When piston 1 is moved to the right by fluid entering left end a of cylinder 4, clamping member 2, linked rigidly through rod 3 to piston 1, and bushing 5, secured rigidly to cylinder 4, simultaneously clamp two thin-walled hollow workpieces 6 and 7. Both clamping member 2 and bushing 5 have cylindrical clamping surfaces of the same radius as the surfaces they clamp. In machining workpieces other than cylindrical (of hollow square shape as shown), they are clamped through split bushing 8 having an inner cross section corresponding to that of the workpiece. The workpieces are released by the action of springs 9 and 10, with the fluid draining from end a back to the tank.
$3744$SHP,GC$