GB732609A - Braking system for aircraft - Google Patents

Abstract

732,609. Fluid pressure aircraft brakes. DUNLOP RUBBER CO., Ltd., TREVASKIS, H. W., DEWAR, D., and MORTIMER, F. R. April 29, 1954 [May 30, 1953], No. 15113/53. Class 103 (1). In aircraft braking systems comprising antiskid control devices, it is arranged that the brakes shall be applied to the wheels to prevent rotation thereof after take off and retraction, but that the pressure shall be released after a predetermined period since the pressurization of the system during long flight period is undesirable. This operation is brought about by a valve device 26 between the undercarriage jack 29 and the lead 34a to the exhaust valve 19 of the anti-skid mechanism. When the jack 29 is pressurized for retraction, the pressure acts below and raises a piston 31 in the central part of the valve housing 26. The upward movement of piston 31 seats a conical valve in member 38 to prevent passage of fluid past the centre of the piston into the chamber above connected to a reservoir by conduit 30a. It also raises a valve 35 off its seat 34 so as to allow pressure fluid from the pilots control valve 46 to pass by pipes 25 and 34a to exhaust valve 19 and pressure chamber 17 so as to apply the brakes. The piston 31 in rising carries with it a rod 40 and flange 41 which press a plug 42 and sealing ring 43 into the part 44 of casing 28 which is of smaller diameter. When the wheels have been retracted for sometime pressure fluid below the piston 31 leaks past the valve 38 at a slow rate and escapes by pipe 30a to the reservoir. The piston 31 thus descends slowly and eventually valve 35 reseats so that the brakes are no longer pressurized. The plug 42 and sealing ring 43 remain in the cylinder part 44 until pressure is released from the cylinder 28 by extension of the undercarriage. Specifications 676,708, 683,490 and 706,351 are referred to.