GB550867A - Improvements in or relating to lathes - Google Patents

Abstract

550,867. Lathes. BAIGENT, G. M. July 14, 1941, No. 8915. [Class 83 (iii)] A lathe has a number of tools arranged around the headstock fed by a rotatable cam-ring coaxial with the work and carrying a cam which feeds the tools sequentially to the work, a second coaxial cam effecting the positive withdrawal of the tools. Bar-stock 20 is fed through the usual collet 21 mounted in a headstock which has four shafts 11 mounted thereon, each shaft carrying a tool-arm provided wtih a holder 14 for a tool 15 and with a follower pin 17 which, for adjustment purposes, is eccentrically mounted on a rotatable member 16. The followers engage a cam-ring 22 provided with a cam 23 which has a steeply rising portion a for moving the tools up to the work, a part b giving the required depth of cut, a dwell portion c for smoothing the cut and a tool-withdrawing portion d. The cam-ring is rotated step-wise in an anticlockwise direction by a handle 24 on a ring member 26 connected to the cam-ring by a pawl 25. At each anticlockwise movement of the handle between stops the cam-ring is rotated through 45 degrees, thus moving one of the tools, Fig. 5, up to the work. The handle is then returned and on its next anticlockwise movement the cam-ring is further rotated to the position shown in Fig. 7 to complete the operative feed. The next return movement moves the tool positively to itsoutermost position, leaving the cam, Fig. 7, in position to actuate the next successive tool. The means for positively returning the tools comprises a cam 28 which is frictionally carried forward by the ring 23 during the first cyclic movement of handle 24 to a position, Fig. 5, abutting the follower 17. A detent lever 30 pivoted at 31 to the cam 28 has a spring projecting into the path of the follower 17 when the latter is in its inner position. The ring member 26 carries a ring 33 having holes which may accommodate the ends of levers 30 coacting with springs 37 on a fixed member 42, the springs normally being effective to hold the levers away from. the ring. When the tool has completed its feed and the parts are in the position shown in Fig. 7 the follower 17 has engaged a lever 30 with the ring 33 so that on the next return movement of the handle the cam 28 is rotated clockwise and the tool is positively returned by the cam slope 29. In a modification, Fig. 10, the tool slides may be mounted on radial guides 40 secured at 41 to the headstock. In a further modification a grooved cam-ring may move the tools positively in both directions. In another modification, one oscillation of the lever 24 may actuate the chuck instead of operating a tool. Specifications 261,360, [Class 83 (iii)], and 358,727 are referred to.