Clamping Device For A Tool On A Machine Tool

Abstract

The invention relates to a clamping device (10) for a tool (18) on a machine tool having a holder block (12) with at least 2, in particular a multiplicity of, apertures (16) for receiving clamping sleeves (14), wherein at least two clamping sleeves (14) are received in the apertures (16). Each clamping sleeve (12) has a clamping element (36), with which a tool (18), in particular a shaft (20) of a tool (18), can be clamped. The clamping sleeve (14) at least partially passes through in each case the aperture (16) in the holder block (12) and has, at its end opposite the clamping element (36), the rear end, an expansion element (34) which engages behind the holder block (12) or a counter-support element (30) of the holder block (12).

Claims

1. A clamping device for a tool on a machine tool comprising a holder block (12), having at least two apertures for receiving clamping sleeves, wherein the clamping sleeves comprise at least two clamping sleeves each of which are received in an aperture of the at least two apertures, wherein each of the at least two clamping sleeves (14) has a clamping element (36) with which a tool (18) can be clamped, and wherein each of the at least two clamping sleeves (14) at least partially passes through an aperture of the at least two apertures (16) in the holder block (12) and each of the at least two clamping sleeves, has, at an end opposite the clamping element (36), an expansion dement (34) which engages behind the holder block (12) or at a counter-support element (30) of the holder block (12).

2. The clamping device as claimed in claim 1, wherein the tool comprises a shaft (20) for clamping to the clamping element, and wherein the expansion dement engages in a spring-loaded manner.

3. The clamping device as claimed in claim 1, wherein a compression spring (26) extends between each of the at least two clamping sleeves (14) and the counter-support element (30) of an aperture of the at least two apertures (16) which is configured to urge an abutment shoulder (46) of the expansion element (34) against the counter-support element (30) of the holder block (12).

4. The clamping device as claimed in claim 1, wherein the expansion element (34) is movable radially inwards and wherein a non-tensioned state of the expansion element (34) has a larger diameter than an aperture of the at least two apertures (16).

5. The clamping device as claimed in claim 1, wherein the expansion element (34) of the clamping sleeve (14) is configured to be compressed when being inserted into an aperture of the at least two apertures (16) and/or into the counter-support element (30).

6. The clamping device as claimed in claim 1, wherein the expansion element (34) has abutment shoulders (46) on expansion tongues (38 to 44) which extend radially outwards on the counter-support element (30) or a rear end of an aperture of the at least two apertures (16).

7. The clamping device as claimed in claim 6, wherein each abutment shoulder (46) extends radially or optionally obliquely at an angle between 70 and 90° to an axis of the clamping sleeve (14).

8. The clamping device as claimed in claim 7, wherein the angle is between 80 and 88°.

9. The clamping device as claimed in claim 7, wherein the angle is about 85°.

10. The clamping device as claimed in claim 1, wherein the expansion element (34) has insertion slopes (56), of which the diameter at a beginning of the insertion slope (56) located at a rear end of the expansion element (34), is smaller than the diameter of an aperture of the at least two apertures (16) and of which the diameter at the end of the insertion slope (56) is larger than an inner diameter of the counter-support element (30).

11. The clamping device as claimed in claim 1, wherein the expansion element (34) has slots (50, 52) which extend between the expansion tongues (38 to 44), and wherein the expansion tongues (38 to 44) are arranged distributed around the periphery of the expansion element (34).

12. The clamping device as claimed in claim 1, the expansion tongues (38 to 44) comprise 2 to 8 expansion tongues.

13. The clamping device as claimed in claim 1, wherein the clamping sleeve (14) has a stop ring (29) which has an outer diameter which, when abutting against the holder block (12) and expanded expansion element (34), fixes a clamping sleeve of the at least two clamping sleeves (14) in the holder block (12).

14. The clamping device as claimed in claim 1, wherein the clamping element (36) is formed by radially inwardly acting clamping tongues (38 to 44), with which a tool (18) can be clamped.

15. The clamping device as claimed in claim 2, wherein, formed on one side of the clamping element (36) is a tangentially extending, radially inwardly pointing protrusion (48), by which pressure is exerted upon the shaft of the tool (18).

16. The clamping device as claimed in claim 1, wherein the holder block (12) is fabricated of metal and the at least two clamping sleeves (14) are fabricated of thermoplastic material.

17. The clamping device as claimed in claim 16, wherein thermoplastic material comprises fibre-reinforced PPA.

18. A machine tool comprising a clamping device for a tool on the machine tool, a holder block having at least two apertures for receiving clamping sleeves, wherein each of the clamping sleeves are received in an aperture of the at least two apertures, wherein each clamping sleeve (14) has a clamping element (36), with which a tool (8) or a shaft (20) of the tool (18), can be clamped, and wherein each clamping sleeve (14) passes through a counter-support element (30) of the holder block (12) or an aperture of the at least two apertures (16) in the holder block (12) and has, at an end opposite the clamping element (36), an expansion element (34) which engages behind a counter-support element (30) of the holder block (12).

19. A clamping sleeve for insertion into a holder block for a tool of a machine tool which holder block has at least two apertures, comprising a clamping element at a first end with which a tool (18) can be clamped, and an expansion element at a second end which engages behind the holder block or at a counter-support element of the holder block.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Further details, advantages and features of the invention are apparent from the following description of several exemplified embodiments with reference to the drawings.

[0055] In the drawings:

[0056] FIG. 1 shows a perspective view of a holder block in accordance with the invention, illustrating the clamping device in accordance with the invention and several tools;

[0057] FIG. 2 shows a further view of the holder block, fitted with clamping sleeves and tools;

[0058] FIG. 3 shows a further view of the embodiment shown in FIGS. 1 and 2;

[0059] FIG. 4 shows a perspective view of a clamping sleeve, a compression spring and a schematically illustrated tool;

[0060] FIG. 5 shows a perspective view of one embodiment of a clamping sleeve;

[0061] FIG. 6 shows another perspective view of one embodiment of the clamping sleeve; and

[0062] FIG. 7 shows a schematic sectional view of the clamping sleeve in the mounted state in the tool block.

DETAILED DESCRIPTION

[0063] FIG. 1 shows a clamping element 10, with which a holder block 12 is associated which receives a multiplicity of clamping sleeves 14 in a likewise provided multiplicity of apertures 16.

[0064] The clamping sleeves 14 shown in FIG. 1 are each fitted with tools 18.

[0065] As can be seen in FIG. 1, a multiplicity of clamping sleeves 14 are received in the holder block 12. An aperture 16 is provided for each clamping sleeve and the clamping sleeves 14 and the apertures 16 are similar to one another.

[0066] During operation, the clamping sleeves 14 can be fitted in any manner with tools 18. Of the tools 18 illustrated in FIG. 1 a respective shaft 20 can be seen, and of the separately illustrated tool 18a the working region 22 can also be seen. For the sake of simplicity, this is illustrated as a cylinder, wherein it is understood that in practice the working region 22 can be configured in the manner of a milling tool, a drill, a rotary grinding tool or in any other manner, and also in any shape and with any dimensions.

[0067] The machine tool has a tool arm which is provided with a chuck in a manner known per se. For the purpose of a tool change, the chuck can grip the shaft 20 of the desired tool 18 and withdraw it from the associated clamping sleeve 14.

[0068] If the tool 18 is no longer required, it can be introduced to the same location, i.e. into the then empty clamping sleeve 14, and the chuck can be released after the tool 18 has been put down at that location.

[0069] The holder block 12 is stored in a movable manner, together with the clamping sleeves 14 and tools 18 via a holding pin 24. Therefore, the tools 18 and the holder block 12 are subjected to corresponding accelerations, depending upon the movement of the holder block 12. Therefore, it is important that the tools 18 are mounted in a radially fixed manner in the clamping sleeves 14 which, in turn, are mounted in a fixed manner in the apertures 16.

[0070] For this purpose, a resilient bearing arrangement is provided which is shown only schematically in FIG. 1. However, a compression spring 26 can be seen in the exploded view illustrated on the right. It surrounds a specific region of the clamping sleeve 14 and permits axially resilient bearing of the clamping sleeve 14 in the holder block 12.

[0071] The tool 18 has a holding ring 28. On said holding ring, said tool is held in a clamped manner in the clamping sleeve 14. Moreover, the holding ring 28 separates the shaft 20 from the working region 22 of the tool 18.

[0072] FIGS. 2 and 3 show further perspective views of the holder block 12 with inserted clamping sleeves 14 and tools 18. The clamping sleeve 14 can be seen in a slightly larger view in FIG. 3. However, FIG. 4 and also FIGS. 5, 6 and 7 are even clearer in this respect. As in the other figures, like reference signs refer to like parts in this case.

[0073] The clamping sleeve 14 has a stop ring 29. It serves as a stop for the compression spring 26 on one of its sides and extends in the aperture 16. The compression spring 26 is supported on its other side on a counter-support element 30 illustrated in FIG. 7. It extends radially outside the clamping sleeve 14 at this location. At the rear end 30, the clamping sleeve 14 has an expansion element 34, and at the front end 32 has a clamping element 36.

[0074] In the illustrated exemplified embodiment, the expansion element 34 consists of four expansion tongues, of which the expansion tongues 38 and 40 can be seen in FIG. 4, and also the two further expansion tongues 42 and 44 can be seen in FIG. 5.

[0075] Each expansion tongue 38, 40, 42 and 44 or, as shown in FIG. 6, only 2 expansion tongues which lie opposite one another has an abutment shoulder 46. It is intended to lie against the counter-support element 30 of the aperture 16. For this purpose, the compression spring 26 is compressed by pushing the clamping sleeve 14 into the aperture 16 and in particular until the stop shoulder 46 snaps outwards on the counter-support element 30 and latches at that location. In this position, the clamping sleeve 14, as can be seen in FIG. 3, is held in an axially flexible manner in the aperture 16.

[0076] The axial elasticity is important when the tool 18 is being fitted because even if the tool arm with the tool 18 penetrates too deeply, this will not result in the destruction of the clamping sleeve 14. Therefore, in accordance with the invention it is possible to also use inexpensive PPA for the clamping sleeve 14.

[0077] The clamping element 36 is intended to hold the tool 18 on the holding ring 28. For this purpose, protrusions 48 which point radially inwards and hold the holding ring 28 by frictional engagement are provided on the end-side of the clamping element 36.

[0078] Incidentally, the diameter of the holding ring 28 is larger than that of the tool 18. Accordingly, the clamping element 36 is provided on the end-side internally with a slightly enlarged diameter, as can be seen in FIG. 6.

[0079] The expansion element 34 has, between the expansion tongues 38 to 44, slots 50 which can be seen in FIGS. 4 to 6.

[0080] Likewise, slots 52 are provided on the clamping element 36; all of the slots extend in an axially parallel manner with respect to the clamping sleeve 14, wherein preferably the slots 52 widen slightly towards the front end.

[0081] FIG. 7 shows the clamping element 10 in accordance with the invention in the mounted state. The compression spring 26 has been omitted from the illustration for the sake of clarity. The tool 18 extends with its working region 22 through the clamping sleeve 14 and in the illustrated exemplified embodiment even through the holder block 12 with the aperture 16. It is understood that the length of the working region 22 is different from tool to tool.

[0082] The clamping element 36 has a step 54 on the inside. It serves as an axial stop for the holding ring 28 in the clamping sleeve 14. The holding ring 28 has a radius on both sides; it can also be formed as a chamfer and serves to facilitate insertion of the holding ring 28 into the clamping element 36.

[0083] In a manner which is known per se, the expansion tongues 38 to 44 also have insertion slopes 56 which facilitate the insertion into the aperture 16 and in particular also into the region of the counter-holding element 30.