ARRANGEMENT FOR HANDLING STACKS OF SHEETS

Abstract

There is disclosed herein an arrangement for handling one or more stacks of sheets. The arrangement comprises a support surface being provided with a plurality of openings for supplying a gas underneath said one or more stacks of sheets, a maneuver unit being moveable relative to the support surface and comprising two side clamping devices, the two side clamping devices being arranged at a distance from each other. The arrangement further comprises at least one top clamping device configured to exert a downward pressure onto said one or more stacks of sheets. The two side clamping devices and said at least one top clamping device are at least partly independently maneuverable thereby allowing the arrangement to maneuver one stack of sheets and also to maneuver a plurality of stacks of sheets arranged in a row one after the other.

Claims

1. An arrangement for handling one or more stacks of sheets, the arrangement comprising; a support surface being arranged to support said one or more stacks of sheets and being provided with a plurality of openings for supplying a gas underneath said one or more stacks of sheets, a maneuver unit being moveable relative to the support surface and comprising two side clamping devices, the two side clamping devices being arranged at a distance from each other along a longitudinal direction and being configured to interact with two opposing sides of said one or more stacks of sheets, and at least one top clamping device configured to exert a downward pressure onto said one or more stacks of sheets, wherein the two side clamping devices and said at least one top clamping device are at least partly independently maneuverable thereby allowing the arrangement to maneuver one stack of sheets and also to maneuver a plurality of stacks of sheets arranged in a row one after the other along the longitudinal direction between the two side clamping devices.

2. The arrangement according to claim 1, wherein said at least one top clamping device includes a vacuum functionality.

3. The arrangement according to claim 1, wherein the two side clamping devices are independently moveable along the longitudinal direction in relation to the maneuver unit.

4. The arrangement according to claim 1, wherein the gas is supplied at a pressure being balanced in relation to the downward pressure from said at least one top clamping device such that there is formed a gas cushion underneath said one or more stacks of sheets.

5. The arrangement according to claim 1, comprising at least two top clamping devices.

6. The arrangement according to claim 5, wherein said at least two top clamping devices are independently moveable along the longitudinal direction in relation to each other.

7. The arrangement according to claim 1, wherein the maneuver unit is translationally and rotationally moveable in a plane parallel to a plane defined by the support surface.

8. The arrangement according to claim 1, wherein the maneuver unit is supported by one or more robot arms.

9. The arrangement according to claim 1, wherein the two side clamping devices have planar surfaces configured to face and interact with said one or more stacks of sheets, thereby allowing the two side clamping devices to interact with stacks of sheets of different heights.

10. The arrangement according to claim 1, wherein said at least one top clamping device is moveable along the longitudinal direction in relation to the two side clamping devices.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The invention will by way of example be described in more detail with reference to the appended schematic drawings, which shows a presently preferred embodiment of the invention.

[0038] FIG. 1 discloses an overview of an arrangement for handling stacks of sheets.

[0039] FIG. 2 discloses an example of a maneuver unit of the arrangement.

[0040] FIG. 3 discloses the arrangement interacting with one stack of sheets.

[0041] FIG. 4 discloses the arrangement interacting with a plurality of stacks of sheets.

DETAILED DESCRIPTION

[0042] FIG. 1 illustrates an arrangement 1 for handling one or more stacks 2 of sheets 3. The arrangement 1 may be located in a production line where the arrangement 1 handles one or more stacks 2 of sheets 3 to position the one or more stacks 2 of sheets 3 correctly in relation to for example a cutting machine 4. Automated handling of stacks 2 of sheets 3 are an important development for many industries such as printing, packaging, manufacturing, and textile. Material of the sheets 3 may be for example paper or metal. The arrangement 1 comprises a support surface 10 at which the stacks 2 of sheets 3 are positioned when being handled. In FIG. 1 the arrangement 1 further comprises a robot arm 40 which supports a maneuver unit 20. The maneuver unit 20 of the arrangement 1 is translationally and rotationally moveable in a plane P1 parallel to a plane defined by the support surface 10. This means that the maneuver unit 20 is moveable above the support surface 10, such that the maneuver unit 20 is able to interact with the stack 2 of sheets 3 with no or minimal contact with the support surface 10. The robot arm 40 is one possible way to provide the translationally and rotationally moveability of the maneuver unit 20. It should be noted that also a combination of more than one robot arm 40 could be used.

[0043] When combined with a cutting machine 4, the arrangement 1 is generally used to position the stack 2 of sheets 3 in the cutting machine 4 to allow the stack 2 of sheets 3 to be cut into smaller stacks 2 of sheets 3. Cutting machines 4 are known in the prior art and historically been operated by personnel which positions the stack 2 of sheets 3 in the cutting machine 4. With the arrangement 1 this kind of personnel may be replaced. When the stack 2 of sheets 3 has been cut into the correct size, the arrangement 1 can be used to move the stack 2 of sheets 3 to a conveyor belt (not shown) to be transported for further processing.

[0044] In FIG. 2, one example of the arrangement 1 is illustrated. At this moment, the maneuver unit 20 is beginning to gather a new stack 2 of sheets 3 to be cut. Generally, multiple copies of an image or product is produced on each sheet 3, adjacent to each other. These images are aligned in a cutting machine 4 and then separated from each other by the cutting machine 4. In other words, the arrangement 1 starts with one stack 2 of sheets 3 and after the cuts there will be a plurality of stacks 2 of sheets 3. For example, in FIG. 2, there are three rows and three columns of images. In this case the arrangement 1 may first position each row for cutting and then each column for cutting, such that in the end there will be nine separate stacks 2 of sheets 3, one with each image. FIGS. 2 and 3 illustrate interaction with one stack 2 of sheets 3 and FIG. 4 illustrates interaction with three stacks 2 of sheets 3.

[0045] The stack 2 of sheets 3 are arranged on the support surface 10, which supports the stack 2 of sheets 3. The support surface 10 comprises a plurality of openings 12 which are used for supplying a gas underneath the stacks 2 of sheets 3. The gas is a pressurized gas, which generally is air. The gas is forced out from the openings to provide a lifting force to the stack 2 of sheets 3 lying on the support surface 10. This facilitates the possibility to maneuver the stack 2 of sheets 3 when lying on the support surface 10. The gas allows the stack 2 of sheets 3 to glide more smoothly over the support surface 10 when pushed or dragged.

[0046] The maneuver unit 20 is provided with two side clamping devices 22. The two side clamping devices 22 are arranged at a distance from each other along a longitudinal direction L and being configured to interact with two opposing sides 6a, 6b of said one or more stacks 2 of sheets 3.

[0047] As is understood by the person skilled in the art, the two opposing sides 6a, 6b of one or more stacks 2 of sheets 3 is when referred to one stack 2 of sheets 3 meant as the opposing sides 6a, 6b of the one stack 2 of sheets. In the context of a plurality of stacks 2 of sheets 3, the term opposite sides 6a, 6b refers to the outer edges of two distinct stacks 2. For instance, if three stacks 2a-c of sheets 3 are arranged side by side in a row, the opposite side refer to the outer sides of the first 2a and second 2b end stacks. The first end stack 2a, positioned at one end of the row, has its outer side facing away from any adjacent stack. Similarly, the second end stack 2b, situated at the opposite end of the row, also has its outer side facing away from adjacent stacks. The third stack 2c is positioned in the middle of the row, between the first 2a and the second 2b stack.

[0048] The two side clamping devices 22 have planar surfaces 23 configured to face and interact with said one or more stacks 2 of sheets 3. The planar surfaces 23 extends along a normal direction to the support surface 10. This allows the two side clamping devices 22 to interact with stacks 2 of sheets 3 of different heights. The planar surfaces 23 provide a consistent interaction with the stack 2 of sheets 3, which may maintain the integrity of the stack 2 and prevent errors or damage during handling.

[0049] In FIG. 2 the arrangement 1 is provided with one top clamping device 30. The top clamping device 30 is configured to exert a downward pressure onto said one or more stacks 2 of sheets 3. The top clamping device 30 can be moved in and out of contact with the stack 2 of sheets and as can be seen in FIG. 2 none of the side clamping devices 22 and the top clamping device 30 are in contact with the stack 2 of sheets 3. In this context, moved in and out of contact involves a movement along the normal direction to the support surface. The top clamping device 30 may, in all embodiments, be a vacuum top clamping device, i.e., a top clamping device 30 having a vacuum or under-pressure functionality allowing it to apply an under-pressure to the top sheets of the stack 2.

[0050] In FIG. 3 the arrangement 1 is interacting with one stack 2 of sheets 3. As can be seen, only the two side clamping devices 22 are used in this example to interact with the stack 2 of sheets 3. The two side clamping devices 22 have a great functionality when there is one stack 2 of sheets 3. By clamping the stack 2 of sheets 3 between the two side clamping devices 22, the stack 2 of sheets 3 can easily be maneuvered over the support surface 10. The maneuver unit 20 together with the supplied gas through the openings 12 in the support surface 10 allows the stack 2 of sheets 3 to slide smoothly over the support surface 10.

[0051] The two side clamping devices 22 are in this embodiment independently moveable along the longitudinal direction L in relation to the maneuver unit 20. This allows the two side clamping devices 22 to operate individually with the stack 2 of sheets 3. By moving one of the two side clamping devices 22, the stack 2 of sheets 3 may be moved towards the second of the two side clamping devices 22. This movement could also be combined with the top clamping device 30 providing a downward pressure to keep the stack 2 of sheets 3 in order. Further, the top clamping device 30 may be moveable along the longitudinal direction L in relation to the two side clamping devices 22. This allows the top clamping device 30 to be moved and positioned at a desired position above the stacks 2 of sheets 3. This allows the arrangement to operate with bigger variety of stack sizes. It also allows the top clamping device 30 to aid in moving or holding the respective stack of sheets.

[0052] Furthermore, the at least one top clamping device 30 may also be used to put a pressure on the one or more stacks 2 of sheets 3 during a cutting process. By putting pressure on the one or more stacks 2 of sheets 3 a more precise cut may be achieved as the sheets 3 are not able to move during the cut.

[0053] In FIG. 4 the arrangement 1 is interacting with three different stacks 2 of sheets 3. If only the two side clamping devices 22 would be used in this case, there may be a mixture of the stacks 2 of sheets 3 or any other type of unorder between the stacks 2 of sheets 3 may occur. To avoid this problem, two top clamping devices 30 is provided. The top clamping devices 30 may be used to put a downward pressure on for example two stacks 2 of sheets 3 each such that the two stacks 2 of sheets 3 are not able to move toward each other, thereby mixture of the two stacks 2 of sheets 3 can be avoided. The top clamping devices 30 can extend over both of the stacks 2 of sheets 3 such that both stacks 2 of sheets 3 are pressed by one top clamping device 30. It should be noted that one top clamping device 30 could be used for more than two stacks 2 of sheets 3 and also for one stack 2 of sheets 3 as well.

[0054] When having two or more top clamping devices 30 these could be independently moveable along the longitudinal direction L in relation to each other. This may allow the at least two top clamping devices 30 to adapt to different sizes of stacks 2 of sheets 3 and to adapt to how the stacks 2 of sheets 3 are distributed. As an example, if there are two stacks 2 of sheets 3, the two top clamping devices 30 may be moved to apply a downward pressure on one each of the two stacks 2. However, if there are three or four stacks 2 of sheets 3, the two top clamping devices 30 may be moved to apply a downward pressure on two stacks 2 each.

[0055] To facilitate the movement of the stacks 2 of sheets 3 over the support surface 10 while the top clamping devices 30 exert a downward pressure on the stacks 2 of sheets 3, the gas supplied through the openings 12 may be supplied at a pressure being balanced in relation to the downward pressure from the top clamping device 30. This forms a gas cushion 13 underneath the stacks 2 of sheets 3.

[0056] By forming the gas cushion 13 underneath the stacks 2 of sheets 3 the order in the stack 2 of sheets 3 may be more easily kept. With balance between the force from the gas applied through the openings 12 and the downward pressure from the top clamping device 30, the stack 2 of sheets 3 will be clamped between the gas cushion 13 and the top clamping device 30. In other words, the stack 2 of sheets 3 could be seen as being in a hovering state above the support surface 10 while still being pushed together by the gas cushion 13 and the top clamping device 30. The gas cushion 13 underneath the one or more stacks 2 of sheets 3 will both assist with clamping the one or more stacks 2 of sheets 3 and facilitate the movement of the one or more stacks 2 of sheets 3 over the support surface 10, due to the hovering state of the one or more stacks 2 of sheets 3.

[0057] The gas cushion 13 is formed by supplying gas at a pressure through the openings 12 in the support surface 10. By having a plurality of openings 10, the gas can counteract the downwards pressure from the top clamping device 30. This counteracting force can be adapted based on the denseness of the openings 12 and at what pressure the gas is provided. How the openings 12 may be distributed over the support surface 10 depend on what type of stacks of sheets that are handled. For example, a stack of sheets of a heavier material may require a higher density of openings 12 and/or that the gas is provided at a higher pressure than a stack 2 of sheets 3 of a lighter material.

[0058] As can be understood from FIGS. 3 and 4, the side clamping devices 22 and the at least one top clamping device 30 allow for using different combinations of clamping to maneuver the stack 2 of sheets 3. For example, with only one of the side clamping devices 22, the stack 2 of sheets 3 can be pushed over the support surface 10. By using both of the side clamping devices 22, the stack 2 of sheets 3 can be clamped and maneuvered around on the table and be rotated. The top clamping device 30 can alone be used to clamp the stack 2 of sheets 3 or stacks 2 of sheets 3 to move and rotate these. Further, a combination of the side clamping devices 22 and the top clamping device 30 can be used to move a plurality of stacks 2 of sheets 3. to achieve these combinations, the two side clamping devices 22 and said at least one top clamping device 30 are at least partly independently maneuverable thereby allowing the arrangement to maneuver one stack 2 of sheets 3 and also to maneuver a plurality of stacks 2 of sheets 3 arranged in a row one after the other along the longitudinal direction L between the two side devices 22. In other words, with the provided arrangement 1 it is not only possible to handle one stack 2 of sheets 3 at a time, but also to handle a plurality of stacks 2 of sheets 3 at the same time.

[0059] Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word comprising does not exclude other elements or steps, and the indefinite article a or an does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.