| 摘要 |
A lathe chuck has a chuck body rotatable about an axis and having a plurality of angularly equispaced and axially forwardly open angled guides, a set of first jaws in some of the guides, and a set of second jaws in the other guides alternating with the first jaws. Respective first and second actuating plates coupled to the respective sets of jaws are axially displaceable to radially displace the jaws in the guides. An actuating shaft axially is displaceable in the body. A rocker connects the shaft with the plates for limited relative axial movement of the plates so that the first jaws can engage the workpiece before the second jaws. The actuating shaft has a tubular front end, a core shaft is axially connected to one of the plates and coaxially received in the actuating-shaft end, and a tube shaft is axially connected to the other of the plates and coaxially surrounds the actuating-shaft end. This actuating-shaft end in turn has a radially throughgoing hole through which the rocker extends. The core and tube shafts have radially aligned seats receiving ends of the rocker. A biasing unit, for instance a spring or pressure-operated piston unit, is engaged between the actuating-shaft end and the tube shaft to bias them apart.
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