Patent GB-249799-A (GB)
Title: Improvements in and relating to machine tools for turning or cutting metals
IPC: B23B5/00
Filed: 1925-06-08
Abstract: 249,799. Potter, W. W. March 28, 1925, [Convention date]. Lathes; chucks.-In a machine-tool, particularly a lathe comprising a casing consisting of two parts one within the other, the inner part serving to house the spindle and the driving gearing, the motions of the machine are controlled by means of dogs mounted on a flexible carrier. The inner casing 11 is removably fitted within the outer casing 10 and carries the work-spindle 12 provided with a pneumatic chuck 13. An electromotor 14 mounted on the casing 10, drives by a chain 16, a main-shaft 17 which is connected through spur gears 19 to a countershaft 21, from which the work-spindle is driven through changegears 22, 23, shaft 24 and gears 26. The feedshaft 27 is driven at a slow speed for the working movement from the shaft 24 through gears 28 - - 31, and a high speed for idle movements is obtained from the shaft 21 through a friction clutch 35 and gears 34, 33, a roller clutch 32 being overrun when the high speed is in action. The feed-shaft carries a pinion 38 engaging a gear 39 of the differential gear driving the cam drum D to reciprocate the tools. The pinion 38 may be disconnected from the shaft 27 to allow hand adjustment of the cam drum. In place of the usual dog wheel, the dogs 59 for operating the various controls are mounted on a flexible chain 41 located in the outer casing member and passing over four sprocket wheels three of which 42 are idlers, while the fourth 43 is driven from the differential gear 39 through a shaft 53, Fig. 11, bevel gears 52, two-part shaft 48 and worm gearing 47. The driving gearing of the chain may be disconnected for hand-setting. The dogs, which mav be mounted on either side of the chain, are secured in position by bolts. The friction clutch 35 controlling the feed shaft speed is actuated bv a rock-shaft 37 connected through bevel segments to a rock-shaft 62 operated by a forked lever 61 which is moved alternately in opposite directions bv dogs on the carrier. Another dog actuates a lever 65 to disengage a latch 66, whereupon a lever 68 connected to the clutch lever 70 is actuated to disengage the main driving clutch 72 and stop the machine. At the same time a brake 73 is brought into engagement with a fixed member 74 to assist in stopping the driving gearing. The machine may be manually stopped by a lever 75. Another dog operates through a lever 75, a rod 77 controlling the valve mechanism of the pneumatic chuck. The rod 77 is provided with bevelled shoulders, and in one direction nf movement of the rod a lever 79 actuates a valve 83 to admit air to a cylinder 86 to open the chuck, while upon opposite movement of the rod 77 a second valve 87 is actuated in a similar manner to close the chuck. This movement of the rod 77 is controlled from a pedal 88. A handle is also provided so that the rod 77 may be moved by hand in either direction. The dogs are so arranged that when they come into operation thev are positioned over one of the sprockets which supports them against lateral thrust. Alternativelv, the thrust on the dogs may be resisted by guide surfaces bolted to the housing. A number of chains having dogs arranged to suit the timing for different jobs may be fitted up for use in the same machine.