OSCILLATING MACHINE DRIVE

Description

[0001] The invention relates to an oscillating machine drive, for example for printing, punching or embossing machines.

[0002] WO 2006 / 098253 A1 discloses a press machine comprising: an eccentric shaft; an eccentric, annular part which is slidably movable with respect to an outer circumference of the eccentric shaft and is designed such that an outer circumference is eccentric with respect to an inner circumference; a sliding piece which is provided on the outer circumference of the eccentric, annular part; and a sliding piece adjusting device which is designed to adjust the height position of the sliding piece with respect to the eccentric, annular part.

[0003] US 5,666,838 A discloses a hot forging press for use in closed-die hot forging operations, wherein the forging press can be operated in conjunction with an automated multi-station transport subsystem to move parts through a progressive multi-station forging die. The press includes a press bed and a vertically moving ram to support the lower and upper dies, respectively. A drive mechanism for driving the ram is equipped with an adjustment system that allows the press's closing height to be set during operation. A programmable logic controller (PLC) is provided to control the pressing operations, including setting the closing height, transporting the parts through the transport subsystem, and operating an ejection subsystem to remove the parts from the dies.In addition, the press has an extended tonnage zone, with the full tonnage zone completely encompassing several dies.

[0004] EP 2 243 571 A1 discloses a mechanical press with cam kinematics for moving the ram, wherein a height adjustment system for setting the tools is provided by means of a toothed eccentric ring mounted in the cam and rotated by a worm gear. The upper part of the ram is separate to facilitate the installation of components. The cam consists of two parts and is mechanically locked by springs that eliminate play with the toothed eccentric ring. The upper part of the cam is released by means of hydraulic cylinders during adjustment, allowing the worm gear to rotate freely in its seat. The worm gear is mounted in the upper part of the cam and driven by a geared motor; its position is controlled by an encoder.

[0005] Printing, stamping, or embossing machines of the type considered here comprise a first, movable platen and a second, stationary platen, as well as an oscillating machine drive that is operatively connected to the first platen. The invention is based on such a drive in which a first platen, movable – for example, against the restoring force of a spring or an arrangement of several springs – with a receiving surface on which the stamping or embossing tool is usually arranged in a stamping or embossing machine, is set into an oscillating motion by a rotatable eccentric, which, due to its eccentricity, acts on the first platen, so that the first platen is moved back and forth between a first reversal position (first dead center) and a second reversal position (second dead center).In the first inverted position, the receiving surface of the first crucible has a relatively large initial distance to a counter surface of a second crucible, which is usually fixed in place, i.e., stationary.

[0006] In this position, the printing, die-cutting or embossing machine is open, so that a sheet of substrate such as cardboard or the like can be inserted into or removed from the printing, die-cutting or embossing machine.

[0007] In the second inverted position, the receiving surface of the first crucible has a second, relatively small distance to the opposite surface of the second crucible, which can also be zero, so that the receiving surface of the first crucible is pressed onto the opposite surface of the second crucible.

[0008] In this position, the printing, die-cutting or embossing machine is closed, whereby a sheet of substrate such as cardboard or the like is processed inside, i.e. printed, die-cut or embossed.

[0009] To minimize friction between the eccentric and the first crucible, the eccentric can, for example, have a cylindrical eccentric body on whose outer surface a hollow cylindrical rolling element is arranged, which rolls back and forth on a rear side opposite the receiving surface of the first crucible (usually in a horizontal plane) during a full rotation of the eccentric body, while the first crucible is simultaneously moved into the (usually vertical) pendulum motion between the two reversal positions (dead centers) described above.

[0010] A disadvantage of this otherwise known type of oscillating machine drive is that fine-tuning or adjustment at the machine level is not possible. Fine-tuning or adjustment means modifying the drive so that the printing, die-cutting, or embossing tool acts uniformly across its entire dimensions in the plane of the first platen's mounting surface against the counter surface of the second platen, because only in this way can high-quality printing, die-cutting, or embossing results be achieved. Previously, this was achieved by using thin, flat inserts (e.g., made of paper or cardboard) or wedges (e.g., made of wood, plastic, or steel) to adjust the first platen relative to the second; a method that is laborious and time-consuming and leads to long downtimes each time the machine needs to be readjusted or fine-tuned, for example, when changing tools.for example, the printing plate, the die-cutting tool or the embossing tool is replaced.

[0011] The present invention therefore aims to provide an improved oscillating machine drive, for example for printing, punching or embossing machines, which makes it possible to fine-tune or adjust the machine with minimal effort and to minimize machine downtime.

[0012] Another task is to allow fine-tuning or adjustment of the machine during operation. Another task is to allow automated fine-tuning or adjustment of the machine. Another task is to allow fine-tuning or adjustment of the machine based on measured values ​​of the contact force between the first and second platens.

[0013] To solve these problems, it is first proposed to arrange an adjustable eccentric on the eccentric body, hereinafter referred to as the main eccentric. Such an adjustable eccentric can, for example, be constructed similarly to a hollow cylinder, i.e., it has an inner circular cylinder surface and an outer circular cylinder surface. However, unlike a true hollow cylinder, these surfaces are arranged eccentrically relative to each other with respect to their longitudinal axes. That is, the longitudinal axes of the inner and outer circular cylinder surfaces run parallel to each other, but with a distance between them that defines the eccentricity of the adjustable eccentric. This adjustable eccentric can be rotatably mounted, and thus adjustable, on the outer circular cylinder surface of the main eccentric, with its inner circular cylinder surface, for example, directly or by means of plain bearings or rolling bearings.

[0014] In the machine drive according to the invention, the main eccentric and the adjusting eccentric are elongated, i.e., they have a relatively greater longitudinal extent in the z-direction and act on the first crucible at at least two points simultaneously. For this purpose, for example, rolling elements can be arranged on the outer surface of the adjusting eccentric at two points.

[0015] It goes without saying that, even with the improvements to the eccentric drive proposed here for reducing friction between the eccentric and the first crucible, a rolling element can be arranged. This element rolls back and forth on the reverse side opposite the receiving surface of the first crucible during a full rotation of the eccentric body, while the first crucible is set into an oscillating motion between the two reversal positions. However, this rolling element now rolls on the outer circular cylindrical surface of the adjusting eccentric, and not, as before, on the main eccentric. Rolling elements in this sense can, for example, be hollow cylindrical, i.e., have a circular cylindrical surface. Alternatively, rolling elements in this sense can also have a curved contact surface only on a portion of their outer surface that rolls on the first crucible.Due to the large thickness of the outer ring and the associated high strength and wear resistance, so-called lifting mast rollers can be advantageously used as rolling elements. Since the rolling element is centric, for example hollow cylindrical, it does not affect the size of the working stroke or its position in space, and the adjustment stroke also remains unaffected.

[0016] For example, if the main eccentric has an eccentricity of 20 mm (i.e., the axis of rotation of the main eccentric runs parallel to the longitudinal axis of the circular cylinder's outer surface, 20 mm apart), this results in a working stroke of ± 20 mm for the machine, totaling 40 mm. The magnitude of this working stroke is not affected by the adjusting eccentric, but its position in space can be changed by adjusting the adjusting eccentric towards or away from the second crucible. For example, if the adjusting eccentric has an eccentricity of 5 mm (i.e., the longitudinal axes of the inner and outer circular cylinder surfaces of the adjusting eccentric run parallel to each other, 5 mm apart), this results in an adjusting stroke of ± 5 mm for the machine, totaling 10 mm.

[0017] The arrangement of the adjusting eccentric on the main eccentric is advantageously designed such that the adjusting eccentric cannot rotate relative to the main eccentric without explicit intervention from a machine operator or machine control system. To achieve a desired adjustment of the adjusting eccentric, an adjustment device can be provided, for example, which acts on the adjusting eccentric to rotate it relative to the main eccentric and then hold it in the selected position to set a specific desired adjustment stroke and subsequently maintain it constant.

[0018] In a simple case, such an adjustment device can, for example, comprise external teeth on the adjusting eccentric and a servo motor or comparable drive unit with a pinion that meshes with the external teeth of the adjusting eccentric, so that actuation of the servo motor causes the adjusting eccentric to rotate relative to the main eccentric. In this case, it may be necessary to use a braking or locking device, or similar means, to ensure that the adjusting eccentric does not rotate unintentionally relative to the main eccentric. An external toothing of the adjusting eccentric can be particularly advantageous in conjunction with a worm gear of a servo motor or comparable drive unit, because the self-locking effect of the worm gear ensures, without additional measures, that the adjusting eccentric cannot be unintentionally adjusted.

[0019] To prevent the adjusting eccentric from unintentionally rotating relative to the main eccentric, it is only necessary to ensure that the drive mechanism is moved along a circular path defined by the eccentricity of the main eccentric, without the drive mechanism itself being rotated about any axis parallel to the main eccentric's axis of rotation (z-axis). In other words, the drive mechanism moves along a circular path in the xy-plane without changing its spatial orientation with respect to the x-axis and y-axis (both perpendicular to the main eccentric's axis of rotation).

[0020] In certain embodiments of the machine drive according to the invention, the drive unit of the adjusting eccentric is therefore attached to an xy guide which is able to provide the two required boundary conditions: movement of the drive unit of the adjusting eccentric with the main eccentric in the xy plane and simultaneous assurance that the drive unit of the adjusting eccentric does not change its spatial orientation in space, i.e., does not undergo any rotation about the z-axis.

[0021] The xy guide can, for example, include two linear guides, one of which allows a displacement in the x-direction and the other linear guide allows a displacement in the y-direction.

[0022] Alternatively, the xy guidance can be realized by a further eccentric drive, in which the simultaneous movement, i.e. the movement of the drive unit of the adjusting eccentric, is realized, for example, by an eccentric shaft that is coupled to the main eccentric, so that the drive unit of the adjusting eccentric experiences the same movement in the xy plane as the adjusting eccentric itself, which is arranged on the main eccentric.

[0023] To counteract undesirable deflection of both the elongated main eccentric and the similarly elongated adjusting eccentric, a support bearing can be arranged between each pair of adjacent rolling elements, in which the adjusting eccentric is supported with its outer surface. Since the adjusting eccentric, as described above, performs a circular movement in the xy-plane together with the main eccentric, its support in a stationary bearing is not readily feasible.

[0024] To achieve this, a section of the surface in the central area of ​​the adjusting eccentric is designed as a centric circular cylinder. A compensating eccentric is positioned in this central surface area and mounted so that it can rotate relative to the adjusting eccentric. This compensating eccentric has the same eccentricity as the main eccentric. Its eccentricity is positioned so that it is rotated 180° relative to that of the main eccentric. This allows the central area of ​​the machine drive to be mounted in a static bearing.

[0025] When the machine drive is in motion, the compensating eccentric is moved along with it in such a way that the eccentricities of the main eccentric and the compensating eccentric are always exactly opposite each other. To prevent jamming between the bearing and the compensating eccentric or between the compensating eccentric and the adjusting eccentric, the compensating eccentric can be connected to the main drive of the machine drive via a linkage gear, so that the main eccentric and the compensating eccentric always move in exactly the same direction.

[0026] In the variant of the machine drive with an elongated main eccentric and an elongated adjusting eccentric that can act on the first crucible at two or more points, it is possible, despite the central support with the help of the compensating eccentric, to adjust the machine drive by adjusting the adjusting eccentric, thanks to the described configuration in which the adjusting eccentric is rotatably mounted relative to the main eccentric and relative to the compensating eccentric.

[0027] The invention is explained in more detail below with reference to an exemplary embodiment and the accompanying drawings. These drawings show... Figs. 1 to 4 an example of a known machine drive with a main eccentric and a relative adjustable eccentric, and Figs. 5 to 10 an embodiment of the machine drive according to the invention.

[0028] In the figures, the y-axis is the vertical axis and the z-axis corresponds to the longitudinal axis of the principal eccentric HE.

[0029] In the Figs. 1 to 4 The image shows a machine drive in various views, where all installed parts are very short and therefore space-saving.

[0030] Fig. 1 shows an isometric overall view Fig. 2 a section in the yz-plane, Fig. 3 a section in the xy-plane and Fig. 4 a section in the xz-plane.

[0031] The machine drive has a point of contact with a first crucible (not shown here), which is represented by the underside of the rolling body RK.

[0032] The machine drive, specifically the main eccentric HE, is mounted in two frame-fixed bearings GL, the machine frame of which is not shown for clarity. An adjustable eccentric VE is rotatably mounted on the main eccentric HE, which in turn is rotatably mounted in the auxiliary frame HG. This auxiliary frame supports the drive unit SM of a worm gear, with the worm SN engaging the worm wheel SR, which is located on the adjustable eccentric VE. The auxiliary frame HG with the drive unit SM is set into a defined xy-axis movement by an eccentric shaft EW, which is coupled to the main eccentric HE by a toothed belt (not shown).

[0033] In the Figs. 5 to 10Figure 1 shows an embodiment of the machine drive according to the invention in various views, in which the main eccentric HE and the adjusting eccentric VE are elongated and have two points of action on a first crucible, shown here only schematically as a plate, which are represented by the undersides of the two rolling bodies RK.

[0034] Fig. 5 shows an isometric overall view Fig. 6 a top view Figs. 7 and 8 a section in the yz-plane at the upper and lower dead center positions of the main eccentric HE, and Figs. 9 and 10 Further explanations regarding individual components of the machine drive.

[0035] Between the two rolling elements RK is another frame-mounted bearing GL. The outer surface of the adjusting eccentric VE is also centered in the area of ​​this frame-mounted bearing GL. In this area, a compensating eccentric AE is arranged on the adjusting eccentric VE, which has the same eccentricity as the main eccentric HE. This compensating eccentric AE is moved synchronously with the main eccentric HE by the coupling gear KG, which is coupled to the main drive HA of the machine drive and engages in an external toothing of the compensating eccentric AE.

[0036] Adjustment is achieved by rotating the adjusting eccentric VE relative to the main eccentric HE. This rotation of the adjusting eccentric VE is effected by an adjusting device SE, of which only a spur gear is shown in the figures. This gear engages with an external toothing of the adjusting eccentric VE and can be locked in place. The adjusting device SE moves with the main eccentric HE in the xy-plane, a movement facilitated by two linear guides: an x-guide XF and a y-guide YF. Reference symbol list

[0037] HE Main eccentric VE Adjusting eccentric AE Compensating eccentric RK Roller body GL Frame fixed bearings HG Auxiliary frame SM Drive unit SN Worm SR Worm wheel EW Eccentric shaft HA Main drive XFx guide YFy guide KG Coupling gear SE Adjusting unit

Claims

1. Oscillating machine drive for a printing, punching or embossing machine, in which a movably mounted first platen is set in an oscillating movement by an eccentric, such that the first platen is reciprocated between a first reversal position (first dead centre), in which its receptacle surface has a first, greater spacing from a mating surface of a second platen, and a second reversal position (second dead centre), in which its receptacle surface has a second, smaller spacing from the mating surface of the second platen or is pressed onto the mating surface of the second platen, wherein an adjustment eccentric (VE) is disposed in an angularly adjustable manner on a main eccentric (HE), characterized in that the main eccentric (HE) and the adjustment eccentric (VE) have rolling elements (RK) at at least two points, the latter acting simultaneously on the first platen, wherein a support bearing (GL) in which the adjustment eccentric (VE) is mounted is disposed between in each case two adjacent rolling elements (RK).

2. Oscillating machine drive according to Claim 1, wherein the main eccentric (HE) has an outer circular-cylinder lateral surface and the adjustment eccentric (VE) has an inner circular-cylinder lateral surface and an outer circular-cylinder lateral surface, which in terms of their longitudinal axes are disposed so as to be eccentric relative to one another, wherein the inner circular-cylinder lateral surface of the adjustment eccentric (VE) is disposed in an angularly adjustable manner on the outer circular-cylinder lateral surface of the main eccentric (HE).

3. Oscillating machine drive according to Claim 1 or 2, wherein a rolling element (RK) is disposed on the outer circular-cylinder lateral surface of the adjustment eccentric (VE), said rolling element having a curved contact surface at least on a part of its outer surface that rolls on the first platen.

4. Oscillating machine drive according to one of Claims 1 to 3, wherein an adjustment device is operatively connected to the adjustment eccentric (VE) in order to rotate said adjustment eccentric relative to the main eccentric (HE) and then to hold said adjustment eccentric in the selected position in order to set a specific desired adjustment stroke and subsequently to keep the latter constant.

5. Oscillating machine drive according to Claim 4, wherein the adjustment device comprises an external toothing of the adjustment eccentric (VE) and a drive device (SM) with a pinion, the latter meshing with the external toothing of the adjustment eccentric (VE), and a braking or arresting device.

6. Oscillating machine drive according to Claim 4, wherein the adjustment device comprises an external toothing (SR) of the adjustment eccentric (VE) and a drive device (SM) with a worm (SN), the latter meshing with the external toothing (SR) of the adjustment eccentric (VE).

7. Oscillating machine drive according to one of Claims 1 to 6, wherein the drive device (SM) of the adjustment eccentric (VE) is attached to an x-y guide which permits simultaneous movement of the drive device (SM) with the main eccentric (HE) and prevents twisting of the drive device (SM) about the z-axis.

8. Oscillating machine drive according to Claim 7, wherein the x-y guide comprises a further eccentric drive, wherein the simultaneous movement of the drive device (SM) is implemented by an eccentric shaft (EW) which is coupled to the main eccentric (HE), such that the drive device (SM) of the adjustment eccentric (VE) is imparted the same movement in the x-y plane as the adjustment eccentric (VE) itself disposed on the main eccentric (HE).

9. Oscillating machine drive according to one of Claims 1 to 8, wherein, in the region of a support bearing (GL) disposed between two adjacent rolling elements (RK), a portion of the surface of the adjustment eccentric (VE) is embodied as a centric circular-cylinder lateral surface in which a compensation eccentric (AE), which has the same eccentricity as the main eccentric (HE), is disposed and mounted so as to be rotatable relative to the adjustment eccentric (VE).

10. Oscillating machine drive according to Claim 9, wherein the compensation eccentric (AE) is operatively connected to the main drive (HA) of the machine drive via a coupling transmission (KG).

11. Printing, punching or embossing machine, comprising a first, movably mounted platen and a second, fixedly disposed platen, and an oscillating machine drive according to one of the preceding claims, which is operatively connected to the first platen.