Patent GB-1258426-A (GB)
IPC: F02M59/48
Filed: 1969-01-15
Abstract: 1,258,426. Lathes; tool-changers. R. K. LEBLOND MACHINE TOOL CO. 15 Jan., 1969, No. 2457/69. Heading B3T. [Also in Divisions B8 and G3] A lathe comprises a turret 20, having tools 21, 22, Figs. 1 and 3, a tool storage magazine 30, arid a tool changer 25, which changes the tool 22 whilst the other tool 21 is carrying out a machining operation on the workpiece 14. Turret 20 is mounted on a cross-slide 18 which is carried by a longitudinal carriage 10. Tool changer 25 is mounted on a cross-slide 33 slidably supported by a longitudinal carriage 32, and includes a tool gripper 34. Turret 20 comprises a tool block 75, Fig. 39, which is indexable relative to a base 60 by a rotary hydraulic motor 131, Fig. 45, which drives gearing 134, 135, 137, 136, 125, 123, 122 and 120. Also connected to this drive is a cam-shaft 140, the cams of which co-operate with switches S26- S29, for controlling the rough indexing positions of the turret 1, the final accurate positions being controlled by a cam 142 which co-operates with switches S2, S31. To assist in the indexing operation, the turret is lifted vertically so as to disconnect a coupling 62, Fig. 39, by fluid pressure piston 67. The tools 21, 22 are clamped in the turret by fingers 170, Fig. 39, actuated by pistons 162, air being supplied to conduits 116 for blowing away dirt prior to gripping the tools, and coolant being supplied to the tool through a conduit (190), Fig. 38 (not shown). The tool storage magazine comprises a chain conveyer 254, Figs. 20-22, located on sprockets 262- 265, the sprocket 262 being driven by a rotary hydraulic motor 270 through gears 268, 269. Tool modules 267 are carried by the chain and are adapted to carry a tool holder 216, each of which is releasably locked by a pin 305, has notches 229, 231 for engagement with gripper 34 and a coding 220 which is read by a head 320 at the pick-up station. The head is adapted to detect any one of thirty-one tools. Tool gripper 34 comprises a pair of gripper cams 400, 401, Fig. 24, which are actuated by a toggle linkage 405 pivoted by an hydraulic piston 383, air conduits 369 being provided for blowing dust out of notches 229, 231. Tool changer slide 32 is supported on ball retainers 421, 422, 426, 427, Figs. 28, 30, and is moved between the turret 20, and tool magazine 30, by an hydraulic motor 450 which drives gearing 452, 454. The supply of fluid to the motor is controlled by a servovalve 455 actuated by an arm 456 which abuts a stylus 43 controlled by three stops (460), Fig. 31 (not shown), 499, Fig. 30, and 48, Fig. 3. Slide 33, Fig. 3, is controlled in a similar manner to slide 32. In operation, a tool 21, Fig. 1, is operating on the workpiece 14 and carriage 31 is in the parked position of Fig. 4. A tool change cycle is initiated by a tape reader slide 32 moves towards turret 20 at a fast rate until a switch on slide 18 is actuated, whereupon slide 33 also moves at a fast rate. Stylus 43x engages turret slide 18, and the slide 33 moves in synchronization with slide 18. A switch is actuated and causes slide 32, Fig. 3, to move at a slow rate until stylus 43 on slide 32 engages a wing 38, whereupon the movement of slide 32 is synchronized with that of carriage 17. The arms of gripper 34 are engaged with the notches in tool 22 so that the latter is moved out of turret 20 when slide 32 moves to the left, Fig. 3. After removal of the tool, slides 32 and 33 move gripper 34 quickly to the parked position, Fig. 4. A switch is actuated and carriage 31 moves to the right, Fig. 3, at a slow rate until the tool passes through an aperture 252 of the magazine 30, Fig. 23, and is deposited-and locked in an empty module 267. Gripper arms 400, 401, Fig. 24, are opened and carriage 31 is moved to the standby position, Fig. 4. Conveyer 254 is actuated so as to move the tools in the magazine past the reader head 320 until the required tool is selected, whereupon the conveyer stops, and the tool is picked up by gripper 34. Carriage 31 once again moves up to turret 20 and the new tool is inserted therein, whilst tool 21 is still operating on the workpiece. Carriage 31 is now moved to the standby position, so that when the machining operation is completed the turret can be indexed so as to bring the new tool into the cutting position. The hydraulic servo control circuit for maintaining the slides in synchronism may be replaced by a completely electrical or electrical-hydraulic circuit.