Patent GB-190409829-A (GB)
Title: Improvements in Lathes and similar Metal Cutting Machines.
Inventor: HARTNESS JAMES
Filed: 1904-04-29
Granted: 1904-07-14
Abstract: 9829. Hartness, J. April 29. Lathes; gearing, driving.-A lathe or other metal-cutting machine has a toothed change-speed gear mounted in a hollow headstock which forms an oil-bath. The invention is described with reference to a turret lathe in which the headstock is traversed across the bed by a screw 60, Fig. 4, rotated by a hand - wheel, or by a worm shaft 67 which can be rocked on a pivot 78 by a handle 80 to disengage the worm from a wheel 65 on the screw. The worm has two parts of opposite hand, sliding on the shaft and held with either part in engagement by a latch 77. The movement of the headstock is limited by a number of notched stop-bars 88 secured in a groove in the bed, any one of which may be engaged by a pawl which can be moved beneath the headstock by a hand-shaft until it is over the desired stop-bar. The engagement of the pawl with a stop-bar holds the headstock against further movement, the worm shaft 67 being driven by a frictionally-driven feedshaft 70. The speed of the feed-shaft may be varied by moving the driving pair of friction discs to or from the discs on the feed-shaft. The pairs of discs are oppositely bevelled, the driving-pair entering between the driven pair, and the shaft of the driving-pair being carried by a yoke which can be rocked by a handle and cam. The chuck spindle 126, Fig. 16, is parallel, so that it can be withdrawn by disengaging from it set-screws 128, passing through the hub of a double wheel 129, 130. End motion is prevented by a rib 131 and lugs 137 on the interior of the headstock casing, washers being placed between the hub and the rib and lugs, adjustment being effected by set-screws in the lugs. The spindle is mounted in taper bushes 138 pressed into holes in webs 120 by springs, and provided with lubricating-rings 143. The spindle can be driven at a number of speeds and in either direction by a pulley shaft 122 continuously rotating in one direction. The various speeds, which are in geometrical progression, are obtained by the aid of a secondary shaft 150, a back-gear shaft, an intermediate shaft 182, and a reverse shaft, and by ratchet and friction clutches. There are three fast and three loose wheels on each of the shafts 122, 150, the fast wheels on one gearing with the loose wheels on the other. Each fast wheel carries a pawl which may be allowed to engage a ratchetwheel carried by the adjacent loose wheel, the pawls being controlled by central rods 162, 163, so that the pairs of wheels may be successively engaged to vary the speed of the secondary shaft by steps. The central rods rotate by friction with their shafts and are temporarily arrested by pivoted fingers 171 on a controller 172 which is depressed and rocked by hand to allow the required rod to be arrested for the interval necessary to allow the desired pawl to engage, after which the finger is tripped by a cam on the shaft with which the rod is rotating. The intermediate shaft 182, which drives the feed-shaft 70 through friction discs as previously described, can be driven at two speeds from the secondary shaft through loose wheels and a clutch 184, these speeds differing by an amount equal to the total range obtained by the ratchet-clutches. The intermediate shaft drives the chuck-spindle either direct through the wheel 129 or through the reverse shaft and the wheel 130, a clutch 194 being placed between the loose wheels on the intermediate shaft. The clutches 184, 194 are similarly operated by central rods 188, 197, provided with handles. Fig. 17 illustrates the actuation of the rod 197, which is recessed to receive a pin 198 connected to the handle 200. Cam-surfaces 207 on the pin engage dogs 204, each having an abutment on the intermediate shaft and bearing against oae end of a slot in the rod 197, so that a longitudinal movement of the pin produces a corresponding movement of the rod by forcing out one of the dogs. The intermediate shaft carries a loose wheel 210 driven from the secondary shaft 150 through the back-gear shaft, not shown, and a reducing-train or back-gear. The wheel carries a pawl which, when the wheel is rotating more quickly than the shaft 182, is frictionally drawn into engagement with a ratchet -wheel 215 on the shaft, this taking place when the clutch 184 is in a neutral position. When the speed of the ratchet-wheel exceeds that of the wheel 215, the pawl is drawn out of engagement. Any of the speeds obtained by the six ratchetclutches previously mentioned may be used with the back-gear.