EP0227763A1

EP0227763A1 - Device for transverse sealing and cutting of a folded-sheet web

Info

Publication number: EP0227763A1
Application number: EP86904131A
Authority: EP
Inventors: Egon Laumen
Original assignee: ELWAPLASTIC MASCHINENBAU GmbH
Current assignee: ELWAPLASTIC MASCHINENBAU GmbH
Priority date: 1985-06-20
Filing date: 1986-06-14
Publication date: 1987-07-08
Also published as: WO1986007564A1; DE3522063A1

Abstract

Pour souder et découper transversalement la feuille (10) qui traverse continuellement l'installation rotative, les deux blocs de soudage (1, 1') pour la transformation du mouvement rotatif, du côté entraînement, avec mouvement vertical de montée et de descente, en un mouvement linéaire adapté à la vitesse de transit de la feuille sont portés par deux traverses (2, 2') qui des deux côtés du cadre sont supportées excentriquement dans deux disques (6) entraînés par des roues droites (7) dans des sens opposés et sont ainsi couplés l'un avec l'autre par des guidages droits (4) entraînées, contre la force de deux ressorts à pression (9), alors que le système de courroie de découpage (14) équipé d'une section de lame volante (15) située sur la traverse supérieure (2) passe devant le bloc de soudage inférieur (1') à travers le guide rainuré à l'intérieur d'une bande (16) (opposée) de coupe réglable, et le système de serrage suivant (17, 18) assure immédiatement le support de la feuille pliée (10) qui n'est plus soumise à une tension.To weld and cut transversely the sheet (10) which continuously crosses the rotary installation, the two welding blocks (1, 1 ') for the transformation of the rotary movement, on the drive side, with vertical movement of ascent and descent, in a linear movement adapted to the speed of transit of the sheet are carried by two crosspieces (2, 2 ') which on both sides of the frame are supported eccentrically in two discs (6) driven by straight wheels (7) in opposite directions and are thus coupled with each other by straight guides (4) driven, against the force of two pressure springs (9), while the cutting belt system (14) equipped with a blade section flywheel (15) located on the upper crosspiece (2) passes in front of the lower welding block (1 ') through the grooved guide inside an adjustable cutting strip (16) (opposite), and the following clamping (17, 18) immediately supports the folded sheet ( 10) which is no longer subjected to tension.

Description

Device for cross-welding and cutting a folded film web

The invention relates to the construction of a machine for manufacturing egg-shaped containers or the like. made of thermoplastic sheet material onto a device for cross welding and cutting the same continuous sheet of folded film.

For this purpose, rotating welding units are preferably used, which consist of two welding rollers rotating in opposite directions, which are provided with electrically heated welding wedges along their lateral surfaces, each in the same angular position. To limit the separation welding time, the welding rollers can be adjusted intermittently vertically to the passage plane of the web material (DE-AS 12 96 356). Otherwise, the welding wedges are designed to be resilient so that when they meet in the welding position to form a shrink-weld seam, they can be pressed into each other into the roller body, after which a separate cutting process then takes place (DE-PS 32 30 816).

Apart from the more serious shortcomings of other known devices of this type, it proves to be difficult in the last-mentioned embodiment without special measures to bring about more than a linear contact of the welding wedges on the spring wedges against one another and, consequently, with sufficient certainty that the welding time is sufficient for to achieve the creation of a durable shrink weld. In addition, with the downstream cutting device of this known device, the setting of the rotating cutting knife requires considerable care, nevertheless the overflow of the stationary lower knife is also relatively noisy.

In order to maintain the undisputed advantages of a rotating welding and cutting device in terms of construction and production technology, the invention is based on the object of developing a drive form for this device which enables the web material to be processed to be processed at a high throughput speed without any particular effort in terms of control ¬ measures to achieve flawless welds and exact cuts.

To achieve this object, the invention forms a device for transverse welding and cutting of a continuous continuous sheet of folding film according to the preamble of claim 1 in such a way that the two welding wedges for transmitting the drive-side rotational movement by way of an oscillating opening and closing Downward movement in a linear movement adapted to the film throughput speed is carried by two crossbeams, which are mounted eccentrically on both sides of the frame structure in a pair of disks which are driven in opposite directions by spur gears and are coupled to one another in an adjustable manner by moving linear guides against the force of two compression springs.

Accordingly, on the one hand, the two welding wedges on the traverses, which are guided together in a straightening linkage on each side, are periodically adjusted towards and away from one another by the counter-rotating eccentric disk drive. On the other hand, the welding wedges protruding beyond the contact circle for their contact position meet with each rotation of the eccentric discs in a certain angle of rotation range, in order to be able to adjust the reciprocating linkage against the force of a pair of compression springs. In this respect, the welding tools according to the invention, in contrast to the device presupposed as known, advantageously describe them a substantially smaller circular movement and detect the running film web without unrolling process with adapted speed in constant flat contact of the welding wedge over a defined linear area, in order to thereby ensure a uniform contact pressure and a sufficient welding time.

According to a further development of the invention, a cutting device for the film web is structurally connected to these welding tools, which, according to the features of claim 2, consists of a straight belt drive which is arranged adjacently with the drive wedge and a tensioning roller on the upper crossbar next to the welding wedge is, a flying knife blade attached to the flat belt by means of a knife holder when cutting the film web in the corresponding

Distance next to the lower welding wedge passes through the slot guide in half of an adjustable counter bar. Here, the independently driven belt drive runs intermittently in sync with the eccentric drive of the welding wedges in order to cut through the film web in the first third of the welding process and then to be stopped again until the beginning of the next welding phase.

According to the features of claim 3, a clamping device is provided for holding the relaxed folded film web during the welding and snowing process, in which a clamping bar arranged on the lower crossmember next to the cutting bar with a spring-pressed pressing edge is timed before until after the welding wedges meet on one opposite counter bar of the upper crossbeam with elastic insert to the system. In this way, the film web, which has relaxed in itself due to the reduction by the eccentric drive over the duration of the welding process, is simultaneously clamped behind the welding point before the cutting device between these pressing points performs the cold cut of the film web, and thus the resultant Shrink weld seam protected from mechanical stress.

The incorporation of the device according to the invention into the mechanical structure of a production line is provided in accordance with the features of claim 4, that the eccentrically driven welding and cutting device is an independently driven pair of feed rollers with air removal and guide plate for the non-contact entry of the relaxing folded film web upstream as well as a conventional storage and transport device for the finished products

The control of the electrical individual drives for the feed roller pair, for the eccentric disc pair and for the cutting belt drive according to the features of the claim in relation to the speed of the continuous passage of the folded film web from a common device in such a way that the welding device each exactly one revolution per Finished product executes and the drive in the actual welding phase runs synchronously with the drive of the feed roller pair, whereas by a subsequent asynchronous running of the two drives the length of the finished product is determined until the next welding phase and the intermittent-synchronous drive of the cutting device cuts the cut Folded film web in the first third of the welding phase.

For the functional mode of operation of such a production line with the individual units arranged one behind the other for the film inlet, the actual processing and for the collecting storage and removal of the finished products, it is therefore of crucial importance in functional as well as constructive terms that the We correspond the diameter of the feed roller pair and the rotating welding and cutting device as well as their controlled movement sequence to each other in order to achieve the planned knockout to realize continuous material flow from the film supply roll or otherwise to the storage of the finished products. Herein, the eccentric drive of the device according to the invention causes the welding tools to perform a much smaller circular movement as they rotate than their drive means. Since the latter are now controlled by the machine in such a way that they rotate about their drive axis exactly once for each product, regardless of the length of the same, it is advantageously achieved that the shrink weld seam is formed on a relaxed film web, because this is fed to the welding device by the feed roller pair faster than it transports the active welding device on its own. However, the film sag that is inevitably formed can be removed in a simple manner by the use of mechanical means and / or the supply of carrier air

Furthermore, the mutual coupling of the welding tools in a straight guide linkage ensures that the two welding wedges continuously adjust parallel to the axis vertical between their eccentric discs and accordingly meet each other exactly vertically during the course of the welding process, which bis¬ only from. a discontinuous drive was possible. Due to the small difference in height that the welding tools have to cover over the duration of their contact, a previously unreached portion of the total circulation can be used for welding and the effective welding time can thus be increased considerably. This process is supported by the spring-loaded suspension of the welding tools within the straight guide in connection with the drive on the part of the eccentric discs in such a way that the radius of the welding tools is reduced even more by the mutual adjustment and one or both of them On the side of the axis vertical, the sector expands the welding time advantageously Prolonged linear movement of the welding wedges covering the film web takes place. In addition, the relatively small movements of the welding tools cause the machine to run more smoothly and with less wear, even with an extremely high number of cycles.

In these processes, the film web is held at the same time fixed by the ^* in regions coinciding welding tools at the same level downstream clamping device so that the taking place between these Anpreßstellen parallel section through the flying knife blade of the welding device is intermittently driven in synchronism with the cutting means without mechanical stress of the entstehen¬ the shrink weld seam takes place. The cutting device and its counter bar are kept adjustable within limits as required in relation to the weld seam.

In a further embodiment of the invention it is also possible to equip the welding device according to the features of claim 6 for the production of a double seam and a separating cut made in between on the crossbeams with two eccentrically driven welding wedge pairs, between which the belt drive of the cutting device on the one hand and the slotted cutting counter bar on the other are arranged. - Likewise, the production of a simple separating weld allows the welding device to be equipped, on the one hand, with a separating welding wedge and, on the other hand, with a coated counter-pressure roller on the eccentrically operated traverses, without the associated cutting device according to the features of claim 7 If necessary, when opening the welding path in the direction of travel of the film, it can be mechanically adjusted further in order to counteract sticking of the ends created by the separating seam and associated flow disturbances.

The invention based on one in the drawing illustrated embodiment explained in more detail. 1 shows a side view of the welding and cutting device in a schematic representation, while FIGS. 2 to 4 each show a cross section in the area of the tools and their drive in the typical functional phases.

As can be seen from the illustration in FIG. 1, the welding and cutting device as a sub-assembly of the production machine, which extends beyond the full width of the folded film web to be processed, with its welding wedges 1 and 1 'on both of them Sides arranged vertically against the film web cross members 2 and 2 '. These traverses 2 and 2 'are each penetrated at their ends in bush-shaped guide elements 3 jointly by the linkage 4 of the straight guide and, at the same time, are supported under spring load on the eccentrically mounted bearing bosses 5 of the disk pair 6, which, for both sides is set in motion in opposite directions by the drive shaft 8 via a spur gear 7. Here, the traverses 2 and 2 ', which are guided perpendicular to one another, are pressed within the linkage 4 by compression springs 9 against the relevant bearing projections 5 such that the welding wedges 1 and 1', which move eccentrically beyond the circumference of the disks 6 in the welding phase when they meet in a certain sector around the vertical axis of the pair of discs 6 on the linkage 4 with their cross members 2 and 2 'can stand out from the bearing approaches 5.

In this way, the drive-side rotational movement of the pair of disks 6 is first converted into an oscillating upward and downward movement of the welding wedges 1 and 1 'and, at the same time, in regions into a linear movement of the same. This translation is used to correspond to the resulting contact area between the welding wedges 1 and 1 'and with the folding sheet web 10 running through the same extended welding time with a durable shrink weld seam. In addition, it is provided that the folding film web 10 is fed from the upstream and synchronously running feed roller pair 11 to the welding device faster than it transports the film web 10 by itself. Because of this, the welding can also be carried out on a relaxed folded film web 10, the film sag occurring being easily compensated for with the aid of the carrier air blown through nozzles 12 and a guide plate 13.

For the simultaneous separation of the folded film web 10 at a certain distance from the resulting weld seam, a straight-line cutting belt drive is arranged on the upper cross member 2 next to the welding wedge 1 and extending over its entire length. In this case, the flying knife blade 15 is fastened to the flat belt 14 ", which is secured via its drive pulley 14 and the tensioning roller 14 ', by means of a knife holder in such a way that it protrudes a bit beyond the contact surface of the welding wedges 1 and' in the intermittent cutting phase to pass through a slot guide on the opposite side within the cutting bar 16 on the lower crossmember 2. In order to adjust the distance between the weld seam and the cut, these two arrangements are each adjustable within limits.

Furthermore, a clamping device is arranged on the lower cross member 2 'of the cutting bar 16 in the film passage direction in order to protect the shrink weld seam that is formed from mechanical stress. In this case, a bracket extending across the film width within a slot guide accommodates the clamping strip 17, which is supported downwards against a compression spring and which, with its pressing edge projecting outwards, in the course of the translational movement towards it from the upper one Traverse 2 worn counter bar 18 with elastic insert and presses into it. Sufficient clamping is thus imparted to the folded film web 10 before the welding wedges 1 and 1 'contact one another and then the cutting process then takes place between the relevant clamping points.

The machine manufacturing process and the control of the electromotive drives used for the pull-in roller pair 11 (= drive I), for the eccentric disc pair 6 (= drive II) and for the cutting belt drive 14 (= drive I) will be referred to in the following particularly on the illustration certain functional phases of the device. In Figs. 2 to 4 of the drawing.

According to FIG. 2, the two welding wedges 1 and 1 'and the knife blade 15 are in the position shortly after a welding and cutting process has ended. From this position, the drives I and II continue to change their rotational speed with respect to one another. This results in the possibility of adjusting the device to the production of a specific product length and changing it as required by regulating or regulating the drive speed to the corresponding value in relation to the film throughput speed determined by the constant speed of the feed roller pair 11. is changed over, according to which the welding and cutting device executes the machining process with each slower or faster revolution in each case at a longer or shorter distance.

Such an asynchronous run of the drives I and II takes place up to the position of the welding wedges 1 and 1 'shown in FIG. 3 shortly before the start of the welding and cutting process, during which the drive III for the cutting belt drive 14 has remained out of operation for the time being.

For running the device into the actual welding and cutting phase in accordance with the central position of the welding wedges 1 and 1 'shown in FIG. 4 under the vertical axis of the pair of eccentric disks 6 and the knife blade 15 shown in the cutting function, the drives I and II then rotate synchronously with one another again. After this synchronous operation has been achieved, the clamping strip 17 first meets the elastic counter strip 18 and thereby fixes the folding film web 10 which relaxes on the tool due to the eccentric movement in relation to the rotation of the pair of discs and intake rollers 6/11. Then the two welding wedges 1 and 1 'meet with the inclusion of the folded film sheet 10, with which the welding process begins. Here, the in Wirk¬ diameter of its circular motion of both sides of the transport plane also reaching weld wedges 1 displace and 1 ^■ mutually in the vertical direction and thus lead over a ent speaking sector a linear movement which coincides with the effective weld time. At the same time, the drive III has now started the cutting belt drive 14, the flying knife blade 15 of which cuts the folded film web 10 in the first third of the welding process at the set distance from the resulting shrink weld seam, without mechanically cutting it due to the clamping on both sides burden. After these processes have ended, the tools and devices concerned then reach the position shown in FIG. 2 again, the one leaving the device

Finished product is handed over to a storage and collecting device (not shown here in particular) and the processes described above are repeated, so that the film pass advantageously takes place without interruption and the manufactured objects have a perfect quality.

Claims

1. Device for cross-welding and cutting a same continuous continuous web of folding material, consisting of two counter-rotating welding rolls, the electrically heated welding wedges of which, when they meet in the welding position, partially press each other into the roll body, in conjunction with a rotating one Cutting roller, the cutting knife of which acts against a stationary lower knife, characterized in that the two welding wedges (1, 1 ') for transmitting the drive-side rotational movement by means of a vertical upward and downward movement into a linear movement of two traverses (2, 2 ') are worn, which are mounted on both sides of the frame structure eccentrically in a pair of discs (6) driven in opposite directions by spur gears (7) and are coupled to one another in an adjustable manner by parallel linear guides (4) against the force of two latch springs (9).

2. Device according to claim 1, characterized in that the cutting device is designed as a belt drive and with a drive pulley (14) and a tensioning roller (14 ') on the upper crossmember (2) is arranged adjacently next to the welding wedge (1), one flying knife blade (15) attached to the flat belt (14 ") by means of a knife holder when cutting the folded film web (10) at the appropriate distance next to the lower welding wedge (1 ') the slot guide within an adjustable cutting bar (16 ) goes through.

3. Device according to claims 1 and 2, characterized gekenn¬ characterized in that a clamping device is provided for holding the relaxed Faltfolienbah (10) during the welding and cutting process, in which one at the lower crossmember (2 ') next to the cutting bar (16) arranged clamping bar (17) with a spring-like pressing edge in time before until after the welding wedges (1, 1 ^! ) meet - on an opposite mating bar (18) the upper cross member (2) comes into contact with the elastic insert.

4. Device according to claims 1 to 3, characterized gekenn¬ characterized in that the eccentrically driven welding and cutting device an independently driven Einzug¬ pair of rollers (11) with air discharge (12) and baffle (13) for the non-contact entry of the (relaxed) Folded film web (10) upstream and a common storage and transport device for the finished products is arranged.

5. Device according to claims 1 to 4, characterized gekenn¬ characterized in that the individual electric drives for the eccentric disc pair (6), for the feed roller pair (11) and for the cutting belt (14) in relation to the

Folded film throughput speed can be switched from a common control device in such a way that the welding device (1, 1 ') executes exactly one cycle per finished product and its drive in the welding phase (over approx. 45) with the drive of the feed roller pair (11) runs synchronously, whereas the length of the finished product is determined by a subsequent asynchronous operation of the two drives (over approx. 315 °) until the next welding phase and the intermittent drive of the cutting device (14) cuts the fold of the folded film web (10 ) in each case in the 1st third of the welding phase.

6. Device according to claims 1 and 2, characterized gekenn¬ characterized in that the welding device for producing a double seam and intermediate cut on the cross members (2, 2 ') is equipped with two eccentrically driven welding wedge pairs (1, 1'), between to them on the one hand the belt drive (14) of the cutting device and on the other hand the slotted cutting (counter) bar (16) are arranged.

Apparatus according to claim 1, characterized in that the welding device for producing a separating weld seam on the eccentrically operated traverses (2, 2 ') is equipped on the one hand with a separating welding wedge (1) and on the other hand with a counter-pressure roller, which may be attached to the opening of the welding path in the direction of travel of the folding sheet (10) is mechanically (further) adjusted.