Patent GB-560201-A (GB)
Title: Improvements in or relating to wheel brake systems for aircraft
IPC: B64C25/44
Filed: 1942-09-15
Abstract: 560,201. Fluid-pressure operated aircraft wheel-brakes. DUNLOP RUBBER CO., Ltd., and TREVASKIS, H. W. Sept. 15, 1942, No. 12982. [Class 4]. [Also in Group XXXIV] A fluid - pressure system for the operation of landing wheel brakes of air craft comprises a pair of regulating valves each adapted to supply pressure fluid to and exhaust it from a fluid pressure operated relay valve device the operation of which effects the supply and exhaust of pressure fluid to and from a group of brakes associated with the wheels on one side of the aircraft. The regulating valves may be operable by a hand lever and a rudder bar to supply pressure fluid at equal or different pressures for braking and steering purposes in known manner. As shown two groups of brakes 1, 2 each of four units are provided, each group comprising the brakes for a pair of wheels on one side of the aircraft. The groups are connected respectively to relay valves 3, 4 arranged to be operated by a pair of regulating valves 6 so as to supply pressure fluid to the brakes from a source 5, the valves 6 being operated, for example, by a hand lever and a rudder bar to supply pressure fluid to the relay valves from a source 7. Each relay valve 3, 4 comprises a casing 8, 9 divided into three chambers by a diaphragm comprising a member 11 and pair of membranes 12, 13. Each membrane is clamped to the casing between a plate 8 or 9 and ring 10 and to the member 11 by a plate 11a or 11b. The chamber a below the diaphragm is connected to one of the pair of regulating valves 6 by pipe 14, the member 15 and radial passages 16. The middle chamber b is connected to atmosphere by radial passages 10a through the ring 10 and by radial passages 11c and a tubular valve member 17 to a chamber 19 which constantly communicates with one group of brakes 1 or 2 by pipes 20, and with the upper chamber c of the casing 8, 9, 10 by restricted passages 30. The fluidpressure source 5 is connected by pipe 26 to a chamber 25. Normally the diaphragm 11 is held in the lower position shown by springs 31 so that an exhaust valve 21 is unseated from the member 17 and the group of brakes 1 or 2 is open to the atmosphere through pipes 20, member 17 and passages 11c, 10a. When pressure fluid is supplied to chamber a by operation of the valve device 6, the member 17 is moved by diaphragm 11 to close the exhaust valve 21 and open the supply valve 23 to supply pressure fluid from the source 5 through pipes 26, 20 to the group of brakes. When the supply from the valve device 6 is stopped the pressure in the brakes -acting through the restricted passages 30 on the - diaphragm 11 partly returns to seat the valve 23 while the valve 21 remains closed. When pressure fluid is released from chamber a by the valve device 6 the diaphragm returns to the position shown so as to connect the brakes to the exhaust passages 10a. According to the Provisional Specification the apparatus may be wholly hydraulic or wholly pneumatic or one part may be Hydraulic and. the other part pneumatic ; further, the control valve device 6 may be such as described in Specifications 507,162 or 525,266.