GB513542A - Improvements relating to the electrical control of hydraulic power means - Google Patents

Abstract

513,542. Hydraulic machines. ALDOUS & CAMPBELL, Ltd., and HALLIDAY, J. W. April 12, 1938, No. 11214. [Class 69 (ii)] [Also in Group XXX] Hydraulic apparatus is brought to rest gradually and exactly at a selected point, for example a hydraulic lift is stopped at a selected floor, by mechanism operated automatically by the cage or moving body as it approaches the stopping place to cause restricted delivery of the operating fluid to, or exit from, the ram cylinder. In the illustrated form showing the application to a hydraulic lift, the main delivery and exhaust valves are cut out on approaching a floor at which it is desired to stop, and a small auxiliary valve automatically brought into operation. Fig. 1 shows in plan a main control valve having a port 4 leading to the ram (not shown) and communicating alternatively with an inlet port 2 from the pressure main and an exhaust port 3. Depression of an appropriate button on the cage or at a floor energises the motor 14 and the solenoid 23. The motor drives worm gear 15 and epicyclic gear 13, while the solenoid applies brake blocks to fix the outer ring of the gear so that the drive becomes effective to move the crank 6 through 90 degrees in one direction or the other until stopped by a limit switch 17, and thus through the connecting rod 5 slides the valve into one or other of its extreme positions, in which the ram is connected to the main or to exhaust. The pressing of a floor-selector switch causes ramps in the well to operate a switch as the car approaches the selected landing and so close the main valve and open one of the auxiliary valves to enable the cage to creep up or down to the landing. The circuit thus established energises one or other of the solenoids 29, 30, Fig. 5, and raises the armature 43 to tilt the bar 40 about the remote pivot 39. This opens one of the needle valves 35 and also compresses the restoring spring 50. At exact floor level another ramp in the wall opens the circuit and all valves are closed. Should the cage creep away from the landing one or other of the needle valves are opened automatically, and restoration takes place. The two needle valves are connected by pipes 55, 57, Fig. 1, to the corresponding pipes of the main valve. Should the current fail, the main valve can be controlled immediately from a hand rope on the wheel 11 which is connected to the crank 6 by chain gear 8, 9. This latter drive is isolated from the motor 14 by reason of the de-energising of solenoid 23 rendering the epicyclic gearing 13 non-effective.