Patent GB-366928-A (GB)
Title: Improvements in or relating to lathes or similar machines
IPC: B23B7/02
Filed: 1930-09-05
Abstract: 366,928. Hydraulic transmission of power. BARNES CORPORATION, J. S., 301, South Water Street, Rockford, Illinois, U.S.A. Sept. 5, 1930, No. 26617. Convention date, Sept. 9, 1929. [Class 69 (ii).] A lathe or like machine tool is provided with an oscillatory carriage which is swung by hydraulic mechanism in a plane transverse to the spindle axis. The tail stock, Fig. 6, consists of a split casing carrying an adjustable sleeve 56 connected to the piston 82 of a hydraulic cylinder 84. The sleeve is clamped by means of a handle 88 which is connected through a rod 94 to the valve 92, Fig. 21, controlling the hydraulic cylinder 84. When the handle 88 is moved to unclamping position, the valve is moved to the left, Fig. 21, thus allowing fluid to flow through a supply passage 106 and passage 108 to move the piston 82 to the right and thus withdraw the centre. When the handle is moved in the reverse direction the valve is first shifted to cause the centre to be moved up to the work and finally the sleeve 66 is clamped in position. The handle 88 is mounted on ball bearings. The front of the machine is provided with a carriage 110 which is clamped to a cylindrical bar 114 and is fitted with a cross slide 146. The working position of the tool is determined by an adjustable rod 130 which carries a roller resting on a pivoted bar 134, the bar being moved about its pivot by means of a hydraulic cylinder 140. An adjustable abutment 142 limits the upward movement of the bar 134. The cylinder 140 thus causes the guide-bar 114 to be oscillated about its axis to move the tool to and from the work. In order to traverse the tool, the bar 114 is moved axially through bearings 118, 120 by means of another hydraulic cylinder 124. During this movement the roller 132 moves along the bar 134. The rear tool carriage 160 is secured to the piston-rod of a hydraulic cylinder 166. The underside of the carriage is provided with a rack bar 180 connected through gears 182, 184, and shaft 186 to a rack 194 controlling the operation of the hydraulic system. This system is shown diagrammatically in Fig. 22. 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. 14 communicate with a passage 252. The valve plunger is connected to a rod 254 which is pivoted to a lever 256 connected to bars 260, 262, forming part of the manual control mechanism. The bar 262 has rack teeth engaging a pinion 270 carried by the shaft of a control handle 278. The end of the bar 262 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 the distributer valve communicates through a pipe 292 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. 22, 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 314 associated with.each needle valve. When the main valve is in neutral position, Fig. 22, 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 position shown in Fig. 23, and the pump discharge is passed through pipe 292 to the distributer valve, while the low pressure fluid in the central 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 and 166 while feed to the cylinder 124 is cut off by the valve 312. This gives a rapid approach of the front and rear tools. If the control handle be now moved to the " half left " position, the distributer valve is shifted to feed the cylinders through the needle valves and the fluid flow to the cylinder 324 is interrupted so that the pump returns to its normal feed delivery position. At this time the valve 312 of the distributer mechanism is positioned in the full-line position, Fig. 22, so that oil flows to the cylinders 124 and traverses the front carriage longitudinally 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 position shown in Fig. 25. In this position oil flows to the cylinder 324 to move the pump to maximum delivery position and is also passed through a pipe 230 to cause return movements of the pistons of cylinders 124, 138 and 166. By moving the control handle to the " half right " position the return movements may be effected at the slow feed rate. After the carriages have been returned, the control handle is again moved to neutral position. In operation 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 engages with the pin 272 on the bar 262 and moves the control valve to the slow feed position. During the movement of the slide 196 a dog 342 acts through lever mechanism on the valve 312 to establish communication between the needle valve ports and the cylinders. As the tool 176 reaches its forward position a lug 350 engages a pin 352 associated with lever mechanism and a lug mounted on the front carriage bar 114 is also adapted, at the end of the travel of the bar 114, to shift a bar forming part of this lever mechanism, the arrangement being such that a link 388 is operated only when both tools have completed their cut. The link 388 imparts rotary movement to the main valve and allows 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. 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 to a sprocket 310 mounted on a clutch element 414 on the main shaft 60. The motor is also connected by a chain to the pump unit 204. 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. In some cases the clutch may be secured in engaged position throughout the operation. Relief valves 458, 460 are provided in the high-pressure and low-pressure pipe lines respectively.