GB825763A - Improvements in or relating to machine-tool chucks and their operating mechanism - Google Patents

Abstract

825,763. Chucks. PRECISION INDUSTRIELLE S.A. June 4, 1956 [June 7, 1955], No. 17249/56. Class 83 (3). A chuck comprises two pairs of oppositely disposed jaws 11a, 11b, 14a, 14b, adjustable radially by levers 8a, 9a, operated by a fluidpressure jack which is freely movable axially of the chuck, levers 8a for jaws 11a, 11b being directed oppositely to levers 9a for jaws 14a, 14b, and coupled to the piston 32 of the jack by a member 30 which is coaxial with a member 31 coupling levers 9a to the cylinder 35 of the jack, so that movements of the piston and cylinder in opposite directions simultaneously operate the jaws. Fig. 2 is a section on line II-II of Fig. 1 and shows the opposite directions of adjacent levers 8a, 9a, which are rocked in the directions F, G respectively, to close the jaws, opposite pairs of which need not be 90 degrees apart. If the jaws are at different diameters, shorter levers are required for those at greater diameter in order to produce the same work-driving torque at each pair of jaws. The levers pivot on shafts 15 and have eccentric portions 16a engaging the opposed surfaces 18a, 19a, of pockets in jaw carriers 10a, to which the jaws are fixed by screws 12. The arms 22a of one pair of diametrically opposite levers are connected to the inner operating tube 31 by a member 25 prevented from rotating in relation to the chuck by a pin 26 on the chuck end plate 27, and those of the other levers are connected to the outer operating tube 30 by a member 29 interlocking with member 25. The jack is mounted on a spindle 1 and rotated therewith by a pin 43 in the driving pulley 3. A non-rotatable casing 45 is mounted on bearings 52 between a distributer 48, having annular grooves 53, 54 and a sleeve 51 fixed to the rotating cylinder 35 and provided with passages 55, 56 in communication with grooves 53, 54, and with the cylinder at both sides of the piston respectively. Pressure oil admitted to either side of the piston through conduits 49, 50 also passes between the distributer 48 and sleeve 51 to lubricate the bearings 52, and is discharged through a nozzle 57 which engages a frame 58 to prevent rotation of the casing. The piston is constrained to rotate with the cylinder by a pin 41 mounted on the piston, and the tube 31 forms a passage for coolant, or for the introduction of a control (not shown), for closing the chuck automatically when the work is introduced. Reference has been directed by the Comptroller to Specification 787,580.