GB622732A - Improvements in machines for turning bar stock - Google Patents

Abstract

622,732. Lathes. SIEGERIST, W. Sept. 24, 1945, No. 24733. [Class 83 (iii)] [Also in Group XXIX] A non-rotating work machine for turning long bar stock has work-feeding mechanism comprising two reciprocable carriages, mechanically operated means for moving said carriages in work-feeding direction with one carriage leading the other, and fluid-operated means for imparting a complete return movement to the leading carriage before the trailing carriage reaches the end of its feed movement, work-gripping devices carried by the respective carriages, and fluid-pressure operated means for successively closing and opening the work-gripping devices of each carriage during the feed movement thereof, and for holding said devices open during the return movement of the carriages. The machine comprises a head A, Fig. 1, carrying rotary cutting heads (not described) through which a non-rotated bar B to be turned is passed. Tubular guides 4 passing through and connected to the head at one end, and supported on brackets 6 carried by a table C at their other ends, support slidable carriages D and E with gripping jaws for feeding the work B. Steadies 5, also carried on the guides 4 at each side of the head A, assist in supporting and guiding the work. The jaws 12 of the gripping members are operated by fluid pressure pistons F, G and the carriages D, E respectively on which these are mounted, alternately take over the feed, and release, with a rapid return and reverse movement. These motions are obtained from two cams H, I, carried by a worm driven shaft 19, against which follower rollers on the carriages are held by rods 23, connected to pistons within fluid-pressure cylinders J, K respectively. The work is also given an additional constant feed and guiding movement by the rolls 65 which are driven by worm gears 56, 57, Fig. 6, the rolls being laterally adjustable and one being spring-pressed at 69 to allow for irregularities in the work. The worm drive to the cam-shaft and end feed rolls is obtained from the head A through a universal joint 25, Fig. 3, and shaft 26 to a gear-box 28 which houses a pair of clutches 32, 33 and bevel gears driving the cross-shaft 40 for the cam-shaft worm drive. The clutches enable the drive to be reversed by operating a handle 39. A sprocket-chain drive 48 from the cam-shaft 19 drives a shaft 49 which is connected through bevel gears 51, 52 to drive the feed rolls 65. The hydraulic circuit, Fig. 10, for operating the work-clamping cylinders F and G, and the carriage pull-back cylinders J, K comprises a reservoir 72 from which oil or other fluid is drawn by two pumps 73, 74 driven by a single motor 75. These pumps may deliver a large quantity of fluid at low pressure or a small quantity at a high pressure controlled by a self-contained valve unit. The outlet circuit from the pumps passes through conduits 78, 79 to check valves 80, 81, respectively, with a connecting line 82. A conduit 83 having a check valve 84 therein leads from conduit 78 to a four-way valve 85 which is solenoidoperated and under control of a switch 106 and tappets 112, 113 on the clamping jaw carriage D. A similar arrangement is provided for the carriage E. Flexible conduits connect these valves to the work-clamping cylinders on the carriages. A conduit 93 leads from the connecting conduit 82 through a reducing valve 94, check valve 95 and reducing valve 96 to the communicating free ends of the pull-back cylinders J and K. Return conduits 101, 103 lead back to the reservoir and conduit 93 respectively.