GB674609A - Improvements in or relating to tailstocks for lathes and the like machine tools - Google Patents

Abstract

674,609. Lathe and like centres. FISCHER AKT.-GES., G. Oct. 26, 1950 [Nov. 30, 1949], No. 26122/50. Class 83 (iii). Tailstocks.-A tailstock for lathes and like machines comprises a work-engaging device enclosed by a sleeve to which is secured a threaded rod, a gear wheel engaging said rod, a bearing enclosing a part of the gear wheel, resilient means axially supporting the bearing, a motor, means connecting the motor to the gear wheel for moving the work-engaging device longitudinally and switching mechanism to stop the motor when the work is engaged, or when the work-engaging device has moved a predetermined distance away from the work. A work-engaging centre 17, Fig. 3, may be eccentrically mounted and is carried in antifriction bearings in a sleeve 13 keyed at 15 for slidable movement within a bore 12 in the tailstock casing 2. The casing is slidable along ways 1, Fig. 1, of the machine and may be clamped by nuts 3a. A threaded rod 18, integral with the sleeve 13, engages a nut 19 provided with a toothed periphery and urged to the left by a spring 22, thrust member 38, and bearing 20. Movement by the spring to the left is arrested when the bearing engages a collar 36 provided on a sleeve 21 integral with the casing 2. The nut 19 is rotated in one direction or the other for forward motion or retraction of the tailstock centre by a reversible electric motor 5 driving through gears 6, 7 and 10. The gear wheel 10 has a flanged extension bearing against a spring 11 and is splined on a shaft 8. A hand lever 33, Fig. 1, operates a switch 32 for the motor to give " forward," " reverse," or " off and has an extension 30 comprising a fork which engages a pin 29, Fig. 3, on a cranked lever 26 pivoted to the casing at 24 and with a lower end 27 engaging the rear end 37 of the sleeve 13. A further pin 28 on the lever engages the flange on the gear wheel 10. When the lever 33 is moved to the forward " on " position, motor 5 rotates the gearing and nut 19 to screw out the centre sleeve 13 until the centre proper contacts the work, spring 22 is then compressed by further movement, the nut 19 being forced back and carrying with it the wheel 10 through contact with the flange on this wheel. The latter moves to the right against a compression spring 8 and its flange bears against the pin 28, thus moving the lever 26 until the switch lever is moved into the " off " position to stop the motor. When the lever 33 is moved to the opposite "on" position and the direction of motor rotation is reversed, the sleeve 13 moves back to contact alternately a pin 27 on the lower arm of the lever 26 and thus again moves the switch to the " off " position to stop the motor. A foot-operated safety switch may be employed in the supply lines to the motor.