Patent GB-590592-A (GB)
Title: Improvements in or relating to apparatus for controlling the operation of one or a plurality of metal cutting and like machine tools
IPC: G05B19/06
Filed: 1943-06-28
Abstract: 590,592. Hydraulic machines. BULLARD CO. June 28, 1943, Nos. 10479 and 10480. Convention dates, Aug. 23, 1940, and June 4, 1941. [Class 69 (ii)] [Also in Group XXII] A machine having means for causing a part such as a tool slide to perform automaticallya cycle of operations has the slide movable in three mutually perpendicular directions by traversing mechanism and a main indexable control member carrying adjustable dogs, one of which starts a traversing motion each time it is indexed, each traversing mechanism having associated therewith a secondary indexable control member with adjustable dogs which effect indexing of the main member when its corresponding traverse has been completed. All the control members are interconnected so that they are indexed simultaneously. In one form of machine such as a lathe, a tool holder 160, carrying a cutter 161 is movable in guides 162 on a slide 163 which is movable transversely in guides 167, 168 on a support 169. Cylinders 166, 171 supplied with fluid pressure, preferably liquid, contain piston rods 164, 170 which effect the two movements of the cutter. Low pressure fluid is supplied by a pump 199 to both sides of each piston to maintain the cutter stationary, one end of a cylinder being connected to exhaust to allow the pressure at the other end to effect a rapid idle traverse, and a second high pressure pump 200 having a variable delivery and fed by the pump 199 delivers measured quantities of fluid to one end or the other of the cylinders to effect a cutting feed at the desired rate. The output of the pump 200 is varied by tilting the casing 201 against a spring 207, as shown by dotted lines. A third pump 198 supplies high pressure fluid to urge all the control valves to neutral position and to release friction clamps 181, 182 on the piston rods which are normally actuated by springs to grip the rods to prevent inadvertent movement of the cutter when no feed is taking place. The pump 200 is described in U.S.A. Specifica - tion 1,931,969. The feed of the tool through cylinder 166 in either direction is started by raising valve 173 or 174 and through cylinder 171 through valves 177, 178, the traverses being controlled by valves 175, 176 and 179, 180 respectively. The feed valves are raised at the appropriate times by dogs placed in the selected holes 324 of a drum 323 which is indexed on the completion of each feed or traverse movement of the tool to terminate that feed and start the subsequent feed, the drum 323 being indexed by dogs 331, 352 on the piston rods engaging stops 334, 353 on drums 332, 354 when the cucter has completed a feed. The drums are connected by gearing 351 and bevel gears 359 so that all are indexed simultaneously when the drum 323 is indexed by an electric motor 328 and a geneva. gear 326. In operation, to start a rapid traverse towards the rotating work, a dog 325 on the drum 323 is brought under a valve 251, 270, 306 or 314 which is raised to admit fluid to one of the valves 186, 193 to release the clamp on the appropriate piston rod and also to raise one of the valves 175, 176, 179 or 180 to connect one end of a cylinder to exhaust and thus allow the piston to be traversed. On completion of the traverse, one of the dogs 331, 352 engages a stop on a drum 332, 354 to move the drum endwise against its spring 338 and cause a plunger 347 to be cammed out of a groove to close a switch 348 in the circuit of motor 328 and index the drums, thus stopping the traverse and allowing the clamp to lock the piston rod which has been moving. A dog 325 on drum 323 may then be brought under one of the valves 173, 174, 177, 178 which is thereby raised to release a clamp through valve 186 or 193 and connect pump 200 to one end or the other of a feeding cylinder, the pump casing being tilted by a dog 325 to the required angle to cause a measured quantity of fluid to be delivered to a cylinder so as to feed the cutter at the required rate. On completion of the feed, the motor 328 is again energized by one of the dogs 331, 352 to index the drums, stop the feed and re-apply the piston rod clamp, the feeds and traverses being caused to follow each other by arrangement of the dogs on the drum 323 until the desired cycle of operations has been completed. Fluid is admitted by valves 251 &c. to plungers 257 at the same time as to valves 175 &c. so that the latter valve will not be raised to start a rapid traverse until the plunger has been completely raised, thus causing the cutter to dwell and finish the cut before the rapid traverse is started. The extent of the dwell is determined by the height of the dog 325 which raises the valve 251 since the latter controls a throttled passage leading to the plunger 257. The feed pump 200 is driven by a gear 203 in the same train which rotates the work so that the speeds of rotation and feed will be related. A hand-operated indexing .device 366 is provided for use when placing the dogs 325 on the drum 323 in setting up the machine. A number of cutters 161 may be controlled from the drum 323.