Three jaw chuck for lathe - has adjustable stop ring to prevent use if one or more jaws are not fitted

摘要

The chuck (1) of a lathe has three jaws (3) which can be moved radially by tangentially moving blocks (6) with teeth which engage teeth (4) in the jaws (3). The blocks slide in helical slots in a ring (8) which is moved axially by a piston (9). To prevent inadvertent tightening of the chuck without one or more of the jaws being in position, a stop (21) limits the travel of the ring (9). When it is necessary to remove the jaws, the stop ring can be rotated by the locking screw (38) and provides sufficient axial travel for the ring to allow removal of the jaws.