AU1645099A

AU1645099A - Method and apparatus for the continuous production of plastics sleeves

Info

Publication number: AU1645099A
Application number: AU16450/99A
Authority: AU
Inventors: Harald Senges
Original assignee: Hetzel & Co KG GmbH
Current assignee: Hetzel & Co KG GmbH
Priority date: 1998-02-18
Filing date: 1999-02-15
Publication date: 1999-09-02
Also published as: DE19806669A1; EP0937574A3; CA2262225A1; EP0937574A2

Description

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION NAME OF APPLICANT(S): Hetzel GmbH Co. KG ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Little Collins Street, Melbourne, 3000.

INVENTION TITLE: Method and apparatus for the continuous production of plastics sleeves The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5**S S ia The invention is based on known plastics sleeves, envelopes or jackets, which are manufactured in such a way that two webs of a long plastics sheet are placed on one another, the two webs e.g. being obtained by the folding round of a single sheet. The said webs are then e.g. horizontally conveyed with the aid of driven rollers and stopped in a cycle corresponding to the length of the finished plastics sleeve. During the stoppage a longitudinal weld, transverse weld, optionally a perforation and a separation or cutting are carried out. This takes place with the aid of welding dies, hole punching dies or cutting knives movable on the plane of the webs. After carrying out these processes it is necessary to reaccelerate the sheet web. This

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S. production procedure leads to the efficiency of such installations being limited.

*•coo The problem of the invention is to provide a method and an apparatus for producing plastics sleeves, in which the efficiency can be increased and/or the costs of the production plant decreased.

For solving this problem the invention proposes a method having the features of claim 1 and an apparatus having the features of claim 17. Further developments of the invention form the subject matter of dependent claims, whose wording, like that of the abstract, is made into part of the content S of the present description by reference.

Through producing the transverse weld during movement, the installation for conveying the plastics webs no longer has to be stopped and then reaccelerated. Even if the conveying speed of the webs does not increase compared with that of known installations, there is an increase in the efficiency of a plant or installation for plastics web production. The welding of the two sheets in the transverse direction and in which case a double weld can be involved, can be brought about in different ways. Whereas in the prior art the plastics sleeves are produced in their own longitudinal direction, it is now also possible to position the plastics sleeves transversely to the longitudinal direction of the sheet web, so that the overall installation can be made shorter.

-2 According to a further development of the invention, during movement the webs can also be welded together along at least one longitudinal edge. This makes it possible to so orient the plastics sleeves that their own longitudinal direction coincides with the longitudinal direction of the webs, so that the apparatus parts responsible for the supply of the plastics sheet and the conveying away of the finished plastics sleeves do not require modification compared with known installations. It is also possible to start with two separate plastics webs, which are then welded together along both longitudinal edges.

According to a further development of the invention, longitudinal welding can e.g. be carried out by a welding wheel, which is rotated about an axis parallel to the web surface and perpendicular to the conveying direction of the webs with a peripheral speed corresponding to the linear speed of the webs. Thus, the welding wheel runs on the continuously moved on plastics sheets and thereby brings about a heating and consequently welding.

It is in particular possible to provide on the opposite side of the web a similar wheel, which rotates in the opposite rotation direction about a parallel rotation axis and with which cooperates the welding wheel. The two wheels enclose the sheet between them and the second wheel can either be constructed as a countermember or also as a welding wheel. As a function of the heating procedure, there need be no contact between the welding wheel, the sheet and the countermember. On contact with the sheet and the welding wheel, the countermember can be driven and carried along by the welding wheel. It can have a size different from that of the welding wheel.

According to a further development of the invention, the transverse welding is performed by a welding jaw or die, which is moved jointly with the plastics webs to the welding position. The welding die can carry out the welding operation, e.g. as a result of heating. The welding die can in this case cooperate with a counterdie positioned on the opposite side of the webs and moved therewith to the welding position. This opposite die can also be an independent welding die or a countermember, against which the upper welding die presses the plastics sheet.

3 The movement of the welding die and/or counterdie can e.g. take place along a closed movement path, said movement e.g. taking place with the aid of chains or toothed belts.

According to the invention the welding die used for producing the transverse weld can simultaneously perform a separating weld, so that the transversely directed separation can also be carried out for separating the individual plastics sleeves from the welding die.

It is also possible according to the invention for the webs to be separated with a knife running transversely to the conveying direction and which is moved together with the webs at the separation point and optionally cooperates with a countermember on the opposite side of the webs.

ooe According to a further development of the invention, the knife and/or countermember can be moved in opposing directions along a circular path.

This circular path approaches the sheeting, until the actual separation or cut takes place at the contact point.

If the plastics sleeves are to have a perforation or hole system along one edge enabling filing in files, according to the invention the webs are oooe provided with such a perforation or hole system during conveying.

The perforations can in particular be made with a hole punching die moved etogether with the webs and which cooperates with a bottom die located on the opposite side of the webs and moved with the latter.

If the holes are to be made along the longitudinal edge of the webs, according to the invention the hole punching dies are located on the circumference of a jointly rotating perforating wheel.

Here again the hole punching die and/or bottom die can be contrarotated along a closed path, Particularly along a circular path.

The apparatus proposed by the invention and having the features of claim 17 is able, per unit of time, to produce a larger number of plastics sleeves 4 than is possible in the prior art. The installation can also have a particularly simple construction, because the high forces occurring through the deceleration of the conveying device and its reacceleration are avoided.

The longitudinal welding device can have a welding wheel, which is rotated at a peripheral speed corresponding to the linear speed of the webs and which cooperates with a counterwheel rotating in the opposite rotation direction and located on the opposite side of the sheeting.

According to the invention, the transverse welding device can have a transversely positioned welding die, which is moved along a closed path parallel to itself with a peripheral speed corresponding to the linear speed of the webs and which cooperates with an oppositely movable countermember posi- *oo* tioned on the opposite side of the sheeting.

oo This movement along a closed path can e.g. take place with the aid of chains guided around at least two gears or toothed belts guided round guide S"members. Over a certain distance the welding die then moves parallel to the sheet webs and can weld the latter.

oo According to a further development of the invention, the welding die and/or countermember can be moved about a fixed axis, so that they are moved along a circular path.

If the plastics sleeves are to have holes, according to the invention the apparatus can have a device for producing a system of holes in the sheeting during conveying.

According to a further development, this device can have a wheel provided with at least one hole punching die, which is driven about an axis parallel to the sheeting and perpendicular to the conveying direction at a peripheral speed corresponding to the conveying speed. This wheel then makes a perforation along the conveying direction or a row of holes transversely to said conveying direction.

5 In particular, the perforating device can be a wheel with at least one hole synchronously contrarotated about a parallel axis on the opposite side of the sheeting and which has a position corresponding to that of the hole punching die and in which the latter engages.

If the row of holes is to be at right angles to the conveying direction of the plastics webs, the hole punching die can be positioned along a line parallel to the rotation axis of the wheel and this also applies with respect to the holes.

However, if the row of holes is to be parallel to the longitudinal direction of the plastics webs, the hole punching dies and holes can be positioned along a circumference of the corresponding member.

o Further features, details and advantages of the invention can be gathered from the following description of a preferred embodiment of the invention and the attached drawings, wherein show: Fig. 1 In highly simplified form, an installation for performing the method proposed by the invention.

o• Fig. 2 A plan view of an apparatus for producing plastics sleeves.

Fig. 3 A plan view of a modified apparatus.

Fig. 4 A known plastics sleeve for explaining the operation of the apparatus proposed by the invention.

The apparatus shown in highly simplified form in fig. I is used for producing individual plastics sleeves from two flat, superimposed sheet webs.

The sheet webs can be separate or interconnected along a longitudinal edge.

In the simplified representation the two sheet webs are shown as a single web 1, which runs horizontally and is located in one plane. For its conveying with a continuous, constant speed, it is possible to provide conveying rollers, which are rotated. This is not shown in detail. The conveying direction in fig. 1 is from left to right in the direction of arrow 2.

6 Considered in the conveying direction, the apparatus has two rollers 3, 4, which in the represented embodiment have the same size, i.e. the same length and same circumference. Each of the two rollers 3, 4 is rotatable about an axis, the two axes being parallel to one another. These rollers 3, 4 are so positioned that they enclose the sheet web 1 between them and are in contact with said web. For example, the upper roller 3 is rotated in the direction of arrow 5 and carries with it the lower roller 4 in the direction of the arrow 6. It is also possible, as a result of the pressure which they exert on the sheet web 1, for the rollers to be moved by said web 1. It is also possible to have a self-contained drive for both rollers, which takes place in synchronized manner to the conveying of the sheet web i. In the vicinity of the front end, the roller 3 contains a strip 7, which is constructed as a welding wheel and is e.g. electrically heated. This electrically heated area, on rolling on the sheet web i, leads to a heating of the latter and consequently to a welding of the two plastics sheet layers forming the sheet web 1. The opposite roller 4 has a similar strip 8, which is either also constructed as a welding wheel or which merely acts as a countermember. During the conveying of the sheet web 1 the two strips 7, 8 carry out a longitudinal welding of the two layers forming the sheet web 1. As a function of the nature of the plastics sleeve to be produced, such strips can also be located at the opposite end of the two rollers 3, 4, so as to be able to bring about a longitudinal welding of the trailing edge 19 of the plastics sheet 1 in fig. i.

S• In the conveying direction according to arrow 2, following the rollers 3, 4 is provided a second roller pair 10, 11, which are once again contrarotatable about two parallel axes. Rotary driving can take place by a selfcontained drive. The upper roller 10 of this roller pair contains a strip 12, which is parallel to the rotation axis over the entire width of the sheet web 1 and can be constructed as a welding die and then, if it contacts the web 1 during the rotary movement, performs a transversely directed weld of the plastics sheet. On the opposite roller 11, i.e. positioned below the web i, is provided a corresponding counterdie 13, which is once again either in the form of a countermember, against which welding is carried out, or as an independent welding die.

7 Thus, a transverse weld on the two layers forming the plastics web 1 can be carried out with the aid of the roller pair 10, 11. As in the case of the longitudinal weld, it can here again be a double weld seam.

In the conveying direction of the web 1 following the roller pair 10, 11 is provided a further roller pair 14, 15 in the same way as the'roller pair 11. At the leading end of the upper roller 4 in fig. 1 are provided in the embodiment shown four hole punching dies 16, whilst at the opposite end of the lower roller 15 are provided four holes 17. In the case of a synchronous contrarotation of the two rollers 14, 15, the hole punching dies 16 engage in the holes 17 and thereby perforate the sheet. The mutual spacing of the hole punching dies 16 and their orientation with respect to the S transverse weld made by the welding die 12 is such that the holes are made at standardized points along the edge of the plastics sleeve.

oo The roller pair 14, 15 is followed by a final roller pair 18, 19, which is once again arranged and driven in a similar way to the preceding roller Spairs. Along a periphery parallel to the rotation axis the upper roller 18 Sis provided with a knife 20, which cuts the web 1 during rotation. The lower roller 19 contains a countermember, e.g. an edge on the border of a depression. In the position shown in fig. 1 it is impossible to see said depression. The knife 20 cuts the finished plastics sleeves from the web 1.

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r The apparatus shown in the drawing operates with a constant, continuous conveying on of the plastics web i, so that at no time during production is it necessary to stop the conveying process.

Fig. 2 shows on a smaller scale a plan view of the arrangement according to fig. 1 with the corresponding rollers. The first roller 3, i.e. to the left in fig. 1, performs the longitudinal weld with the aid of the welding wheel 7 located on its one or on both ends. The roller is provided at both ends with an axle journal 21, which can be used for the mounting support of the roller 3 and for driving the same, but no details are shown.

The following roller 10 for producing the transverse weld, the roller 14 for producing the perforation and the roller 18 for separating the plastics 8 sleeves 22 from the web 1 are mounted in the same way. All the rollers can be constructed so that they cooperate in the conveying of the sheet 1. This can e.g. be brought about by a corresponding surface design. It is obviously also possible for the conveying of the web 1 to be carried out by other, not shown conveying rollers. In this case the devices for carrying out the different processes can be somewhat differently constructed, as shown in simplified form in fig. 3. Here the welding wheels 7 for producing the longitudinal weld are positioned on a shaft 23, which only brings about the rotation of the two welding wheels 7. The welding die 12 is located on the circumference of two wheels 24, so that it is even possible to omit the shaft. The welding die produces the transverse weld If the row of holes 26 is only to be made along one edge or border of the web 1, the corresponding wheel having the hole punching dies 16 can also be oo*.

positioned on a single shaft 21. The knife 20, which transversely completely separates or cuts the sheet web is again arranged in a similar manner to the welding die 12.

Fig. 4 shows a plastics sleeve, as can be produced by the method proposed in the present invention. Along its one longitudinal edge the plastics sleeve 28 contains two parallel longitudinal welds 29, which leave between them a free space in which a strip can be placed. In the prior art said longitudinal weld 29 is produced in such a way that it represents a weld in the r longitudinal direction of the cohesive sheet web i. However, this is S unnecessary according to the invention. The longitudinal weld 29 of the plastics sleeve 28 can also be a transverse weld 25 of the sheet web 1. In this case the hole punching dies 16 are arranged along a straight line parallel to the rotation axis of the roller 14. The same applies regarding the holes 17 in the lower roller The weld 30 forming the lower edge of the plastics sleeve 28, which forms the transverse weld in the prior art, can then be the longitudinal weld.

The two welds 29 can be simultaneously produced with the aid of a single device, either with a welding wheel 7, which produces two welds in juxtaposed manner, or with a welding die 12, which contains two welding wires.

9 Material welding can take place ultrasonically and not only by a heat contact process.

The reference numerals in the following claims do not in any way limit the scope of the respective claims.

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Claims

1. Method for the continuous production of plastics sleeves in which 1.1 two sheet webs are placed flat upon one another and 1.2 the sheet webs are continuously moved on, 1.3 at a distance corresponding to the dimension of the sleeve (28) in the conveying direction, the web is provided with at least one transverse weld (25) and 1.4 the welded sheet webs are separated from one another by a cut running transversely to the conveying direction.

2. Method according to claim 1, wherein the webs are welded to one another along at least one longitudinal edge during the movement.

3. Method according to claim 1 or 2, wherein the longitudinal weld is produced by a welding wheel which is rotated about an axis parallel to the surface of the webs and perpendicular to the conveying direction of the webs at a peripheral speed corresponding to the linear speed of the webs

4. Method according to one of the preceding claims, wherein the welding wheel cooperates with a contrarotating wheel located on the opposite side of the webs 0* Method according to one of the preceding claims, wherein the sheet webs are moved between the welding wheel and the counterwheel

6. Method according to one of the preceding claims, wherein the trans- verse weld (25) is made by a welding die which is moved to the welding position together with the sheet webs

7. Method according to claim 6, wherein the welding die (12) cooperates with a counterdie (13) positioned on the opposite side of the sheet web and moved together with said sheet webs

8. Method according to claim 6 or 7, wherein the welding die (12) and the 11 counterdie (13) are moved in opposition along a closed path, particularly along a circular path, with a peripheral speed corresponding to the linear speed of the sheet webs and at least at the welding position enclose between them and in particular contact the sheet web

9. Method according to one of the claims 6 to 8, wherein the welding die (12) performs a separation weld. Method according to one of the preceding claims, wherein the sheet webs are separated with a knife (20) running transversely to the conveying direction and which at the separation point is moved together with the webs

11. Method according to claim 10, wherein the knife (20) cooperates with a countermember positioned on the opposite side of the sheet webs and moved in particular together with said sheet webs

12. Method according to claim 10 or 11, wherein the knife (20) and/or the S countermember are moved in opposition along a closed path, particularly along a circular path. S..

13. Method according to one of the preceding claims, wherein the sheet webs are provided with a perforation (26) during their conveying. S.. ~14. Method according to claim 13, wherein the perforation (26) is made with a hole punching die (16) moved together with the sheet webs and which in particular cooperates with a lower or bottom die on the opposite side of and moved together with the sheet webs Method according to claim 13 or 14, wherein the hole punching dies (16) and/or the bottom die are moved in opposition along a closed path, partic- ularly along a circular path.

16. Method according to one of the claims 13 to 15, wherein the perforation (26) is made on the longitudinal edge in the conveying direction. 12

17. Apparatus for the continuous production of plastics sleeves (28) having 17.1 a conveying device for the continuous conveying of two weldable sheet webs placed on one another, 17.2 a device for producing a transverse weld (25) at right angles to the conveying direction of the sheet webs and during the conveying process, as well as having 17.4 a separating device, which 17.4.1 separates the welded sheet webs during conveying at right angles to the conveying direction.

18. Apparatus according to claim 17, with a device for the continuous weld- ing of the sheet webs along a longitudinal edge of the webs 9*99

19. Apparatus according to claim 17 or 18, wherein the longitudinal welding device has a welding wheel which is rotated at a peripheral speed corresponding to the linear speed of the sheet webs and which cooperates with a contrarotating counterwheel positioned on the opposite side of the sheet webs

20. Apparatus according to one of the claims 17 to 19, wherein the trans- verse welding device has a transversely positioned welding die which is movable along a closed path parallel to itself with a peripheral speed corresponding to the linear speed of the sheet webs and which cooper- ates with a contrarotatable countermember (13) positioned on the opposite side of the sheet web

21. Apparatus according to claim 20, wherein the welding die (12) and/or counterdie (13) are moved about a fixed axis.

22. Apparatus according to one of the claims 17 to 21, with a device for producing a perforation (26) in the sheet webs during conveying.

23. Apparatus according to claim 22, wherein the perforating device has a wheel (14) provided with at least one hole punching die (16) and which is driven about an axis parallel to the sheet webs and perpendicular to 13 the conveying direction at a peripheral speed corresponding to the linear speed.

24. Apparatus according to claim 23, wherein the perforating device has a wheel (15) with at least one hole (17) synchronously contrarotated about a parallel axis on the opposite side of the sheet webs and-whose position corresponds to that of the hole punching die (16). Apparatus according to claim 23 or 24, wherein the hole punching die (16) and holes (17) are positioned along a circumference of the particular wheel (14, *o

26. Apparatus according to claim 23 or 24, wherein the hole punching die (16) and holes (17) are positioned along a straight line parallel to the rotation axis of the particular wheel (14, *o99 90060: 9 9. 9 9.. S 14

27. Plastics sleeves when produced by a method or an apparatus as claimed in any one of the preceding claims.

28. Method and/or apparatus for the production of plastics sleeves substantially as hereinbefore described with reference to the drawings and/or Examples.

29. The steps, features, compositions and compounds disclosed herein or referred to or indicated in the specification and/or claims of this application, individually or collectively, and any and all combinations of any two or more of said steps or features. S DATED this FIFTEENTH day of FEBRUARY 1999 Hetzel GmbH Co. KG by DAVIES COLLISON CAVE Patent Attorneys for the applicant(s)