GB1071866A - Hydraulic system for controlling winches - Google Patents

Abstract

1,071,866. Winch hydraulic control apparatus. NEW YORK AIR BRAKE CO. Jan. 31, 1966 [March 4, 1965], No. 4106/66. Heading B8B. [Also in Division F2] A hoisting system comprises a plurality of winches 13, each driven by a reversible hydraulic motor 14 controlled by a valve 18, the latter having a sliding spool movable by a reversible electric motor 55 in association with a feedback means 53 associated with the winch cable 15. The electric circuit controlling each motor 55 comprises a speed control 68 and ganged on-off reversing switches 66, 67. All the motor control circuits for the plurality of winches are connected in parallel and are controlled by a master circuit 57 including a speed control 59 and on-off reversing switches 61-62. The valve 18 comprises two connections 32, 33 to the hydraulic motor, two connections to an hydraulic reservoir 31 and a connection 37 to a discharge pressure compensated variable delivery pump 34 fed from the reservoir 31. The sliding spool in the valve 18 has a threaded bore at one end into which threads a rotary actuator 52 driven by the motor 55 and the other end of the spool engages a rotary actuator 53 driven by rollers 54 engaging the moving cable 15. The actuator 53 is rotationally rigid with the spool but axially movable relative thereto. In operation, any creeping down of a load 12 when the motor 55 is not energized causes the actuator 53 to turn the valve spool relative to the stationary actuator 52 and the spool is axially moved, whereby fluid is supplied to the hydraulic motor 14 causing a winding in of the cable. The latter movement reverses the spool movement and the fluid supply is cut off. For power raising or lowering of the cable, the relevant direction of rotation and speed of the motor 55 is selected causing the valve spool to move accordingly, accelerating the cable motion until the actuator 53 rotates the spool at the same rate as does the actuator 52, whereby the spool axial motion is stopped and a constant velocity of cable motion is obtained. When the motor 55 is de-energized, the movement of the cable-controlled actuator 53 relative to the actuator 52 causes the spool to move and shut off the fluid supply to the hydraulic motor 14.