Patent GB-946987-A (GB)
Title: Machine tool with tool-changer
IPC: B23Q3/157
Filed: 1961-03-02
Abstract: 946,987. Machine tool details. KEARNEY & TRECKER CORPORATION. March 2, 1961 [Aug. 18, 1960], No. 7613/61. Headings B3B, B3C, B3K and B3N. [Also in Division E2] A machine tool comprises an operating station having tool support means 40, tool change means 64 including tool-engaging clamp means and power-drive means to actuate the tool change means and the clamp means. The tool spindle 40 is carried in a head 37 movable vertically on a column 28 movable on a bed 25. The work is carried on a pallet 50 indexable on a saddle 48 which can be moved in the direction of the tool axis for drilling feed &c. The machine is controlled by push-button or by tape means in cabinets 41, 42 to control hydraulic or electric motors to perform cutting operations by moving the tool head, column and work-saddle. The control means also change the milling, drilling, boring or tapping tool in the spindle by moving the latter to a tool-change position and selecting a tool in a drum 68 mounted on a fixed support 63; and selecting a tool in a drum 68 mounted on a fixed support 63; and further control the speed of movement of the tool. Each tool has a key 87, Fig. 2, to engage a keyway in a socket 84 secured by a screw 85 in the magazine. A tool is retained in its socket by a spring-pressed lever 91 having a projection 94 engaging a groove in the tool. The lever 91 is released either by a treadle-actuated cam when setting- up the machine or by a plunger 114 which is actuated when a toothed lever 107 is moved by a cylinder device 111 to engage and lock a gear 103 on the drum. The drum is rotated by a solenoid-controlled hydraulic motor driving through chain-gearing and stopped by a retractable switch mechanism 131 actuated by coded means 126 on a selected tool. Positioning of the drum is determined by a roller spring- pressed into a recessed disc. To interchange tools, the tool in the spindle and the next selected tool are each gripped between twin-jaw clamps 181, 182, Fig. 3, which are moved longitudinally by a gear 238 rotated by a rack 263 operated by an hydraulic rack bar in a cylinder 244, Fig. 7. The bar 263 is connected by a latch 312 to the jaw 268, but the latch is released as the clamping position is approached to allow a cam 294 on the bar to be advanced to engage a pin 288 on the pivoted jaw 283 to force the jaw into a retaining groove in the tool. The tool change means is then advanced to a forward position by an hydraulic device 215 operating through a swinging lever 223 connected to a slide 169. The tools are thus withdrawn from their sockets. A rack 209 is then moved to rotate a housing 186 through 180 degrees, the slide 169 is retracted, and the tools are inserted into the drum and spindle respectively. A variable speed hydraulic motor 354, Fig. 13, rotates the tool spindle 40 through speed-changing electromagnetic clutches 369, 379, 385. A synchro 353 is rotated with the tool spindle to provide a reference for stopping it in a set angular position having regard to the key on the tool. The key engages a recessed plate at the front of the spindle and the tool shank is clamped by a collet 422 actuated by springs 428. To release the collet, pressure is admitted to a line 455 to cause opposite axial movements of a floating sleeve 437 and piston 446, thus compressing the spring and rendering it ineffective, without exerting any end-thrust on the bearings. When the tool includes a tap 475, Fig. 14, springs 473, 474 are provided to allow the tap to float. Any fluctuation in the rate of feed of the tap relatively to the spindle causes a rod 478, Fig. 13, to move axially and actuate a lineal potentiometer 444. Specification 946,988 is referred to. Reference has been directed by the Comptroller to Specifications 916,501 and 916,502.