GB833119A - Improvements in chucks - Google Patents

Abstract

833,119. Chucks. JACOBS MANUFACTURING CO. Jan. 6. 1958 [Feb. 5, 1957]. No. 322/58. Class 83 (3). A bevel-closing chuck comprises a jaw-assembly 30 movable axially in a tapered recess 27 by a plug 33 which is moved by a screwthreaded connection 34, 44, operated by a gear 35, and means 45 for preventing rotation of the plug relatively to the housing 20, 26 of the chuck. The gear 35 is located in the upper part 20 of the two-part housing, between ballbearings or, as illustrated, a bronze ring 36 at its upper end and a ring 37 at the lower end. Screw-threads 44 in the hub of the gear engage threads 34 on the plug, which slides on a rod 45 of square cross-section or, as illustrated, having splines to prevent rotation of the gear. The jaws 29 are preferably connected by synthetic rubber to form a collet 30, and the end of housing part 26 is notched at 28 to receive a wrench for assembling parts 20, 26. Teeth 39 are formed on the gear 35, which have larger apex-angles at their outer periphery than at the inner periphery, and the gaps between tooth roots are of constant width (Fig. 8, not shown). Radial passages 43 receive an operating key for turning the gear. In a modification, Fig. 13, the rod 45 is replaced by ribs 101 on the plug, which engage slots 102 in the housing. A key 42 for rotating the gear 99 has a grooved handle 51 and a tommy-bar 56, of a size which will bend or break before the gear-teeth break. The key may be suspended, e.g. from the cable 65 of an electric drill, by a strap 57 of synthetic rubber having an eye to receive a brass grummet 49 in which the key rotates. In a further modification. Fig. 10, a sleeve 75 is arranged between the plug 74 and gear 67, being screw-threaded externally to engage threads in the gear, and internally to engage the plug. Rings 77, 79 on the sleeve and plug restrict movement of these parts. In a further modification (Fig. 12, not shown), a splined-key or one of square or hexagonal cross-section is integral with the plug, and slides in the machine spindle, which engages screwthreads in the chuck. In order to avoid interference between the teeth of an incorrectlypositioned key 42 and the edges formed by the intersection of the key-passages 43 and a shoulder 24, Fig. 2, in the chuck-body, the shoulder may be of conical form (Fig. 22, not shown).