GB342203A - Lathe tail stock - Google Patents

Abstract

342,203. Turning. BRILL, K. F., 68, Nordoberhausenstrasse, Sterkrade, Rhineland, Germany. March 24, 1930, No. 9334. Convention date, March 27, 1929. [Class 83 (iii).] In a lathe tailstock wherein the back centre is maintained in contact with the work by fluid pressure, relief means are provided to permit the centre to recede when the work expands due to a rise in temperature. The centre 4, Fig. 1, is attached to a plunger 1 sliding in a cylinder 7 formed in the tail-stock 3. An extension 8 of the plunger slides through a stuffing box 9 which divides the tail-stock into two compartments, and is secured by a wedge 10 to a block 2 which may be advanced or retracted within the tail-stock by the usual screw and hand wheel 6. In operation, the centre is pressed against the work by the wheel 6, pressure is admitted to the cylinder 7 from a hand pump or a pressure line and the block 2 is then withdrawn slightly within the limits of the clearance 14 provided between the slot 27 in the extension 8 and the wedge 10. As the work expands the centre is pushed back and fluid is displaced through a relief valve to the fluid reservoir, the clearance 14 being less than the penetration of the centre into the work so that rearward movement of the centre is stopped before the work becomes disengaged. As the work contracts again, fluid returns to the cylinder 7 from the main or is supplied by the pump. Should the fluid pressure fail due to fracture of a pipe &c. the centre cannot recede a distance greater than the clearance 14. A gauge 26 is provided for controlling the fluid pressure. In a modification the centre 4, Fig. 3, is slidable in a cylinder 16 which is movable within the tailstock 3 by a screwed stem 17 therein and a nut 18 carrying a hand wheel 19. Rotation of the hand wheel feeds the centre against the work, whereupon rotation of a wheel 25 screws a spindle 21 into the cylinder and causes the pressure to be increased by means of a plunger 20, a spring 22 being interposed between the plunger and spindle. Expansion of the work forces back the plunger 20, and if the gauge 23 registers too high a pressure this may be relieved by the wheel 25. The spring 22 returns the centre as the work contracts and the tail-stock is slotted at 24 to allow the gauge 23 to move with the cylinder 16.