Patent GB-552671-A (GB)
Title: Improvements in lathes
IPC: B23B31/40
Filed: 1940-07-12
Abstract: 552,671. Lathes. JONES & LAMSON MACHINE CO. July 12, 1940, No. 11664. Convention date, July 25, 1949. [Class 83 (iii)] The tail-stock of a lathe is movable laterally to a position allowing the insertion and removal of the work in a direction axially of the headstock spindle. A tray for supporting work blanks in line with the spindle and to receive finished work therefrom is connected with the tailstock so as to be moved into operative position when the tailstock is moved from its normal position and to be moved to a work receiving and delivery position when the tailstock is returned to normal position. In the latter position of the tray it also forms a guard for the operator. A chip guard to direct chips to the back of the machine and an improved work holding mandrel are also described. The tailstock 56, Fig. 4, carrying the spindle 115 is secured to a pivot 61 in a support 64 and the tailstock is swung into the operative position of Fig. 4 or to the inoperative position of Fig. 5, by fluid pressure admitted to a cylinder 104, the piston 105 of which is connected to a rack bar 101 engaging a gear 100 fast on the pivot shaft 61. The valve controlling the cylinder 104 is disposed on the front of the headstock. A work-supporting tray 150 is fixed to a pair of arms 154 pivoted on a shaft 152 and connected by a link 160 to an arm 158 of a sleeve free upon a shaft 42 and formed with a gear 157 meshing with gear 100. The parts 160, 158 form a toggle so that during the initial upward swing of the tailstock, the tray is moved forward thus acting as a guard by keeping the operator away. After this movement the tray moves inwardly to the position shown in Fig. 5 so that a work blank shown in the dotted line position is substantially in line with the headstock spindle. The tail-stock is locked in operative position by a pair of plungers 72, Fig. 8, carried by the tail-stock and engaging in spaced lugs 75 on the support 64. The plungers are actuated by turning a spindle 80, Fig. 4, by a handle 95, the lower end of the spindle having a flat part 82 with curved ends 83. By turning the spindle clockwise the parts 83 press the plungers 72 apart into locking position by engagement with adjustable abutment members 84 in the plungers, and upon turning the spindle 80 anticlockwise the spindle part 82 engages hooks 90 connected to the plungers and withdraws the latter from locking position. The axial movement of the tailstock spindle 115 into and out of work engaging position is effected by a fluid pressure cylinder of which the spindle 115 forms the piston rod. The spindle is locked in operative position by a split bearing actuated by a screw 125, Fig. 4, and handle 127 and the movements of the screw are arranged to control the valve 120 controlling the fluid supply to the cylinder. For this purpose, the head 126 of the screw 125 is provided with two eccentrically arranged studs 129, 128. Upon turning the screw in a direction to unlock the tail-stock, the pin 129 enters a slot 130 in the valve-actuating lever 131 and thereafter moves the valve in a direction to withdraw the spindle 115. On turning the screw in the opposite direction, the valve is actuated by the pin 128 to move the spindle into engagement with the work and thereafter the spindle is clamped. Chips falling on to the rear face 185 of the tool carriage 41 are directed to the rear of the machine by a plate 183 fixed to the carriage 41, and a plate 181 pivoted to the plate 183 and in sliding engagement with the machine bed. Mandrels.-The work, e.g. a shell 6, Fig. 9, is held by a mandrel 10 provided with two sets of gripping dogs 12, 11 engaging inclines formed respectively in a plunger 18 and a sleeve 14 having a limited axial movement on the reduced end 16 of the plunger. Springs 20 tend to hold the dogs retracted and the dogs are expanded by axial movement of the plunger effected by an actuating bar 28. Spring plungers 26 in the bush 14 urge the bush in a direction to expand the dogs 11.