GB735703A - Improvements in or relating to collets and collet chucks - Google Patents

Abstract

735,703. Chucks; hollow-spindle lathes. NATIONAL RESEARCH DEVELOPMENT CORPORATION. June 19, 1953 [March 21, 1952], No. 7425/52. Class 83 (3). A collet for use in a collet chuck comprises a number of wedge-shaped members 1a, Fig. 1, held by rings 4, 5 to form a number of circumferentially-spaced slots 1b to receive jaws 6, the conical surface formed by the members and jaws engaging a complementary surface 6a in the chuck-body 17. The jaws have openings 7 engaged by the ring 5 and are moved in unison along the surface 6a to thereby move radially inwards to grip a work-piece by a ring 12 having projections 13 which engage the jawends between the members 1a. The ring is prevented from turning by pegs 15 and is moved axially by a ring-nut 19 engaging threads on the body 17. The jaws are urged in the direction to release the work by springs 11. In a modification, the jaws project from the ends of the slots to engage a cup-shaped member movable axially by a ring-nut splined to the body 17. In another arrangement, the jaws 106, Fig. 2, are fixed by projections 107 between a washer 108 and a ring 100 to a sleeve 81 having fingers 83 engaging splines in the body 17<SP>11</SP>. The sleeve is moved axially relatively to the body by toggle levers 91a, 91b acting between an adjustable abutment 92 and a pin 90 fixed to the sleeve. The toggle is moved by a cam surface 98 in a sleeve 97 engaging a roller 91c at the pivot-point of the levers, the sleeve being slidable by handle 101 moving a yoke 104 pivoted at 103 and having projections 104a engaging a groove 104b in the sleeve. There are preferably three peripherally-spaced sets of toggle levers, each housed in a recess 88 in an outer fixed sleeve 87. A ring 109, e.g. of rubber, may be provided in a groove between the jaws and the ring 100 to prevent entry of swarf into the collet. The ring 109 may be backed by a number of segments bonded thereto and surrounded by a spring circlip.