Patent GB-542418-A (GB)
Title: Improvements in and relating to turning machines and tools therefor
IPC: B23B5/00
Filed: 1940-07-08
Abstract: 542,418. Lathes. TRIGGS, W. W. (Cleveland Hobbing Machine Co.). July 8, 1940, No. 11401. [Class 83 (iii)] A lathe has a rotary tool mounted on a spindle at right-angles to the work axis the tool being fed along the work and being rotated at a non-uniform rate in timed relation to the feed movement, by means including a cam having a number of surfaces of non-uniform slope. In one form the tool T, Fig. 7, has portions 5, 6 at different radial distances from the tool axis and arranged to turn the parts 1, 2 respectively of the shaft W. The shoulder 3 is formed by the edge 9 of the tool while the latter rotates at such speed that the edge 5 rolls on the part 1. At parts away from the shoulders the tool may roll on the work with or without slip the tool rotation being preferably slowed down while the uniform parts of the work are turned. In a multiple spindle machine, Figs. 1 and 2, a spindle carrier 10 is rotated by a motor 13 and worm gearing 16 around a central column 11 which serves as a sump for lubricant. The spindle carrier comprises eight similar units each including a tool head C adjustable along radial horizontal ways 20 by means of a screw 26. The tool T is mounted on a spindle 23 mounted in a member 24 adjustable about a horizontal axis in the part 25 engaging the ways 20. The slidable work head D comprises a frame 30 movable on vertical ways 21, 22. The upper end of the work piece is supported in a tailstock 34 movable on ways 35, by means of a pinion engaging a rack 41 and rotated by a hand lever 37. The lever may be rotated about an axis parallel to the plane of the guideway to clamp the tailstock. Each work spindle is driven from its own motor through belt gearing 43. A roller 45 on each work head engages a fixed annular cam 50 to impart traverse to the work pieces during the rotation of the spindle carrier. A new blank is positioned as the roller passes the low cam portion 52. The blanks are then brought up to the tools by the cam rise 53 then fed slowly upwards past the tools unloaded at the loading station and the spindles then returned to the lower position for reloading. The motors are automatically stopped as the work approaches the loading station by means of switches 57, 58 on the carrier operated by cams on the work head the motors being restarted as the work leaves the loading station. The supply of coolant is also stopped and started as the work approaches and leaves the loading station. The control panel, Fig. 8, includes a switch 57 which is momentarily closed to energize a solenoid 63 and start the motor and establish a holding circuit 65. This opens a solenoid valve 61 controlling the supply of coolant. When the work head reaches its upper limit the motor is stopped and valve 61 closed upon opening the switch 58. The tool T is rotated by a cam 70 on the work head engaging a rack rod 71 geared to a pinion 74 on the tool spindle. The cam part which corresponds to the formation of the shoulder 3 is arranged to rotate the tool so that it rolls without slip on the smaller part of the blank. The inclination of the edge 9 and the speed of rotation may be varied to alter the form of the shoulder. In a modification, Fig. 9, a single spindle lathe has a tool carriage 86 fitted with a cross slide 87 and traversed by a lead screw 92. The tool spindle is rotatable in a housing secured to the cross slide and is rotated by a pinion operated by a rack rod engaging a fixed cam so that as the tool carriage is traversed the tool is rotated at varying speeds by the cam.