Improved hydrostatic chuck or arbor

1,119,808. Chucks; mandrels. ERICKSON TOOL CO. 31 March, 1966, No. 14247/66. Heading B3B. An hydraulic chuck or mandrel includes a body member and a thin sleeve member which define an hydraulic chamber therebetween, packing rings adjacent the ends of the sleeve to seal the chamber, and a collar member adapted to retain the sleeve against the body at one end, pressure applied to hydraulic fluid in the chamber serving to deform the sleeve to grip a tool or workpiece mounted in or on the chuck or mandrel. An hydraulic chuck includes a body 1 having a bore 4 therethrough with a grooved portion which with a thin sleeve 7 defines an hydraulic chamber 8 sealed by 0-rings 5, 6. One end of the sleeve 7 is flanged and bolted to the body 1 while the other has a bevelled lip 20 secured by a correspondingly bevelled lip 19 of a collar 18 which is also bolted to the body 1. A screw-operated plunger 14 in a transverse passage in the body is used to apply hydraulic pressure to deform the sleeve 7 to grip the workpiece A. A toothed member 26 engages teeth on the workpiece to prevent slipping. In a first modification (Fig. 4, not shown), both ends of the sleeve are bevelled and two identical collars hold the ends of the sleeve. In a second modification (Fig. 6, not shown), the hydraulic chamber is provided by a grooved portion in the sleeve and not in the body member. In a third modification (Fig. 7, not shown) one end of the sleeve is externally threaded, the sleeve being thereby adjustable to ensure proper engagement of the lips of the sleeve and collar. In a modification of this arrangement (Fig. 9, not shown), a separate screw-threaded collar is provided. Radial keys (64), (Fig. 8, not shown), may be provided to prevent slipping of the workpiece. The deformable sleeve may be mounted on the outside of a suitable body member to form an hydraulically-operated mandrel.