Patent GB-932451-A (GB)
Title: Improvements in turret lathes and other machine tools
Inventor: HILL HARRY RONALD
IPC: B23B3/18
Filed: 1958-10-23
Abstract: 932,451. Turret lathes; machine tool details. TECALEMIT Ltd. Jan. 25, 1960 [Oct. 23. 1958], No. 33980/58. Class 83 (3). A turret lathe or other machine tool comprises a tool-carrying indexible main turret slidable longitudinally along the machine bed and adapted to be fixed in adjusted positions, a rotatable work spindle carried by a headstock movable along the bed towards and away from the main turret, a further indexible tool-turret rotatable on a horizontal axis spaced above the bed and mounted to be adjustable longitudinally between the main turret and the headstock with means for feeding tools in the second turret towards and away from the work axis, indexible means for controlling such movements and indexible means for controlling the traversing movements of the headstock in conjunction with the tool positions of the main and second turrets. The bed 3, Figs. 1-4, is provided with a pair of top guideways 2 on which the headstock 9, 10 is adapted to be traversed by an hydraulic piston-and-cylinder arrangement 16, 14, Fig. 3. The headstock driving spindle 11 is held against axial movement by a bracket 12 and is splined externally to engage internal splines on a sleeve 6 in driving engagement with the chuck 7. A guide bar 32, secured to the bracket 12, is slidable relative to a steady lug 35 on the headstock. An indexible main tool-turret 4, Fig. 1, is adjustable along the guideways 2 opposite the headstock and is clamped by bolts 5 in the required position. An arched member 18, through which the headstock may pass, is supported by guideways 22 on the sides of the bed and carries a second toolturret 25. The latter is arranged on a horizontal axis parallel to and directly above the headstock or work axis. The tools 26, Fig. 3, on this turret are moved down to engage the work by hydraulic piston-and-cylinder gear 29, 27. The archway 18 is first adjusted along its guides to the position required relative to the work for cutting-off &c., and clamped by screws 31. The turrets are indexible by conventional mechanism, either by hand or automatically. A selector stop drum 38 arranged around the headstock spindle is indexed in unison with the turrets. The tool turret 25 also carries a selector stop drum 250, Fig. 1, which for automatic control functions in a similar manner to the selector 38 so that the latter only will be described. Feed and traverse control. The selector stop drum 38, Figs. 1-3, which moves longitudinally with the headstock, is divided into sectors according to the number of tool-turret indexing positions. Each sector has two main adjustable stop members 46, 44. The first 46 controls the slowing down from fast approach at the point where the tool commences cutting and the second stop controls the actual cutting speed and finally the dead-stop position at the end of the cut. The stops 46, Fig. 7, are slidable along the drum for adjustment and are clamped on plain rods 42 by screws 48. The stops 44 are adjustable by screwed rods 43 running the length of the stop drum and the actual stop comprises the block 44 and a projecting part 54 which is adjustable by worm gearing 50, 51, when the machine is set up. Both stops 46, 44 co-operate with a beam 57, Fig. 6, which is supported by a parallel link motion 60, 64, 62, 66, from a fixed part of the machine. Connected to the links of the parallel motion are various control-valves, tappets and dashpot-actuating gear including an hydraulic actuating cylinder for moving the links. At the commencement of an operation the beam is raised until it contacts the shoe of stop 46 which slides along the beam until the end is reached, at this point the high-speed traverse is slowed and the tool commences cutting. The cutting feed is determined by the amount of projection of stop part 54 against which the beam 57 now presses. Movement of the beam 57 towards the stop drum closes a feed-rate slide-valve 78, Figs. 7 and 18. When stop part 54 reaches the end of the beam the latter moves to its final stopping position to close the valve 78 and the stop block 44 acts as a dead stop member against a fixed corresponding stop member 55. After a " dwell " the headstock may return automatically at high speed, or, may be arranged to remain in the advanced position. Some of the control devices are air-operated and the dashpot is partly air and partly hydraulic. Specifications 802,677 and 845,187 are referred to.