Force-compensated split-jaw lathe chuck

A lathe chuck comprising:

• a chuck body rotatable about a chuck axis and formed with a plurality of angularly spaced and radially extending inner guides and with a plurality of angularly spaced and radially extendng outer guides;
• respective inner and outer jaw parts radially displaceable in said chuck body in said inner and outer guides;
• means including at least one operating element engageable with said inner jaw parts for radially displacing same in said chuck body in the respective inner guides;
• respective coupling members axially displaceable in said inner jaw parts and each displaceable between a coupling position engaging the respective outer jaw part and coupling same to the respective inner jaw part for joint radial movement therewith and a decoupling position for relative radial displacement of the respective jaw parts;
• respective cams radially displaceable in said inner jaw parts in engagement with the respective coupling members between radially outer positions holding the respective coupling members in said coupling positions and radially inner positions in which the respective coupling members can assume said decoupling positions;
• respective weights radially displaceable on said chuck body adjacent said inner jaw parts;
• respective levers centrally fulcrumed in said body and having axial back ends in radial force-transmitting engagement with said weights and axial front ends in radial force-transmitting engagement with the respective inner jaw parts, said levers being pivotal on said body first-class fashion with opposite radial displacement of the respective ends;
• and
• respective means for connecting said levers for going axial displacement with the respective coupling members, said levers being axially limitedly displaceable relative to the respective weights and to said body.