Patent GB-369220-A (GB)
Title: Improvements in or relating to lathes or similar machines
IPC: B23B7/00
Filed: 1930-09-05
Abstract: 369,220. Hydraulic transmission of power. BARNES CORPORATION, J. S., 301, South Water Street, Rockford, Illinois, U.S.A.-(Assignees of Svenson, E. J. ; 301, South Water Street, Rockford, Illinois, U.S.A.) Sept. 5, 1930, No. 32231/31. Convention date, Sept. 9, 1929. Divided on 366,928. [Class 69 (ii).] A lathe or similar machine tool particularly a lathe such as those described in Specifications 366,928 and 368,792, is provided with a number of carriages which are operated by means of hydraulic cylinders, the supply of fluid to the carriages being controlled by a single longitudinally movable control valve. The actuating-mechanism of the front tool carriage includes a cylinder 140 whose piston-rod operates a guide-bar 134 .which serves as a rest for the front carriage and imparts oscillating movement thereto. The front carriage is moved longitudinally by means of a cylinder 124. A rear tool carriage which moves transversely of the work axis is operated by a cylinder 166. The underside of the rear carriage is provided with a rack-bar connected through gears to a rack 194 controlling the operation of the hydraulic system which is shown diagrammatically in Fig. 15. A low pressure gear pump 218 draws oil from a reservoir 220 and supplies a variable delivery, rotary plunger pump 205, the eccentricity of the rotor to vary the delivery being controlled either manually by a handle 212 or automatically by means of a small hydraulic cylinder 324. The pipe 216 conveys the fluid to the main valve 200, the plunger 224 of which is reciprocable and partially rotatable within the casing 226. The valve plunger is provided with a central passage way and with radial passages. The end of the valve plunger communicates with a chamber 242 and the central passage through the plunger extends into a piston 248 having fine passages 250 which, in the position shown in Fig. 8, communicate with the passages 252. The valve plunger is connected to a rod 254 which is pivoted to a lever 256 connected to the manual control mechanism. A bar 262 has rack teeth engaging a pinion 270 carried by the shaft of a control handle 278, and the end of the bar carries a pin 272 coacting with dogs mounted on a slide 196 which is controlled by the movements of the rear tool carriage. The control handle 278 is also connected through a link 284 with the plunger 286 of a distributer valve 288. The passage 290 of this valve communicates with the main valve and from this passage oil flows through passages controlled by needle valves 300, 302, 304, respectively, to the tool feed cylinders 140, 166, 124, respectively. The flow through these needle valves determines the slow feed of the tools. The flow from the valve 304 is passed through a valve 312 operated in timed relation with the movement of the slide 196. If the distributer valve is moved to the left, Fig. 15, which occurs when the control handle is moved fully to the right, the needle valve ports are closed and the fluid flows freely to the appropriate cylinders through byepasses associated with each needle valve. When the main valve is in a neutral position, Fig. 15, the pump discharge passes via the chamber 242 and pipe 318 back to the pump. When, in operation, the control handle is moved fully to the left, the main valve is moved to the Fig. 16 position and the pump discharge passes through pipe 292 to the distributer valve, while the low pressure fluid in the chamber 228 flows to the cylinder 324, thus displacing the rotor of the pump 205 to give full discharge. The distributer valve is positioned to cut out the needle valves and allow the full oil flow to pass to the feed cylinders 140, 166, while feed to the cylinder 124 is cut off by the valve 312. This gives the rapid approach movement of the front and rear tools. If the control handle be now moved to the " half-left " position the cylinders are fed through the distributer valves and the pump is returned to its normal delivery position. At this time the distributer section 312 is in the full-line position, Fig. 15, so that oil flows to the cylinder 124 and traverses the front carriage to the left. When the tools reach the limit of their forward movement the control handle is moved fully to the right, thus shifting the main valve to the Fig. 18 position whereby the pump is moved to its maximum delivery position and the rapid return movements of the pistons in cylinder 124, 140, 166 are effected. By moving the control handle to the " half-right " position the return movements may be effected at the slow feed rate. After the return movements the control valve may be returned to its neutral position. The machine may be controlled automatically after the control handle has been moved to the left to start the cycle. In this case at the end of the quick approach movement of the tools, a dog on the slide 196 causes the control valve to be moved to the slow feed position. During this movement a dog 343 acts through lever mechanism on the valve 312 to establish communication between the needle valve parts and the cylinders. When both the rear and the front carriages have completed their forward movements, a link 388 is operated by means of lugs on the carriages, to impart a rotary movement to the main valve and allow fluid to flow through passages 250, 252 into the chamber 400. This unbalances the valve and moves it to the left to the reverse position for quick return of the tool slides and during the return movement the main valve is rotated by a spring back to its normal position. Pressure in the chamber 400 is then relieved through a pipe 404. At the end of the return movement a lug 276 on the slide 196 engages the pin 272 and moves the slide bar 262 to the left, thus restoring the main valve to the neutral position. The machine is driven from an electric motor 406 connected by a chain to a sprocket 410 on a clutch element 414 on the main shaft 60. The motor is also connected to the pump unit 205. The clutch is operated by a collar 428 by means of a hydraulic cylinder 442 forming part of the main hydraulic system. When the operating handle 278 is moved to the rapid approach position, oil flows through the pipe 308 to the cylinder 442 which is thus operated to engage the clutch and start the spindle rotation. When the main valve is shifted to return the tools, the piston 444 is returned and the clutch disengaged. Relief valves 458, 460 are provided in the high pressure and low pressure lines respectively.