Patent GB-499137-A (GB)
Title: Improvements in or relating to milling machines
IPC: B23Q11/00
Filed: 1937-06-14
Abstract: 499,137. Milling-machines. KEARNEY & TRECKER CORPORATION. June 14, 1937, No. 16482. Convention date, June 20, 1936. [Class 83 (iii)] A milling-machine has a column carrying a knee fitted with the usual saddle and table, a selectively driven shaft for supplying power from the column to feed rate gearing carried by the knee, a continuously driven shaft connectible to a common driver actuated by the feed gearing, the said common driver being connectible to operate the knee saddle and table at any predetermined rate. The column 31. carries a vertically traversable head 32 fitted with a vertical spindle 33. The knee 34 moving in guides on the column carries a saddle 36 movable to and from the column and carrying a transversely moving work table 37. A motor 38 mounted within the column, Fig. 3, is belt connected through a pulley 42 and friction clutch 52 to a hollow main shaft 43, and a fan 49 on the motor shaft circulates air around the motor to cool the same. The hollow main shaft extends into the separate gear compartment 51 and carries a bevel gear 53 driving reversing bevels 54, 55 selectively engageable by a splined clutch spool 57, to impart a reversible drive to the shaft 56 of the spindle driving train. The reversing clutch is operated from a knob 60 having axial positions determined by detent mechanism. The shaft 56 is connected by change gears 62 to the shaft 64 of change-speed gearing 65. The shaft 64 carries a sliding pair 66 imparting a two-speed drive to shaft 71 which carries'gears, Fig. 4, coacting with two sliding pairs 73, 74 on another shaft 72 giving eight speeds in all to that shaft. The shaft 72 is connected through vertical shaft 84, gears 85, splined shaft 90 and two-speed gear pair 92 to the tool spindle 33. The spindle-head is moved vertically either automatically as described below or manually from a hand wheel 98 through shaft 99, bevel gearing 102, Fig. 21, gearing 104, 108 and threaded sleeve 110 engaging a screwed rod 111 secured in the head. The gear pair 66 of the speed-change mechanism is shifted by a handle 125, Fig. 3, on a lever 118 connected to a crank arm 120. A second lever 128 operated by a handle 150 actuates a cam disc 131, Fig. 12, which operates rockers 135, 136 to shift the gear pairs 73, 74 respectively. Quarter revolutions of the cam plate are arranged to engage each of the four gears in turn. A handle 158 on the spindle head is connected through lever mechanism to the sliding pair 92 to shift these gears. For indicating the spindle speed, the lever 128 carries a dial 168 divided into quadrants and the lever 118 has an opening which enables one half or the other of each quadrant to be observed according to the position of the lever 118. The figures thus observed give the two spindle speeds obtained from the two positions of handle 158 of the spindle head gears. Starting and stopping of the spindle are controlled by the main clutch 52 operated by a lever 171, Fig. 23, connected through bevel gears 174, shaft 176, and rack-and-pinion gearing 177 to the clutch shifter 179 which operates a bell member 185 actuating the clutch fingers 186. When the clutch is disengaged, a brake 183 is engaged to stop the spindle-driving train. The clutch-operating shaft 176 is hollow and encloses a control cable extending from a pushbutton 191 to the motor 38. A sleeve 194 further protects the bottom part of the cable from lubricant in the housing 51. One side of the housing 51 is provided with a breather opening protected by louvres and baffle plates to prevent escape of lubricant. The main shaft 43 carries a gear 217 connected through shaft 215 and worm gearing 214 to a vertical shaft 211 operating the feed speeds of the table. A sleeve 218 on the driving pulley is similarly connected through shaft 227 and worm gears 228 to another vertical shaft 212 operating the quick traverse speeds. The shafts 211, 212 drive horizontal shafts 231, 232, journalled in a bracket 233 secured to the knee. A coolant pump 243 located in the bottom of the compartment 44 is driven by the shaft 211 and delivers coolant to the cutter-spindle. The bracket 233 is associated with telescoping plates 245, 256 serving as guards to prevent foreign matter from entering the compartment 44. The power feed-shaft 231 is connected by change gears to a shaft carrying two splined gear pairs 261, 262, Fig. 8, selectively engageable with gears on a parallel shaft 267 which is connectible by a gear pair 275 to a shaft 274. A clutch gear 279 on the shaft is selectively engageable with a gear 280 on shaft 267 or with a clutch gear 282 continuously driven from a pinion 283. A gear 285 on shaft 274 drives an overrunning gear 286 on shaft 288. The gears of this feed train are shifted by a pair of cams 316, Fig. 8, each similar to the cam 131, Fig. 12, and actuated from a crank 289 on the knee through a shaft 290, spiral gears 292 and gearing 296. The cams are so arranged that the cam which shifts the pairs 261, 262 is operated through its entire cycle following each quarter revolution of the cam controlling the gears on shaft 274, sixteen changes of speed being thus obtained. The selected speed is indicated on a dial 236 which is driven with 16: 1 reduction from crank 289 so that successive turns of the crank to operate the cams 316 bring the dial markings successively against a stationary pointer. The shaft 288 carries a gear 342 which drives in opposite directions a pair of gears on the elevating gear shaft 347 driving the elevating screw 357 through bevel gearing, and also another pair of gears on a cross-traverse shaft 351 having a threaded portion engaging a nut 360 in a bracket 361 depending from the saddle. The direction of movement of both shafts is determined by shiftable clutch sleeves 355, 359, Fig. 5, the sleeves being operated independently by means of manual control levers 371, 372, Fig. 6, and having detent mechanism which determines forward, reverse and neutral positions. The clutches 355, 359 may also be operated automatically from the movements of the knee or table. For this purpose, trip dogs 391, 392 on the knee may operate a lever 393, connected by a rod 394 to a sleeve operating the clutch 355. Similarly, dogs 397, 398 on the saddle act through a member 399 and trip rod 401 on a member 402 secured on the shaft operating the clutch 359. The shafts 347, 351 may also be turned manually by hand wheels or cranks 405, 406 and means are provided for preventing the hand cranks from being clutched to their shafts while the corresponding power drive is in operation. For this purpose each of the clutch operating levers 371, 372 carries a slotted guard portion 425 of which only the enlarged centre portion 426 is wide enough to receive the cylindrical hub of the corresponding hand crank so that the levers must be in central position with the clutches in neutral before the hand mechanism can be moved to engage the hand crank clutch. The hand cranks themselves are also locked against rotation by lugs 427 on the guard rings when the power clutches are in operation. For the rapid traverse movements of the table, the shaft 232 has a friction clutch 430 engageable by means of a hand lever to drive a shaft 434, Fig. 8, connected to the shafts 347, 351 and their associated reversing mechanisms. The shaft 288 overruns the gear 286 when this drive is in operation. To slide the table on the saddle 36, a shaft 438 driven from the wheel 350 at either feed or rapid traverse rates is connected through bevel gearing 440 and reversing bevel gearing 445, 446 to a screw running in a, nut secured to the saddle. The clutch sleeve 448 of the reversing mechanism is operated by an external lever 453. A hand crank may be employed to move the table manually. The power traverse of the head 32 is also derived from the shaft 438 which carries a spur gear 463 connected, Fig. 5, to a vertical shaft 467 connected through reversing bevel gearing, Fig. 2, to a shaft 471 geared to the shaft 103 of the spindle-head elevating-gear, Fig. 21. Interlocking means are provided to prevent rotation of hand wheel 98 by the power mechanism. The reversing mechanism of this train is controlled by a hand lever 477 and trip dogs 481, 482 may be arranged to move the reversing clutch to neutral at either end of the power movement.