INTERNAL CLAMPING MEANS FOR CLAMPING A PLURALITY OF WORKPIECES

Abstract

An internal clamping arrangement having a base with a clamping mandrel that extends in a main extent direction and has a guide face and at least two clamping sleeves. The clamping sleeves are displaceable in the main extent direction and are pushed onto the guide face of the clamping mandrel from the direction of a distal end of the clamping mandrel. The clamping sleeves have a clamping portion which can be expanded by displacement, and the outside of which has a clamping face for a respective one of the workpieces. The internal clamping arrangement has at least three piston chambers which act between the base and the at least two clamping sleeves and between the clamping sleeves.

Claims

1. An internal clamping means for clamping a plurality of workpieces, with the following features: a. the internal clamping means has a base with a clamping mandrel which is oriented in a main extent direction and has a guide face, and b. the internal clamping means has at least two clamping sleeves that are displaceable in the main extent direction and have a clamping portion which is expandable by means of displacement, and the outside of which has a clamping face for a respective one of the workpieces, and c. the at least two clamping sleeves are pushed onto the guide face of the clamping mandrel from the direction of a distal end of the clamping mandrel, and d. the internal clamping means has at least three piston chambers which act between the base and the at least two clamping sleeves and between the clamping sleeves.

2. The internal clamping means according to claim 1, with the following further features: a. the internal clamping means has at least three clamping sleeves which are displaceable in the main extent direction, and b. the internal clamping means has at least four piston chambers which act between the base and the at least two clamping sleeves and between the clamping sleeves.

3. The internal clamping means according to claim 1, with the following further features: a. the piston chambers are formed in portions by the clamping sleeves themselves.

4. The internal clamping means according to claim 3, with at least one of the following further features: a. at least one piston chamber is peripherally delimited by the guide face of the clamping mandrel and by the two clamping sleeves, and/or b. the first and/or the last piston chamber is peripherally delimited by the base and by the proximally first or proximally last clamping sleeve respectively.

5. The internal clamping means according to claim 3, with the following further feature: a. fluid channels are provided which penetrate the clamping mandrel and open into the piston chambers through bores in the guide face.

6. The internal clamping means according to claim 1, with the following further features: a. the clamping sleeves have a conical pressure face on an inside of the clamping portion, and b. outer cone faces are provided for radial pressurisation of the pressure face.

7. The internal clamping means according to claim 6, with the following further feature: a. an outer cone face which is provided stationary with respect to the base, and outer cone faces are provided on the clamping sleeves.

8. The internal clamping means according to claim 1, with the following further feature: a. the clamping sleeves each have a sliding portion with an inner side which is guided slidingly on the guide face of the clamping mandrel.

9. The internal clamping means according to claim 1, with the following further feature: a. the clamping sleeves are each formed in one piece.

10. The internal clamping means according to claim 1, with the following further feature: a. the clamping sleeves are formed identically.

11. The internal clamping means according to claim 1, with at least one of the following further features: a. the guide face is formed cylindrically, and/or b. a stop cap is provided at the distal end of the clamping mandrel, and/or c. a spacer sleeve is pushed onto the clamping mandrel and forms a stop for a proximally first clamping sleeve or for a workpiece.

12. A method for clamping a plurality of workpieces with an internal clamping means according to claim 1, including the following steps: a. the clamping sleeves are brought by the pressure in the piston chambers into a relative position relative to one another in which the clamping portions are not tensioned or are only slightly tensioned, and b. by lowering the fluid pressure in a first piston chamber or by raising the fluid pressure in a further and/or last piston chamber, the clamping portion of the proximally first clamping sleeve is tensioned and thereby the first workpiece clamped, and c. by subsequently lowering the fluid pressure in the second piston chamber or raising the fluid pressure in a further or the last piston chamber, the clamping portion of the proximally second clamping sleeve is tensioned and thereby the second workpiece clamped.

13. A method for unclamping a plurality of workpieces with an internal clamping means according to claim 1, including the following steps: a. with the pressure in the piston chambers, the clamping sleeves are successively displaced such that the tension in their clamping portions is reduced.

14. The internal clamping means according to claim 3, wherein the piston chambers are formed as annular chambers.

15. The internal clamping means according to claim 8, wherein on the inner side, a recess for fluid guidance is provided which is communicatively connected to a piston chamber adjoining the sliding portion in the distal direction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Further advantages and aspects of the invention arise from the claims and the following description of a preferred exemplary embodiment of the invention, which is explained below with reference to the figures.

[0033] FIGS. 1 and 2 show an internal clamping means according to the invention in the installed and partly disassembled states.

[0034] FIG. 3 shows the clamping means from FIGS. 1 and 2 in sectional depiction.

[0035] FIG. 4 shows a clamping sleeve of the internal clamping means in enlarged sectional depiction.

[0036] FIGS. 5 and 6 show the internal clamping means with indicated piston chambers, and a flow diagram for pressurisation of these piston chambers during clamping and unclamping.

[0037] FIGS. 7A to 7D show the clamping means in various stages of clamping.

[0038] FIGS. 8A to 8E show the clamping means in various stages of unclamping.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0039] FIGS. 1 and 2 show an internal clamping means 100 according to the invention, wherein FIG. 1 shows this in the installed state and FIG. 2 in the partially disassembled state. The internal clamping means has a base 10 which, by definition, comprises all the parts which remain stationary relative to one another in operation during clamping and unclamping. The base 10 here has an attachment flange 12, from which a clamping mandrel 14 extends. The attachment flange 12 marks the proximal end of the base. The distal end of the base at the distal end of the clamping mandrel 14 is formed by a stop cap 22 which is attached at the end by means of a screw 24. Starting from the attachment flange 12 and in the distal direction, there follows a spacer sleeve 20 which is pushed onto the clamping mandrel. On the distal side of the spacer sleeve 20, the clamping mandrel 14 has an outer cone face 16. The largest part portion of the clamping mandrel 14 is formed by a cylindrical guide face 14A, which is penetrated by fluid channels 90, 91, 92, 93 in a manner to be explained below.

[0040] Three clamping sleeves 60 are provided displaceably on the guide face 14A, and each has a sliding portion 66 for sliding displaceability on the guide sleeve 14A, a cone portion with an outer cone face 64, and proximally adjacent thereto a clamping portion 62.

[0041] The first clamping sleeves 60 are pushed onto the clamping mandrel 14 in the manner illustrated in FIG. 1, such that the clamping portion 62 of the proximally first clamping sleeve 60 is arranged on the outside of the base-side outer cone face 16. The second and third clamping sleeves 60 are pushed successively onto the clamping mandrel 14 and the guide face 14A in the direction of the distal end, such that their clamping portions 62 are each arranged on the outside of the outer cone face 64 of the respective next clamping sleeve 60 in the direction of the attachment flange 12.

[0042] As evident from the sectional depiction in FIG. 3, the clamping means 100 is provided for receiving three workpieces 110. These workpieces 110 and the clamping sleeves 60, and in particular their clamping faces 62A, are matched to one another such that a clamping face 62A is provided for each workpiece 110. The workpieces are gearwheels which, merely for reasons of simplification, are depicted without toothing. The gearwheels are machined jointly by material removal after clamping.

[0043] FIG. 4 shows one of the clamping sleeves 60 in detail. The clamping sleeve has three part portions. The left portion in the figure is a clamping portion 62 with the outside clamping face 62A and with an inside pressure face 62B, by means of which the clamping face 62A is pressed outward for the purpose of clamping. The clamping portion 62 is sufficiently deformable thanks to cutouts 62C. A centre portion of the clamping sleeve 60 is formed by an outer cone portion 64 which serves the purpose of force-loading of the pressure face 62B of the adjacent clamping sleeve 60. On the right in FIG. 4, the sliding portion 66 is shown which has an inner sliding face 66B, in which a depression 66C is provided in order to be able to pressurise and pressure-relieve the adjacent piston chamber.

[0044] FIG. 5 shows the arrangement of four piston chambers 80, 81, 82, 83 which are configured as an annular chambers and are delimited by the base 10 and the clamping sleeves 60. In the present design with three clamping sleeves 60, four such piston chambers are provided which can be pressurised and pressure-relieved individually via fluid channels 90, 91, 92, 93 (not specified in detail). The proximally first piston chamber 83 is delimited on the inside and in the direction of the proximal end of the internal clamping means by the clamping mandrel 14. On the radial outside and in the direction of the distal end of the inner clamping means, the piston chamber 83 is delimited by the proximally first clamping sleeve 60. The distal piston chamber 80 is also delimited on the inside by the clamping mandrel 14 and its guide face 14A. On the radial outside and in the direction of the distal end, it is delimited by an inside of the stop cap 22. In the proximal direction, the last piston chamber 80 is delimited by the distal last clamping sleeve 60.

[0045] The middle two piston chambers 81, 82 are delimited on the inside by the guide face 14A of the clamping mandrel 14 and otherwise by a respective two of the clamping sleeves 60.

[0046] By pressurisation or pressure-relief of the piston chambers 80, 81, 82, 83, the clamping sleeve 60 can be force-loaded in the proximal direction, i.e. to the left in relation to FIG. 5, or in the distal direction, i.e. to the right in relation to FIG. 5.

[0047] The processes of clamping and unclamping are illustrated with reference to FIG. 6 and the associated FIGS. 7A to 7D and 8A to 8E. In FIG. 6, the various stages of clamping and unclamping are indicated by dotted lines, and their reference signs correspond to the figure numbering of the associated figure.

[0048] FIG. 7A shows the state of the clamping means at time T0. At this time, the piston chambers 81, 82, 83 are pressurised by air pressure or fluid pressure, while the distal piston chamber 80 is not yet pressurised.

[0049] Starting from here, as illustrated in FIG. 6, at time t1 the distal piston chamber 80 is also pressurised, so that from time t2 it is pressurised like the other piston chambers 81, 82, 83. This in itself does not yet lead to a shift of the clamping sleeves 60 or to clamping, since no positive pressure effective in the direction of the proximal end yet exists in any of the piston chambers.

[0050] Only when pressurisation ceases in piston chamber 83 at time t2 does the pressure in the distal piston chamber 80 push all three clamping sleeves 60 in the direction of the proximal end, as illustrated in FIG. 7B. At the proximally first clamping sleeve 60, this leads to the clamping portion 62 being pressed outward via its internal pressure face 62B by the outer cone 16, and hence to the desired clamping state being achieved on the left workpiece 110. This first workpiece 110 is now clamped.

[0051] Then at times t4 and t5, the pressurisation of the piston chambers 82 and 81 ceases so that successively the second and third clamping sleeves 60 are moved relative to the respective clamping sleeve 60 arranged on their left, and thus pressed outward by the outer cone faces 64 provided on the clamping sleeves positioned on the left. When the state of FIG. 7D is reached, all workpieces 10 are clamped so that the proposed material-removal machining can take place. After machining, the workpieces are unclamped again.

[0052] FIG. 8A firstly shows the still clamped state. With reference to the flow diagram in FIG. 6, it is evident that now firstly the pressurisation of the first piston chamber 80 ceases, wherein—as shown in FIG. 8B—initially this does not yet lead to a movement of the clamping sleeves or to complete elimination of the clamping state, since now all piston chambers 80, 81, 82, 83 are switched pressureless.

[0053] Only when the pressure chamber 81 is repressurised at the transition to time t9 does the actual unclamping begin. The pressurisation of the piston chamber 81 moves the proximally last clamping sleeve 60 in the direction of the distal end, i.e. to the right. This releases the clamping state in the clamping portion 62 of this clamping sleeve. Then, as evident in FIG. 6, at the transition from time t10 to t11, the pressurisation of the piston chamber 81 ceases again, but because of the fact that now all piston chambers 80, 81, 82, 83 are pressureless again, this does not lead to a displacement of the clamping sleeves 60.

[0054] Only when the further pressure chambers 82 and 83 are briefly pressurised successively at times t12 and t15, in accordance with FIGS. 8D and 8E, are the two further clamping sleeves 60 successively displaced in the direction of the distal end, so that the clamping state is also released for the other two workpieces.

[0055] When the state of FIG. 8E has been reached, all workpieces can be jointly removed from the clamping means.