GB549211A - Improvements in or relating to fluid pressure remote control systems - Google Patents

Abstract

549,211. Hydraulic machines ; valves. CLEVELAND, F. J. (Bendix Aviation Corporation). May 7, 1941, No. 5938. [A Specification was laid open to inspection under Sect. 91 of the Acts, Nov. 8, 1941.] [Classes 69 (ii) and 135] [Also in Group XXXIII] For synchronizing the movements of two or more elements of an aircraft control or a landing gear a self-adjusting valve described below is inserted between the pump and the power cylinders of a hydraulic servomotor to secure equality of flow to the cylinders. A system is described comprising two double-acting jacks fed through two reversing valves from pipes 38, 39 leading from a valve casing 22 supplied with pressure fluid through a pipe 21. Passages 23, 24, 25 are formed in the walls of the casing which has a cylindrical liner 27 in which slides a grooved piston 26. Holes 33, 34 in the liner admit pressure fluid to the grooves in the piston, the fluid issuing through longitudinally arranged narrow slits 36, 37 in the liner to the passages 24, 25 and the pipes 38, 39. Any increase of flow through one slit or the other causes a fall of pressure in the passages 24 or 25 and consequently on the corresponding end of the piston which then moves to correct the inequality. This subject-matter appears also in the Specification, corresponding to the Provisional Specification, placed open to inspection under Sect. 91 on the 8th November, 1941. The following subjectmatter appears only in the Specification as accepted. Fig. 4 shows a modified valve in which pressure fluid through a pipe 21a can flow directly to a passage 60 and past non-return valves 54 55 to the pipes 38a, 39a, but return flow through the two pipes 38a, 39a, is equalized by the valve 26 which is similar to that shown in Fig. 1 except that it has a single central groove 49. Two such valve devices are shown in Fig. 6 connected to opposite ends of two jacks 13, 14 the two inlets 21a being connected by pipes 66, 67 to a valve 65. This valve places the two pipes alternatively into communication with the pressure and reservoir sides 64, 68 of a pump system including an accumulator 62 and in either case the return flow from the jacks is controlled by one of the valves 26 while the pressure fluid has free access through the valves 54, 55 to the appropriate ends of the two jacks. Should unequal but proportionate flow through the two branches be required the slits 36, 37 are made of different shapes or sizes or the areas of the valve ends exposed to the fluid pressure may differ.