| 摘要 |
A power chuck has a chuck body rotatable about an axis, forming at least one cylinder, and having a front face. A plurality of jaws are displaceable radially on the front face between radially inner and outer end positions by an operating member axially displaceable on the body between a pair of axially offset end positions. Mechanism between the jaws and the member displaces the jaws toward the radial inner positions on displacement of the member in a first axial direction and displaces the jaws toward the radial outer positions on displacement of the member in a second axial direction opposite the first direction on the body. A drive piston the one cylinder of the body is fixed on and axially jointly displaceable with the member and forms in the one cylinder at least one compartment pressurizable to urge the drive piston and the operating member in one of the axial directions. A control piston is displaceable in another cylinder in the body between a chuck-ready position and a chuck-unready position and a spring is braced against the control piston and urges same into the chuck-unready position. Passages between the cylinders conduct hydraulic or pneumatic fluid therebetween to urge the control piston into the chuck-ready position when the compartment is pressurized and formations between the control piston and operating member hold the control piston in the chuck-unready position when the operating member or the jaws are in either of their end positions. |
