GB2088825A - Apparatus for unrolling and cutting a sheet of material - Google Patents

Abstract

Apparatus for unwinding and cutting a sheet of material from a roll 2 including a support shaft 3 on which the roll of material is to be disposed and which is rotatably mounted in a support frame, a support surface 9 on which unrolled material can be supported for cutting, a pressing roller 11 to act transversely on the material upstream of the support surface, the pressing roller being arranged to act on the material in a plane 12 offset from the support surface 9 during cutting, and guide means for a cutting member 10 which is displaceable transversely relative to the support surface, the guide means being a cage 13 beneath the material support surface 9 and a sliding member 14 supporting the cutting member and being movably guided inside the cage. The offset pressing roller causes the newly cut end 28 to lift off the support surface thus facilitating the next operation. The roller 11 may be disengaged to fit a new sheet and the cutter may be removed to fit new blades, a sliding spring device normally holding the freely rotatable roller in position and providing a halt for the end of the cutting stroke. An adjustable braking system may be provided for the shaft supporting the roll. <IMAGE>

Description

SPECIFICATION Apparatus for unrolling and cutting a sheet of material The present invention relates to an improved apparatus which permits the unwinding and cutting of a sheet of material (film, paper, or the like) stored in the form of a roll, and which is in particular suitable for use in shops for making packages.

Up to the present time many devices have been proposed for unwinding and cutting material in sheet form, such as a film, cellophane wrapping, a sheet of paper, or the like.

In one very old arrangement, which is described in French Patent Specification No. 360,562, a sheet of paper stored in the form of a roll is cut by a fixed toothed cutter situated between two edges, which grip the paper and move so that the paper encounters and is cut by the cutter. A device of this kind is complex, lacks accuracy, and does not enable a clean cut to be made.

British Patent Specifications Nos. 441,550 and 944,122 describe devices of simple construction which enable a sheet of material to be unrolled and cut. Generally speaking, these devices include a frame supporting a roll of material, a cutting table onto which the material is unrolled and a cutting means having two cutting edges displaceable transversely on a guide rail disposed above the cutting table.

An installation of this kind is particularly simple in design, but nevertheless it has a certain number of drawbacks. For one thing, it is difficult to contemplate its use when in other than a longitudinal orientation. Also, after one cutting operation, when it is desired to draw off a further amount of material, the cutter guide rail hampers gripping of the free end of the material.

Furthermore, with modern plastics wrapping materials, the material may tend to stick to the surface of the cutting table, although a suggestion for overcoming the latter problem, in British Patent Specification 441,550, is the provision of an underlay system including two rollers which tend to lift the end of the sheet of material after the cutting operation. Another suggestion to meet this problem is in French Patent Specification No.

1,426,296 which suggests positive delivery by crank operated rollers to advance a grippable edge of the material.

A final and common problem with the prior art, particularly when the sheet used is a film of plastics material, is that because of static electricity and of design there can be some resistance to the feeding of the material, and this can give rise to poor unwinding and even to creasing.

According to the present invention there is provided apparatus for unwinding and cutting a sheet of material from a roll including a support shaft on which the roll of material is to be disposed and which is rotatably mounted in a support frame, a support surface on which unrolled material can be supported for cutting, a pressing roller to act transversely on the material upstream of the support surface, the pressing roller being arranged to act on the material in a plane offset from the support surface during cutting, and guide means for a cutting member which is displaceable transversely relative to the support surface, the guide means being a cage covered by the material support surface and a sliding member supporting the cutting member and being movably guided inside the cage.

Preferably, the apparatus is such that when in use with the material unwound and cut in a horizontal plane the pressing roller is arranged to act on the material in a plane below the support surface and is as close as possible to a surface connecting the plane to the support plane.

The invention offers a significantly improved cutter with the possibility of the free end of the material moving spontaneously away from the support surface after the cutting operation. The gripping of the end of the sheet is then facilitated when it is desired to pull off another length of material.

According to a preferred feature the support surface is made from a metal sheet folded in such a manner as to form a cage serving as support and guide means for a carriage carrying the cutting member. This makes it possible for the material support surface to be kept completely clear and ensures operating safety. The support frame is also advantageously associated with means which on the one hand make it possible to release the pressing roller, and on the other hand enable the cutter carriage to be extracted.

In order that the invention may be more clearly understood, the following description is given by way of example only with reference to the accompanying drawings in which: Figure 1 shows in perspective an apparatus constructed in accordance with the invention; Figure 2 is a view in perspective of a cutter carrier carriage, this view having been deliberately distorted in order to make it clearer; Figure 3 is a section on the axis A-A in Figure 1, showing in greater detail the manner in which the cutter carrier carriage is guided and supported; Figure 4 is a detailed view in perspective of an arrangement making it possible during normal operation to support the pressing roller, and to stop the cutter carrier carriage at the end of its movement; and Figure 5 is a partial view in section and in perspective, showing in greater detail a modified form of cutter carrier carriage and the manner in which the material is presented to the cutter.

The accompanying drawings show an apparatus for unwinding and cutting a sheet of material 1 stored in the form of a roll 2 with a horizontal axis, but the apparatus can be used with the roll axis vertical just as well.

The roll of material 2 is mounted on a support shaft 3 adapted to turn freely in bearings provided for the purpose on a frame 4. The roll 2 is held by means of fastening cones 5 and 6, which can be moved on the shaft 3. This frame 4 is advantageously made from metal tubing of square section and is provided with feet enabling the apparatus to stand on a work surface, if desired.

Optional holes 7 and 8 are shown provided in the frame to allow it to be fastened on a wall, while the frame 4 could be made from any other suitable material, for example from a plastics material, or metal rods.

The apparatus comprises a support surface 9 for supporting the material 1 during the cutting, and also a transversely displaceable carriage 10 which supports a cutting means, for example one or more blades 24, 25, enabling the material to be cut during displacement of the carriage in either direction. A pressing roller 11 acts on the upper surface of the material 1 upstream of the guide surface 9.

As can be seen in greater detail in Figures 3 and 5, the pressing roller 11 acts on the material so that the material passes under and around part of the roller 11 and passes in a plane 12 which is parallel to and offset from the support plane 9. In the illustrated case, since the apparatus is intended to be used for working horizontally, this plane 12 is below the support surface 9. The resultant change of direction in the material means that after the cutting operation the free end rises (as shown in broken lines in Figures 3 and 5), so that the gripping of this end 28 is facilitated when it is desired to pull off another length of material. This raising action is assisted by the preferred step of disposing the pressing roller 11 in such a manner that it is as close as possible to the surface 13 connecting the plane 12 to the support plane 9.

In the present case the surfaces 12, 13 and 9 are formed from a metal sheet folded over in accordance with the configurations shown in Figures 3 and 5, in such a manner that a cage is obtained, in which can be disposed the sliding portion 14 of the carriage 10.

The cutter carrier carriage 10 0 includes a sliding part 14 adapted to be displaced in the cage formed under the support surface 9. This sliding part 14 is formed for example and as illustrated in Figure 2, of two plates 1 5 and 1 6 connected together by two pins 1 7 and 1 8 carrying spacers 1 9 and 20. A bent arm 23 carries at its top end the cutting blades 24 and 25. In Figure 2 the angle n formed by the bent arm 23 has been deliberately enlarged, but actually it is usually close to 450. In order to avoid all risk of accident, the blades 24 and 25 are covered by a guard which is a slider acted on by the operator. Only this guard or slider is accessible to the operator when the blades have to be moved in order to make the cut.

In this embodiment the guide for the sliding part 14 is formed by whe walls of the cage formed under the support face 9. The plate 1 5 is disposed askew in the cage and its two edges 40 and 41 are supported in the corners 42 and 43 of the cage. The sliding element of the cutter carrier carriage could optionally be of a different construction and, as shown in Figure 5, could consist of a block guided in the cage, for example, by two surfaces 22 and 23 extending over the entire width of the cage. For increased safety, a guard plate 26 is disposed in front of the cutting unit, this plate being curved over at its top end 27.

In the embodiments illustrated in Figures 3 and 5 the plate 26 is also formed by folding a metal sheet and is fastened, for example by welding, under the surface defining the plane 12. This entire arrangement is mounted at the end of the frame 4, parallel to the roll of material 2.

The operation of an installation of this kind is as follows.

The sheet of material 1 passes from the roll between the pressing cylinder 11 and the surface 12 and has a free end 28 which normally tends to be held away from the surface 9, as shown in broken lines in Figures 3 and 5. When it is desired to cut off a length of material, it is sufficient to grip the end 28, to pull off the desired length, and then to place the sheet on the support surface 9 and also on the curved end 27 of the protector plate 26. By means of the slider 10 the cutter carrier carriage is moved, so that the blade 24 or 25 cuts through the material. After the cutting operation the new end 28 tends to lift spontaneously off the support surface 9, thus facilitating a further operation.

Figure 4 illustrates a simple device which makes it possible to disengage the roller 11 from the surface 12 when desired, for example in order to fit a new sheet of material, and at the same time enables the cutter carrier carriage to be stopped at the end of its stroke and to be removed, for example in order to change the blade when that is desirable. This device has an arrangement mounted in one of the two side members, 30 in the present case, of the support frame 4 for the roll of material 2 and the pressing roller 11. As previously stated, these members are preferably made from tubes of square section. It is therefore possible to dispose the device inside these tubes. Thus, in this embodiment the roller 11 rests in a notch 31 provided in the side face of the member 30. The other end rests in a bearing provided in the opposite member.In order to prevent its dislodgment, the end 32 of the roller 11 is in normal use held by a sliding stop acted on by a spring 33. This stop is composed of a square tube whose dimensions are such that it can slide freely inside the tube 30. An opening 34 is provided in the side of the member, in such a manner that the whole arrangement can be displaced from front to rear. This displacement is effected by means of a small outside handle 35. In addition, a projection 36 on the slidable square tube takes up position at the end of the guide passage of the cutting means 14 and halts the latter at the end of its stroke. In normal operation the spring 33 thus makes it possible to hold the roller 11 so that it can rotate freely and halt the cutting means by means of the stop 36. When it is desired to lift the roller 11 or to remove the cutting means, for example in order to change the cutting element, it is sufficient simply to operate the handle 35 and move the sliding stop inside the member 30. On the one hand the bearing 31 acting on the pressing roller 11 and on the other hand the open end of the passage are thus freed.

The apparatus can be used in such a manner that the material is held vertically. In this case the only additional precaution to be taken regards holding the shaft supporting the material to be dispensed. This shaft must be mounted in a closed bearing in order to prevent it from falling out.

When the roll of material is heavy and large in diameter, in order to avoid a flywheel effect when the sheet is pulled off, it is preferable for each end of the shaft supporting the roll to be mounted in bearings of, for example, polyamide and for an adjustable braking system to be provided at one end.

It is possible to stack a plurality of such apparatuses whether or not each of them is equipped with a cutting system, thus making it possible with one and the same arrangement to have a plurality of sheet materials available.

In comparison with previous devices, the apparatus offers great simplicity of construction and utilisation, since the material can be extracted by pulling it with a single hand, if necessary.

Moreover, owing to the fact that it contains practically no moving parts wear is reduced, and it is safe to use because the cutting means is fully protected, while the material to be dispensed is easily placed in position and the cutting elements can also be easily changed because of the system of locking the pressing roller and stopping the cutting means.

Claims (9)

1. Apparatus for unwinding and cutting a sheet of material from a roll including a support shaft on which the roll of material is to be disposed and which is rotatably mounted in a support frame, a support surface on which unrolled material can be supported for cutting, a pressing roller to act transversely on the material upstream of the support surface, the pressing roller being arranged to act on the material in a plane offset from the support surface during cutting, and guide means for a cutting member which is displaceable transversely relative to the support surface, the guide means being a cage covered by the material support surface and a sliding member supporting the cutting member and being movably guided inside the cage.

2. Apparatus according to claim 1, and such that when in use with the material unwound and cut in a horizontal plane the pressing roller is arranged to act on the material in a plane below the support surface and is as close as possible to a surface connecting the plane to the support plane.

3. Apparatus according to claim 2, wherein the plane, the support surface and the connecting surface are defined by sheet metal folded in such a manner as to form a cage in which the sliding member is disposed.

4. Apparatus according to claim 1, 2, or 3, wherein the sliding member includes an element slidable in the cage formed under the support surface, this element supporting a bent arm supporting, at its top end, the cutting blades and a protective hood.

5. Apparatus according to claim 4, wherein the element is formed of two spaced and interconnected plates and is guided by the walls of the cage, one plate being disposed askew in the cage with its two edges engaging in the corners of the cage.

6. Apparatus according to claim 4, wherein the element is a block guided by surfaces extending over the entire length of the cage.

7. Apparatus according to any preceding claim, wherein a protective plate having a curved top edge is disposed in front of the cutting unit.

8. Apparatus according to any preceding claim, wherein the support frame is made from metal tubes of square section, and including means firstly to engage and disengage the pressing roller and secondly to allow removal of the cutter carriage.

9. Apparatus for unwinding and cutting a sheet of material substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.