A line of Prohold hydraulic chucks available from American Workholding enables additional hydraulic operations before or after the initial chucking of the workpiece. Designed for use with vertical turret lathes as well as vertical and horizontal machining centers, the chucks lack a mechanical drawbar or external cylinder for opening and closing the jaws. Hydraulics are internal to the chuck body, enabling the unit to be charged up and sent into a machine tool untethered by a continuous oil supply. A removable side plate enables easy access to the on-board hydraulic components.
The 24"-diameter, six-jaw chucks provide 1.3" jaw stroke. The chucks feature pivoting top jaws with two serrated grippers each, resulting in a 12-point clamping arrangement to better center the raw castings, the company says. After the jaws clamp the part, pressure builds to 1,000 psi and a sequence valve opens a flow of oil through the moving chuck jaws. The oil flows into a piston/cylinder in the top jaws, which pulls the part down to the face datums on each jaw. According to the company, a variety of work supports, swing clamps and other equipment can be combined with the chuck jaws operation.