BLANK HOLDER DEVICE FOR A DRAWING DEVICE FOR PRODUCING HOLLOW CYLINDRICAL BODIES

A blank holder device for a drawing device, for example a drawing press. The blank holder device has a blank holder sleeve, which, in a predetermined position exerts a blank holder force on a blank part. The sleeve is fastened to a head part and is stationary relative to it. To move the blank holder sleeve in a stroke direction, the head part is borne, through a head part guiding arrangement, at least at two front guide locations, to undergo translational motion in a stroke direction, and it is braced to be essentially stationary in all directions at right angles to the stroke direction. On the side opposite the blank holder sleeve, the head part is connected with at least one drive element of the blank holder drive device and that can, together with the head part, be moved by a motor and a coupling arrangement in the stroke direction.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefits of German Application No. 10 2017 106 356.0 filed Mar. 24, 2017. The said German application No. 10 2017 106 356.0 is incorporated herein by reference in its entirety as though fully set forth.

BACKGROUND OF THE INVENTION

The invention relates to a blank holder device for a drawing device for producing hollow cylindrical bodies, such as, for instance can bodies, in particular for pressurized containers/cans or beverage cans. The shaping performed by means of the drawing device is done by ironing, for example. The blank part for this, also called a “cup”, can be a bowl-shaped or cup-shaped piece that has been shaped in a first shaping step. The blank part can also be a plate-shaped, for example round, sheet metal part, that can be called a “blank”. The blank part can be shaped into a hollow cylindrical body using a drawing punch or a ram of the machine or press. The hollow cylindrical body has a bottom and, made of the same material, a wall that is closed in a peripheral direction and that is connected with the bottom without a seam or joint. On the side opposite the bottom, the hollow cylindrical body is open. To allow a drawing punch to shape the preferably cup-shaped blank part, there is a blank holder device. The blank holder device has a blank holder sleeve with a sleeve end face which, when in a blank holder position, presses the blank part against a clamping surface with a blank holder force and projects, e.g., into the cup-shaped blank part. Starting from this clamped position, the drawing punch then performs the shaping, for example by ironing.

Such shaping devices are known in the art. DE 28 43 742 A1 shows a punch arrangement for ironing, wherein a medium flows through the punch arrangement to control the temperature of the ironed container and the punch arrangement, to reduce shrinkage of the container on the punch and to make stripping easier.

The device disclosed in DE 25 19 521 A1 has a blank holder sleeve of a blank holder device, this blank holder sleeve being arranged coaxial with a drawing punch. The blank holder can be moved relative to the drawing punch by pressurization of a pressure chamber, and is arranged so that it is guided on the drawing punch.

DE 601 15 640 T2 discloses a blank holder device wherein the blank holder is hydraulically driven. The blank holder can be moved along a main axis. ‘Extending laterally offset to the main axis are piston rods of a hydraulic drive cylinder, these piston rods fluidically subdividing a movable cylinder housing that is guided along the piston rods into two work working chambers. Depending on the pressurization of the chambers, the cylinder housing can be moved relative to the piston rods. The cylinder housing is connected with the blank holder or the blank holder sleeve.

US 2016/0318089 A1 also shows a shaping device with a blank holder. The blank holder has a head part on which the blank holder sleeve is arranged. On a side of the head part opposite the blank holder sleeve there are drive rods which can move the head part and the blank holder sleeve in a stroke direction. The drive rods are borne so that they are movable in the stroke direction.

The blank holder devices known from the prior art have turned out to be insufficiently precise. The wall thickness of the hollow cylindrical container that is formed can fluctuate. The wall thickness tolerances lie in the micron range. During production, insufficient precision can lead to an undesirably high proportion of rejects. Therefore, it can be considered the goal of this invention to create an improved blank holder device that has sufficient accuracy and reduces the proportion of rejects among the hollow cylindrical bodies that are produced.

SUMMARY OF THE INVENTION

This is accomplished by a blank holder device having the features of the claims. The invention relates to a blank holder device22for a drawing device10, for example a drawing press. The blank holder device22has a blank holder sleeve43, which, when in a blank holder position II, exerts a blank holder force FN on a blank part14. The blank holder sleeve43is fastened to a head part23and is stationary relative to it. To move the blank holder sleeve43in a stroke direction H, the head part23is directly borne, through a head part guiding arrangement50, at least at two front guide locations51, so that it can undergo translational motion in stroke direction H, and it is braced so that it is essentially stationary in all directions at right angles to the stroke direction H. Every front guide location51is preferably formed by a head part guiding unit52with a guide element53extending in the stroke direction H. The head part52is guided directly along the guide elements53. On the side opposite the blank holder sleeve43, the head part23is connected with at least the one drive element25that belongs to the blank holder drive device24and that can, together with the head part23, be moved by means of a motor31and a coupling arrangement30in the stroke direction H.

The inventive blank holder device has a blank holder sleeve fastened to a head part. The blank holder sleeve has, on the side opposite the head part, a sleeve end face which, when the blank holder sleeve is in a blank holder position, is set up to press a blank part, for example a cup-shaped blank part, against a clamping surface with a specified blank holder force, especially a blank holder force that is controllable by open-loop or closed-loop control. If the blank part is cup-shaped, the blank holder sleeve can, when in its blank holder position, project into the cup-shaped blank part. The blank part can also be in the form of a flat, preferably circular sheet metal part.

The blank holder device has a blank holder drive device with at least one drive element that can be made to undergo translational motion in a stroke direction. The drive element can be in the form of a drive bar or a drive rod, for example. The front end of the drive element is connected with the head part, and starting from the head part it extends away in the stroke direction toward a back end on the side opposite the blank holder sleeve. The blank holder drive device is set up to move the head part and, along with it, also the blank holder sleeve in the stroke direction by moving the at least one drive element. The blank holder sleeve can execute a movement between an initial position and the blank holder position.

The blank holder device has a head part guiding arrangement. The head part guiding arrangement is set up to bear the head part at least at two front guide locations so that it can undergo translation motion in the stroke direction, and to brace it against movements in all other degrees of freedom. Thus, the front head part guiding arrangement allows the head part to undergo only translational motion in a single degree of freedom. The head part guiding arrangement is passive and is not set up to move the head part or to produce a driving force acting on the head part. The head part guiding arrangement preferably acts directly on the head part.

The head part is guided, by means of the head part guiding arrangement, in one translational degree of freedom near or on the level of the blank holder sleeve when viewed in the stroke direction, and the head part is braced in all other degrees of freedom. This allows very exact positioning of the blank holder sleeve when it is in the blank holder position, or very exact movement of the blank holder sleeve into the blank holder position. Hollow cylindrical bodies, in particular can bodies, must be produced with a specified wall thickness having tolerances in the micron range. The invention is based on the knowledge that to accomplish this, the blank holder sleeve must, when it is in its blank holder position, exert the same blank holder force onto the blank part at every location on the sleeve end face. A blank holder sleeve that is inclined or tilted with respect to the stroke direction or to a main axis can, even at small angles of tilt or inclination, produce a blank holder force that is not uniform in the peripheral direction around the main axis or along the entire sleeve end face. This in turn leads to deviations in wall thickness and to rejects when producing hollow cylindrical bodies. Therefore, the head part is not only indirectly guided and driven through the blank holder drive device, but rather a head part guiding arrangement is additionally present, which exactly guides the head part at least at two front guide locations. The head part guiding arrangement transfers no driving forces to the head part. This allows very exact guiding at the front guide locations. This in turn exactly positions the blank holder sleeve, in particular in its blank holder position, and reduces the number of rejects when hollow cylindrical bodies are produced.

The head part is preferably plate-shaped.

The head part guiding arrangement can have at least two head part guiding units, every one of which is present to form a guide location. At least two of the front guide locations that are present or the head part guiding units that are present are preferably arranged with a transverse spacing to one another in a transverse direction at right angles to the stroke direction. In a preferred embodiment, every head part guiding unit has a guide element extending in the stroke direction and a guide bearing part that is movable relative to it. For example, the guide element can be formed by a guide rod and the guide bearing part can surround the guide rod at the respective front guide location. It is preferred that the guide bearing part form a guide sleeve that completely surrounds, or essentially completely surrounds, the guide rod. At every front guide location the guide bearing unit in question can form a plain bearing or a roller bearing.

If there are more than two front guide locations, for example four front guide locations, they can form two groups, which are arranged with a spacing to one another in the transverse direction. In the stroke direction, the front guide locations of a common group can be arranged so that they are aligned.

It is preferred that the guide bearing parts of the head part guiding units be arranged on the head part and that the guide elements or the guide rods be arranged on a machine frame or a machine base of the blank holder device. For example, the head part can extend from one of the guide elements to another one of the guide elements in a transverse direction at right angles to the stroke direction. Alternatively, the head part could also have the guide elements or the guide rods arranged on it, and the guide bearing parts could be arranged on the machine frame or on the machine base.

The blank holder device preferably also has a drive guide arrangement. The drive guide arrangement is set up to bear the at least one drive element of the blank holder drive device so that it can undergo translational motion at least at one back guide location. At this at least one back guide location, the at least one drive element can be movable in only one degree of freedom and be braced in all other degrees of freedom.

In one embodiment, there are at least two drive elements, which are borne at least at one back guide location so that the drive guide arrangement can make them undergo translational motion in the stroke direction. A transverse spacing of the back guide locations in a transverse direction at right angles to the stroke direction can be smaller than the transverse spacing of the front guide locations of the head part guiding arrangement. This allows, on the side of the head part opposite the blank holder sleeve, an arrangement of the blank holder drive device that occupies little space in the transverse direction.

In a preferred embodiment, the blank holder drive device has a motor and a coupling arrangement, this coupling arrangement being directly coupled, at a coupling location, with the at least one drive element, and making a drive connection between the motor and the at least one drive element. The coupling arrangement transfers a driving force from the drive motor to the at least one drive element. This driving force can act on the at least one drive element at an angle to the stroke direction.

In one sample embodiment, each drive element is borne at a back guide location between the coupling location, at which the coupling arrangement acts, and the head part. Alternatively or in addition, every drive element can extend away from the head part in the stroke direction, starting from the coupling location, toward a back end, and be borne at a back guide location between the coupling location and the back end.

The head part preferably has a central through opening for a drawing punch that is arranged so that it can be moved along a main axis in the stroke directions. Through the central through opening and the blank holder sleeve, the drawing punch can act on the cup-shaped blank part and shape it with the help of a die tool. In particular, the blank holder sleeve is arranged coaxial with the main axis or to the drawing punch.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1shows a block diagram of a sample embodiment of a drawing device10, which can also be referred to as a drawing press. The drawing device10has a drawing punch12, which can also be referred to as a ram, that is arranged so that it can be moved by means of a drawing punch drive11along a main axis A in a stroke direction H. A front end13of the drawing punch12forms a so-called “punch” and acts on a blank part14(cup), which according to the example is cup-shaped or bowl-shaped, and shapes it into a hollow cylindrical body using a die tool15. In the sample embodiment, the die tool15has an ironing channel16, which is arranged coaxial with the main axis A and has a entrance opening16aand an exit opening16b. The ironing channel16has multiple ironing dies17along it that are arranged coaxial with the main axis A. The inside diameters of the ironing dies17are different, and become smaller the closer the ironing die17is located to the exit opening16b. The die tool15is also referred to as a “toolpack”.

The drawing punch12can shape the blank part14by ironing. This involves the drawing punch12moving the blank part14through the ironing channel16and the ironing dies17, forming a hollow cylindrical body with a bottom and a wall that is connected to the bottom and that has a specified wall thickness. In the area of the exit opening16bof the ironing channel16there can be a stripper18, which is only very schematically illustrated and which is set up to strip the hollow cylindrical body that has been shaped from the drawing punch12when the latter executes a return stroke back through the ironing channel16.

The drawing device10also includes a blank holder device22. The blank holder device22has a head part23that can be made to undergo translational motion in stroke direction H. To move the head part23there is a blank holder drive device24comprising at least one drive element25that can be made to undergo translational motion in stroke direction H. According to the example, there are two such drive elements25, which are formed by drive rods26. Each drive rod26has a front end, with which it is fastened to head part23. Starting from the front end27, each drive rod26extends away from head part23in stroke direction H toward a back end28.

According to the example, the head part23is made as an integral part from one body, without a seam or joint. It can be plate-shaped.

At a coupling location29, every drive element25or every drive rod26is directly coupled with a coupling arrangement30(FIGS. 4 and 5). The coupling arrangement30makes a drive connection between a motor31of the blank holder drive device24and the drive elements25, and, according to the example, the drive rods26. The coupling arrangement30can have different designs. At the coupling location29, it acts directly on the at least one drive element25and is set up to convert a rotation of the motor31into a translational motion of the respective drive element25in stroke direction H.

In the very schematic sample embodiment of the blank holder drive device24illustrated inFIG. 4, the motor31drives an eccentric32. The eccentric32acts on a coupling element33that is pivotably borne at a pivot bearing location34between the coupling location29and the cam32. The eccentric32is movably guided along the coupling element33. At the coupling location29, a coupling pin35connected with the drive element25is also movably guided along the coupling element33. Rotation of the eccentric32about the axis of rotation of the motor31causes the coupling element33to swivel on the coupling location29and causes translational motion of the coupling pin35together with the drive element25in question or with the drive rod26in question.

In departure from the illustration according toFIG. 4, it is also possible for the eccentric32to be connected with a connecting rod-like coupling element33, which is arranged so that it can pivot at a location between the eccentric32and the coupling location29and is guided so that it can be moved in the direction in which the connecting rod-like coupling element extends. Such an arrangement can also cause the at least one drive element25to move in stroke direction H.

Another example of a blank holder drive device24is schematically shown inFIG. 5. In departure from the previous sample embodiments, coupling arrangement30is in the form of a knee lever arrangement. In this embodiment, the coupling element33is rotatably supported on the eccentric32, on the one hand, and, on the other hand, rotatably supported on a knee joint. At the knee joint36, a first knee lever37and a second knee lever38are connected together in an articulated manner. The end of first knee lever37opposite the knee joint36is supported in an articulated manner on a machine frame or a machine base39. The end of second knee lever38opposite the knee joint36is arranged in an articulated manner on coupling pin35. Rotation of the eccentric32about the axis of rotation of the motor31changes the knee angle between the two knee levers37,38at the knee joint36, which can cause the at least one drive element25to move in the stroke direction H.

The above-described sample embodiments of the coupling arrangement30allow the motor31to be arranged at a right angle to the stroke direction H, offset to at least one drive element25, for example on the level of the at least one drive element25, when viewed in stroke direction H. A possible variation of this is for the motor31also to be arranged behind the at least one drive element25, when viewed in stroke direction H. In this case, coupling element33of the coupling arrangement30can be, for example, a connecting rod.

The head part23has a blank holder sleeve43fastened to it. The blank holder sleeve43is arranged coaxial with the main axis A. It is located on the side of the head part23facing away from the at least one drive element25. Starting from the head part23, the blank holder sleeve43extends toward a free end, on which there is a sleeve end face44that forms an annulus that is concentric with the main axis A. A normal vector of the end face44extends in the stroke direction H parallel to the main axis A (FIG. 3). On the side opposite the sleeve end face44, the blank holder sleeve has, for example a mounting flange45, by means of which it can be detachably fastened, for example by means of a threaded connection, to a fastening surface46of the head part23. The fastening surface46extends in a plane at right angles to stroke direction H.

The head part23is borne, by means of a head part guiding arrangement50, at least at two front guide locations51—according to the example exactly two front guide locations51, so that it can undergo translational motion in the stroke direction H. In the sample embodiment, the head part guiding arrangement50allows only translational motion in the stroke direction H, and prevents movement in other translational degrees of freedom and, in the sample embodiment, also in all rotational degrees of freedom. The two guide locations51are arranged with a first transverse spacing d1in a transverse direction Q at right angles to the stroke direction H. According to the example, every guide location51is formed by a head part guiding unit52, these head part guiding units52being best shown inFIG. 6. The head part guiding units52are arranged on opposite sides, in the transverse direction Q, with respect to the main axis A or the drawing punch12.

Every head part guiding unit52has a guide element53extending in stroke direction H, each of which in the sample embodiment is formed by a guide rod54. Every guide element53has a guide bearing part55borne at it so that this guide bearing part55can be moved in the stroke direction H. According to the example, each guide bearing part55surrounds, in the shape of a sleeve, the guide rod54that is associated with it. The guide bearing part55is solidly connected with the head part23. The guide elements53or guide rods54of the head part guiding units52, of which there are two according to the example, are solidly connected with the machine frame or machine base39, for example by means of the supports56illustrated inFIG. 6.

In the sample embodiment, the head part23is essentially plate-shaped with a ring-shaped middle part57, that has an projection58on each of its sides that are opposite in the transverse direction Q. Every projection58has a through hole in it, in which a guide bearing part55of a respective head part guiding unit52is seated. The guide bearing part55can form a plain bearing or a rolling bearing at the front mounting point51in question. Alternatively, it is also possible to arrange the guide rods26on the head part23and the guide bearing parts55on the machine base39.

In departure from the described embodiment, every head part guiding unit52can also form a group with multiple guide locations51, which can be arranged next to one another, for example aligned with one another, in the stroke direction. The two groups of guide locations51are arranged on opposite sides of the main axis A, with spacing in the transverse direction Q.

In the middle part57of head part23there is a central through opening59, which is symmetrically arranged with respect to main axis A and is aligned with the cylindrical passage of the blank holder sleeve43. The central through opening59allows the drawing punch12to pass through the head part23.

The blank holder drive device24can move the head part23together with the blank holder sleeve43in stroke direction H, so that the blank holder sleeve43moves between an initial position I (FIG. 1) and a blank holder position II (FIG. 2). In the blank holder position II, the blank holder sleeve43projects into the blank part14, which is cup-shaped according to the example, so that the sleeve end face44lies against a bottom of the blank part44and presses the bottom against a clamping surface62with a blank holder force FN. The clamping surface62is in the shape of a ring around the entrance opening16aof the ironing channel16on the die tool15. Alternatively to the sample embodiment shown, it is also possible for a plate-shaped blank part to be pressed, by the blank holder sleeve43, against the clamping surface62with the blank holder force FN.

InFIG. 1andFIGS. 7 and 8it can also be seen that in addition to the head part guiding arrangement50there is also a drive guide arrangement63, which is set up to guide the drive element25or the drive rods26in stroke direction H. Every drive element25is translationally guided by the drive guide arrangement63at least at one back guide location64. According to the example, the drive guide arrangement63has a main guide body65which is arranged on the machine base39and has a plain bearing or rolling bearing sleeve for a drive rod26or a drive element25at each back guide location64. At the back guide location64, a drive rod26completely passes through the main guide body65. The main guide body65is arranged between the coupling location29and the head part23. The back guide locations64are arranged with a spacing from the head part23in the stroke direction H. In the transverse direction Q, the back guide locations64in the main guide body65have a second transverse spacing d2, which is smaller than the first transverse spacing d1between the two front guide locations51of the head part guiding arrangement50.

The drawing punch12can be borne at the main guide body65also, such that it is movably guided in the stroke direction H. For this purpose, the main guide body65in the sample embodiment has a drawing punch guide sleeve66arranged on it, which extends away from the main guide body65in the stroke direction H on the side opposite the head part23.

In the sample embodiment illustrated inFIG. 7, the drive elements25or the drive rods26are only borne on one back guide location64each. In the sample embodiment illustrated inFIGS. 1 and 8, each drive element25is borne at two back guide locations64. For this purpose, it is possible to arrange, on the machine base39, an additional guide body67for each of them with a plain bearing or rolling bearing sleeve, the associated drive element25extending through the additional guide body67, which is borne there at another back guide location64so that it is movable in the stroke direction H. The coupling location29is preferably arranged between the two back guide locations64of a drive element25.

As has already been explained, in the sample embodiment described here there are two drive elements25or two drive rods26, which are fastened to the head part23. InFIGS. 6 through 8it can be seen that the two drive elements25can be connected together through a connection unit70at their respective coupling location29. The connection unit70creates a solid connection between the two drive elements25. This can ensure that the driving force is uniformly introduced onto the head part23through the two drive elements25and additionally reduces the danger of tilting or gouging. The connection unit70can be closed, for example, in the shape of a ring around the main axis A. In the area of the main axis A, the connection unit70has a passage71for the drawing punch12or the drawing punch guide sleeve66(FIGS. 7 and 8). According to the example, the passage71is in the form of a central guide for the drawing punch12.

As an alternative to the sample embodiments inFIGS. 6 and 7, the connection unit70can also have a different shape, for example it can be closed in the shape of a semi-ring (FIG. 8). This eliminates the passage and a resulting central guide.

The drawing device10works as follows:

First, a blank part14, which is cup-shaped according to the example, is positioned on the clamping surface62of the die tool15so that the open side facing away from the bottom is facing the drawing punch12and the blank holder sleeve43. The blank holder drive device24moves the head part23, and with it the blank holder sleeve43, out of its initial position I into the blank holder position II in which the sleeve end face44presses on the edge of the bottom directly adjacent to the wall inside the blank part14and presses this bottom edge against the clamping surface62with a clamping force F. In the blank holder position II, the blank holder force FN can be controlled, e.g., through a bellows cylinder of the blank holder drive device24and a gas or air pressure prevailing in the bellows cylinder.

Simultaneously with or following the movement of the blank holder sleeve43into the blank holder position II, the front end13of the drawing punch12is moved against and, according to the example, into the cup-shaped blank part14, and lies against the bottom of the blank part14. As soon as the blank holder sleeve43has reached its blank holder position II and exerts the required blank holder force FN, the drawing punch12, driven by means of the drawing punch drive11, moves or draws the blank part14into the ironing channel16and moves it through the ironing dies17. During this ironing, the blank part14is shaped into a hollow cylindrical body that has a specified wall thickness. The inside diameter of the hollow cylindrical body that is shaped corresponds to the outside diameter of the drawing punch12following its front end13.

Once the drawing punch12has moved the shaped hollow cylindrical body completely through the ironing channel16, this drawing punch12is moved, by means of the drawing punch drive11, back through the ironing channel16in the stroke direction H. While this is happening, the hollow cylindrical body that has been shaped is stripped off the drawing punch12by means of the stripper18. The drawing punch drive11moves the drawing punch12back into its initial position.

The blank holder drive device24moves the blank holder sleeve43back into its initial position I after the blank part14has been pulled completely into the ironing channel16in the first phase of the shaping and is no longer acted upon by the blank holder sleeve43.

When the blank holder sleeve43assumes its initial position I and the drawing punch12also assumes its initial position after the shaping, a new blank part14can be loaded.

In order to achieve the required tolerance of the wall thickness of the hollow cylindrical body that has been shaped, it is necessary that the blank holder sleeve43exert a very uniform blank holder force FN along its entire periphery. Therefore, very exact alignment of the blank holder sleeve43coaxial with the main axis A or positioning of the sleeve end face44at right angles to the main axis A is required.FIGS. 4 and 5schematically illustrate that the coupling arrangement30can exert a driving force FA on the drive pin35or the drive elements25at an angle to the main axis A, this driving force FA having a driving force component FP parallel to the main axis A and a driving force component FR at right angles to the main axis A. This introduction of the driving force FA at an angle to the main axis A presents the danger that the drive elements25and the head part23incline or tilt the blank holder sleeve43relative to the main axis A, so that the blank holder sleeve43is not exactly coaxially positioned about the main axis A and the sleeve end face44is not aligned exactly at a right angle to the main axis A. According to the invention, the alignment of the blank holder sleeve43is clearly improved by the head part guiding arrangement50. The head part23is directly borne at multiple front guide locations51by the head part guiding units52so that it is movably guided in the stroke direction H, while the head part23is braced by the head part guiding arrangement50against movements in all other degrees of freedom. This also makes it possible to tolerate a driving force FA on the drive elements25that is introduced in a direction not parallel to the main axis A or not in the stroke direction H. The danger of misalignment of the blank holder sleeve43is reduced or avoided. The result is a blank holder force FN that is uniform in the peripheral direction about the main axis A, which in turn leads to a very uniform wall thickness of the hollow cylindrical body that is shaped, and prevents rejects in production, or reduces their number.

In the sample embodiments illustrated here, the stroke direction H or the main axis A are horizontally oriented. Alternatively, the stroke direction H can also be oriented in the vertical direction or at an angle to the vertical and horizontal directions.

As is very schematically illustrated inFIG. 1by the dashed line, the drawing punch drive11and the blank holder drive device24can be electronically and/or mechanically coupled with one another. It is also possible for only a single motor to be present, whose rotation is used both to move the drawing punch12and also to move the blank holder sleeve43or the head part23.

The invention relates to a blank holder device22for a drawing device10, for example a drawing press. The blank holder device22has a blank holder sleeve43, which, when in a blank holder position II, exerts a blank holder force FN on a blank part14. The blank holder sleeve43is fastened to a head part23and is stationary relative to it. To move the blank holder sleeve43in a stroke direction H, the head part23is directly borne, through a head part guiding arrangement50, at least at two front guide locations51, so that it can undergo translational motion in stroke direction H, and it is braced so that it is essentially stationary in all directions at right angles to the stroke direction H. Every front guide location51is preferably formed by a head part guiding unit52with a guide element53extending in the stroke direction H. The head part52is guided directly along the guide elements53. On the side opposite the blank holder sleeve43, the head part23is connected with at least the one drive element25that belongs to the blank holder drive device24and that can, together with the head part23, be moved by means of a motor31and a coupling arrangement30in the stroke direction H.

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