DEVICE FOR MACHINING A PLANAR WORKPIECE

Abstract

The invention relates to a device for machining a planar workpiece, having a machine stand which has a support surface (application surface) for a planar workpiece, and further having a machining head which can be moved relative to the support surface, which machining head has a tool for machining the workpiece and also has a holding unit (“hold-down unit”) with a pressure plate whereby the workpiece is pressed against the supporting surface; characterized in that the pressure plate has a structure which is comprised of a plurality of pieces, preferably two pieces, wherein at least one of the pressure plate parts is movable back and forth relative to at least one other pressure plate part, namely it is movable between the application position, in which the pressure plate part presses the workpiece against the application surface when the workpiece is applied to said application surface, and a released position, in which the pressure plate piece is at a minimum distance away from the workpiece when the workpiece is applied to said application surface.

Claims

1.-10. (canceled)

11. A device for machining a planar workpiece, having a machine stand which has a support surface (application surface) for a planar workpiece, and further having a machining head which can be moved relative to the application surface, which machining head has a tool for machining the workpiece and also has a holding unit (“hold-down unit”) with a pressure plate whereby the workpiece is pressed against the application surface, wherein the pressure plate has a structure which is comprised of a plurality of pieces, preferably two pieces, wherein at least one of the pressure plate parts is movable back and forth relative to at least one other pressure plate part, namely it is movable between the application position, in which the pressure plate part presses the workpiece against the application surface when the workpiece is applied to said application surface, and a released position, in which the pressure plate piece is at a minimum distance away from the workpiece when the workpiece is applied to said application surface; wherein the pressure plate is divided horizontally or vertically, wherein at least one of the pressure plate parts is movable back and forth, in a swinging movement, between the application position and the released position, by means of a displacing unit.

12. The device according to claim 11, wherein all of the pressure plate parts mutually independently are moved back and forth between an application position in which a given pressure plate part presses the workpiece against the application surface when the workpiece is applied to said application surface, and a released position, in which the pressure plate piece is at a minimum distance away from the workpiece when the workpiece is applied to said application surface.

13. The device according to claim 11, wherein the pressure plate has an application side by means of which the pressure plate can be applied to a planar workpiece, and the pressure plate has a workpiece passageway extending through the pressure plate perpendicularly to the application side, wherein the opening cross section of the workpiece passageway is divided between the pressure plate parts, wherewith in the case of a two-part realization it is preferably divided in the amount of one half for each pressure plate part, or extends completely over one of the pressure plate parts.

14. The device according to claim 13, wherein the pressure plate is divided in half, with the two pressure plate parts each having a partial application side which is the same size as the other, and wherein the workpiece passageway is formed from a first and a second recess in the edge regions of the two pressure plate parts.

15. The device according to claim 11, wherein a chip removal system (removal by suction) is formed on a side of the pressure plate which is opposite to the application side, which removal system is comprised of a suction chamber into which the workpiece passageway and a suction line open out.

16. The device according to claim 11, wherein the pressure plate has an application side (4) via which the pressure plate can be applied against a planar workpiece, wherein a bearing means to facilitate smooth movement is disposed on the application side, so that the machining head can be easily guided over the workpiece surface when the pressure plate is applied to the workpiece.

17. The device according to claim 16, wherein the bearing means to facilitate smooth movement has at least one spherical roller which has air flowing around it, so that foreign bodies on the workpiece in the region around the spherical roller(s), e.g. metal chips, will be kept appreciably away from the spherical roller(s).

Description

DRAWINGS

[0024] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0025] FIG. 1 illustrates an embodiment of the inventive holding unit, in a perspective rear view, with the pressure plate parts being aligned;

[0026] FIG. 2 is a perspective front view of the embodiment according to FIG. 1;

[0027] FIG. 3 is a perspective front view of the embodiment according to FIG. 1, wherein the upper pressure plate part is displaced with respect to the lower pressure plate part;

[0028] FIG. 4 is a lateral view of the embodiment according to FIG. 3;

[0029] FIG. 5 is a perspective front view of the embodiment according to FIG. 1, wherein the lower pressure plate part is displaced with respect to the upper pressure plate part;

[0030] FIG. 6 is a lateral view of the embodiment according to FIG. 5;

[0031] FIG. 7 illustrates the embodiment according to FIG. 1, wherein both pressure plate parts are disposed in an extended position; and

[0032] FIG. 8 is a lateral view of the embodiment according to FIG. 7.

[0033] Corresponding reference numerals indicate corresponding parts through the several views of the drawings.

DETAILED DESCRIPTION

[0034] Example embodiments will now be described more fully with reference to their accompanying drawings.

[0035] FIGS. 1 to 8 illustrate an embodiment of the inventive holding unit 1, with different positions of the pressure plate parts 2.2 and 2.2. The holding unit 1 is comprised essentially of a pressure plate 2 which is linearly displaceable by means of a displacing unit 3. The pressure plate 2 is divided horizontally into two essentially identical separate pressure plate parts 2.1 and 2.2. Both of the pressure plate parts 2.1 and 2.2 can be linearly displaced with respect to each other by the displacing unit 3. For this purpose, the displacing unit 3 has an upper pneumatic unit 3.1 which engages the upper pressure plate part 2.1 and a lower pneumatic unit 3.2 which engages the lower pressure plate part 2.2. The two pressure plate parts 2.1 and 2.2 are linearly displaceable with respect to each other and perpendicularly with respect to the support surface of the workpiece, with the aid of the pneumatic units 3.1 and 3.2.

[0036] The pressure plate has a tool passageway 5 through which a tool, e.g. a milling cutter, can be applied to the workpiece when the pressure plate 2 is in the application position (pressing position). The tool passageway 5 opens out into a suction chamber 7 on the side of the pressure plate 2 which is opposite to the application side 4. Further, a suction line 8 of a chip removal system opens out into the suction chamber 7. The upper pressure plate part 2.1 also has a minimal lubrication means 10 the outflow nozzle of which is coordinated with the tool passageway 5 on the application side 4.

[0037] Further, on the application side 4, spherical rollers 9 are disposed which are intended facilitate easy transport of the holding unit 1 over the workpiece. The spherical rollers 9 are in the form of spherical rolls with air flowing around them. For spherical rolls known from the prior art, the air flow serves to reduce the rolling resistance between the sphere and its bearing support, and thereby to facilitate transport of heavy loads. In the present embodiment, however, the air flow is employed to remove contaminants which may be present on the tool, e.g. chips, from the spherical rolls, in order to effectively prevent damage to the workpiece, e.g. by scratching.

[0038] FIG. 3 clearly shows the division into two parts, of the pressure plate 2 and the tool passageway 5. The pressure plate 2 has a horizontal division whereby the tool passageway 5 is also exactly divided into two. The tool passageway 5 is thus formed by two semicircular recesses 6.1 and 6.2 (FIG. 5) at opposite longitudinal edges of the pressure plate parts 2.1 and 2.2, which recesses form a closed tool passageway 5 when the pressure plate parts 2.1 and 2.2 are aligned, as shown in FIGS. 1, 2, 7, and 8. Further, comparison of the Figures will show that the suction chamber 7 is divided horizontally in a manner similar to the division of the pressure plate 2, whereby an upper and a lower chamber half are formed, with the upper chamber half being directly connected to the upper pressure plate part 2.1 and the lower chamber half being connected to the lower pressure plate part 2.2, so that when the pressure plate parts 2.1 and 2.2 are displaced with respect to each other the suction chamber parts are correspondingly displaced along with them.

[0039] The inventive features which are disclosed in the present Specification, the drawings, and the claims may be essential for realizing the disclosure when realized individually or in any combination.

[0040] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.