Patent GB-762298-A (GB)
Title: Improvements in or relating to milling machines or like machine tools
IPC: B23Q35/18
Filed: 1954-03-30
Abstract: 762,298. Copy-milling. CINCINNATI MILLING MACHINE CO. March 30, 1954 [May 18, 1953], No. 6482/54. Class 83 (3). A tracer-mechanism for milling-machines &c. comprises adjacent " rate and direction motor control " and " depth control " valves 56<SP>1</SP> and 145, and an abutment 185 between them which can be moved into a position where movements of the former valve due to a tracer 38 are transmitted to the latter valve. The milling- machine comprises a bridge 12 traversed by an hydraulic-motor 23 and rack-and-pinion gearing 18, 19. The bridge carries a transverse-slide 14 moved by an hydraulic-motor 24 and gearing - 25, 26. The slide 14 carries a vertical-slide 15 moved by a screw 27 and motor 29. For 3- dimensional copying, the motor 29 is controlled either automatically by the tracer-operated valve 145 or manually by a control-valve 160 operated by a hand wheel 30, a screw 163 and a nut 162. A valve 166 is set to move a valve 157 according to whether manual or automatic operation is required. A further " Retract " setting of the valve 166 causes pressure to be supplied via line 171 to move a plunger 172 to depress a lever 174<SP>1</SP>, and the valve 145 to raise or retract the cutter and tracer-slide. Normally, rocking movement of the tracer 38, which is of the type described in Specification 753,620, operates only the motors 23 and 24 via a collar 51 and a sleeve 55, and upward movement of the tracer operates only the motor 29 via a rod 176, the lever 174<SP>1</SP> and the valve 145. However, excessive rocking-movement of the tracer, whether under manual or automatic control, moves the sleeve 55 and valve 561 upwardly until the floating-lever 182 contacts the lever 174<SP>1</SP> and rocks it to cause retraction of the slide 15. To control the motors 23, 24, the tracer 38 is slightly offset to " anticipate " the pattern and rocks about a pivot 34 to move the collar 51 transversely, and thus displace the sleeve 55 operating the valve 56<SP>1</SP>. The valve 561 controls a motor 44, pressure being supplied to the motor from a pump P by valves 48, 47 and 64. Rotation of the motor causes movement of an inclined-ring 46 to set the valves 47, 48 as described in Specification 763,219. In the position of the valve 47 shown in Fig. 3, the motor 23 only is operating at full pressure. Pressure from the pump P passes via passages 72, 73, 75 and 78. The line 78 is connected to one of four balancing-valves 86 by passage 78a, thus closing the valve against a spring 102. The balancing-valve 88 is connected to the exhaust side of the motor 23 and moves to a position of equilibrium so that there is a constant flow of the motor exhaust-fluid in accordance with the setting of the valve 47. The operation of the motors 23, 24 may be controlled manually, after moving the valve 64 upwardly, to cut out the motor 44 normally connected to lines 65, 67, by a hand wheel 188, Fig. 2. If it is desired to move the tracer up to the pattern under manual control and then to proceed automatically, a valve 181, Fig. 3, is set as shown so that as soon as the valve 561 is moved by deflection of the tracer, fluid is directed to the valve 64 to move it to " automatic " position. In turning the valve 181 to a second position, a pin 180 moves the abutment 185 between the levers 1741, 182 so that movement of the arm 182 by deflection of the tracer always causes movement of the lever 174<SP>1</SP>, normally only moved by upward-movement of the tracer. The machine is then set for automatic-control of the slide 15 and manual-control of the motors 23, 24.