GB555586A - Improvements in or relating to valve devices controlled by fluid pressure - Google Patents

Abstract

555,586. Hydraulic control systems ; valves ; fluid-pressure brakes. BENDIX AVIATION CORPORATION. Feb. 25, 1942, No. 2502. Convention date, Aug. 13, 1941. [Classes 69 (ii) and 135] [Also in Group XXXIV] A fluid-pressure control system in which fluid. under pressure is stored in an accumulator ready for operation of a brake, clutch &c., or for operating jacks controlling parts of aeroplanes is constructed so that the pump such as a gear pump 12 supplies fluid to the accumulator 18 via pipes 15, 17 fitted with a check valve 16, and a byepass valve 14 byepasses the pressure fluid back to the reservoir 10. when the pressure in the accumulator 18 reaches a predetermined value, and the valve 14 remains in action until a lower predetermined pressure is reached: Above the. higher pressure the fluid returns to reservoir 10 via a relief valve 22 and a conduit 20. The pressure fluid passes from the accumulator 18 via a pipe 24 which as shown connects to a valve: 25 which can be operated by: a treadle 36 for operating the shoes 29 of a brake, and'to a cock 26 which, is connected'to a fluid motor 31. The byepass valve 14 is constructed as shown in Fig. 2, and comprises a ball valve 57 which is normally pressed on a seat 58 by a plunger 44 moved towards the right by a spring 45 acting upon the flange of a sleeve 48 to which is secured a disc 50 for pressing upon the plunger 44. The sleeve 48 cuts off connection between the pressure pipe 13 and a pipe 19 leading to the reservoir 10. The area of the valve seat 58 is less than the area of the plunger 44 so that the fluid pressure has to be greater than the spring pressure before the valve 57 opens. When the valve 57 moves the plunger to the left and opens up connection to the reservoir 10 the valve is pressed against a valve seat 63 of larger area than the plunger so that the valve is maintained in this position until a considerable drop in pressure occurs in the pressure system due to the plunger 44 now working at a mechanical disadvantage instead of at an advantage. The construction of valve may be modified by replacing the spherical valve by a double conical one. and the sleeve valve 48 may be replaced by a grooved piston valve. The various valves are constructed without the use of rubber. The Specification as open to inspection under Sect. 91 comprises also the constructions of the accumulator 18 and the valve 25. The accumulator 18 is preferably formed of a hemi-spherical member 71 connected by a screwed nut 72 with a pear-shaped member 70, and clamping to a rubber or like diaphragm 73 fitted at the tip with a metal disc 76. The member 70 is filled with an inert gas under pressure and as the diaphragm 73 is distended by pressure fluid, preferably a liquid such as oil, the pressure of the gas increases and by acting on the diaphragm maintains the fluid under pressure. The valve 25 is constructed as shown in Fig. 4, (Cancelled), and normally the pipe 28 is connected to exhaust via passages 106, 102, 105 and a valve 113 which is normally open and is integral with a spring-pressed valve 112 which cuts off the pressure fluid. On depression of treadle 36 a lever 38 is moved counterclockwise and a thrust link 115 moves a plunger 101 to the left and closes valve 113 thus closing the connection to the reservoir, and at the same time valve 112 is opened to connect the pressure fluid to the brakes. This subject-matter does not appear in the Specification as accepted.