US3578528A

US3578528A - Apparatus for forming handles on paper bags

Info

Publication number: US3578528A
Application number: US642999A
Authority: US
Inventors: Peter Weisshuhn
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-05-09
Filing date: 1967-05-09
Publication date: 1971-05-11
Anticipated expiration: 1988-05-11

Abstract

APPARATUS AND METHOD FOR FORMING HANDLES ON PAPER BAGS WHEREIN A RUNNING PAPER WEB, PARTIALLY SEVERED TRANSVERSELY AT INTERVALS, IS PASSED TOGETHER WITH AN EXTRUDED SHEET OF THERMO-PLASTIC MATERIAL IN A FLOWING CONDITION, THROUGH A NIP BETWEEN A CHILLING ROLLER AND PRESSURE ROLLER-THUS EFFECTING A BOND. DTHE CHILLING ROLLER HAS DEPRESSIONS FORMED IN ITS SURFACE WHICH PROVIDES UNBONDED THERMO-PLASTIC SECTIONS OVERLYING LINES OF PARTIAL SEVERANCE OF THE PAPER WEB SO THAT WHEN THE WEB IS COMPLETELY SEVERED AT SAID INTERVALS THE UNBONDED SECTIONS OF THERMOPLASTIC MATERIAL FORM BAG HANDLES.

Description

y 11, 1 P. WEISSHUHN 3,578,528 Q APPARATUS FOR FORMING HANDLES ON PAPER BAGS Filed May 9, 1967 3 Sheets-Sheet l INVENTOR y 11, 1971 P. WEISSHUHN 3,578,528

APPARATUS FOR FORMING HANDLES ON PAPER BAGS Filed May 9, 196? 3 SheetsSheet 2 IO I0 INVENTOR.

y 11, 1971 P. WEISSHUHN 3,578,528

APPARATUS FOR FORMING HANDLES ON PAP ER BAGS 3 Shets-Sheet 5 Filed May 9, 1967 I NVEN TOR United States Patent 3,578,528 APPARATUS FOR FORMING HANDLES ON PAPER BAGS Peter Weisshuhn, 204-1985 Bellevue Ave, Vancouver, British Columbia, Canada Filed May 9, 1967, Ser. No. 642,999 Int. Cl. B29c 23/00 U.S. Cl. 156-380 9 Claims ABSTRACT OF THE DISCLOSURE Apparatus and method for forming handles on paper bags wherein a running paper web, partially severed transversely at intervals, is passed together with an extruded sheet of thermo-plastic material in a flowing condition, through a nip between a chilling roller and pressure roller-thus efiecting a bond. The chilling roller has depressions formed in its surface which provides unbonded thermo-plastic sections overlying lines of partial severance of the paper Web so that when the web is completely severed at said intervals the unbonded sections of thermoplastic material form bag handles.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to the making of paper bags and in particular to the forming of carrier handles thereon.

Prior art In the making of paper bags, it is now standard practice to run a continuous fiat web of bag making paper through a bag making machine which continuously forms the fiat sheet into a tubular section, then cuts the tubular Section into sections of predetermined lengths from which the bags are formed.

The continuous nature of the operation is relatively inexpensive as most bag making machines are fully automated.

The competitive nature of the paper converting industry and particularly with respect to the sale of bags, has resulted in many attempts to provide bags having carrying handles to facilitate the carrying of groceries and the like by shoppers. However, due to the extra production steps involved, the cost of providing such handle equipped bags is relatively high.

The present invention provides a method and apparatus whereby carrying handles may be formed on bags without in any way affecting production of a bag making machine.

The present invention provides a means whereby the production of carrying handles and their attachment to bags is or can be completely automated and, by virtue of the fact that the handles are constructed of a very inexpensive material, results in a bag which is marketed at a price substantially the same as that of a handleless bag.

Furthermore, the manner by which the handles are applied to bags in accordance with the present invention adds to the strength of the bags in providing reinforcement therefor and thereby increases the load carrying capabilities of the bags.

SUMMARY OF THE INVENTION The present invention contemplates the provision of handles on a running paper web prior to a latters entry into the bag making machine by rolling a continuous strip of thermoplastic material on the paper web as the latter is running, bonding the plastic material at predetermined intervals along its length to the paper web, providing hand size openings in the plastic material adjacent meeting edges of the unbonded sections, severing the unbonded sections of thermoplastic material transversely of its length following a handle formed therein, and arranging the paper bag machine to sever the paper web after the latter has been formed into a tubular section transversely of its length on a line extending between the bonded sections of the thermo plastic material.

The apparatus for forming the carrying handles on the running paper web of bag forming paper prior to the feeding therein of the paper web into a paper bag making machine inclules a pressure roller, a chilling roller in rolling engagement with said pressure roller forming a nip through which the paper web is arranged to pass, said chilling roller having a non-continuous depressed area formed in its rolling surface, said depressed area having a floor and leading and trailing edges, means for extruding a continuous strip of thermoplastic material onto the chilling roller in advance of the nip in line with the depressed area, said strip being of lesser width than said area, means for drawing the portion of the plastic material overlying the depressed area into engagement with the floor so as to maintain said portion in spaced relation to the paper web as said web and plastic material pass through the nip, and means at said depressed area for severing said portion on a line extending substantially transversely of the length of strip adjacent the trailing edge of said portion and for cutting a hand sized opening in said portion, said bag making machine being arranged to sever the paper web transversely of its length on a line extending beneath the said portion of plastic material.

In one embodiment of the invention, cutting of the thermoplastic material, the use of high or radio frequency currents in conjunction with tear-seal type electrodes is contemplated, and in another embodiment it is proposed to cut the thermoplastic material by pneumatic means.

DESCRIPTION OF THE DRAWINGS A detail description following, related to the drawings, gives exemplification of preferred embodiment of the invention which however, is capable of expression in structure other than that described and illustrated.

FIG. 1 is a diagrammatic side view of one embodiment of the apparatus of the invention, illustrating the passage of the paper web therethrough,

FIG. 2 is a central sectional view of the chilling and pressure rollers of the embodiment of FIG. 1, taken at the nip, illustrating the position of the paper web and thermoplastic material therein,

FIG. 3 is an enlarged sectional central view of the embodiment of the apparatus of FIG. 1 taken at the nip between the chilling and pressure rollers,

FIG. 4 is an isometric view of a portion of the chilling roller of the embodiment of FIG. 1, illustrating a de pressed area and cutting electrodes.

FIG. 5 is an enlarged diagrammatic side view of a portion of FIG. 1,

FIG. 6 is a plan view of a length of paper web illustrating in sequence the steps in theformation of a handle,

FIG. 7 is an isometric view of a chilling roller of another embodiment of the invention,

FIG. 8 is an isometric view of a chilling roller of yet another embodiment of the invention, and

FIG. 9 is an enlarged central sectional view of a portion of the chilling roller taken along line 9-9 of FIG. 8.

DETAILED DESCRIPTION In the paper bag making industry many automated machines have been developed whereby a continuous running web of paper is formed into a tube from which sections of desired length are cut and then formed into individual paper bags. The bag making operation is extremely rapid and one machine may make thousands of paper bags per hour at a small cost per bag.

The present invention involves the adhering of the paper web, in intermittent and alternate bonded and nonbonded sections, a thin sheet of thermoplastic material, the distance between each successive non-bonded section being equal to the length of paper web required for each bag. A hand hole is then cut in each of the non-bonded sections, each non-bonded section then severed adjacent its juncture with the following bonded section, and the web then fed into the paper bag making machine which is arranged to sever the paper web across an area overlaid by each of the non-bonded sections, the severed edge of the paper web sections at which each of the non-bonded sections of the thermoplastic material is located being the top edge of a bag to be formed.

The adhering of the thin sheet of thermoplastic material to a paper web is a well known process and is carried out by extrusion coating of thermoplastic material in its flow condition upon the continuously travelling web, then feeding the thermoplastic material and paper web into a nip formed between a pair of rollers, one of the rollers being chilled in the manner known in the industry to cool the thermoplastic material, thereby bonding it to the paper. This process is well known in the industry and need not be described further in detail.

FIGURE 1 Referring now the FIG. 1 which illustrates in diagrammatic form one embodiment 9 of the apparatus in accordance with this invention, a paper web 10 which is normally supplied in a roll 11 is fed around a roller 12 having a transversely extending groove 14 in its rolling surface over which the paper extends. Located adjacent the roller 12 is a rotary knife apparatus 15 having a knife blade 17 which is correlated in angular velocity to the rotational speed of the roller 12 so that the knife blade 17 will enter the groove 14 as said roller 12 rotates and makes a transverse cut in the paper web partially across the latter and in line with a handle to be formed thereon. The circumference of the roller 12 and-the angular movement of the rotary knife 15 is such that the cuts made in the paper Web are spaced a distance equal to the length of a section of paper web required to form one bag (see FIG. 5).

From the roller 12 the paper web passes over a tension roller 19 and through a nip formed between a pressure roller 20 and a chilling roller 21 having a rolling surface. The paper web is maintained in engagement with the chilling roller 21 by means of a second tension roller 22 and then fed into a bag making machine which, as previously explained, forms the web into a tubular shape and cuts the latter into sections from which the bags are formed. The direction of movement of the paper web and the direction of rotation of all rollers is shown by arrows accorded the numeral 23.

Mounted above the nip between the chilling and pressure rollers is an extruder 25 of known design which is arranged to extrude a thin strip 27 of thermoplastic material on to the chilling roller 21 in advance of the nip. The thermoplastic material and paper Web pass throug the nip, the plastic material being cooled by the chilling roller and at the same time being bonded to the paper web. This method of forming a plastic and paper laminate is well known in the industry and it is considered, need not be discussed or described in this application. The width of the strip of thermoplastic material is slightly less than the length of cut 18 and is centered on the latter so that the cut 18 will extend on both sides of the strip of material.

The circumferential length of the chilling roller 21, as illustrated in FIG. 1 of the drawings, is equal to the length of the bag sections cut by paper bag making machine and, said roller has formed in its rolling face, a substantially rectangular depressed area 30, the width of which is slightly greater than the width of the strip of plastic material 27, and of a depth slightly greater than the thickness of said strip of plastic material. The depth of the depressed area as shown in FIGS. 2 and 3 is of course exaggerated for purpose of clarity, and the floor 31 of a depressed area is arranged so that it follows concentrically the curvature of the rolling surface of the chilling roller.

A high frequency electric current used to cut the strips of thermoplastic material is proposed. The use of high frequency electric currents to cut and seal sheets of thermoplastic material is well known, and involves the passage of high frequency electric current between a pair of electrodes spaced on either side of the sheet to be cut, the voltage of the current and the length of time that the plastic material is exposed to the action of the electric currentbeing of course dependent upon the thickness of the material and its molecular makeup. Those thermoplastic materials containing polar molecules will have a high heatability factor and are therefore much easier to cut than those materials which contain dipolar molecules.

FIGURES 2, 3, 4, 5 AND 6 The chilling roller 21 is provided with a pair of electrodes 32 and 33 which are located in the depressed area 30. Electrode 32 is annular in shape and is located substantially centrally within the depressed area, whereas electrode 33 is curved extending transversely from side to side of the depressed area in spaced following relationship to electrode 32. These electrodes 32 and 33, is illustrated in FIGS. 2 and 3, extend at their

tips

35 and 36 respectively slightly beyond the rolling face of the chilling roller, a distance approximately one-half the thickness of the strip of plastic material 27 and, as illustrated inthe last mentioned figures, are secured to the chilling roller by means of electroconductive rods 38 which serve as conductors and which pass through radially extending passages 39 formed through the chilling roller and secured by means of nuts 40 threaded over the inner ends of said rods. Both the rods 38 and the electrodes 32 and 33 are insulated from the chilling roller by insulation 41.

The apparatus 9 is also provided with a curved plate electrode and, in spaced relationship to the rolling surface of the chilling roller, following the nip between said chilling roller and said pressure roller.

Electrodes

32, 33 and 45 are connected by means of leads 46 to a source of high frequency electric current.

It is to be understood that the connection between electrodes 32 and 33 and the source of electric current shall include rotary contact points again of known manufacture, and therefore which are not shown whereby connection can be made between the rotating chilling roller 21 and a stationary source of electric power.

The floor 31 of the depression is corrugated with circumferentially aligned corrugations 47 extending from the leading edge 48 of said depressed area to the electrode 32 and, between electrode 32 and electrode 33 the floor 31 is formed having conically shaped depressions 49, bases 50 of the depressions 49 being adjacent electrode 32 and extending at their apices toward electrode 33.

In forming the carrying handles, the chilling roller is provided, in a known manner, with a charge of static electricity of opposite value to the static charge normally found on the plastic material to be used. It Will be appreciated therefore that on passage of strip of plastic material 27 through the nip, that portion of said material overlying the depressed area will be drawn, by reason of the differing static charges between the chilling roller and the material, on to the floor of the depressed area and out of contact with the paper web adjacent. This will of course provide alternate non-bonded and bonded areas between the paper web and plastic material as both the paper web and material pass through the nip, the bonded are as illustrated in FIG. 6 being accorded the numeral 51 and the non-bonded area being accorded the numeral 52. The chilling roller is so angularly related to the paper web that upon passage of the latter through the nip, the

leading edge 48 of the depressed area 30 will fall slightly in advance of the line of precut 18 (FIG. 6, position b).

As the paper web and thermoplastic material pass electrode 45, the passage of electric current between said electrodes 32 and 33 cuts an annular opening 53, the diameter of which is represented by the diameter of the electrode 32 in the non-bonded area 52 of the material, and the nonbonded material will also be severed along a line as represented by the electrodes 33. It will be seen therefore that the non-bonded area 52 in which the opening 3 has been formed is secured to the paper web only at its leading edge as represented by the leading edge 48 of the depression. At the same time, said non-bonded area 52 will be cooled by its contact with the floor 31 of the chilling roller and will assume in its fixed state the shape of the floor 31 including the corrugations 47 and conical depressions 49.

In advance of the nip the paper web is partially cut by the rotating knife 17 (FIG. 5) across the area to be covered by the plastic material. The precut is slightly wider than the width of the plastic film.

The paper web and plastic material 27 are then passed into the paper bag making machine which is arranged to complete the severance of the paper web on the line of the precut 18 (FIG. 6, position 0), and form the paper bag having as its upper edge the edge from which the non-bonded portion 52 of the strip of thermoplastic material extends (FIG. 6, position d).

It will be appreciated that a handle 60 is formed having a hand receiving opening 53. The corrugations 47 and conically shaped depressed areas 49 of the floor 31 results in similar corrugations and conically shaped depressions formed in said handle 60. The corrugations therein stiffen the handle, and the conically shaped depressions 49 permit lengthening of the material at the opening 53 so that the portion of the handle 60 to be grasped by an individual carrying the bag, will assume a horizontal rather than a vertical position.

It will also be understood that the apparatus as herein described and illustrated has been greatly simplified for purposes of clarity. It will be appreciated that the circumferential length of the chilling roller can be two or more times the length of the bag section to be cut by the bag machine which would consequently necessitate the provision of two or more depressed areas and corresponding electrodes spaced at bag section length intervals in the rolling surface of the chilling roller.

It will also be apparent that although the specification and claims are directed to the forming of only one handle per bag, a plurality of such handles can be formed in side by side relationship in the manner as described so that the bags, have carrying handles on opposite side panels.

FIG. 7 illustrates a chilling roller 70 of another embodiment 71 of the invention. Embodiment 71 is in all respects the same as embodiment 9, with the exception of the form of the chilling roller 70, which is of hollow construction and is formed having a depressed area 73 similar to depressed area 30 of embodiment 9 in which

electrodes

75 and 76 similar to electrodes 32 and 30 are located. Chilling roller 70, however, has a circumferentially extending slot 78 formed therein terminating at one end 79 at the electrode 76, and extending partially around the circumference of the roller and terminating at its other end 80 at a transversely extending electrode 81, the latter being connected by leads, not shown, to a source of electric power. The chilling roller is also provided with air nozzles 85 located below its rolling surface, said nozzles being connected in a known manner to a source of cool air, not shown, and arranged to direct a cooling blast of air against the thermoplastic material drawn inwards through the slot 78 so as to set the material before it comes into contact with surfaces of the chilling roller.

By means known in the industry, the air pressure within chilling roller 70, is maintained slightly below atmospheric pressure so as to produce a slight vacuum.

Chilling roller 70 permits the strip of plastic film extending between electrode 76 and electrode 81 to be completely severed and then drawn, by the vacuum, into said chilling roller. The sections removed from the thermoplastic material can then be gathered and re-used in the extrusion coating process.

FIGURES 8 AND 9 FIGS. 8 and 9 illustrate a chilling roller of another embodiment 91 of the invention.

Chilling roller 90 is also of hollow construction having a rolling face 92 and an inner face 93, and is supported by struts 95 on a hollow shaft 96 for rotation in the direction indicated by the arrow 97, the shaft being suitably driven.

This shaft 96 is also connected via a rotary air seal 98, of known manufacture, to a conduit 100, the latter being connected to an evacuating air pump, not shown.

A shallow depressed area 102 of the same size and configuration as depressed area 30 of chilling roller 21 is formed in rolling face 92. This depressed area has a floor 103 which terminates at its trailing end 104 in a curved slot 105, the slot extending through the roller and opening at its inner face 93. Also formed in the floor 103 in advance of and spaced forwardly of the slot 105', is an annular slot or groove 106 which communicates with the interior of the roller through passages 107 formed through the wall of the roller and opening at its inner face 93. The floor 103 is also formed with corrugations and conical depressions, not shown, of a nature identical to the corrugations 47 and conical depressions 49 of embodiment 9.

The curved'slot 105 and passages 107 are connected to the hollow shaft 96 by conduits 110 welded to the inner face 93 of the roller, whereby upon operation of the evacuating air pump, air will be continuously drawn into the

slots

105 and 106. Furthermore, chilling roller 90 is also provided with a charge of static electricity in the known manner.

It is to be understood that embodiment 91 of the apparatus is exactly the same as embodiment 9, differing only in the type of chilling roller used.

In the operation of embodiment 91, the strip of plastic material accorded the numeral 112, is extruded on to the surface of the chilling roller in a flow condition. As the strip of thermoplastic material flows over the floor 103 of the depressed area, the air being drawn inwards through the slot 105 and groove 106 cuts said material along edges of the slot and groove, said material being completely severed along a line followed by slot 105 and having an annular portion corresponding to annular groove 106 out therefrom, thereby forming a handle similar to the handle by embodiment 9 of the invention.

It will be appreciated during the handle forming operation performed by the apparatus that the circular portion cut from the thermoplastic strip in all embodiments of the invention need be removed from the chilling rollers after each handle forming operation.

The various embodiments of the invention as herein described are the same in all respects with the exception of the chilling rollers. Each embodiment utilizes a roller similar to the roller 20 as illustrated in FIG. 1.

In order to remove said circular cut-out portion from the chilling roller in each case, it is only necessary to apply a strong electrostatic charge, again in a known manner, to roller 20 so that as a handle passes between the chilling roller and roller 20, the charge on the latter will attract the circular out-portion away from the chilling roller, the strength of the static charge on the chilling roller being consequently, much reduced.

After the handle has passed between the roller 20 and the chilling roller, the latter may be again charged, again in a known manner, to perform another handle forming and cutting operation.

The equipment and apparatus necessary for applying and wiping static electrical charges from rollers and the like in the paper converting industry, is well known. it

is considered therefore unnecessary to illustrate or describe equipment for this purpose.

It will be appreciated that the apparatus as herein described not only permits the uninterrupted forming of carrying handles on a paper web used in paper bag construction, but considerably strengthens the paper bag ultimately formed, the strength thereof depending upon the strength of the type of thermoplastic material used. Materials such as a vinylidene chloride-vinyl chloride copolymer which contain polar molecules and which have high tensile strengths are suitable.

What is claimed as new and desired to be secured by Letters Patent is:

1. Apparatus for forming bag carrying handles on a running web of paper preparatory to feeding said web into a bag making machine including a pressure roller, a chilling roller in rolling engagement with said pressure roller forming-a nip through which the paper Web is arranged :to pass, said chilling roller having a non-continuous depressed area formed in its roller surface, said depressed area having a floor, leading and trailing edges, means in advance of the nip to partially sever the paper web across the area to be covered by the plastic material, means in advance of the nip and in line with the depressed area for extruding a strip of thermoplastic material onto the chilling roller so as to extend onto the rolling surface of the latter in advance of and following said depressed area, said strip being of lesser width than the width of said depressed area, means for drawing the portion of plastic material overlying the depressed area into engagement with the floor so as to maintain said portion in spaced relation to the paper web as said web and plastic material pass through the nip, and means at said depressed area for severing said portion on a line extending substantially transversely of the length of the strip adjacent the trailing edge of said portion and for cutting a hand sized opening in said portion, said bag machine being arranged to sever the paper web transversely of its length on a line of precut extending beneath the said portion of plastic material.

2. Apparatus as claimed in claim 1, including means for extruding the thermoplastic material continuously onto the chilling roller.

3. Apparatus as claimed in claim 1 in which the means for severing the thermoplastic material and forming the opening therein comprises a pair of electrodes located in the depressed area, one of said electrodes being annular in configuration and the other being arcuate in configuration and spacedly following said electrode, said other electrode extending from one side to the other of the floor, said electrodes protruding beyond the rolling surface of the chilling roller approximately one-half the thickness of the strip of plastic material, a third electrode in spaced adjacent relationship to the chilling roller forming a passage through which the paper web and strip of plastic material are arranged to pass following the nip, and means for passing a high frequency electric current between said pair of electrodes and said third electrode.

4. Apparatus as claimed in claim 3 wherein the floor of the depressed area formed having a plurality of conically shaped depressions formed in the area of said floor between said pair of electrodes, said depressions having their bases adjacent said annular electrode and their apices extending towards the arcuate electrode, said floor having circumferentially extending corrugations formed therein between the leading edge of the depressed area and the annular electrode.

5. Apparatus'as claimed in claim 1 wherein the means for drawing the strip of thermoplastic material into engagement with the floor of the depression comprises means for charging the chilling roller and plastic strip with opposite static electrical charges.

6. Apparatus as claimed in claim 1 in which the chilling roller is of hollow construction and is formed having a circumferentially elongated opening formed in its rolling face, said opening terminating at its leading edge at the trailing edge of the floor of the depression, and including means at the other end of the opening for severing the thermoplastic material, and means for providing a vacuum at the opening to draw the severed portion of the thermoplastic material onto the chilling roller.

7. Apparatus for forming bag carrying handles on a running web of paper preparatory to feeding said web into a bag making machine including a pressure roller, a chilling roller in rolling engagement with said pressure roller forming a nip through which the paper web is arranged to pass, said chilling roller having a non-continuous depressed area formed in its rolling surface, said depressed area having a floor, leading and trailing edges, said floor having a narrow slot formed therein extending transversely thereacross and having a narrow annular groove formed therein in spaced relation to and forwardly of the slot, means in advance of the nip to partially sever the paper web across the area to be covered by the plastic material,,means for extruding a continuous strip of thermoplastic material in a fiow condition onto the chilling roller in advance of the nip in line with the depressed area, said strip being of lesser width than said area, means for drawing the portion of the plastic ma terial overlying the depressed area into engagement with the floor so as to maintain said portion in spaced relation to the paper web as said web and plastic material pass through the nip, air evacuating means, and passage means connecting the air evacuating means and the slot and groove arranged to permit air to be drawn inwardly through the latter so as to sever the thermoplastic material overlying said slot and groove, said bag making machine being arranged to sever the paper web transversely of its length on a line of the precut extending beneath the said portion of plastic material.

8. Apparatus as claimed in claim 7 wherein the floor of the depressed area is formed having a plurality of conically shaped depressions formed in the area of said floor between said groove and said slot, said depressions having their bases adjacent said annular groove and their apices extending towards said slot, said floor having circumferentially extending corrugations formed therein between the leading edge of the depressed area and the annular groove.

9. Apparatus as claimed in claim 7 wherein the means for drawing the strip of thermoplastic material into en gagement with the floor of the depression comprises means for charging the chilling roller and plastic strip with opposite static electrical charges.

References Cited UNITED STATES PATENTS 3,384,530 5/1968 Mercer et al. l5650OX BENJAMIN R. PADGETT, Primary Examiner S. J. LECHERT, 111., Assistant Examiner US. Cl. X.R.