POWER-OPERATED CHUCK FOR A TOOL SPINDLE OF A MACHINE TOOL

1 . Power-operated chuck for a tool spindle of a machine tool, in particular a lathe, comprising a chuck body and at least one chucking device which is guided in a radial guide of the chuck body and which, for exerting a desired chucking force on a workpiece chucked in the chuck, can be adjusted relative to the chuck body by a chucking-force generator via at least one drive member arranged in the chuck body, wherein the at least one chucking device has a measuring device for measuring a chucking force exerted by the chucking device on the workpiece chucked in the chuck and an evaluating device for evaluating the chucking force measured by the measuring device.

2 . Chuck according to claim 1 ,

wherein the evaluating device is preferably interchangeably accommodated as a modular subassembly in a recess formed in the at least one chucking device.

3 . Chuck according to claim 2 ,

wherein the recess is formed in a side face of the chucking device, said side face being opposite the chucking surface, coming to bear against the workpiece, of the chucking device.

4 . Chuck according to claim 1 ,

wherein the evaluating device has an interface for transmitting data between the evaluating device and an external device, preferably an external hand-held device.

5 . Chuck according to claim 4 ,

wherein the interface is a wired interface for transmitting data between the evaluating device and the external device when the spindle is stopped.

6 . Chuck according to claim 4 ,

wherein the interface is a wireless interface, in particular a radio interface or an optical or electro-optical interface, for transmitting data between the evaluating device and the external device when the spindle is stopped or during spindle operation.

7 . Chuck according to claim 1 ,

wherein the evaluating device has a first memory or a memory having a first memory area for storing at least one desired chucking force required for carrying out a chucking operation which is established or can be established beforehand, and

wherein the evaluating device furthermore has a microprocessor for comparing the chucking force measured by the measuring device with the at least one desired chucking force filed in the memory.

8 . Chuck according to claim 1 ,

wherein the evaluating device has a second memory or a memory having a second memory area for storing the chucking forces preferably measured continuously or at predetermined times or during predetermined events by the measuring device.

9 . Chuck according to claim 8 ,

wherein the evaluating device, while taking into account the chucking forces measured preferably continuously or at predetermined times or during predetermined events, is designed for making a prognosis which predicts the number of chucking operations until the point at which the chucking force drops below the desired chucking force.

10 . Chuck according to claim 1 ,

wherein the measuring device has at least one chuck-force measuring sensor which is arranged on the at least one chucking device in a frictional connection between the chuck body and the chucking surface, coming to bear against the workpiece, of the chucking device.

11 . Chuck according to claim 10 ,

wherein the chucking-force measuring sensor is designed for sensing a change in length, caused by the chucking force, of one of the members transmitting the chucking force.

12 . Chuck according to claim 11 ,

wherein the chucking-force measuring sensor is formed by a strain gauge.

13 . Chuck according to claim 10 ,

wherein the chucking-force measuring sensor is formed directly as a force sensor.

14 . Chuck according to claim 13 ,

wherein the force sensor is formed by a quartz crystal.

15 . Chuck according to claim 10 ,

wherein the chucking-force measuring sensor is designed as a pressure sensor.

16 . Chuck according to claim 1 ,

wherein the measuring device and/or the evaluating device has at least one transducer for converting the physical parameter measured with the at least one chucking-force measuring sensor into a chucking force and for storing the converted chucking force as an actual chucking force in at least one memory.

17 . Chuck according to claim 1 , wherein, furthermore, a pair of induction coils are provided for the non-contact transmission of energy to the at least one chucking device for the electrical supply of the measuring device and/or evaluating device.

18 . Chuck according to claim 1 ,

wherein the at least one chucking device also has an identifier device for the clear identification of the chucking device.

19 . Chuck according to claim 1 ,

wherein the chucking device has a top jaw and a chuck jaw detachably fastened thereto.