DE2110741A1 - Device for unwinding a material web from a supply roll - Google Patents

Description

Applicant: Oce-van der Grinten NV, St. Urbanusweg Io2, Venlo / Holland

Device for unwinding a web of material from a

Supply roll.

The invention relates to a device for unwinding a web of material in sections from a supply roll, with at the Material web attacking conveyor members for the intermittent drive of the material web, with a support device on which the Roller is rotatably mounted, as well as with a device counteracting the rotation of the roller.

Such devices are often used when a wound web of material is to be cut into pieces. When such a sheet is required, a web section of the desired length is unwound and then cut off. Because of the intermittent drive of the web, with which the roller is repeatedly set in motion, tension occurs in the web. In particular, if the supply roll is relatively heavy and / or the unwinding speed of the web is relatively high , care must be taken that these tensions do not reach an amount at which the web could tear.

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When the web drive is switched off, the roll does not stop immediately, which is why more web material is unwound than is necessary is. In order to avoid difficulties in re-driving the web, the over-unwound length of web should be prevented from doing so will accumulate in an inappropriate way.

There are already proposals known to absorb shock loads and prevent adverse build-up of web material. From NL-PS 6 it is known, for example, a movable Provide collecting roll, which rests on the path between the supply roll and a conveyor roll, whereby a certain Amount of web material is taken up. With this device, when the drive of the web is switched on, the web material becomes immediately withdrawn at the drive speed, although the movement of the supply roll is due to the influence of weight the collecting roll only gradually becomes faster. When the drive of the web is switched off, the collecting roll moves to remove the excess Take up web material which has been unwound from the supply roll.

From a technical point of view, the known solutions are proportionate complicated. It is often cumbersome to properly feed the web from a new supply roll through the apparatus. Particularly in the case of a long standstill, there is the problem that the part of the material web is deformed in the collecting device is, for example, by absorbing or releasing moisture.

It is therefore the object of the invention to overcome the difficulties mentioned Avoid species as much as possible. This object is achieved according to the invention in a device of the type mentioned at the beginning solved in that the support device of the supply roll is slidably arranged on supports extending in the horizontal direction is, and that means is provided which engages the support means to the sliding movement of the To counteract support links. With such a construction, the conveyor links to be unwound after the drive is switched on Web material first from a lateral sliding movement

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the supply roll to the conveyor links. During this movement, the supply roll is gradually accelerated. If the The tension in the web and the force of the device counteracting the sliding movement of the roller towards the conveyor links are equal the roller has reached its highest speed and will not slide any further. After the drive has been switched off, this leads Set the supply roll back to its original position, keeping the web under tension, thereby removing excess unwound Material is accumulated.

A particular advantage of the device according to the invention is to be seen in the fact that the collecting effect of the device increases with increasing The diameter of the supply roll becomes larger. This results in an almost optimal adaptation of the gathering effect to the diameter the role guaranteed. Compared to known devices, the device according to the invention has the additional The advantage that the space requirement is less and that that part of the web between the supply roll and the conveyor members can extend in a straight line, from which it follows that no deformation occurs at standstill - and the leading edge can easily be used in a new web.

In a practical embodiment of the invention the means is that of the sliding movement of the support means counteracts, preferably designed so that it exerts a greater counterforce when the support device is the conveyor members approaching. As a result, the point in time at which the lateral movement of the support device to the conveyor links ceases is more precisely controlled, at a given speed of movement of the conveyor links, while the support device does not accelerate too much when the drive of the conveyor links is switched off, whereby additional attenuators are not required and wherein heavy impact loads on the limit stops for the movement can be avoided.

Preferably, the counteracting device consists of one

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or several springs which act on the support device, for example on both sides of the web.

The invention is to be explained in more detail with the aid of the drawing. Show it:

1 shows a schematic longitudinal section through a device according to the invention;

FIG. 2 shows a cross section along the line II-II 'in FIG. 1; and

3 shows an embodiment of the device which counteracts the sliding movement of the support device and the supply roll.

In the device shown in FIG. 1, a supply roll 1 contains web material which is wound onto a roll 2 whose trunnions 3 are arranged in bearing blocks 4. The bearing blocks 4 can be made of Vulkolan (Wz), a linear polyurethane from Farbenfabriken Bayer AG. exist, or be lined with it.

The bearing blocks 4 are attached to angled plates 5 which are rigidly connected to one another by a connecting rod 6 to form a support device for the roll 1.

This support device is provided with rollers 7 and 8, which are guided in rails 9, which are in horizontal Extend direction and are attached to the machine frame Io.

One end of a spring 11 is attached to each plate 5, the other end of which is attached to a pin 12 / which is attached to the frame Io is arranged.

These springs are preferably designed in such a way that they exert a small force in order to prevent the support device against stops to press.

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The material web 14 is fed from the supply roll 1 to the conveyor members 15, 16 / which are drive rollers here. These can be covered with rubber to keep the web elastic. At least one of these rollers is driven intermittently, in order to bring the web to a processing device in which, for example, rectangular pieces are cut from the web will.

When the drive of the rollers 15, 16 is switched on, is achieved the advance of the web between rollers 15 and 16 almost instantaneously at full speed. That between the rollers withdrawn web material is primarily obtained by a sliding movement of the support device and the roller to the right, such as from Pig. I. can be seen. When this happens, the springs 11 exert a constantly increasing counterforce. If this spring force is the same the tensile force acts on the web to the right, which is transmitted via the bearing journals 2, the sliding movement of the support device ends, so that it stands still. From this point on, the web is fed further, completely through a rotation of the supply roll 1, the web gradually reaching the required speed as it slides towards the rollers 15 and 16. The web therefore reaches the desired transport speed very quickly, while the supply roll only gradually reached the corresponding speed. This prevents excessive tensile stresses from occurring in the web.

When the drive of the rollers 15, 16 is stopped and the tensile force on the web decreases, the springs 11 pull the support device to the left in FIG. 1. The part of the web 14 which is located between the supply roll 1 and the conveyor rollers 15, 16 extends, kept permanently under tension, whereby the web material is taken up, which after switching off the drive is unwound because the supply roll 1 does not stop immediately. In this way, undesired accumulation of the web material is prevented.

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The construction of the device can be modified in many ways; for example, the support device as Slide are formed, which is moved on a rail, or a telescopic rail can be provided on which the bearing blocks for the supply roll are attached.

Instead of training or covering the bearing blocks with a friction material, normal bearings with less friction can be used Find use. In such a case the means which counteract the rotation of the roller may be a braking arrangement be that acts, for example, on the bearings of the role. The sliding movement of the support device and the supply roll can also be restrained with the help of a weight that is connected to the support device via a rope. In Fig. 3 is a such embodiment shown schematically. In this figure, a support device 17 is via a rope 18 with a Drum 19 connected, which is placed on a rotatable bearing shaft 2ο is.

The shaft 2o also carries an eccentric pulley 21, over which a rope 23, which is loaded by a weight 22, runs.

When the device 17 is moved to the right in FIG. 3, the distance between the cable 23 and the shaft 2o increases continuously, fesSsHr that the moment caused by the weight 22 increases and with it the force which counteracts the movement of the device 17 to the right.

- patent claims -

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Claims (3)

Claims (lj. device for unwinding a web of material in sections from a supply roll, with conveyor members engaging the web for an intermittent drive of the web, with a support device in which the roll is rotatably mounted, and with a device counteracting the rotation of the roll, characterized that the support device of the supply roll is displaceable in the horizontally extending support members, and that a device acting on the support device is provided which counteracts its sliding movement towards the conveyor members. 2. Device according to claim 1, characterized in that that the / sliding movement of the support means counteracting means is designed so that the device exerts a greater counterforce when the support device is the conveyor members approaching. 3. Device according to claim 2, characterized in that the device consists of one or more springs, which act on the support device. 109840/1153 Blank page