Patent GB-190223552-A (GB)
Title: Improvements in Turret Lathes.
Inventor: HARTNESS JAMES
Filed: 1902-10-28
Granted: 1903-10-28
Abstract: 23,552. Hartness, J. Oct. 28. Lathes.-A semi-automatic lathe for operating on bar stock has a hollow headstock forming an oil bath enclosing the change gearing for driving the lathe spindle and the feed-shaft. The lathe also has a stop-motion to limit accurately the travel of the cutting-tools, a power-operated cross-slide on the turret rest, a hand-operated double lever carrying cutting-off tools, and a selector mechanism for varying the traverse of the turret in both directions according to the tool in use. The bed 50, Fig. 1, is mounted in a tray 53 with adjustable shields 55 front and back to catch oil and cuttings. The hollow spindle 66, provided with a chuck 67 and roller feed 68, is mounted in cone bearings in the walls 62, 63, Fig. 7, of the headstock 58. The back thrust in the front bearing 64 is taken by washers 74, and the spindle is constantly drawn inwards to prevent slackness by springs 71 placed between a washer 72 and a divided sleeve 70 held in a groove in the spindle by a screwed ring 69. Outward movement of the spindle is prevented by a collar 76 clamped on the sleeve 70. In the rear bearing 65, the coned sleeve 80, feathered on the spindle, is pushed into the bearing by a similar arrangement of springs. The lathe spindle is driven either by a motor on the bed geared through a shaft 89 to the main driving- shaft (not shown), or from a countershaft connected by a belt to the main driving-shaft. Two wheels, loose on the main shaft, but capable of being separately clutched to it, gear with two wheels keyed on an intermediate shaft (not shown), which also carries two loose wheels formed with clatch faces to engage the two keyed wheels. One of the keyed wheels gears with a wheel 124 loose on a back shaft 127, but capable of being clutched to it, while the two loose wheels on the intermediate shaft gear with wheels 125, 126 keyed on the back shaft. The yokes for operating the clutches on the main and intermediate shafts are separately operated by an arm on a rock-shaft 104, Fig. 1, which is moved longitudinally to engage the arm with one or other of the yokes and then rocked in either direction to engage the desired clutch. The longitudinal and rocking movements are imparted to the shaft 101 by rocking and sliding movements, respectively, of a shaft at right-angles to it and provided with a handle 112. Each of the wheels 124, 125, 126 can thus be driven at two different speeds, the automatic clutch for coupling the wheel 124 operating only when the wheels 125, 126 are not driven. The wheel 125 gears with a wheel 136 loose on the lathe spindle and having an extension formed as a pinion 141 gearing with a wheel 138 keyed on the spindle 137, which carries two other keyed wheels 139, 140 gearing with wheels 142, 143 loose on the lathe spindle. By operating a clutch collar 146 by a handle 150, Fig. 1, either of the wheels 136, 142, 143 may be separately clutched to the lathe spindle, so that the six speeds of the back shaft 127 are converted into eighteen speeds of the lathe spindle 66. The headstock is partially filled with oil, and the cover is removable to expose the gearing. The yoke 151 for opening and closing the chuck is connected to the roller feed, so that the chuck may be opened or closed and the feed started or stopped by a single handle 160. The feed-shaft 164 for operating the turret is in two parts connected by a universal joint 166, Fig. 8, and is driven from a wheel 174 on the hub of the wheel 136 through a nest of gears, consisting of seven pairs of wheels. The upper set of seven wheels are keyed on a shaft 172, one of them gearing with the wheel 174. The lower set are loose on a shaft 173 movable longitudinally and carrying spring-seated keys 189, 190 which alternately engage with one of the lower set of wheels as the shaft is moved longitudinally by rocking a shaft 196 by a handle 197, the shaft 196 having an arm 195 with a ball-and-socket connection with the shaft 173. The wheels are arranged in such order that the alternate engagement of the two keys produces a regular alteration of speed of the shaft 173. The feed-shaft 164 is driven from the shaft 173 by bevel gearing 191, and a reversing crown train 170, the feed-shaft being moved longitudinally by a handle 201 to reverse the feed. On the feed-shaft is feathered a two-part worm 206, 207, Fig. 22, carried by a worm-box 208 supported in the rear of the saddle apron 209 by a rod 210. The worm can be moved in the box by a sliding rod 231 with a handle 232 so that either part can be brought into engagement with a worm-wheel 211 on an eccentric pin 212, the teeth of the wheel being cut as shown in Fig. 25 to suit the reverse inclinations of the worm threads 206, 207. The worm-wheel carries a pinion (not shown) which may be geared to a rack on the bed or to a train of gearing for operating the cross-slide, the pin 212 being rocked by a handle 300. The worm box is supported with one or other of the worms in gear by the rod 210 pivoted to an arm 213 on a shaft 214, which has an arm 215 carrying a handle 216 capable of a slight rocking movement. The rod 210 is held up by the engagement of a semicircular stop 217 on the handle with a similar stop 218 pivoted on the apron. A rod 227, which is connected to a bell crank 229, pivoted on the apron and to the worm box, has a cross-pin 228 engaging below and above pins 222, 223 on a disc 221 on the stop 218, so that movement of the rod either upwards or downwards will rock the latch against the action of a spring 225 and release the arm 215, allowing it to move to the dotted position, lowering the worm box and disengaging the worm. The vertical movement of the rod 227 is obtained by arresting the traverse of the saddle in either direction by a positive stop, which causes the worm box to rock the bell crank, the saddle being pressed against the stop till the worm is disengaged. The stop for arresting the traverse of the saddle is part of a selector mechanism comprising a number of stop-bars 241, Fig. 10, shown as two for each turret tool, and a corresponding number of stops 248. The stop-bars are arranged in the flat top 240 of the bed, and the stops in the saddle 60. Each pair of stops is normally supported by a wedge 249, Fig. 17, there being one wedge for each tool. The turret has a number of notches, one for each tool, so arranged ,that for each position of the turret, a notch registers with one of the wedges, allowing its pointed end 253 to enter as the bevelled end 1250 slides down an incline on the carriage, thus lowering the pair of stops for that tool. At the end of the forward traverse of the saddle, one stop drops into a notch 246, and stops the feed as before described. When the saddle moves backwards, the stop rides up the inclines 245, 217. In order to allow the second stop to engage its corresponding bar to limit the return movement of the saddle, the bar is inverted as shown to present a square end. To prevent the dropping of two stops at the same time, a rod 250 is journalled in the saddle and provided with pins to engage alternate stops. The rod may be moved longitudinally to engage either of each pair of stops, or may be left in an intermediate position to engage all the stops. The rod is rocked by a handle 252 to raise or release the stops. The turret may have a base-plate 280, Fig. 30, secured to it with guides to receive cross-slides, only one such slide being shown. The slide consists of three parts 281, 282, 283 connected by a bar 284 and each provided with tools 285, 286, 287. The slide is traversed by a screw 289 rotated by hand or by gearing 291, which is brought by the revolution of the turret into engagement with the train of gearing on the saddle previously mentioned. A shaft 293 carrying a hand-wheel and an idle pinion can be moved longitudinally to disconnect the gearing. A shaft 311 on the baseplate 280 carries screw stops 316 arranged in aligning pairs in collars on opposite sides of a lug 310 on the cross-slide, so that any pair may be brought into line with the lug by rotating the shaft by a hand-wheel 312, the cross-feed being then stopped by the disengagement of the worm 207, 208 in the same manner as the traverse of the saddle. The cutting-off or other tools 265, Fig. 37, are secured in a lever 262 pivoted at 260 on the headstock and swung by hand until one or other of the rollers 271 engage a worm 267 journalled on the headstock and rotated by a handwheel to feed in the tool being used. Screws 273 and stops 274 limit the inward movement of the tools. The lever is normally held in the position shown by a spring pin.