GB345508A - Lathe tail stock - Google Patents

Abstract

345,508. Lathes. BRILL, K. F., 68, Nordoberhausenstrasse, Sterkrade, Rhineland, Germany. March 31, 1930, No. 10174. Addition to 342,203. [Class 83 (iii).] In a modification of the lathe tail-stock described in the parent Specification, in which the centre is held in contact with the work by fluid pressure, relief means being provided to allow the centre to recede when the work expands due to a rise in temperature, an air buffer is provided in communication with the pressure chamber for the centre so that pressure variations of short duration, e.g. due to vibrations in the machine, do not cause a recession of the centre. In one form the pressure chamber 7, Fig. 3, for the centre 4 is connected to an air-vessel 30, cocks being provided at 31 for communication with the atmosphere, at 31<11> for cutting off communication with the air-vessel and at 31<1> for shutting off the fluid supply to the chamber 7. In a modification the pressure gauge 33 carries electrical contacts connected by leads 34 to a motor driving a pump for the pressure fluid, the action being such that when the pressure in the chamber 7 falls the motor is started to maintain the pressure and when the pressure rises the motor is stopped. Fluid is supplied by a pipe 12. In another form the feed screw 18, Fig. 4, for the centre is rotated through worm gearing 35 from a hand-wheel 19 and the pressure in the chamber 7 is varied by a plunger 20 screwing in the sleeve 17 and rotated by a spindle 21<1> and a hand-wheel 25. The pressure gauge 33 may carry electrical contacts connected by leads 38 to a motor 37 which rotates the spindle 211 in one direction or the other through gearing 36 according to whether the pressure rises or falls. An indicator, either optical or acoustic, may be operated from the leads 38 to indicate changes of pressure. In a simplified tail-stock for medium or light lathes the pressure in the chamber 7 is maintained by the air pressure in the vessel 30, extreme variations of pressure being regulated by the plunger 20. In this construction compressed air is supplied to the vessel 30 and an automatic regulating valve of known type may be provided for maintaining the pressure constant.