Adjustable bar feed chuck for automatic lathes - has locking pegs preventing collet rotation machined from solid on conical surface of collet

摘要

The outer cylindrical sleeve (11) of the barfeed chuck has a screwthread (13) at one end for attachment to the barfeed. The other end is inserted the inner collet (12) which has a threaded end allowing it to be screwed in or outer of the sleeve (11). Immediately behind the land (32), at the collet nose, is a taper fitting into a matching taper in the sleeve mouth, so that the grip on the bar to be fed can be adjusted by rotating the collet. The compliance of the sleeve and collet is achieved by slots (15) in the relatively stiff sleeve and slots (21) in the relatively compliant collet. The collet is locked against rotation by rectangular pegs (24) protruding from the collet and engaging the slots (15) of the sleeve. The pegs are simply machined from the solid and generally follow the conical surface of the collet nose. A cup-ended key (36) is pushed onto the land (32) to close the empty collet, thus disengaging the pegs and allowing the collet to be adjusted. ADVANTAGE - Reliable locking of collet. Longer chuck life. Simple, easy-to-produce design.