Patent GB-338946-A (GB)
Title: Improvements in control apparatus for fluid-pressure operated systems
IPC: G05D16/18
Filed: 1929-08-22
Abstract: 338,946. Triggs, W. W., (Scovill Manufacturing Co.). Aug. 22, 1929. Working valves.-A system comprising a number of valve-controlled units operated by fluid pressure has its valves controlled by a second fluid pressure system, the valves of the second system being controlled by electromagnetic devices. The first system may comprise some manually-controlled units, and means may be provided whereby automatic control is exercised after the completion of manually-controlled operations. The invention is described with reference to apparatus in which rods are formed by extrusion, coiled, and delivered: A billet 125, Fig. 6, is placed in a cradle in a slide 147 which is then moved by a hydraulic cylinder 150 to bring the billet into position opposite a container 134, Fig. 8. A tube 170 operated by a hydraulic cylinder 175 pushes the billet into the container and withdraws, following which the slide 147 moves to bring the extrusion die into position, a latch 164 operated by an air cylinder 169 engaging a notch 165 in the slide. The container 134 is then moved to abut the die by hydraulic cylinders 144, and the tube 170 to abut the slide. A main ram 123 is operated by a hydraulic cylinder 124 to extrude the metal through twin bores in the die and tube 170. The ram 123 and tube 170 are then withdrawn, the extruded stock cut off by a cutter operated by a hydraulic cylinder 180, and the stump expelled. The extruded rods each pass through driven feeding rolls 266A, Fig. 4, and an oblique bore 108 in a rotating block 107. and the coils formed rest on platforms 106 around posts 105. The platforms are connected to a crosshead 302 operated from air cylinders 304, and adapted to abut against the piston rods of auxiliary air cylinders 305. When the platforms are raised, the coils are pushed therefrom by members 312 operated by air cylinders 314, the platforms being subsequently cooled by immersion in water in tanks 102; alternatively, the platform and coils may be immersed before raising to the discharge position. The cylinders 124,.144, 150 are controlled by valve units 323, 327, 329 respectively, each comprising inlet and exhaust valves pneumatically operated under the control of pilot valves at a manual control station 325. The remaining cylinders are controlled by valves V<3> - - - V', each valve being operated by a solenoid included in the wiring of a direct current system having mains 353, Fig. 9, and bus bars 356, 357, 350. The valves V<3>, V', are operated by hand switches 113, 114, and control air pipes leading to the valve unit 341 of the cylinder 175.. The remaining valves V<5> - - - V<9> are controlled by relay devices A, B, D - - - H, the solenoids of which are in an alternating current system having mains 355 and bus bars 358, 359, 351. By the manually-controlled portion of the cycle of operations, the billet is fed, the rods are extruded, and the ram 123 and tube 170 withdrawn, and a hand switch 112 is momentarily closed to raise the relay A and close a holding circuit therefor in preparation for automatic control of the remaining part of the cycle. The withdrawal of the tube 170 closes a switch S<4>, which raises relay B and operates the valves V<5>, V<6> to advance the cutter. The cutter movement closes a switch S<3> to raise the relay D; this lowers relays A, B and causes the return of the cutter and an initial lowering of the platforms 106. The platforms, as before stated, may be operated in two different cycles. If a switch 111 is closed, and a switch 110 is in its upper closed position, the initial lowering closes a switch S<5>, to raise the relay E and operate the valve V<8> to raise the platforms. When the latter reach discharge position, a switch S' is closed to raise relay G and operate the valve V' to advance the discharge members 312; switches S<8>, S<9> are then closed to raise relay H, thus causing the lowering' of relay G and return of the discharge members, the raising of relay F, and the down movement of the. platforms into the water tanks. Subsequently, a switch S<12> is opened to return the platforms to initial position. In the other platform cycle, switch 111 is open and switch 110 in its lower closed position, and control is effected through a switch S<6>. Switches S<10>, S<11> prevent raising of the platforms into discharge position unless the discharge members have been previously withdrawn. The hydraulic valve units used in the apparatus may comprise inlet and exhaust valves 425, 448 Fig. 10, operated by pistons in air cylinders 438, which may be controlled by a valve 474, Fig. 14, having large and small pistons 482, 487. The piston 487 is exposed to atmospheric pressure, and the piston 482 to the pressure in a chamber 484, which communicates with the valve chest or with the atmosphere under the control of valves 507, 500, Fig. 16, on a spindle 502, actuated by a solenoid. The valve 474 and its associated parts may be connected by piping with the hydraulic valve unit, and be disposed at a central station, or may be applied to the control of the air cylinders used in the apparatus. In order that manual control may be exercised when necessary, the solenoid cores for valve-operation have a button 690, which may be actuated by hand or through a lever. Specification 338,947 is referred to.