Patent GB-444434-A (GB)
Title: Improvements in or relating to milling, cutting or like machine tools
IPC: B23Q1/68
Filed: 1935-03-05
Abstract: 444,434. Milling &c. machines. WANDERER-WERKE VORM. WINKLHOFER & JAENICKE AKT.-GES., Sch÷nau, near Chemnitz, Germany. March 5, 1935, No. 6910. Convention date, March 5, 1934. [Class 83 (iii)] A milling or other machine tool having a longitudinally movable work table and an adjustable tool head has means for giving the tool head, independently of its position, slight movements perpendicular to the plane of the work travel to withdraw the tool from the work at the end of the cut and restore it at the end of the return movement of the work. The machine table 53 is operated by a hydraulic cylinder 51 controlled by a main control valve 41, 42 supplied by a variable delivery pump 40. An auxiliary pump 60 supplies fluid to a common control valve 57 which is operated by dogs on the table to control the movements of the main valve and which also controls the hydraulic actuation of auxiliary members of the machine including a vertical adjustment of the milling head 215, to withdraw the tool from the work, the clamping of the spindle head to the column, the clutch 222 controlling the rotation of the milling-spindle, and the delivery of the main plunp 40. The pump 40 delivers to a passage 23 of the main valve and the discharge pipe 22 passes through a back pressure valve 2, 3 to a return pipe 20. The system is kept filled by a make-up pressure container 90 and a safety byepass valve 43 is provided. The normal delivery of the pump is determined by a manually adjustable cam 109, but by means of a lever 108 operated by a cylinder 106 the pump delivery may be increased for idle travel of the table by inclining the housing of the pump. When the pressure in the cylinder 106 is released, a spring 147 returns the pump to the normal delivery position. The auxiliary pump 60 delivers fluid through pipe 61 to a chamber 58 of the auxiliary control valve which is shown in Figs. 10 and 11 and in partial development in Fig. 1. A valve 293 connected with the auxiliary pump supply by a line 61a and with the auxiliary valve 57 by lines 102, 103 controls fluid supply through lines 102a, 103a to a double acting cylinder 100 which is connected by a lever 210 to a sleeve 213 carrying the adjusting spindle 214 of the milling head so that when fluid is admitted to the top of the cylinder 100, the head is raised to withdraw the tools from the work while fluid admission to the bottom of the cylinder 100 restores the tool to the cut. From the valve 293 a line 218 communicates with a cylinder 220 controlling the main clutch 222 of the driving train of the spindle 227 carrying the cutter 216. This train includes change speed gearing 226. The clutch member 222 is connected by plates 308, 310, Fig. 18, with the driven member 225. As long as fluid pressure in the cylinder 220 is maintained, the clutch is held in engagement, but when the pressure is released, a spring 224 disengages the clutch and a conical braking member 314 engages a part 315 to bring the spindle quickly to rest. This interruption of the spindle drive is timed to occur when the spindle head is lifted away from the work and the fast travel of the table is in engagement. A three-way cock enables the clutch to be cut off from the fluid supply when required. A further line 219 from the valve 293 supplies a cylinder 228 having a piston 229 which is returned by a spring 231. The reduced piston portion 230 compresses water contained in a chamber 232 and forces it through a pipe 234 into a flexible rubber diaphragm member 235 which actuates a cover 285 to clamp the spindle head support for the cutting operation. The diaphragm 235 is located in a vertically movable member 281 which is guided at 282, 283, Fig. 17, in the frame members 263,237. When the diaphragm is expanded by pressure in the pipe 234, a spindle 284 is moved axially, whereupon a sleeve 296 operates bevel ended rods 299, 300 which in turn through their outer bevelled surfaces actuate T-headed bolts 302 to clamp the support member 294 to the columns. In some cases this clamping may be effected by normal operation of the nut 295 to move the clamping member 284. The over-arm 264 is clamped to the support 294 by similar taper ended bolts operated by a nut 306. The main control valve, Fig. 2, comprises an element 41 and a reversing element 42. The element 41 has end abutments 113, 114 which are separated by a spring 117, the spring being compressed when the valve is in one of its end positions and serving to restore the valve to its central position, Fig. 2, when fluid pressure is relieved in the actuating lines 92, 93. In the position shown in Fig. 2, the pipes 46, 47 are both cut off from the main pump supply so that the table is hydraulically locked, and the pump delivery from the pipe 23 is byepassed to the return pipe 22. If the cam 109 is appropriately adjusted, the main pump may be arranged to give zero delivery when the table is locked. When the auxiliary valve is in the table-locking position, Fig. 1, fluid is admitted to the top of cylinder 100 so that the milling head 215 and tool are raised from the work, the head being unlocked. For slow feed movement of the table to the right, the auxiliary valve is automatically set to admit fluid pressure through the pipe 92 thus moving the element 41 to the left, the pin 114 being moved back until the surface 205 engages the end with 189. In this position pressure fluid from the main pump passes through the pipe 46 to actuate the table. The piston 101 is at the same time raised to lower the tool to the work, the spindle driving clutch is engaged and the spindle head clamped. If now the auxiliary valve is moved axialy, fluid is admitted to the pipe 105 and the cylinder 106 to move the main pump to maximum delivery position and give a quick table movement to the right. At the same time the tool head is unclamped, the spindle arrested and the tool raised from the work. For a feed movement to the left, the main valve elements 41, 42 are both moved to their left hand positions. This causes pressure fluid to flow through the line 47 while the auxiliary valve connections cause the tool drive to be re-engaged, the tool head clamped and the tool restored to the cut. The delivery of the pump is now determined by the cam 109. For quick motion to the left the main valve parts are moved to the position shown in Fig. 8. In this position the table cylinder parts lying in front of and behind the piston 49 are interconnected. The fluid from the space 51 therefore passes to the front of the piston in addition to the maximum delivery of the pump 40 so that a high table speed is obtained. This speed is preferably employed for the idle return of the table and the high speed to the right is used to traverse the table over the distances between different parts of the work. As for other high speed parts of the table cycle the tool head is unclamped, the tool spindle raised, and its rotation stopped. The valve 293, Fig. 20, is set by a hand lever 327 and has three positions determined by a spring ball 357. In one position, no fluid can pass through this valve to the pipes 218, 219 and 103a so that the spindle head is unclamped in its raised position with the spindle stationary. In another position fluid can flow into the pipes 219, 103a and 218 so that the spindle head clamping, lifting, and lowering mechanisms and the spindle-driving clutch may all be automatically operated. In another position of this valve, the spindle head is in its lowered position with the clutch engaged, but the spindle head is not clamped so that it may be vertically adjusted. The movements of the auxiliary valve to give the required cycle of feed and quick traverse movements are effected automatically by dogs 54, 55 on the table which impart axial and rotary movements to a spindle 56 connected by an arm 191, Fig. 13, to a member 199 on an axially movable shaft 200. Another lever arm 201 on this shaft is connected to the auxiliary control valve 57. Thus, when the spindle 56 is rotated by one of the table dogs, the shaft 200 is moved axially and rotary movement is imparted to the auxiliary control valve, but when the spindle 56 is moved vertically the valve 57 is moved axially. The valve may also be moved in either direction by a ball jointed hand lever 194 which is moved to the left for left-hand table feed and vice versa. The rotary adjustment of the auxiliary control valve is determined by a pair of pawls 157, 158 engaging in circumferential notches in the head of the valve. The axial positions are determined by locking bolts 162, 163 engaging in notches 164, 165, 167, 168 in the valve head. The position of the parts shown in Fig. 11 corresponds to the locked position of the valve in which axial motion is prevented by the peaks 178, 184, but after rotation of the valve in either direction, the axial movement which gives the change to the high table speed may be effected. The spindle 214, which is raised to lift the tool from the work, is screwed into the milling head at 259, Fig. 14, and is mounted in a sleeve 213 which is raised and lowered by the lever 211 and has an abutment shoulder 244 which ensures constant depth of cut. The head may be adjusted independently of the tool relieving mechanism by rotating the adjusting spindle by bevel gearing 252. Play in the screw and nut 259 is taken up by a nut 260 having a differential external thread 261 screwing into the head 215. The head carries a horizontally adjustable over-arm 264 and the cutter spindle is mounted in an axially adjustable sleeve 265. To effect this adjustment a stub shaft is connected by helical gearing 268 to a shaft 269 driving through helical gear 270 and worm 271 a rack on the spindle sleeve. To clamp the sleeve in adjusted position, a spindle 272 operates a rack engaging a wheel 276 on a screw spindle 277 which engages the clamping member 279.