Abstract: A chuck assembly for a light alloy wheel is used with a lathe for machining a workpiece, and includes: a chuck body fixed to be coaxial with a lathe spindle; a flexible power chuck including radially extending first second cylinder chambers located on first and second sectional surfaces, respectively, of the chuck body perpendicular to a chuck body axis along outer peripheries of the first and second sectional surfaces, respectively, and pistons received in the first and second cylinder chambers, the pistons being moveable by fluid pressure to grip the inner surface of the rim member in a compensating manner; and a retracting chuck to grip and center the hub mounting portion, and then pull the disk portion to press against a reference surface of the chuck body, whereby the lathe can machine an entire radially outer surface of the rim member.

Abstract: A retractable chuck has a housing adapted to be fastened to a spindle of a lathe, a plurality of shafts mounted in the housing and having proximate ends near the lathe adapted to be coupled to a drawbar of the lathe, and jaws each fastened to one of the shafts. The shafts are formed with a guide groove and guide pins fixed to the housing are received in one of the guide grooves. Each of the grooves has a first portion extending parallel to the central axis of the respective shaft, and a second portion extending obliquely with respect to the central axis of the shaft from one end of the first portion near the lathe toward the proximate end of the chuck. This makes it possible to clamp a stepped workpiece.

Abstract: A chuck assembly which can chuck thin and brittle workpieces that differ widely in size with high accuracy and reliability without warping them. The chuck assembly includes a tubular chuck body having three first cylinders and a plurality of second cylinders arranged along a circumference in a plane perpendicular to the axis of the chuck body at equal angular intervals. The cylinders have pistons adapted to protrude under oil pressure. The three first cylinders are also arranged at equal angular intervals. The chuck assembly further includes a pressure-biasing means for applying, independently of the oil pressure, pressure to the pistons of the first cylinders against a workpiece, so that the piston are less likely to be retracted by the reaction force from the workpiece. That is, this chuck assembly has a self-centering function.

Abstract: A chuck mounting arrangement includes a chuck mounting unit fixed to the head of a spindle of a lathe and having a plurality of jaws and a scroll plate for radialy moving the jaws inwardly and outwardly. A power chuck selected from various types is inserted into the chuck mounting unit so that its adaptor will be clamped by the jaws. The scroll plate is then turned manually to move the jaws inwardly into engagement with the recessed portion formed at the rear of the adaptor. Thus the power chuck is fastened to the spindle. A drawbar mounted in the hollow spindle is provided at its front end with a joint member having its front end splitted into a plurality of joint pieces which are adapted to spread open when moving forward with their own resilience and to be pushed inwardly by a clamping sleeve provided therearound when being retracted. When the power chuck is fixed to the spindle by the chuck mounting unit, the joint pieces grip a chuck control shaft projecting from the rear end of the power chuck.

Abstract: A device for securing dies on a die mount is disclosed, which includes a plurality of first and second clamps which are tiltably mounted on a die mount and a camshaft extends through openings in the clamps and serves to secure the dies.