Abstract: The invention relates to a method of chucking easily deformed workpieces (6) sensitive to deformation, particularly thin-walled rings, wherein the workpiece (6) to be chucked is placed between the jaws (2) of a chuck (1) comprising a pole block (7) having at least one magnet (4) in a chuck body (3) behind the jaws, and wherein the workpiece is centered by closing the jaws (2) and fixed in this centered position by the magnet (4). The invention further relates to a chuck (1) comprising a magnet (4) provided in a pole block (7) behind the jaws (2).

Abstract: A machining apparatus has a chuck rotatable about an axis and having radially displaceable and angularly spaced jaws, a double-acting cylinder having a piston flanked by a pair of separate compartments and operatively connected to the jaws for radially shifting same. One of the compartments is pressurized with a working pressure pressing the jaws against a tool or workpiece and the other of the compartments with a counterpressure opposite to the working pressure. An instantaneous rotation speed of the chuck is detected, and a pressure differential between the working and counterpressures is varied in accordance with the detected instantaneous rotation speed.

Abstract: A chuck rotatable about an axis has an actuator system with a housing rotatable about the axis and connected to the chuck, a threaded rod in the housing, extending along the axis, connected to the jaws, and axially displceable to radially shift the jaws, an electric motor, a drive wheel rotatable about the axis on the housing and driven by the motor, and a harmonic drive. This drive has a wave generator rotationally fixed to the drive wheel, a flexspline surrounding the wave generator and having external teeth, and a ring gear fixed on the housing meshing with the ring gear, and normally rotating jointly with the threaded shaft, a threaded connection between the flexspline and the threaded rod. A sensor on the chuck detects an instantaneous rotation speed of the chuck, and a controller connected between the sensor means and the electric motor axially shifts the chuck in accordance with the sensed rotation speed.