Jaw locking means for lathe chucks

In a lathe chuck having a master jaw guided for sliding movement relative to the chuck body in ways in the chuck body extending radially to the chuck axis by the jaw setting means of the lathe to a workpiece holding position, and a soft jaw mounted on and secured to the master jaw for conjoint movement therewith as a unit, the master jaw and the soft jaw being mounted for movement across the face of the lathe chuck as the master jaw slides in the ways, the ways and the master jaw having opposed surface portions limiting movement of the master jaw toward the chuck face, the improvement comprising:

• a slot in the soft jaw extending transversely therethrough,
• and means for frictionally locking said master jaw and soft jaw unit in a fixed position relative to the chuck body including
• a cam means mounted in said transverse slot,
• said cam means including a member movably mounted in said slot having portions extending laterally from sidewalls of the soft jaw in generally parallel relation to the chuck face, and
• locking members extending from said extended portions of said movable member towards the chuck face for frictionally engaging the same at end portions thereof, and
• actuating means for causing the end portions of said locking members to come into frictional engagement with the chuck face and said soft jaw to move away from said chuck face to cause said opposed surface portions of said master jaw and the ways to be frictionally engaged so that said master jaw and soft jaw unit is frictionally locked in a fixed position relative to the chuck body, said actuating means includes a cam-type actuator for causing movement of said movable means.

In a lathe chuck having a master jaw guided for sliding movement relative to the chuck body in ways in the chuck body extending radially to the chuck axis by the jaw setting means of the lathe to a workpiece holding position and a soft jaw mounted on and secured to the master jaw for conjoint movement therewith as a unit, the master jaw and the soft jaw being mounted for movement across the face of the lathe chuck as the master jaw slides in the ways, the ways and the master jaw having opposed surface portions limiting movement of the master jaw toward the chuck face, the improvement comprising:

• a slot in the bottom of the soft jaw extending transversely therethrough and defining a ceiling wall extending in an inclined relation to the chuck face,
• and means for frictionally locking said master jaw and soft jaw unit in a fixed position relative to the chuck body including
• a wedge-shaped block mounted in said transverse slot for slidable movement laterally relative to said ceiling wall thereof,
• said block having portions extending laterally from sidewalls of the soft jaw,
• leg members extending from said extended portions of said block toward the chuck face for frictionally engaging the same at the ends of said leg members, and
• actuating means for causing movement of said block laterally along said ceiling wall to cause movement of the ends of said legs into frictional engagement with the chuck face and movement of said soft jaw away from said chuck face to cause said opposed surface portions of the master jaw and the ways to be frictionally engaged so that said master jaw and soft jaw unit is frictionally locked in a fixed position relative to the chuck body.