| 摘要 |
1,144,580. Chucks. H. GIRAUD, and V. MARTIN. 16 Aug., 1966 [13 Sept., 1965], No. 36578/66. Headings B3B and B3T. A chuck, e.g. for a lathe is provided with a reversible motor which may be connected by a coupling to a planetary differential gear unit to effect radial adjustment of the jaws of the chuck. When the chuck jaws are to be adjusted to grip or release a workpiece the normal rotary drive to the chuck which is transmitted through a hollow spindle 6 is stopped and a reversible motor 7 is connected through an electromagnetic powdertype coupling 9 to a sun-wheel 10 of a first group of planetary pinions 13 causing orbital rotation thereof since they are in mesh with an internal gear 15 connected to the stationary spindle 6. Corresponding orbital movement occurs, of a second group of planetary pinions 14 which are smaller than and connected to pinions 13 and which mesh with an internal gear 17 connected to the end of a hollow shaft 19 which thereby rotates at reduced speed. Shaft 19 passes through the hollow spindle 6 and carries at its end adjacent the chuck a sun-wheel 21, rotation of which causes rotation about their own axes of a third group of planet wheels 22 which in turn cause rotation of internal gear 23 connected to a rotatable scroll member 24 which engages teeth on the chuck jaws 4. The latter are thereby adjusted radially inwards or outwards according to the direction of rotation of reversible motor 7. The gripping pressure of the jaws 4 on a workpiece is determined by the coupling 9 which acts to disconnect the drive from motor 7 at a preselected torque. Alternatively the motor 7 may be of a variable torque type. For normal drive of the chuck and workpiece sun-wheel 10 is disconnected from the motor 7, hollow spindle 6 is rotated by external drive means and the entire train comprising sun-wheel 10, planet wheels 13, 14, shaft 19, sun-wheel 21, planet wheels 22, internal gear 23 and chuck 3 all rotate with and at the same speed as spindle 6. |
