Patent GB-288340-A (GB)
Title: Improvements in or relating to automatic chucking lathes and like machine tools
IPC: B23B3/18
Filed: 1928-04-05
Abstract: 288,340. Potter, W. W. April 7, 1927, [Convention date]. Lathes.-A metal-cutting machine-tool such as an automatic chucking-lathe comprises slow and high speed feed motions for the tool carrier automatic means being provided for changing the rate of feed relative to the, spindle speed during operation and the spindle being stopped while the high speed is in operation :'or bringing the tools up to the work and withdrawing them therefrom. The spindle 11 carrying a chuck 12 is driven by change-speed gearing from a power shaft 13 which carries a main pulley 14 and is driven through a clutch 15. The shaft 13 carries a fast gear 28 and loose gear 22 engaging respectively with an overrunning gear 29 and fixed gear 24 on a shaft 25, the arrangement being such that when the clutch 23 is engaged the gear 29 overruns its drive. The shalt 25 is geared by similar mechanism including a clutch 27 and overrunning gear 31 to a shaft, 21 connected through hand change gearing 20, shaft 18, and spur gearing 17 to the spindle 11. When the main clutch 15 is disengaged by means of a yoke 35 a friction brake 32 engages a surface on the headstock and immediately arrests the shaft 13 and thus also thespindle. A gear 36 on the spindle is connected through chain and sprocket gearing 38 - - 41 with a shaft 42 from which the feed shaft 48 is operated. The change speed mechanism shown in Fig. 4 enables the feeds to be varied independently of the spindle speeds. The high speed of the feed shaft for the idle motions is obtained directly from the pulley 14 through belt gearing 50, 51 to a shaft 52 geared to shaft 46 through a clutch 58. Shaft 46 is connected to the feed shaft 48 through a clutch 47. The change feed mechanism includes gears 63, 78 either of which may be connected to the shaft 73 by a clutch 81 and when the clutch is in neutral position a ratchet gear 72 takes up the drive. Shaft 73 is geared at 84 to the shaft 46, the gear 84 having a ratchet device which overruns when the high speed clutch 58 is in operation. The feed-shaft 48 drives the turret cam-drum 85 through bevel gearing 87 and worm gearing 89. The cam drum is raised above the centre of the hole in the frame through which the drum is inserted so as to obtain as direct a thrust as possible on the turret slide roller. The cross-slide 100 is reciprocated by a cam drum 102 having two sets of cams 103 and two rolls 104, the cams being spaced circumferentially round the drum so that the slide is first moved by one roll engaging its cam and then further in the same direction by the second roll engaging the second cam. In this way the axial length of the cam-drum for a given travel is reduced. Each roll has a reduced stem 105 journaled in ball bearings in the cross-slide. The cross-slide cam-drum is driven from the feed. shaft through gearing 106 - - 109, shaft 112, and worm gearing 113, the gear train having a disconnectible clutch which is automatically disengaged - when the cross-slide is not required. The feedshaft drives through worm gearing 132 a control drum 127 provided with dogs for operating the various clutches. The dog 136 controls the feed clutch 47 through a lever 137 having a handle for manual' operation and' connected to an operating-yoke 124. The clutch 58 controlling the speed of the feed-shaft is operated by a dog 141 through a lever 142 and a latch device. At the end of the cut, the latch is released and the spring 151 then moves an operating rod 145 to engage the high-speed feed. The clutch 34 controlling the starting and stopping of the spindle is controlled by dogs 153 through lever 154 and further linkage connected to the yoke 35. The spindle speeds and tool feeds are automatically controlled by dogs through latch mechanism which ensures quick operation of the clutches. The gear 55 drives a gear 162 which is connected through a crank disc 16 and slotted lever to a block 172 which is thus continuously reciprocated. Beneath the block 172 are a series of bars 173, one for each clutch, these bars carrying pivoted fingers 174 coacting with notches in the underside of the block, When any finger is engaged with its notch the corresponding bar 173 is carried along with the block 172 to actuate the selected clutch. Pivoted beneath each finger is a bell-crank 176 whose vertical arms are engaged by rods 177 coacting with plungers having springs 180 tending to move the rods to engage the corresponding fingers with the block 172. This movement is normally prevented by latch-pins 181 on a lever 182, but when one of the levers 182 is engaged by a dog 184 on the drum 127 the latch pin is withdrawn and the spring 180 then acts to effect a clutch movement. When the finger is depressed by the bevelled end of its notch the corresponding plunger is moved to compress the spring and allow the latch to re-engage. For moving a clutch to a neutral position both fingers are actuated simultaneously from a single bell-crank and the notches are elongated to allow lost, motion. The dog wheel shaft is extended at 200 and carries a cam disc 194 operating a lever 197 to feed a back-facing bar 198. Beds and framings.-The ways of the machine are in the form of removable bolted strips 199, Fig. 21, preferably of hardened steel which can be trued by grinding. Reference has been directed by the Comptroller to Specification 17055/06.