TOOL COUPLING DEVICE

Abstract: The present invention relates to a tool coupling device comprising a coupling element (10) attachable to a machine tool and a tool adapter (11) intended to clamp a tool for chip forming machining. A plug (18) on the adapter (11) is related to a contact surface (30; 38) that is intended to be in engagement with a correspodning contact surface (29; 37) related to the coupling element (10), said engagement clamping the adapter (11) against the coupling element (10).

Description: The present invention relates to a tool coupling device comprising a coupling element that can be attached directly or indirectly to a machine tool and a tool adapter intended to clamp a tool for metal cutting, said coupling element being provided with an axial boring that has at least one internal guiding surface, a plug provided on the adapter and designed to be guided into said boring, said plug being related to a contact surface running in transverse direction to the tool adapter and designed for engagement with a corresponding contact surface related to the coupling element for clamping the adapter against the coupling element, and that one of the contact surfaces is provided on clamping means being displaceable in a transverse direction to the adapter. A tool coupling device of the above type is described in SE-­ B-427 732. In this known tool coupling device the clamping means has a tendency to upset when clamping the tool adapter. Besides, the clamping means is relatively spacious which means that the tool coupling cannot be used at small dimensions of the coupling element. An aim of the present invention is to provide a tool coupling device comprising clamping means with an essentially reduced tendency to upset. This and other aims have been achieved by giving the invention the characterizing features of the appending claims. The invention is described more in detail with reference to the enclosed drawings exemplifying two different embodiments. It is to be understood that these embodiments only are intended to illustrate the invention and that the invention can be varied within the scope of the appending claims. On the drawings Fig. 1 discloses a longitudinal section through an embodiment of a tool coupling device according to the invention. Fig. 2 discloses a section along the line II-II in Fig. 1. Fig. 3 discloses a longitudinal section through another embodiment of the tool coupling device according to the invention. Fig. 4 discloses a section along the line IV-IV in Fig. 3. The embodiment disclosed in Figs. 1 and 2 comprises a coupling element 10 and a tool adapter 11. The coupling element 10 is designed for connection with a base holder 12 of the type disclosed in SE-B-423 875. The coupling element 10 is thus provided with a centering plug 13 that is designed to be guided into a boring of the base holder 12. The coupling element 10 is locked against rotation by a wedge 14 that is attached to the coupling element 10. Said coupling element 10 is connected to the base holder 12 by a clamping bolt arranged in the base holder 12, said connection being carried out in a manner described in SE-B-423 875. The coupling element 10 is at the end that is directed from the base holder 12 provided with an axial boring 15, that has cylindrical guide surfaces 16, 17. The front surface 17, i e the surface located closest to the tool, has a somewhat smaller diameter than the rear guide surface 16. The adapter 11 is provided with a plug 18 that is provided with guide surfaces 19, 20 corresponding to the guide surfaces 16, 17 in order to achieve slip fit between the plug 18 and the boring 15. The adapter 11 is provided with a wedge corresponding to the wedge 14 in order to lock the adapter against rotation relative to the coupling element 10. In the plug 18 a bolt 21 is screwed. The portion of the bolt 21 projecting from the plug 18 is planed at two diametrically opposite sides, said planed surfaces are generally saw-­ toothed. The teeth 22 on these saw-toothed surfaces are arranged to receive between themselves teeth 23 that are arranged on the opposite faces on two nuts 24, 25. The nuts 24, 25 are slidingly guided in cylindrical borings 26, 27 in the coupling element 10. The nuts 24, 25 are in respect of force transmission connected by a clamping bolt 28, one end of which has a left-hand thread and the other end has a right-hand thread. When rotating the bolt 28 the the nuts or clamping means 24, 25 move either towards each other or from each other. The teeth 22, 23 are mutually designed in such a way that contact is established only on the flanks 29 of the nuts 24, 25 that are orientated towards the adapter 11 and the flanks 30 on the bolt 21 that are oriented from the adapter resp. The flanks 30 are consequently constituting contact surfaces related to the plug 18 and running in the transverse direction of the adapter 11. These contact surfaces are intended to co-operate with the flanks 29, that constitute contact surfaces related to the coupling element 10 when clamping the adapter 11 against the coupling element 10. According to the invention the flanks 29 constitute a number of, in the disclosed embodiment four, in the longitudinal direction of the adapter 11 separated partial surfaces that together constitute the active contact surface of the coupling element 10 or of the clamping means, i e the nuts 24, 25, when clamping the adapter four partial surfaces running in the longitudinal direction of the adapter, said surfaces constitute together the active contact surface of the plug 18 for co-operation with the contact surface 29. The nuts 24, 25 are non-rotationally guided relative to the coupling element 10 by a guide pin 31 arranged in the coupling element 10. The guide pin 31 projects into a groove 32 in the nuts 24, 25, said groove running in the transverse direction of the adapter 11, whereby the nuts 24, 25 can be displaced in said transverse direction. The embodiment of Figs. 3 and 4 corresponds in all essential parts to the embodiment of Figs. 1 and 2. In the plug 18 a bolt 33 threaded at both ends is screwed. A nut 34 planed at two opposite sides is screwed on the bolt 33. The planed sides as well as the interacting sides of the nuts 24', 25' are generally saw-toothed in order to provide teeth 35, 36. The interacting flanks 37, 38 of the teeth 35, 36 constitute six partial surfaces being separated in the longitudinal direction of the adapter 11, said partial surfaces constituting together the contact surfaces related to the coupling element 10 and the plug 18 when clamping the adapter 11 towards the coupling element 10. Due to the provision of contact surfaces 38 on the nut 34 they are indirectly arranged on the bolt 33. The clamping bolt 39 is in respect of force transmission connected to the nuts 24', 25', i e screwed into the nut or clamping means 24' and arranged to slide freely through the nut or clamping means 25', the head of the clamping bolt 39 bearing against the nut 25'. Due to the fact that the contact surfaces of the clamping means disclosed in the embodiments of Figs. 1-4 comprise in axial direction separated partial surfaces 29; 37 the tendency of the clamping means to upset when clamping the adapter 11 has decreased essentially.

Claims: 1. Tool coupling device comprising a coupling element (10) that can be attached directly or indirectly to a tool machine, and a tool adapter (11) designed to clamp a tool for metal cutting, said coupling element being provided with an axial boring (15), that has at least one internal guide surface (16,17), a plug (18) provided on the adapter (11) and designed to be guided into said boring (15), said plug (18) being related to a contact surface (30; 38) running in transverse direction to the tool adapter (11) and intended to be in engagement with a corresponding contact surface (29; 37) related to the coupling element (10) for clamping the adapter (11) against the coupling element (10), and that one (29; 37) of the contact surfaces (29,30; 37,38) is provided on clamping means (24; 24') being displaceable in a transverse direction to the adapter (11), characterized in that the contact surfaces (29; 37) of the clamping means (24; 24') comprise at least two in the longitudinal direction of the adapter (11) separated partial surfaces. 2. Device according to claim 1, characterized in that the clamping means comprises two in the transverse direction of the adapter opposite facing clamping elements (24,25; 24'25'), that by means of a clamping bolt (28; 39) are mutually connected in respect of force transmission in such a way that they are displaced in opposite directions when rotating the clamping bolt (28; 39). 3. Device according to claim 2, characterized in that the clamping means (24,25; 24',25') are non-rotational guided by means of a guiding pin (31) arranged in the coupling element (10), said pin (31) engaging a groove (32) in the clamping means (24,25; 24',25'), said groove (32) running in transverse direction of the adapter (11). 4. Device according to claim 2 or 3, characterized in that the opposite facing surfaces of the clamping means (24,25; 24'25') are generally saw-toothed, and that the saw-toothed surfaces are provided with at least four partial surfaces (29; 37) separated in the longitudinal direction of the adapter (11) in order to apply the clamping force. 5. Device according to anyone of the previous claims, characterized in that the contact surfaces (30; 38) related to the adapter (11) are arranged directly or indirectly on a bolt (21; 34) screwed into the plug (18) of the adapter (11). 6. Device according to anyone of the claims 2 - 5, characterized in that the clamping bolt (39) is threadably connected to one of the clamping means (24') and arranged to run freely through the other clamping means (25'), the head of the clamping bolt being arranged to bear against said last mentioned clamping means. 7. Device according to anyone of claims 2 - 5, characterized in that the clamping bolt (28) is threadably connected to the two clamping means (24,25), one thread being left-handed and the other right-handed.

Inventors: HOFFMAN, CHRISTER, KOERNER, ULRICH, Körner, Ulrich
Applicants: SANTRADE LTD.
Application year: 1986
Main classification: B23B31
IPC codes: B23Q3, B23B31