ADAPTER FOR A COLLET CHUCK, COMPRISING A MOUNTING

Abstract

The present invention relates to a device for heating adapters for mounting tools for use in machine tools, comprising a base part in which an adapter for inserting or removing the tool can be arranged such that the insertion direction of the tool extends towards the base part, and a heating part which is designed for heating the adapter arranged in the base part, the base part and the heating part being displaceable relative to one another in the insertion direction of the tool. In this case, the base part comprises a mounting device that is designed for retaining the adapter in a fixed manner on the base part during heating. The invention further relates to a system formed of a device of this kind and an adapter, and to a method for operating the device.

Claims

1. Device for heating adapters for mounting tools for use in machine tools, comprising a base part in which an adapter for inserting or removing the tool can be arranged such that the insertion direction of the tool extends towards the base part; and a heating part which is designed for heating the adapter arranged in the base part; the base part and the heating part being displaceable relative to one another in the insertion direction of the tool; and the device being characterised in that the base part comprises a mounting device that is designed for retaining the adapter in a fixed manner on the base part during heating.

2. Device according to claim 1, wherein the heating part comprises at least one induction coil that is designed to heat the adapter, arranged in the base part, by means of electromagnetic induction.

3. Device according to claim 1, wherein the mounting device is made of a material that is at least one of electrically conductive or magnetically weakly conductive.

4. Device according claim 1, wherein the mounting device is designed to enclose the adapter over the entire periphery thereof, in portions, when retaining said adapter.

5. Device according to claim 4, wherein the mounting device comprises one or more apertures in the portion thereof that encloses the entire periphery of the adapter, in which apertures magnetisable elements extend towards the retained adapter.

6. Device according claim 1, wherein the heating part furthermore comprises a stop portion that is designed to come into contact with the retained adapter at a specified relative position of the heating part with respect to the base part, during displacement of the heating part relative to the base part.

7. Device according to claim 6, wherein a positioning means is furthermore assigned to the base part, which means is designed to move relative to the mounting device when the heating part is displaced with respect to the base part, to be lockable with respect to the base part, and to form a stop for the heating part in the corresponding relative position with respect to the base part in the locked state.

8. Device according to claim 1, wherein the device further comprises a cooling part that is designed to cool the adapter arranged in the base part and to be displaceable with respect to the base part in the insertion direction of the tool.

9. System formed of a device according to claim 1 and an adapter for mounting tools for use in machine tools, which tool extends out of the adapter on one side when mounted.

10. System according to claim 9, wherein the adapter and the mounting device are provided with elements for interlocking interaction for retaining the adapter on the base part.

11. System according to claim 10, wherein the adapter and the mounting device have complementary dimensions in the region of the interlocking interaction.

12. System according to claim 9, wherein the adapter comprises a thin-walled portion that surrounds the tool.

13. System according to claim 9, comprising a plurality of adapters which comprise identical elements for interlocking interaction with the mounting device and differ in their outer dimensions.

14. System according to claim 9, further comprising a collet chuck for use in a machine tool, which chuck is designed to receive the adapter or one of the adapters.

15. System according to claim 14, wherein the collet chuck is furthermore designed to selectively receive at least one of the adapters or a collet.

16. Adapter for a system according claim 9, wherein the adapter has a cylindrical outer contour in portions, which contour is provided in the axial direction between a first and a second portion that each have a conical outer contour.

17. Adapter according to claim 16, wherein the outer contour that is cylindrical in portions has an outer diameter that is greater than that of the first portion having the conical outer contour and smaller than that of the second portion having the conical outer contour.

18. Adapter for a system according to claim 9, wherein the adapter comprises an external thread.

19. Adapter according claim 18, wherein the adapter comprises a multi-start external thread.

20. Adapter according to claim 18, wherein the external thread is formed in the first portion having the conical outer contour.

21. Adapter according to claim 20, wherein a contact surface is formed between the thread turns in the first portion having the conical outer contour, which contact surface is wider than half the groove width of one thread turn.

22. Adapter according to claim 16, wherein the adapter is free of axial slots.

23. Adapter according to claim 16, wherein the adapter comprises at least one groove that is open towards the tool.

24. Method for inserting a tool into an adapter, or for removing the tool from the adapter of a system according to claim 9, said method comprising the steps of: retaining the adapter in the mounting device; displacing the heating part with respect to the base part until the adapter is located in a heating region of the heating part; operating the heating part in order to heat and expand the adapter; inserting a tool into the adapter or removing the tool from the adapter; removing the adapter from the mounting device.

25. Base part for use in a device according to claim 1.

26. Device according to claim 1 wherein the mounting device is made of a non-conductive material.

27. System according to claim 9, wherein the adapter has the outer dimensions of a collet.

28. System according to claim 11, wherein the adapter and the mounting device are formed as a female and male taper, respectively.

29. System according to claim 14, wherein the chuck is formed such that, in the received state thereof, the thin-walled portion of the adapter protrudes beyond the collet chuck in the axial direction.

30. Adapter according to claim 23 wherein the adapter comprises at least one channel for guiding coolant.

31. Method according to claim 24, further comprising the step of cooling the adapter such that the adapter shrinks and firmly encloses the tool.

Description

[0036] Further features and advantages of the present invention will become clear from the following description of an embodiment, when considered together with the accompanying drawings, in which, in detail:

[0037] FIG. 1 is a schematic cross section of a device according to the invention;

[0038] FIG. 2 is an enlarged cross section of the base part of the device from FIG. 1;

[0039] FIG. 3a is a side view of a first design of an adapter according to the invention;

[0040] FIGS. 3b and 3c are a side view and an oblique plan view of a second design of an adapter according to the invention;

[0041] FIG. 3d shows a third design of an adapter according to the invention; and

[0042] FIG. 4 shows a modified variant of the device from FIG. 1.

[0043] FIG. 1 is a schematic cross section of a device according to the invention for heating adapters for holding tools for use in machine tools, which device is denoted very generally by reference sign 10. The device 10 comprises two essential parts, specifically the heating part 20 shown at the top in FIG. 1 and the base part 30 shown at the bottom. FIG. 1 furthermore shows an adapter 100 that is retained on the base part and extends upwards from the base part 30 into the heating part 20.

[0044] The heating part 20 and the base part 30 can be displaced relative to one another, in particular in the direction specified by the extension of the adapter 100 in the axial direction thereof, described in more detail below, and in which a tool (not shown in the figures) can be inserted into the adapter. For this purpose, the heating part 20 can for example be displaceably fastened to a frame which is fixed relative to the base part 30.

[0045] For this purpose, the heating part 20 comprises a housing 22 in which a pair of induction coils 24 is arranged, which coils are supported in cavities in the housing 22. In the drawing in FIG. 1, the axes of said induction coils 24 also extend in the vertical direction, such that the axes of the induction coils 24 extend in parallel with the axis of the adapter 100. The induction coils are supplied with power by means of electrical supply lines (not shown) and are operated such that the alternating fields generated thereby induce currents in the adapter 100.

[0046] The heating part 20 further comprises a stop element 26, the upper face of which is in contact with the adapter 100 in the position shown in FIG. 1. In the case of vertical displacement of the heating part 20 downwards towards the base part 30, said stop element 26 ensures that said displacement ends at a suitable relative position of the heating part 20 with respect to the adapter 100 and thus to the base part 30. In this suitable position shown in FIG. 1, the induction coils 24 are positioned with respect to the adapter 100 such that, when operated by means of an alternating current, currents are likewise induced in the adapter 100 by means of electromagnetic interaction, which currents heat the adapter 100 on account of the ohmic resistance thereof. The resulting thermal expansion then expands the adapter 100 such that the provided tool can finally be inserted therein.

[0047] The stop element 26 shown is a component that could also be used together with the heating part 20 shown here when inductively heating larger components than the adapter 100, said stop element primarily being used in such cases in order to concentrate the magnetic field at the end face of the corresponding component. However, a concentration of this kind is not desirable when an adapter 100 is present, on account of the thin-walled design of said adapter, since magnetic field strengths that are too great could result in damage to the adapter 100. Accordingly, the stop element 26 is removed from the heating part 20 prior to operation of the induction coils 24, or is moved into a position inside the heating part 20 in which it can no longer have any effect on the adapter 100.

[0048] In order that it is not necessary to move the stop element 26 closer to the adapter 100 again when the heating part 20 is displaced again with respect to the base part 30 when using the same or a structurally identical adapter 100, the base part 30 comprises a positioning means 32.

[0049] Said positioning means 32 can be clearly seen in particular in the enlarged view of the base part 30 in FIG. 2. Said means comprises a telescopically extensible tube assembly 32a comprising a fixed outer tube and a displaceable inner tube which is preloaded upwards in the vertical direction by means of a spring 32b received in the outer tube.

[0050] When the heating part 20 is placed on the base part 30, a portion of the housing 22 of the heating part 20 comes into contact with the inner tube, such that the tube assembly 32a is compressed counter to the action of the spring 32b, it being possible, upon reaching a suitable relative position between the heating part 20 and the base part 30, for example the position shown in FIG. 1, for the positioning means to then be fixed in this position by means of a lever 32c. It is thus possible for the optimum position, identified using said contact element 26, to also be assumed again after the stop element 26 has been removed from the heating part 20, in that the heating part 20 is lowered relative to the base part 30 until the housing 22 of the heating part 20 again comes to rest on the positioning means 32.

[0051] The base part 30 furthermore comprises a pedestal 34 on which a mounting device 36 is arranged. Said mounting device 36 substantially consists of a frustoconical receiving portion 36a that comprises a planar base and is provided with suitable engagement elements, for example an internal thread or projections carrying out the same function, by means of which elements the external thread 102 (described later) of the adapter 100 can be screwed in. The mounting device 36 encloses the lower portion 104 of the adapter 100 over the entire periphery thereof and therefore acts as a shield against the magnetic field generated by the coils 24, with the result that heating of the portion of the adapter 100 received in the mounting device is initially inhibited. In order to compensate for said shielding effect, apertures 38 are provided in the mounting device 36, through which apertures ferrite elements 38a extend inwardly from the outside, towards the adapter 100. Said ferrite elements 38a conduct and concentrate the external magnetic field through the mounting device 36 as far as the adapter 100, such that the lower portion 104 of said adapter is also heated and expanded.

[0052] If the adapter 100 has been sufficiently heated and therefore expanded, a provided tool having suitable dimensions can then be inserted from above into the interior 101 (shown only here) of the tool 100, where said tool remains clamped after the adapter has been cooled again.

[0053] Furthermore, three embodiments of adapters will be described with reference to FIG. 3a to 3d, which adapters can undergo a shrinking process in the device 10 from FIG. 1. In this case, FIGS. 3a and 3b are side views of the first and the second embodiment, respectively, FIG. 3c is an oblique plan view of the second embodiment, and FIG. 3d is a cross section of the third embodiment.

[0054] Firstly, FIG. 3a again shows the adapter 100 from FIGS. 1 and 2. In this case, the adapter 100 has an axis A along which the mentioned tool can be inserted into said adapter and about which said adapter is substantially rotationally symmetrical.

[0055] Only at the face thereof shown at the bottom in FIGS. 1 and 2, i.e. on the face remote from the emergence of the tool, is said symmetry interrupted by the already mentioned external thread 102 being provided in the outer wall of the adapter 100. As explained above, the adapter 100 can be screwed into the mounting device 36 of the base part 30 by means of the external thread 102, the frustoconical shape of the corresponding lower portion 104 of the adapter 100 and the complementary shape of the receiving portion 36a, as well as the high pitch of the thread 102, making it possible to achieve highly precise positioning of the adapter 100 in the mounting device 36.

[0056] The adapter 100 furthermore has an outer shape that allows it to be used in conventional collet chucks; in particular, a large portion of the extension of said adapter is likewise frustoconical along the axis A thereof, such that said adapter can be screwed into a collet chuck by means of a union nut. The adapter 100 comprises a thin-walled extension portion 106 only at the upper face thereof facing the emergence of the tool, which portion closely surrounds the tool received in the adapter 100. As a result, the tool is more securely mounted in the adapter 100, both in the radial and in the axial direction, compared with conventional chucks and known adapters, thus further increasing the precision of the module formed of the adapter 100 and the tool (not shown). In a variant, however, the extension portion 106 may also be of such a length that the tool is mounted merely within the extension portion 106 and no longer protrudes into the frustoconical portion 104 of the adapter 100.

[0057] The variant 100 of an adapter shown in FIGS. 3b and 3c shows that it is, however, also possible to omit said portion 106 in adapters according to the invention, said variant not comprising a portion of this kind, the outer shape of the adapter 100 being otherwise identical to the adapter 100 from FIG. 3a. In particular, the frustoconical portion 104 has the same outer dimensions and the external thread 102 has the same pitch as in the case of the adapter 100 from FIG. 3a. Since said parameters are the same in differently shaped adapters 100 and 100, said adapters can each be screwed into the mounting device 36 of the device 10 from FIGS. 1 and 2 in the same manner and can undergo a shrinking process therein.

[0058] It should furthermore be noted that the two embodiments of an adapter 100 and 100 according to the invention have an outer contour 110 and 110, respectively, that is cylindrical in portions and that is provided in the axial direction between the frustoconical portion 104 and 104, respectively, and a further frustoconical portion 108 and 108, respectively. In this case, the outer diameter of the cylindrical outer contour 110 and 110, respectively is in each case greater than that of the frustoconical portion 104 and 104, respectively, and smaller than that of the further frustoconical portion 108 and 108, respectively.

[0059] A further difference between the embodiments 100 and 100 from FIGS. 3a, 3b and 3c is that the embodiment 100 comprises four grooves 112, spaced apart by 90 in each case, on the inner face thereof facing the tool, which grooves are open towards the tool and through which grooves coolant can thus be guided along the tool. Since said coolant is fed into a machine tool from the lower face in FIGS. 3b and 3c, i.e. the face of a mandrel, both the adapter 100 and in particular the tool can be cooled thereby, and coolant can be transported into the region in which an object is machined by the tool.

[0060] This supply of coolant can be understood in particular with reference to the third embodiment of an adapter 100 according to the invention, shown in FIG. 3d, in which, in addition to the at least one groove 112 already mentioned, a channel 116 is furthermore provided, which channel extends through the body of the adapter at an angle to the axis A. Otherwise, in particular with respect to the outer dimensions thereof, the third embodiment 110 corresponds to the second embodiment 110 and comprises, just like said second embodiment, to frustoconical portions 104 and 108 and a cylindrical portion 110 arranged therebetween. It should merely be noted that, for the sake of clarity, the first frustoconical portion 104 of the adapter 110 is shown without an external thread, although said thread may also be provided.

[0061] As already mentioned, coolant is fed into the part of the adapter 110 at the bottom in FIG. 3d through an access point 114, which coolant then flows through the first flow path 114a, to the groove 112, and in said groove along the tool, and also flows through the second flow path 114b and along the outer face of the cylindrical portion 110, in the channel 116, in order to finally also flow towards the tool radially from the outside. In this case, it should be reiterated that the adapter 100 is received in a chuck during operation, which chuck is located radially outside the cylindrical portion 110 and guides the coolant, together therewith, between the second flow path 114b and the channel 116.

[0062] Finally, FIG. 4 shows a modified variant of the device from FIG. 1, which variant differs from FIG. 1 both by the shaping of the positioning means thereof, which means is denoted here by reference sign 32, and by a length adjustment assembly 40 being provided for the tool that is to be inserted into the adapter. It should be noted that said length adjustment assembly 40 can in principle also be combined with the base part 30 from FIGS. 1 and 2, and that the heating part 20 and the mounting device 36 from FIGS. 1 and 2 are used in the variant in FIG. 4.

[0063] Therefore, for reasons of clarity, said heating part 20 and said mounting device 36, as well as further components that are also present in the same or a similar form in the device from FIG. 1, will not be described again, and reference is made to the corresponding passages above in which said components are described.

[0064] The positioning means 32 comprises an annular element 32a which extends around an upper region of the base part 30 and functions, in a manner similar to the tube assembly 32a of the positioning means 32 from FIGS. 1 and 2, as a height-adjustable support for the heating part 20. The annular element 32a can likewise be displaced with respect to the base part 30 towards the axis of the adapter 100 by means of the action of the heating part 20 that is moved towards the base part 30 or manually. In order to fix the annular element 32a in a position that corresponds to a position of the heating part 20 suitable for the adapter 100 currently retained in the base part 30, a bolt 32c is furthermore provided, which bolt can be inserted into a hole in the annular element 32a and engages, on the axial inner face of the annular element 32a, with one of a series of grooves 32d on the base part 30. Since the bolt 32c is wedged between the annular element 32a and the corresponding groove 32d, the annular element is fixed in the current spatial and angular position thereof and can function as a stop for the heating part 20.

[0065] Finally, the length adjustment assembly 40 for the tool that is to be inserted into the adapter will be explained. Said assembly comprises a hollow portion 42 which is at the bottom in the extension of the axis of the adapter 100 and extends as far as the lower opening of the adapter 100. A tube 44 is displaceably guided in the hollow portion, which tube comprises an actuation portion 44a at the lower end thereof for displacing the tube 44 in the hollow portion 42. Furthermore, a stop 44b is provided on the base part 30, which stop limits the displacement of the tube 44 in the hollow portion 42.

[0066] A rod 46 is furthermore retained at the upper end of the tube 44, which rod has a reduced diameter, in particular a diameter that is smaller than the inner diameter of the adapter 100 when shrunk or, in other words, smaller than the diameter of the tool that is received in the adapter 100. When the tube 44 is displaced upwards, after a particular point in time, the rod 46 will be located inside the adapter in part. Here, said rod consequently functions as a vertical stop for a tool that is to be inserted into the adapter 100 from above, the diameter of said rod being, as mentioned, sufficiently small that it can be removed again from the interior of the adapter 100 from below without problem, even after the tool has been shrunk into the adapter 100. Since the rod 46 is thus inserted into the adapter, from below, to a specified extent before the tool is inserted and shrunk in, the position of the tool, and thus the projection thereof upwards, out of the adapter 100, can be adjusted very precisely.