368,251. Milling-machines. CINCINNATI MILLING MACHINE CO., Cincinnati, Ohio, U.S.A.-(Assignees of Einstein, S. ; Avon Building, Clinton Springs Avenue, and Nenninger, L. F. ; 3525, Shaw Avenue, both in Cincinnati, Ohio, U.S.A.) Sept. 25, 1930, No. 28720. Convention date, Sept. 28, 1929. [Class 83 (iii).] In a driving mechanism for a milling-machine or like machine tool the cutter or work holder is driven from a power train through intermediate speed variation mechanism, and a branch transmission, under manual control, is provided for the power shifting of selectors for the various speeds, this transmission being disconnected when the selectors are ready to engage any desired speed. The machine comprises a bed A having a column B provided with a spindle C carrying a milling-cutter 281. The front of the column is provided with vertical guideways for the usual knee D which supports a saddle E movable longitudinally of the spindle and carrying a table F movable transversely. A control handle 50 is carried by a sleeve mounted in the saddle and is connected through telescopic shaft 52, bearing block 53 on the knee, and rack and pinion gearing, to a vertical splined control shaft 58. A second handle 63 is also provided to oscillate the shaft 58. The movement of the shaft 58 is transmitted through a rod 65, and shaft 65a, to a shifter 68 which operates a coupling 69, Fig. 15, splined on a shaft 70 connected through bevel gears 75 to a shaft 76 actuating the feed mechanism for the table, saddle, and knee. In one position the coupling 69 engages a clutch 72 for the high-speed traversing-movements while in the other position, teeth 231 on the coupling engage a gear 71 for the slow feed at a selected speed. A handle 78 on the knee, Fig. 28, is arranged through the mechanism shown to impart vertical reciprocatory movement to the shaft 58, such movement being transmitted through a shaft 87, eccentric 88, arm 89, bell-crank lever 90, Fig. 5, and shaft 91 to a clutch 92 which may be thus engaged with a clutch part 94 driven from the feed gear. The bell-crank 90 is also under the control of a cam 99 operated by a handle 100 and engaging a pin 98 on one arm of the bell crank. The cam 99 also operates a bell crank 102 controlling the clutch 103 of the spindle speed selecting- mechanism, the driven member 105 being operated through worm gearing 109 and spur gearing 107. The spindle driving train, Fig. 7, comprises an electric motor 111 connected by a chain 112 to a driving sleeve 114 which may be locked by means of a disc clutch 118 to the shaft 116. Two sliding gear pairs 123, 128 impart a four-speed drive to a countershaft 126, and a shaft 131 is driven at eight speeds from the countershaft through a sliding pair 132. A gear 138 on the shaft 131 may engage either directly or through a reverser 139 with a gear 137 on a shaft 136 carrying a sliding pair 145, which may thus drive the spindle 141 at either of two sets of eight automatically selected speeds either direction. The shifts of the gear pairs for automatic changes of the spindle speeds are effected from the worm gearing 109 constantly driven from the main driving sleeve through a train 148, 150. The drive of the worm 109 is transmitted through the clutch 103 to a cam shaft, Fig. 8, having a series of cams 155, 158, 161 controlling the shifts of the gear pairs 128, 132, 123 respectively. The cam paths are so arranged that the eight changes of speed of the shaft 131 are obtained in the desired sequence. A gear 169 in the cam shaft operating train rotates a dial 172 to give a visual indication of the particular gear in engagement. If desired the changes may be effected by operation of the clutch 103 by the operator. Preferably the cam shaft 153 is provided with a star wheel 174, Fig. 14, having notches 175 to correspond with the different gears, the positions being determined by a load-and-fire spring plunger 176 which completes a movement started by the power drive of the cam shaft after the clutch 103 has been disengaged. The gear pair 145 which selects the high or low speed range and the gear 138 selecting the direction of rotation are operated by a cam 179, Fig. 10, which has an oscillatory movement effected by means of a handle 184 acting through bevel gearing 186. The cam 179 carries a notched wheel coacting with a load-and-fire plunger similar to that described above for completing the changes started by shifting the handle 184. The feed transmission includes a rapid traverse at fixed high speed and sliding gear change-speed mechanism giving sixteen selected speeds. The main shaft 196, Fig. 15, of this mechanism is driven from the worm gearing 109 and is connected thereto by spur gears 197. Sliding pairs 200, 203 impart a four-speed drive to a shaft 204, while a sliding pair 210 on a shaft 215 enables this shaft to be driven at eight speeds. A sliding pair 217 enables sixteen speeds to be given to the shaft 216, these speeds being imparted to a ring gear 224 connected by spring- ball safety devices to a member 71 coacting with the clutch 69 splined on the shaft 70, this clutch being also engageable with a member 73 driving at high speed from the main driving sleeve through gears 235. The sliding gears are power-shifted by means of cam shafts which are driven through the clutch 92 and shaft 91. The cams coact with load-and-fire plungers as described above to complete the speed changes and the particular speed in engagement is indicated by a dial 266 driven from the shaft 91. The operation of the clutch 92 for effecting the speed changes is controlled by the operator by manipulation of either of the handles 100, 78 the clutch being disengaged and the movement completed by the spring- plunger mechanism when the dial indication shows that the required speed is just about to engage. The same control handles, moved in the opposite direction serve to control the clutch 103 of the spindle-selector mechanism. The main clutch 121 on the shaft 116 is controlled by a lever 268 which is interconnected with the feed clutch 71, 231 so that power actuation of the feed is prevented when the spindle is stopped. The member 68 may, however, be actuated by the handle 50 for coupling the quick traverse feed drive if desired. The shaft 76 is connected to the means for operating the feeds of the knee, saddle, and table respectively. The shaft 76, Fig. 36, is connected through spur gearing 283, shaft 287, and spur gearing 288, to a gear 289 which is connected directly to a gear 290 and indirectly through a reversing pinion 293 to a gear 294, the oppositely driven gears 290, 294 being in constant mesh with gears 323, 324 on a shaft 325. The gears 290, 294 are selectively clutched to a shaft 292 carrying a bevel gear 299 on the feed screw 303, working in nut carried by the knee, the screw 303 serving for the hand or power traverse of the saddle on the knee. The bevel gear 299 may be actuated manually from a shaft 301 rotated by a handle 302, and a hand-wheel 306 is also provided for manual operation of the screw 303. The clutch member 298 controlling the direction of this feed is operated by a shifter carried by a rod 308 which may be actuated by a handle 316, Fig. 38, or by a handle 319. The oppositely driven gears 324, 323 are selectively locked to the shaft 325 by a clutch 326, this shaft driving a nut 331 carried by the knee and coacting with a screw 332 for power actuation of the knee. The clutch 326 is controlled by a yoke 333 on a rod 334, Fig. 38, which may be shifted by either of the handles 337, 340 located at the front and rear respectively of the machine. The handles normally occupy a horizontal position and when they are moved the knee movement takes place in the same direction as the handle movement. The nut 331 may also be operated manually by means of a rod 342 actuated by a handle 343, or by a rod 345 operated by the detachable handle 302. The drive for the table is effected from the shaft 346, Fig. 36, which through reversing bevel gearing 350 operates the table screw 351 working in a nut 354 on the saddle. Shifting of the reversing clutch 356 is effected by a yoke on a rod 360 operated from a handle 363, Fig. 40, or from a handle on the front of the machine. The table screw is also provided with hand actuating means at 368.