Patent ID: 7503566

Claim:
A workpiece-gripping device for tool machines having a motorized chuck mounted on an operating head, comprising: a housing, a driving shaft journaled in the housing in an axially locked position and so as to be rotatable about an axis thereof, said driving shaft being provided with a shank engageable in the chuck; a locking member configured to engage a reaction member integral with the operating head when the shank engages the chuck, whereby the rotation of the device is prevented when the chuck is driven; at least a pincer having jaws, of which at least one is movable and operatively connected via transmission means to said driving shaft for opening and closing; elastic means arranged so as to cooperate with said at least one movable jaw to contrast rotation of said chuck and driving shaft for jaw opening via said transmission means, said at least one jaw being movable in oven position through rotation thereof about a jaw axis that is parallel with the axis of said driving shaft; an eccentric portion integral with the driving shaft and in camming cooperation with said movable jaw for rotation thereof about said jaw axis in contrast to said elastic means.