GB2185241A

GB2185241A - Method and device for feeding a web of material from a roll

Info

Publication number: GB2185241A
Application number: GB08624011A
Authority: GB
Inventors: Wilhelm Propper
Original assignee: Benz and Hilgers GmbH
Current assignee: Benz and Hilgers GmbH
Priority date: 1986-01-10
Filing date: 1986-10-07
Publication date: 1987-07-15
Also published as: GB8624011D0; FR2592867A1; BR8605065A

Abstract

A web (1) of material, e.g. packing foil, is fed from a brake-equipped roll (4, 2) of the material to a material-dispensing region (13), by forming a reserve of web material around a roller system (6) in which the web (1) follows a zig-zag path enabling the web (1) to be continuously unrolled and fed to the region (13) downstream of the roller system (6). The system (6) comprises a first roller means (8,9) displaceable relative to a second roller means (9). The unwinding action is braked and released automatically in dependence upon the position of the roller means (8,9) relative to the roller means (7). <IMAGE>

Description

SPECIFICATION Method and device for feeding a web of material from a roll The invention concerns a method and device for feeding a web of material, e.g. packing foil, from a brake-equipped roll to a processing point.

In a method for use on butter packing machines and published by the applicant, an initial unwinding roller which is rotated by a main drive is used for continuous unwinding of the web of material, e.g. foil, to that point on the web of material at which the web is guided around a sprung dancer roller. Downstream of the dancer roller the web of material is contracted in stages by a roller contraction device. By this means a roller system enabling the web to follow a zig-zag path is drawn downwards by the dancer roller and the distance of contraction is measured. Once either the maximum or minimum zig-zag heights are reached, the dancer roller activates a microswitch which switches over a coupling to set a slower or faster drive on the initial unwinding roller, as appropriate.

The main disadvantage attendant upon this state of the art is that the machine's initial pair of unwinding rollers has to be turned by the drive using two different gearings, such that the first gear feeds slightly more length of the web of material than is required for the relevant stage of the cycle, while the feed given by the second gear results in the movement of slightly less length of the web of material than is required per cycle. Even a change in feed arrangement is a particularly laborious procedure.

The invention is based on the objective of defining a simple and economical method and device which enable substantially uniform unrolling of the web of material to be effected.

According to one aspect of the invention there is provided a method for feeding a web of material from a brake-equipped roll of the material to a material-dispensing region, by forming a reserve of web material around a roller system in which the web follows a zigzag path enabling the web to be continuously unrolled and fed to the said material-dispensing region downstream of the said roller system, the said roller system comprising a first roller means displaceable relative to a second roller means, wherein the unwinding action is braked and released automatically in dependence upon the position of the displaceable first roller means relative to the second roller means.

Usually the second roller means will be fixed relative to the first roller means.

According to another aspect of the invention there is provided a device for feeding a web of material by the method of the invention, the device comprising a support for a roll of the material to-be fed, brake means to arrest the unwinding of the roll from the support and a roller system enabling the web of material unwound from the roll to follow a zigzag path and to be continuously unrolled and fed to a region downstream of the said roller system, the said roller system comprising a first roller means displaceable relative to a second roller means enabling the unwinding action to be braked and released automatically in dependence upon the position of the displaceable first roller means relative to the second roller means.Preferably the said first roller means includes a support frame supporting one or more guide rollers, the support frame being directly linked to the brake means so that the action of the brake is dependent upon movement of the support frame.

Suitably the said second roller means comprises a plurality of guide rollers fixed relative to the said first roller means. The displacement of the first roller means may be controlled by a tension spring fixed thereto.

The objective underlying the invention is fulfilled in that the unrolling action is braked by automatic regulation as a function of the position of a movable part of the said roller system. By this means the unrolling action is braked as a function of the stage of feed of the web of material, i.e. the unrolling is braked such that virtually continuous unrolling is constantly obtained. The advantage of this type of method in the unrolling of webs of material is that-it is possible to dispense with the initial unwinding roller which would otherwise be necessary, instead of which all that is required is a deflection roller. By this means, furthermore, it is possible to dispense with components for the initial unwinding roller's driving wheels.The overall result is thus a means whose conspicuous feature is its action of substantially continuous unrolling using particularly simple components.

The procedure is performable by means of a device for controlling the feed of a web of material, e.g. packing coil, from a brakeequipped wound roll to a processing point by means of a feed device for transporting the web of material, and also using a said roller system which holds a reserve web of material on guide rollers mounted in a set position, plus at least one guide roller arranged on a support frame. In this preferred embodiment the support frame for the guide roller(s) which is (are) supportable on movable bearings is kept in a direct relation with the wound roll brake means. This makes it possible to dispense with the drive facility from the main motor which would otherwise be required, and unwinding drive is obtained in this case from the weight and position of the movable guide roller(s) and is controlled by action upon the wound roll brake means.The higher the speed of the feed cycle for the web of material, the less the effect of the movable part of the said roller system on the brake means, such that the winding roll is correspondingly released and the unwinding of an appropriate length of web of material is made possible. If, on the other hand, the length of the removed section of material is less, then the movable support frame exerts a greater effect on the brake means, with the result of further braking of the wound roll, such that the length of the section of material dispensed by the wound roll is correspondingly shorter. This results in automatic regulation of the wound roll brake means.

An appropriate arrangement and selection of the movable guide rollers, which are referred to as dancer rollers, makes it possible to estahlish such sensitive automatic regulation of the wound roll brake means as to provide very precise compliance with the respective length of material required and to enable continuous unwinding from the wound roll. This is especially aided by the arrangement of several (e.g. five) guide rollers adjacent to each other on the support frame, the support frame being suitably connected by a spring to a brake rod forming part of the brake means. The spring used for this purpose may be a compression spring. Where five guide rollers are used, there is obtained, in accordance with the pulley gearing principle, 1/10th cycle feed movement for each section of web between each pair of rollers.This results in extraordinarily sensitive regulation by means of the interaction between the support frame and the brake rod.

By way of example a preferred device for carrying out the method in accordance with the invention will be described with reference to the accompanying diagrammatic drawing.

The drawing shows a device (not illustrated in detail) for feeding a web 1 of material, for example packing foil, to a winding machine (not shown). A wound roll 2 is mounted on a bearing shaft 3 which can automatically be braked or released by brake means 4 in a manner explained below. The web 1 is brought from wound roll 2 around a deflection roller and thence over a roller arrangement 6 including guide rollers 7,8 disposed in such a manner as to enable the web 1 to follow a zig-zag path when passing around the rollers 7,8. The roller arrangement 6 serves to provide a reserve of web material. The guide rollers 7 are mounted on fixed bearings whereas guide rollers 8, sometimes described as dancer rollers, are mounted on movable bearings.

The guide rollers 8 are arranged in a movahle support frame 9, the movement of which is dependent on tension spring 11 attached to the frame 9. Alternatively a compressed-air jack (not shown) could be used instead of the tension spring 11. Upstream of the said roller arrangement the web of material 1 is brought around a deflection roller 12 and guided towards a feed device 13 whereby the feed of the web of material towards the winding machine can be controlled together with the operating cycle at a processing stage. Support frame 9 is angled at one end to accommodate a compression spring 1 5 between the frame 1 and a brake rod 14 which forms part of the brake means 4.

The illustrated device operates as follows: By means of the feed device 13 the web 1 is fed a specific distance, for example 270 mm. By the action of the roller arrangement 6, web tension causes upward movement of movably-mounted guide rollers 8 together with their support frame 9 against the action of tension spring 11, such movement amounting, according to the familiar pulley rule, to one tenth of the dispensed length where there are five guide rollers, i.e. 27 mm where the dispensed length is 270 mm. This reduces the load on compression spring 15 arranged between support frame 9 and brake rod 14, and thus the brake means 4 is released. A consequence of this is that a corresponding length of web material is drawn off the wound roll 2, causing the roller arrangement 6 to be refilled with web material. This refilling causes downward movement, due to tension spring 11, of support frame 9, with fresh action upon compression spring 15, with the result that the brake means 4 is once again actuated by the brake rod 14, so that wound roll 2 is braked once again. This alternate braking and brake releasing results in sensitive, automatic regulation of the unwinding of the web material from the wound roll 2.

Instead of the support frame 9 moving up or down as shown by the double-headed arrow the guide rollers 8 could be arranged to move in pendulum fashion.

Claims

1. A method for feeding a web of material from a brake-equipped roll of the material to a material-dispensing region, by forming a reserve of web material around a roller system in which the web follows a zig-zag path enabling the web to be continuously unrolled and fed to the said material-dispensing region downstream of the said roller system, the said roller system comprising a first roller means displaceable relative to a second roller means, wherein the unwinding action is braked and released automatically in dependence upon the position of the displaceable first roller means relative to the second roller means.

2. A method in accordance with Claim 1, wherein the material is packing foil.

3. A method in accordance with Claim 1 or Claim 2, wherein the second roller means is fixed relative to the first roller means.

4. A method for feeding a web of material from a brake-equipped roll substantially as herein described with reference to the accompanying drawing.

5. A device for feeding a web of material by the method defined in Claim 1, the device comprising a support for a roll of the material to be fed, brake means to arrest the unwinding of the roll from the support and a roller system enabling the web of material unwound from the roll to follow a zig-zag path and to be continuously unrolled and fed to a region downstream of the said roller system, the said roller system comprising a first roller means displaceable relative to a second roller means enabling the unwinding action to be braked and released automatically in dependence upon the position of the displaceable first roller means relative to the second roller means.

6. A device in accordance with Claim 5, wherein the said first roller means includes a support frame supporting one or more guide rollers, the support frame heing directly linked to the brake means so that the action of the brake is dependent upon movement of the support frame.

7. A device in accordance with Claim 6, wherein the support frame supports a plurality of guide rollers, the support frame being connected by a spring with a brake lever which forms part of the brake means.

8. A device in accordance with Claim 7, wherein the spring is a compression spring.

9. A device in accordance with Claim 8, wherein the support frame has an angled portion which houses the compression spring.

10. A device in accordance with any one of Claims 5 to 9, wherein the said second roller means comprises a plurality of guide rollers fixed relative to the said first roller means.

11. A device in accordance with any one of Claims 5 to 10, wherein the displacement of the first roller means is controlled by a tension spring fixed thereto.

12. A device for feeding a web of material substantially as herein described and illustrated by the accompanying drawing.