GB780025A - Anti-skid control device for fluid pressure brakes - Google Patents

Abstract

780,025. Anti-skid brake control units. BENDIX AVIATION CORPORATION. Oct. 20, 1955 [Nov. 17, 1954], No. 30031/55. Class 103 (1). An anti-skid control device for fluid pressure brakes, particularly for aircraft wheels, includes valve elements in the fluid lines which have the effect of preventing the fall off of wheel r.p.m. during a skid recovery phase due to the braking pressure being reduced more than is necessary to correct an incipient skid. As shown in Figs. 1 and 3, the anti-skid control device comprises an inertia mass consisting of a rim member 62 clutched to a flywheel 60 rotatable with the wheel 16 by a spring-urged band element 68, the effect of which is to allow overrunning of the wheel 60 by the rim 62 but not vice-versa. Rotation of wheel 60 in advance of or behind its shaft 26 results in channel 53 therein and in the bushing 48, moving into or out of register so that chamber 42 having a pressure therein equivalent to the brake pressure may be put into communication with chamber 56 connected to an hydraulic reservoir by a passage 59 and opening 61. A valve &c. shown more clearly in Fig. 10 controls flow of fluid through into the space 42 in a manner such as to give the control characteristics described above. The valve includes a resilient member 74 having a plurality of apertures 76 such that engagement of the central portion with head 86 of the stem 84 reduces the available area for fluid flow. A similar valve 14, but having only a central aperture in the resilient member 74, is located so as to directly connect the pipes leading to the inlet port 30 and the line 20 to the brake cylinder. Fig. 8 shows wheel speed and brake pressure variations with time, the object of the invention being to bring the wheel speed recovery points " a " and minimum brake pressure point " b " into substantial simultaneity so that braking may take place to the maximum possible degree during the recovery period.