Centring block for centring a tooling board in a flat bed die-cutting, stripping or blanking machine and centring assembly

A centring block (12) for centring a tooling board (14) in a flat bed die-cutting, stripping or blanking machine is provided, the tooling board (14) having a protruding alignment element (30), comprising a first clamp (24) and a second clamp (26) which are arranged adjacent to each other to define a reception space (28) between them and which are mounted linearly moveable separately from each other in a direction perpendicular to a main extension plane of the tooling board (14) and at least one biasing means (34) which is configured to bias the first and the second clamps (24, 26) towards an aligning position against the tooling board (14), wherein each of the clamps (24, 26) comprises a stop portion (31) for restricting a movement of the tooling board (14) in an insertion and an opposite direction and to fix the tooling board (14) is in a centre position. Furthermore, a centring assembly (10) comprising a centring block (12) is provided.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This patent application is a National Stage Application under 35 U.S.C. § 371 of International Patent Application No. PCT/EP2021/051502, filed on Jan. 22, 2021, which claims priority to European Application No. 20020067.3, filed on Feb. 13, 2020, the entireties of which are incorporated herein by reference.

The invention relates to a centring block for centring a tooling board in a flat bed die-cutting, stripping or blanking machine and a centring assembly for a flat bed die-cutting, stripping or blanking machine comprising a centring block.

Flat bed die-cutting machines, flat bed stripping machines or part separation machines may be part of a production line in which paper, cardboard, corrugated board or plastic are processed, for example for packaging. For example, a plurality of blanks on the same sheet are die-cut and subsequently separated in a flat bed die-cutting machine with an adjoining flat bed stripping device.

In order to enable the processing of different packaging, an exchangeable tooling board which is specific for a kind of packaging to be processed is mounted in the respective machine. For flat bed die-cutting machines, for example, these tooling boards are pressure plates which have cutting knives or pressure pads attached thereto. The tooling boards are usually inserted into the machine from the side with respect to the transport direction of the workpiece.

It is essential that the machines work with very high precision. The exchangeable tooling board must be exactly adapted to the pressure applied and aligned with the edges of cut in the preceding station. If upper and lower exchange tools are provided, as it is the case in the die-cutting or stripping machines, these tools further need to be precisely aligned with each other.

For aligning the tooling board in a centre position, flat bed die-cutting, stripping or blanking machines usually comprise centre blocks which can restrict a movement of the tooling board upon insertion of the tooling board in the machine respectively inhibit a movement of the tooling board after the tooling board has been inserted.

The known centring blocks comprise swivel mounted clamps which can encompass an alignment element of the tooling board. However, such centring blocks are complicated to assemble and expensive and are dedicated to high level machines.

Therefore, it is an object of the invention to provide a centring block which is cost-effective and easy to assemble and are applicable for entry level machines.

This object is achieved by a centring block for centring a tooling board in a flat bed die-cutting, stripping or blanking machine, the tooling board having a protruding alignment element, comprising a first clamp and a second clamp which are arranged adjacent to each other to define a reception space between them and which are mounted linearly moveable separately from each other in a direction perpendicular to a main extension plane of the tooling board. The centring block further comprises at least one biasing means which is configured to bias the first and the second clamps towards an aligning position against the tooling board, wherein each of the clamps comprises a stop portion for restricting a movement of the tooling board in an insertion and an opposite direction and to fix the tooling board is in a centre position.

By means of the centring block, the tooling board can be precisely located in a defined position. When the tooling board is inserted in the machine, it will abut the stop portion when it has reached the centre position.

When the clamps are in the aligning position and the alignment element of the tooling board is in the reception space, the clamps are enabled to centre the tooling board in a desired centring position. In this condition, the alignment element of the tooling board is surrounded by the clamps such that a movement of the tooling board is restricted by means of the clamps.

The aligning position of the clamps is in particular a position in which the clamps are in their maximum extended position.

Due to the clamps being linearly moveable, the assembling of the centring block is simple and the positioning of the tooling board can be very precise. In particular, positioning tolerances of the tooling board are less than upon use of a centring block with swivel mounted clamps.

When the tooling board is inserted in the machine, the biasing means may bias the clamps against the tooling board.

According to one embodiment, at least one of the clamps, in particular both of the clamps, comprise a slanted surface facing away of the reception space and in a direction opposite to the insertion direction, wherein a clamp is moved against a biasing force of the biasing means when a force is applied on the slanted surface to lift the clamp. In particular, the slanted surface is inclined with respect to a movement direction of the clamps.

Due to the slanted surface, a clamp is lifted when the tooling board abuts the slanted surface during insertion of the tooling board in a machine. Therefore, inserting the tooling board in a machine may be very easy. In particular, no manually handling of the clamps is required for inserting the tooling board.

An extension of the slanted surface in the direction of movement of the respective clamp is preferably such that the alignment element of the tooling board abuts the slanted surface of the clamp. That means, that an extension of the slanted surface in the direction of movement of the respective clamp may be at least as large as a height of the alignment element measured from a surface of the tooling board facing towards the centring block. Then, the clamp can be lifted by means of the alignment element.

According to one embodiment, each of the clamps has an indentation wherein the indentations of the clamps together form the reception space for an alignment element of the tooling board. Thus, no additional element is required to form the reception space. Furthermore, the tooling board, in particular the alignment element, is automatically received in the reception space during insertion of the tooling board in a machine.

Each of the clamps may be fastened to a slidably moveable shaft and a bearing element may be provided at, e.g. fixed to each shaft, wherein the bearing element provides a contact surface for the biasing means.

The shaft may serve to guide the respective clamp in a linearly moveable manner, for example by means of the shaft being slidably received in a guidance hole.

Due to the bearing element providing a contact surface for the biasing means, the centring block may be very compact.

The bearing element may also serve to restrict a movement of the clamps in a direction towards the tooling board.

The biasing means may be a helical spring which is mounted concentrically around the shaft and rests on the bearing. Therefore, the structure of the centring block may be quite simple.

According to one embodiment, the centring block comprises an unlocking element which is moveable in a release direction against a biasing force of the biasing means, wherein the bearing elements rest on the unlocking element when the clamps are in the aligning position such that the clamps are lifted when the unlocking element is moved in the release direction. Thus, by moving the unlocking element in the release direction, the tooling board, not precisely the alignment element is released from the reception space and may be removed from the machine.

For moving the unlocking element from a position outside of the machine, the centring block may comprise a handle which is in operative connection with the unlocking element such that the unlocking element is moved in the release direction when the handle is actuated. In particular, the handle may be actuated by a user.

By means of the handle, a user may operate the unlocking element with one hand. With the other hand, he can pull the tooling board out of the machine at least a little bit such that the alignment element is moved out of the engagement with the centring block. Then, the tooling board can be moved out of the machine without actuating the handle. Therefore, one person alone is enabled to exchange the tooling board.

Preferably the handle and the unlocking element are connected such that a movement of the handle in a direction parallel to a main extension plane of the tooling board results in a movement of the unlocking element perpendicular to the main extension plane of the tooling board. Thereby, the handle may be actuated in an ergonomic way. In particular, a user may pull or push the handle in order to release the tooling board.

According to one embodiment, the unlocking element or the handle comprises a guiding slot which extends inclined to a movement direction of the unlocking element, the other one of the unlocking element and the handle comprising a pin which runs in the guiding slot such that upon actuation of the handle the unlocking element is forced to move in the release direction. By this means, the unlocking element and the handle may be in operative connection in a simple way.

The pin may be firmly fixed to the respective element.

In this context, a pin also means a screw or a bolt.

The centring block may further comprise a support element for fixing the centring block to an elongated rail of a flat bed die-cutting, stripping or blanking machine. On the support element, all elements of the centring block may be mounted. Therefore, the centring block may be preassembled, such that a mounting of the centring block in the machine may be easy and quick. In particular, the centring block may be obtained from a supplier in a preassembled form.

The support element for example comprises a sheet metal part. Additionally, the support element may comprise support blocks to increase the stability of the centring block and to improve the guiding of the clamps.

The object of the invention is further achieved by means of a centring assembly for a flat bed die-cutting, stripping or blanking machine, comprising a centring block as previously described, a tooling board comprising an alignment element, wherein the centring block is configured to centre the tooling board by centring the alignment element, and at least one elongated rail for slidably guiding the tooling board into and out of the a flat bed die-cutting, stripping or blanking machine.

Such an assembly has the advantage, that a tooling board may be slidably guided into its centre position in a very easy way. A user exchanging the tooling board does not need to actively centre the tooling board, but just needs to push the tooling board into the machine until it abuts the stop portion of one of the clamps.

The centring assembly10comprises a centring block12, an exchangeable tooling board14and two elongated rails16. The rails16are configured for slidably guiding the tooling board14from the side into and out of a flat bed die-cutting, stripping or blanking machine in an insertion and an opposite direction.

The tooling board14is for example a pressure plate.

InFIG.1, the tooling board14is shown in a defined centre position. When the tooling board14is in its centre position, a precise processing of paper, cardboard, corrugated board or plastic in a flat bed die-cutting, stripping or blanking machine may be possible. In particular, the process accuracy may be very high.

In order to precisely position the tooling board14, the centring block12is provided which is described in detail with reference toFIGS.2and3.

FIG.2shows a perspective view of the centring block12.

For fixing the centring block12to an elongated rail16, the centring block12comprises a support element18. On the support element18, all elements of the centring block12, which will be described in the following, may be mounted.

In the shown embodiment, the support element18comprises a sheet metal part20and two support blocks22, in particular an upper support block22aand a lower support block22b. The support blocks22are for example plastic blocks or metal blocks. The sheet metal part20is for example a bent part which, when viewed from the side, has a C-form.

The centring block12further comprises a first clamp24and a second clamp26. The clamps24,26are arranged adjacent to each other to define a reception space28between them. The reception space28is configured to receive an alignment element30which is attached to the tooling board14(see for exampleFIG.4). Thereby, the tooling board14may be fixed in the centre position, as shown inFIG.1.

In order to receive the alignment element30of the tooling board14, the clamps24,26are mounted linearly movable and separately movable from each other in a direction perpendicular to a main extension plane of the tooling board14. Thus, the clamps24,26may be lifted in order to receive the alignment element30of the tooling board14in the reception space28.

Both clamps24,26comprise a slanted surface32facing away of the reception space28and in a direction opposite to the insertion direction. When a force is applied on the slanted surface32of a clamp24,26, for example by the tooling board14, in particular the alignment element30, the clamp24,26is lifted. Thereby, the alignment element30may move into the reception space28. Thus, the slanted surface32is arranged at the lower, outer edge of the respective clamp24,26.

To form the reception space28, each of the clamps24,26has an indentation29. The indentations29of the clamps24,26together form the reception space28, in particular when the clamps24,26are in the alignment position.

For accurately centring the tooling board14, each of the clamps24,26comprises a stop portion31.

As soon as the alignment element30abuts a stop portion31of one of the clamps24,26, a further movement of the tooling board14in the insertion direction is inhibited.

A width of the reception space28extending in the insertion direction preferably corresponds to a width of the alignment element30. Thereby, a movement of the tooling board14may be reliably inhibited.

To ensure that the clamps24,26return into an alignment position after having been lifted, the centring block12comprises biasing means34which are configured to bias the clamps24,26towards the aligning position, in particular against the tooling board14. The biasing means34are for example springs, in particular helical springs.

When the clamps24,26are lifted, they have to be moved against the biasing force of the biasing means34.

In order to mount the clamps24,26, each clamp24,26is fastened to a slidably moveable shaft36.

The shafts36are respectively received in bores38in the support blocks22, in particular linearly moveable and slideably guided in the bores38.

A bearing element40is fixed to each shaft36, wherein the bearing element40provides a contact surface for the biasing means34. Another contact surface for the biasing means34is provided at the upper support block22a. Thus, the biasing means34is retained between the bearing element40and the upper support block22a.

Furthermore, the bearing element40provides a stop for the respective clamp24,26such that the clamps24,26may rest in the alignment position.

Of course, it is also possible that separate bearing elements40for providing a stop and for providing a contact surface for the biasing means34are provided on each shaft36. However, by providing only one bearing element40on each shaft, the centring block12may have a compact and space saving design.

In the shown embodiment, the bearing elements40have a ring shape, wherein the rings surround the shafts36and are fixed to the shafts36by means of screwing, welding, gluing etc. Of course, other shapes of the bearing elements40are possible.

When a tooling board14is inserted in a flat bed die-cutting, stripping or blanking machine comprising a centring block12, one of the clamps24,26may be lifted due to the alignment element30abutting against the slanted surface32and upon further movement exerting a force on the slanted surface32.

For manually lifting the clamps24,26, for example in order to release a tooling board14, the centring block12comprises an unlocking element42.

The unlocking element42is moveable in a release direction against a biasing force of the biasing means34.

In particular, the bearing elements40rest on the unlocking element42when the clamps24,26are in the aligning position such that the clamps24,26are lifted when the unlocking element42is moved in the release direction.

The unlocking element42is arranged between the support blocks22a,22b, in particular directly above the lower support block22b.

Due to the bearing elements40resting on the unlocking element42, the bearing elements40and thus the clamps24,26are lifted when the unlocking element42is lifted.

In the shown embodiment, the unlocking element42comprises a block44, for example a plastic or metal block, and a plate like element46which is fixed to the block44. In particular, the plate like element46is attached to a side surface of the block44which is faced towards the sheet metal part20of the support element18.

By means of the plate like element46, the unlocking element42may be supported at the sheet metal part20of the support element18.

As can be seen inFIG.2, the plate like element46extends over the block44, in particular at least at opposing side surfaces of the block44.

In an overhang of the plate like element46extending sidewards from the block44, guide cut-outs48are provided, which extend in the release direction.

The guide cut-outs48allow to moveably mount the unlocking element42at the support element18. In particular, the unlocking element42is for example mounted to the support element18by means of screws. However, the screws are not completely tightened to allow a movement of the unlocking element42. For fixing the unlocking element42more securely, a washer may be provided.

Like the support blocks22, the unlocking element42, in particular the block44, comprises bores in which the shafts36are received and slidably guided.

For easy operation of the unlocking element42, the centring block12comprises one or two handle(s)50which is/are in operative connection with the unlocking element42such that the unlocking element42is moved in the release direction when the handle(s)50is/are actuated. The handle(s)50may be actuated from outside of the machine when the centring block12is mounted in a flat bed die-cutting, stripping or blanking machine. InFIG.2, two handles50are extending in opposite directions from support block22aallowing to actuate unlocking element42from opposite sides of the blanking machine.

Each handle50is guided within and extends through a hole of a bearing element51attached to support element18.

In particular, the handle50and the unlocking element42are connected such that a movement of the handle50in a direction parallel to a main extension plane of the tooling board14results in a movement of the unlocking element42perpendicular to the main extension plane of the tooling board14.

To establish an operative connection between the unlocking element42and the handle50, the handle50comprises a guiding slot52which extends inclined to a movement direction of the unlocking element42and the unlocking element42comprises a pin54which runs in the guiding slot52such that upon actuation of the handle50the unlocking element42is forced to move in the release direction. In an alternative embodiment, the unlocking element42may comprise the guiding slot52and the handle50may comprise the pin54.

The handle50may be made from one piece, for example as a sheet metal part, or, as shown in the Figures, from several parts.

The guiding slot52and the pin54can be seen more clearly inFIG.3, which shows a sectional view of the centring block12. In the depicted embodiment, the pin54is a screw.

FIG.3also shows the fastening of the clamps24,26to the shafts36. In particular, the shafts36are received in a respective bore56in the clamps24,26and fixed by a headless screw.

In a side view, the clamps24,26have an L-shape, wherein the bores56are placed in a leg of the L which extends parallel to a main extension plane of the tooling board14.

Optionally, sliding bushes may be inserted in the bores38of the support blocks22and also in bores of the unlocking element42.

In the following, the operation of the centring assembly10is described with reference toFIGS.4to7.

FIG.4shows an insertion of a tooling board14. In particular,FIG.4shows a condition of the centring assembly10when the alignment element30has just abutted the slanted surface32of the clamp24and is now moved into the reception space28.

As soon as the alignment element30abuts the stop portion31of the clamp26, the tooling board14is in its centre position. The clamp24may now move back into the alignment position due to the biasing force of the biasing means34.

FIG.5shows the assembly ofFIG.1during insertion of the tooling board14in a direction opposite to the direction shown inFIG.4. However, the mechanism of the centring block12is the same, only that instead of the clamp24the clamp26is lifted by the alignment element30.

FIG.6shows a side view of the centring assembly10with the tooling board14being in the centre position. In this condition, the tooling board14is fixed in its position due to the clamps24,26encompassing the alignment element30respectively due to the alignment element30being received in the reception space28.

FIG.7shows how the tooling board14may be released from the centring block12in order to remove the tooling board14from the flat bed die-cutting, stripping or blanking machine.

In particular, in the condition visualized inFIG.7the handle50is actuated, for example by pulling the handle50, and the unlocking element42is lifted. Thus, the alignment element30is released from the reception space28and the tooling board14can be removed.