GB1340247A - Winch control system - Google Patents

Abstract

1340247 Friction clutches; clutch control BYRON JACKSON Inc 14 Dec 1971 [28 Jan 1971] 58081/71 Headings F2C and F2L [Also in Divisions G3 and B8] A tensioning winch control system on a ship comprises a winch 13 for the tensioning cable L driven through a slipping clutch C to apply a substantially constant tension to the cable, the amount of clutch slip being controlled in response to signals from a cable position sensor 16 and a cable tension sensor 15. The cable L from the drum 13 passes between rollers 17, 18 and 22 of an hydraulic tensionmeter forming the sensor 15, the roller 22 being carried on a floating shaft of an hydraulic sensing unit 24 producing an hydraulic pressure signal which is a function of the cable tension. The cable position sensor 16 comprises a threaded shaft driven by the cable passing over the roller 17 secured to the shaft and rotation of the shaft causes a rotationally secured nut to move along the shaft to control movement of a piston controlling the amount of signal air passing through the sensor from a source to line 85a. The sensor 16 is adjustably supplied with air through line 86a, to oppose movement of the said piston from calibration purposes. In order to control the speed at which the cable L may change position an air pressure signal is generated in line 26a proportional to the drum speed by a coupled tachometer signal generator 25 and electromagnetic transducer 26. The output from the hydraulic unit 15, the position sensor 16 and the transducer 26 are compared by a computer means 27 to generate an air pressure signal to control the clutch C, the computer means 27 comprising a plurality of coaxial chambers having flexible diaphragm and floating pistons therebetween, each chamber being fed by its associated signal pressure and one chamber having a reference pressure supplied thereto, the net movement of the floating pistons controlling the exit air pressure signal from the computer through line 300. The latter passes the pressure signal into a pressure controller C1 which proportionally adjusts the output pressure therefrom at line 302 of an air pressure source at line 303. The pressure signal from line 302, 325 controls a booster 326 supplying higher pressure air to control the clutch C, a selection valve 329 in the booster output line 328 permitting the booster signal to be isolated whereby the clutch may be controlled by a manual valve. A second controller means C2 is provided between the sensor 15 and the computer 27 to generate an air pressure signal proportional to the hydraulic pressure signal of the cable tension sensor 15. The slipping clutch comprises an outer housing 54, 57, 58 chain driven from the winch motor, and incorporating a pair of liquid cooled friction plates 56, 61 movable relative to each other by an expansible element 67 controlled by the air pressure supplied thereto from the control arrangement, and a driven plate 62 splined to the drive shaft 11 to the drum frictionally engaging between the first said plates.