GB527074A - Improvements relating to hydraulic remote control apparatus - Google Patents

Abstract

527,074. Hydraulic control gear. GREEN, D. S., and PARKIN, W. H. Oct. 10, 1938, No. 29302. [Class 69 (ii)] A hydraulic remote control apparatus with transmitting and receiving stations and a single liquid connec tion of the kind des cribed in Specification 419,310 is controlled so as to be self-locking in any set position, anc the receiving end o: the system comprises a hollow piston 4 working in a cylinder 3 connected by a pipe C to the cylinder 2 of the transmitter A The cylinder C is acted upon by a spring 5, the compression of which can be varied by adjustment of a screw cap 9 on the end of the cylinder, and the piston rod 12 is arranged to actuate a bellcrank lever 14 which operates a rod 16 connected by a spring 18 to the governor of a variable pitch airscrew propeller. The spring 18 acts in opposition to the spring 5, and normally the spring-load on the piston 4 is balanced by the fluid pressure transmitted by the piston 1. As the cylinder 4 moves inwards its spring load increases, and as this is effected bv a counter-clockwise movement of the operating, handle 20 a downward increased pressure on the piston 1 is provided for by fitting a cam 25 on the lever 23 which depresses the piston 1. This cam is acted upon by a spring-pressed roller 26 on a lever 29, and its contour assures increased pressure on the piston 1 as the handle 20 is moved to cause the piston 4 to move inwards. The pressure exerted by spring 18 is small in comparison with that of spring 5, and so when the engine is switched off and the force exerted by the spring ceases, the function of the system prevents movement of the control.