provided.

Referring now to Fig. 14 there is illustrated a pair of paper rolls 70 feeding through various rollers 71, an adhesive applicator 72 then upstanding folding horns 73 to provide a folded over and pressed tube. There is then provided a cutter 74 to cut the tube into discrete lengths since this forming process is substantially similar to the forming process hereinbefore described is not described in any more detail. Then the cut discrete lengths of the tube are delivered to a quick feed conveyor 82 where they are delivered to a folding and mounting station identified by the reference numeral 15 which folding and mounting station is shown in more detail in Fig. 13. The folding and mounting station 15 comprises a support wheel 75 for carrying a length of tubing against a former wheel 76 which in turn rotates near a collection wheel 77 which in turn delivers to a gluing head 78. This is replicated above and below a conveyor table 80 which delivers the bags 21 (e) from a magazine 81. The table 80 ip turns delivers to rollers 79 and then to a finished bags store where bags identified by the reference numeral 21 (f) have handles thereon. - 12 IE U2 07 5 β In operation, as mentioned already, the lengths of tube can be relatively easily made and they are then delivered to a quick feed conveyor 82 where in conjunction with the former 76, the tube is bent into a central hand gripping portion and a pair of opposing orthogonally projecting legs. A bag 21 (e) is fed onto the conveyor table 80 from the magazine 81. Simultaneously a handle, which has been cut, is carried by the collection wheels 77 from wheel 75 to wheel 76 and then to wheel 77. The handles are then pressed to both the bottom and top of the bag 21(e) and delivered out through the rollers 79 as finished bags 21 (f). in the specification the terms “comprise, comprises, comprised and comprising” or any variation thereof and the terms “include, includes, included and including” or any variation thereof are considered to be totally interchangeable and they should all be afforded the widest possible interpretation and vice versa.

The invention is not limited to the embodiment hereinbefore described, but may be varied in both construction and detail.

Claims (8)

1. A method of producing a gusseted bag of the type having, in use a rectangular base and four upstanding sides comprising:leading a flat web of paper off a roll; applying adhesive adjacent one edge thereof; folding the web to form a loose elongate tube; leading the elongate tube around a pair of vertically spaced apart plates, namely, a substantially horizontally arranged bottom plate and a narrower top plate, one of the exposed side edges of each plate initially coinciding with the top plate and inclining downwardly and across the bottom plate in the direction of travel of the tube side so that the other side edges coincide; pressing the sides inwards by two opposed sets of converging opposed idler wheels, the idler wheels being of decreasing thickness and diameter in the direction of travel of the tube and rotatable about an axis orthogonal to the tube; and simultaneously pressing the tube down on the uppermost of the plates by rollers to seal the adhesive and to retain the tube during formation of the sides; cutting the tube into discrete lengths to form exposed end edges; holding the top sheet of each length tube while moving the bottom sheet away from the top sheet to fold the top sheet back on itself - 14 •E 0 207 5β about a central transverse fold line while holding the top sheet; flattening the top sheet back on itself; applying adhesives to the exposed surfaces of the tube expose by the folding; folding the top sheet forwardly over itself about another transverse fold line between its exposed adjacent end edge and the central fold line to cause contact with some of the adhesive; folding the bottom sheet back over itself and the top sheet about another fold line between its adjacent exposed end edge and the central fold line to cause contact with the reminder of the adhesive; flattening the bag so formed; and attaching a pair of handles thereto.

2. A method as claimed in claim 1 comprising:leading the cut tube onto a rotating conveyor drum having mounted above it a plurality of transversely arranged spaced apart bars and drive chains; engaging the bottom sheet at its exposed edge by hook to retain it on the drum; applying a vacuum to the top sheet; releasing the vacuum when the top sheet is folded about the central line; - 15 •Ε 020756 after applying the adhesive, folding the top sheet forwardly by moving the drive chains faster than the drum to impinge against the top sheet to fold down against the adhesive; pushing the bottom sheet by a rotating arm and then across and against the top sheet; and pressing the sheets together by a roller proud of the conveyor.

3. A method as claimed in claim 1 or 2, in which the web is folded to form the elongate tube by feeding the web onto a plate having opposed upstanding arcuate guide arms, the free ends of which project across the plate to guide the web back onto itself with the portion on which the adhesive is applied uppermost.

4. A method as claimed in any preceding claim in which as the tube is being folded about the central fold line, the tube is simultaneously folded inwardly transversely to the direction of travel to lie about the two fold lines in line with the outermost side edges of the tube.

5. A method as claimed in any preceding claim in which the web is printed prior to.the application of adhesive for the formation of the elongate tube.

6. A method as claimed in any preceding claim comprising:leading a flat web of paper off a pair of rolls; applying adhesive adjacent one edge thereof of each web; folding each web to form an elongate tube; flattening each tube; cutting each tube into discrete lengths; - 16 IE 02 ο7 5 6 folding each length of tube about a pair of spaced apart incline fold lines to form a handle having a central handle grip portion and a pair of opposed orthogonally projecting legs; feeding a bag and a pair of handles, one above and the other below the bag, towards each other; applying adhesive to part of the leg of each handle; and pressing the legs of each handle onto the bag.

7. A'method of producing gusseted bags substantially described herein with reference to and as illustrated in the accompanying drawings.

8. A gusseted bag produced in accordance with any of the preceding claims.