| 摘要 |
1,254,431. Chucks. EDWARD WILLIAMS (HOLDINGS) Ltd. 17 April, 1969 [21 May, 1968], No. 24151/68. Heading B3B. A fluid pressure operated chuck comprises a tubular central part 10 adapted to be mounted on a rotary spindle 12, a bevel-closing collet 13 received in the part 10, a sleeve 14 having an end cap 15 engageable with the collet to move it axially, springs 17 arranged to act between an abutment 16 on the part 10 and the sleeve 14 for urging the collet into a normally closed position, a stationary cylinder 21 surrounding the central part and adapted in use to be attached to a headstock 22, an annular piston 26 operable by fluid pressure in the cylinder 21, movement of the piston 26 in one direction causing a conical surface 26a thereon to force a series of balls 18 radially inwards between complementary surfaces 10b, 14b on the parts 10, 14 respectively whereby the sleeve 14 is moved axially against the pressure of springs 17 to release the end cap 15 from the collet 13. The balls 18 are held in a cage and urged radially outwards by spring elements (20, Fig. 2, not shown) so that during rotation of the chuck in use the balls make no contact with surfaces 10b, 14b. Guide rollers 24 projecting into inclined slots in a skirt extending from the piston 26 impart angular movement to the piston as it is moved axially. Piston 26 is returned to its idle position by a series of individual pistons 28 operable in cylinders 27 angularly spaced around the chuck axis in a member 23 secured to the cylinder 21. |
