Patent GB-970092-A (GB)
Title: Improvements in or relating to machine tools
IPC: B23Q35/18
Filed: 1962-07-03
Abstract: 970,092. Machine tool details; cutting by fusion. H. ERNAULT-BATIGNOLLES. July 3, 1962 [Oct. 27, 1961; April 25, 1962], No. 25536/62. Headings B3K, B3T and B3V. A copying lathe, milling machine, torch cutting machine &c. comprises a frame, a member movable relative to the frame in a first and second direction by power means, a feeler engaging a pattern, and a mechanical drive interconnecting the member and a controller, so that movements in the second direction will impart corrective displacement to the controller to vary the movement of the member in the first direction. A lathe comprises a frame 1, a stationary head stock 2, a tailstock 3 slidable on ways 4, 5, a carriage 6 slidable on ways 7, 8, and a cross slide 11 slidable on ways 12 on the carriage. Work spindle 16, is driven by a motor through a variable speed transmission 17, and a lead screw 29 is driven from spindle 16 by a belt 32, through a gear-box 35 and gears 37, 38. Longitudinal displacement of carriage 6 is produced by an hydraulic piston 26 and transverse movement of slide 11 is produced by an hydraulic piston 23. Piston 26 is controlled by a spool valve 28 connected to leadscrew 29 which is supplied with fluid by a pump 115, which also supplies fluid to a spool 101 secured to a feeler 102, for controlling piston 23. Spool 101 is mounted on slide 11 which also carries a cutting tool 108. Lead screw 29 is biased to the left, Fig. 1, by a spring 75 and is displaceable to the right by a solenoid 76, and meshes with a gear 51, Fig. 2, secured on a shaft 82 rotatable in carriage 6. A further gear 83 is mounted on a shaft 87 and meshes with a worm 84 carried by slide 11, and is rotatable but axially fixed relative thereto. Shaft 82 has a clutch member 82a engageable with a similar member 89 on slide 6, and a clutch member 93 engageable with a similar member 94 secured to shaft 87 and solenoids 92, 96, are provided to move the shafts against springs 91, 95 to engage the required clutches. In operation gear-box 35 is set to the required gear ratio, a solenoid 67 is energized to engage clutch 65, and spindle 16 and lead screw 29 are rotated. Solenoid 76 is de-energized, lead screw 29 is moved to the left by spring 75, thus moving spool 28 leftward and applying pressure to the right-hand side of piston 26, and carriage 6 is displaced to its endmost leftward position. Clutch 93, 94 is engaged, thus connecting gear 83 for rotation with gear 81, and pump 114 is operated continuously to supply fluid to spools 28, 101. Assuming feeler 102 is moved from c to a on pattern 103, spool 101 is moved inwardly, and fluid is exhausted from the lower part of cylinder 22 to the sump 114, via lines 122, 124. Slide 11 moves relative to carriage 6 to retract tool 108 from the work. Worm 84 moves with slide 11 and rotates gears 83, 81 to move lead screw 29 axially a small amount, thus moving spool 28 in a direction tending to oppose the movement of carriage 6 and reducing the longitudinal feed of tool 108 approximate to a constant cutting velocity. In a modification, Figs. 6, 7 lead screw 29a is fixed axially and spool 28a is carried by a rack 131 mounted on slide 11. Rack 131 meshes with a gear 83a secured to gear 81 meshing with the lead screw. In a further modification, Figs. 8, 9, shafts 82, 87 are coupled by a clutch 94 engageable by a solenoid 92 and gear 83 is permanently coupled to shaft 87 by a friction clutch 151. Shaft 87 can be locked to carriage 6 by an electromagnetic brake 153 energized from a circuit having switches 156, 144. Switch 144 is mounted in a bracket 142 secured to carriage 6 and the bracket also supports a slider 140 spring urged against slide 11. When slide 11 is displaced leftward, Fig. 9, slider 140 engages bracket 142 at 143b and switch 144 is depressed to de-energize the circuit and release the brake 153. Shafts 87, 82 are freely rotatable, and as slide 11 recedes, rack 84 rotates gears 83, 81 to move lead screw 29 axially. Specification 690,010 is referred to.