Patent GB-541995-A (GB)
Title: Improvements in or relating to boring and milling and like machines
IPC: B23B39/02
Filed: 1940-04-11
Abstract: 541,995. Boring, milling &c. machines. KEARNEY & TRECKER CORPORATION. April 11, 1940, No. 6594. Convention date, April 15, 1939. [Class 83 (iii)] A boring milling and like machine tool has a rotary spindle mounted in a slidable ram and driven through variable speed gearing, the spindle being connected to feed mechanism including speed changing gearing mounted on the ram for effecting the sliding movement of the ram at a selected speed. A hollow bed 21 carries a longitudinally reciprocable bed 22 and has also extensions 23 carrying tool spindle columns 25, 26 which are adjustable to and from the table by screws 51, 52. Headstocks 27, 28 are mounted on the respective columns and carry horizontally slidable rams or spindle carriers 29, 30 having tool spindles 31, 32. The rams 29, 30 may be manually moved by a pilot wheel 34 and clamped by a lever 36. Vertical adjustment of the head. stocks is effected by screws 39, 40 operated from actuating shafts 37, 38. Each headstock is counterbalanced by a weight 45 attached to a chain 46, and may be clamped in any adjusted position by a clamping lever 50. For setting the headstocks on the columns dial indicators 62 co-operate with measuring rods 63 placed between the indicator and an abutment 64 on the bed. As the head is moved down the part 65 engages the rod 63 and operates a lever 67 to move a rod 70 against a spring 71 and thus Fig. 6, actuates the spindle 73 of the dial indicator. After the spindles have been adjusted to the same height, their alignment may be checked by telescopes 75, 76 mounted on the spindle heads and directed on targets 78, 79, each telescope having cross hairs which register with a corresponding mark on the opposite target when the spindles are aligned as described in Specification 546,405, [Group XX]. If the spindles are misaligned in a horizontal plane the columns may be transversely adjusted by means of tapered gibs which are moved in opposite directions to perform the adjustment. If one of the spindles is misaligned angularly the gibs may be scraped to effect the required angular adjustment of the column. Each spindle head has an independent driving motor 87, 88 and each includes a saddle 90 slidable on ways on the column including side bearing surfaces 92. The clamping mechanism is operated from a handle 50 which operates an eccentric 103 to shift a rod 102 and so actuate an equalizing bar 101 connected to two pairs 95, 96, Fig. 10, of vertically spaced clamping arms. The bar 101 carries pivotal shoes 105 engaging abutment screws on the clamping arms the clamping ends of which are engaged with surfaces 97, 98 to draw the saddle against the forward face of the column. The sliding rams 29, 30 are each guided by side elements 111, 112, Fig. 14. Taper gibs 113- 115 are provided to obviate slackness in the ram bearings. An extension 118, Fig. 1, has a horizontal surface which assists in supporting the ram in its withdrawn position. The ram is moved longitudinally by rack and pinion mechanism 122, Fig. 14, operated from the wheel 34. For clamping the ram the lever 36 actuates a screw which engages a hardened insert 126 to force the ram against the bearing surfaces 108, 109. The tool spindle 32, Fig. 12, is supported in taper roller bearings 128, 129 and roller bearings 130, 131. The motor 88 drives a shaft 135 connected by gears 136 to a shaft 137 which carries two sliding gear pairs 138, 139 giving a four speed drive to a shaft 140. Another shaft 141 carries a gear 142 and a pair 143 which are slidable to impart a three speed drive from shaft 140 to shaft 141 which thus has twelve speeds. The gears are changed from a crank 145 on a shaft 146 which actuates the cam plates 148, 150, a different gear being obtained for each turn of the crank. From the gear box 134 the drive passes to a range changer 156 mounted in the ram giving a further two-speed drive through a sliding pair 161 operated from a lever 167. There are thus in all 24 spindle speeds and reverse is effected by reversing the motor 88. Power feed of the ram 30 is obtained from the spindle 32 through worm gearing 171, Fig. 12, which is connected through pick-off gears, bevel reversing gearing and clutch sleeve to a worm 188, Fig. 14, driving a worm wheel 189. A clutch sleeve 191 has notches engageable by the arms 194 of the hand feed wheel by means of which the sleeve may be moved axially to engage axial clutch teeth with the wheel 189. The axial power feed of the ram is thus correlated to the spindle rotation for performing spiralling or similar operations, the speeds being changeable without interfering with the pitch of the spiral. The forward feed may be arrested at a preselected position by turret stop mechanism 195, Fig. 1, having selectively-operating stop rods 196 cooperating with a stop plunger 197 which acts through a lever 198 to disengage the clutch in the ram sliding train. For precision adjustment of the ram, a dial indicator 200 is operated by the rod 197 and the ram is adjusted by a hand wheel 202, Fig. 13. Rapid movements of the ram are manually effected from the wheel 34 after the arms 194 have been moved to disengage the clutch sleeve 191. The work table may be fed by a motor 204, Figs. 1 and 16, which drives a gear box 205. The main shaft 206 drives a splined shaft 208 connectible by two sliding gear pairs to a shaft 212. This shaft is connectible by two sliding gear pairs to a shaft 215. A clutch pinion 216 on this shaft is engageable with a loose gear 217 geared to a wheel 218 connected by an overload release 219 and over-running clutch 220 to a driving shaft 221. When the clutch gear 217 is disengaged a gear 222 thereon engages a pinion 223 on a shaft 224 which is driven from the clutch 216 and gear 225. These gears operate as a range changer so that in all 32 speeds are obtained for the shaft 221. The changes are effected from a crank on the side of the base and indicated on a dial. A rapid traverse clutch 228 driven from a wheel 229 may be engaged to drive a wheel 231 connected to a gear 232 on the shaft 221, the over-running clutch 220 permitting the high speed rotation of the shaft without interference from the feed drive. The shaft 221 is connected through a cross shaft 237, and shaft 239 to gear boxes 241, 242 on the columns, these gear boxes being arranged to provide a reversing drive to a shaft 246 which operates the elevating screw 40. When the reversing clutch is in neutral the manual elevating gear may be used and an interference guard 251 prevents application of the hand crank unless the clutch is in neutral. A reversing clutch gear 254, Fig. 16, is selectively engageable with gears 255, 256 which drive in opposite directions pinions 259, 260 on the table feed screw 257. The clutch gear 254 is shifted by a fork on a rod 263 operated by a rock shaft 265 from either of the levers 267, 268 which may be connected to further levers operable from another position. The table screw may also be operated from a hand crank 274. A dial indicator may be used in conjunction with measuring rods for precise indication of the table position. Head wheels 279, 280 arranged on transverse shafts are connected through worm gearing and a friction clutch to the shaft 273, the clutch being actuated by a hand lever 289. The power clutch control rod 263 has a notch 291 engaged by a plunger connected to the operating means of the friction clutch when the power clutch is in neutral position thereby permitting movement of the clutch for the hand feed and locking the power clutch against movement. Where the power clutch is engaged the hand wheel clutch cannot be operated. The table may be clamped to the bed by a clamping lever 295 acting through an eccentric 296, Fig. 7, on a lever 297 which operates a rod 300 carrying a shoe which bears on the inclined face of a gib carried by the table 22. The traverse clutch 228 is actuated by a rod 311 connected to a cross shaft 309 having hand levers 307, 308. The table and heads may also be controlled by trip mechanism. For the vertical head movement a trip rod carries collars co-acting with an arm connected by linkage to the reversing clutch 248 which is neutralized to stop the head at the end of a predetermined travel in either direction. The spindle motors and the feed motor are fed from lines Ll ... L3, Fig. 17. A master switch 325 controls all the motors and the feed and spindle motors also have individual switches 326 ... 328. Closing push buttons 331 complete the circuit of a solenoid 336 to close the master switch and establish a holding circuit 340. The master switch may be opened by depressing either of the stop buttons 332. With the master switch closed the feed motor may be similarly controlled by start and stop push buttons such as those controlling the solenoid 354 of the switch 328 of motor 88. If motor 88 becomes overloaded an overload relay 351 opens and breaks the circuit of switch 328. Motor 87 has a similar overload relay. For controlling the direction of rotation each of the motors 87, 88 has a reversing switch 371. The feed motor may only be started after one or both of the spindle motors has been started and stops if either spindle motor is overloaded. An overload relay 387 is also included in the circuit of the feed motor itself. A rapid traverse switch 392 may be closed by the lever 308 to obtain rapid traverse of the table without actuating either of the spindle motors as long as the lever 308 is held in rapid traverse position.