Patent GB-460483-A (GB)
Title: Improvements in metal cutting and like machine tools
IPC: B23B3/18
Filed: 1936-04-03
Abstract: 460,483. Lathes. CURTIS, M. S. April 3, 1936, No. 9970. [Class 83 (iii)] A lathe or other machine tool has the spindle driven by infinitely variable gearing of the positive drive type and the feed gearing is driven from the spindle also through positive infinitely variable gearing. A power pulley 35 is connected to the spindle 12, Fig. 3 by gearing 33, chain gearing 24 comprising a gear faced chain engaging pairs of spaced gear cones 22, 23 and 25, 26 change gears 19, and gears 17, 16. The gear cones are slidably keyed on their shafts and are operated by a pair of pivoted arms 28, 29 which simultaneously move one pair of cones together and the other pair apart so as to give an infinitely variable gear of the positive type. The spindle is connected through chain gearing 37 to a countershaft 39 which is connected by similar variable-speed chain gearing 40 .. 43, shaft 44, change gears 440, and gears 443 to a feed shaft 50 to impart the variable low speed drive thereto. A shaft 54, belt driven from the main shaft is connected through gears 52 and clutch 51 to the shaft, 50 to impart a constant high speed drive the low speed drive being overrun by means of ratchet mechanism when the clutch 51 is engaged. Another clutch 58 connects the feed shaft to a shaft 60 which is geared at 64 to the cam drum for operating the slide 69 of the turret 70. Shaft 60 is also geared at 74 with a dog-carrying control drum 77 which rotates once for each complete cycle. The clutch 58 is actuated from a dog 78 on the drum through lever mechanism and a lever 79 which may also be manually operated by the handle portion 85. Clutch 52 controlling the high and low feed speeds is operated by dogs on the drum through a lever 87 which is also controllable by a handle portion 93. The cone gears of the variable speed spindle and feed trains are operated by hydraulic gearing. The operating levers 28, 29 are actuated by pistons 94, 95 whose common piston rod carries an arm connected by link 99 to toggles operating the lever arms. Another arm 105 on the piston rod operates a slide valve connecting with a second slide valve 111 to contro 1 admission and exhaust to the cylinder ends 135, 137. The slide valve 111 is operated by a cam 112. Fig. 2 mounted on a spindle which is rocked by a lever 118 actuated by a dog 115 which also has a cam portion imparting a transverse oscillation to the lever 118 to control an exhaust valve 124. Fluid is supplied from a pump 127 and exerts a balanced pressure on the pistons 94, 95. Exhaust from the cylinder end 137 is normally closed but may pass through a port 109 and passages 145, 146 in the slide valves to the valve 124. Similar passages provide exhaust from the cylinder end 135. If valve 111 is moved to the right, Fig. 6, the exhaust passages 145 ... 147 come into register and when valve 124 is opened fluid is exhausted from cylinder 137 and the excess pressure in cylinder 135 causes the pistons and the slide valve 107 to moved to the right until part 146 is closed, when equilibrium is again established. This movement of the pistons effects the desired speed change. If desired the valve 124 may be opened first and then the slide valve 111 shifted by its cam to give progressive speed change as is required for facing work. The lever 118 may also be operated by its handle 147 to effect the speed changes. A lever 149 with a handle 150 may be manually or automatically operated in a similar manner to control the feed speed changes.