GB540609A - Improvements in or relating to self-tightening chucks - Google Patents

Abstract

540,609. Chucks. JACKSON, L. MELLERSH-. (Jacobs Manufacturing Co.). April 17, 1940, No. 6959. [Class 83 (iii)] A self-tightening chuck of the kind in which the tool is gripped by a number of eccentric jaws 40 is constructed so that the jaws are mounted in eccentric roller bearings capable of micrometric adjustment, and the jaws are formed with helical ribs 45 which taper in cross section and are arranged in relatively staggered overlapping relations so that the area of the gripping surfaces is greater at portions nearer the axes of rotation. The chuck comprises a body 10 with a tapered bore 12 for the arbor, and knurled at 15 for hand holding to cause relative rotation of the body and a sleeve 20 which normally rotates with the body owing to a flat spiral spring connection. The sleeve is formed with internal teeth 22 which engage gears 38 mounted in the body to rotate the jaws to closing position when the sleeve 20 is braked by hand pressure on a knurled boss 24 on the sleeve. The jaws are formed with crown teeth 42 which engage the gears 38, and the jaws abut a cover plate 30 which is formed with a boss 51 extending to the face 11 of the body 10. The jaws are mounted around rollers arranged on eccentric parts 32 which are adjustable by means of extensions 33 with slots to receive a screw-driver which by the aid of an indicator sets the position of the jaws. After the jaws have been set they are clamped in position by a plate 52 secured by posts 54 which screw into the body 10. The relative motion between the body 10 and sleeve 20 is limited by an arcuate flat piece of stamped metal 19 welded to the body 10, and an arcuate piece of metal secured to the sleeve.