GB612057A - Improvement in variable load brakes - Google Patents

Abstract

612,057. Brake-operating mechanism for vehicles. SVENSKA AKTIEBOLAGET BROMS-REGULATOR. May 16, 1946, No. 14862. Convention date, May 26, 1945. [Class 103 (i)] Vehicle brake-mechanism of the kind whereby the braking power is automatically varied in dependence upon the loading of the vehicle is so constructed that the braking ratio (that is, the ratio of the total pressure of the brake shoes against the vehicle wheels to the weight of the vehicle) increases with the load throughout the loading range. Since the coefficient of friction decreases with increasing brake shoe pressure, the braking ratio may thus be kept, with varying loading of a vehicle, at a value equally near the limit at which the wheels continue to roll and do not slide. The brake-applying mechanism shown comprises a cylinder 3, lever 2 and linkage 4 connected to the brake shoes 17. Automatic adjustment of the fulcrum 1 of the lever 2 is effected by linkage 10, 7, 9 and a curved leaf spring 5 acted upon at its ends, in opposite directions through pull-rods 6 and levers 12 by forces which are proportional respectively to the pressure on the supporting springs 15. The pull-rods 6 coact with stops 8, the arrangement being such that the load Ql or Q<SP>2</SP> on the spring 15 which is at the vehicle end that happens to be the more lightly loaded, effects the fulcrum adjustment. The mechanism is similar to that described in Specification 565,517, the spring 5 being such that the deflection thereof decreases as the load on it increases, but by means of the lever 7, this deflection is multiplied to give a displacement of the fulcrum 1 such that the braking ratio increases with the load. By the interposition of a transmission linkage having the necessary gear ratio, a spring may, however, be used, the deflection of which increases uniformly with the load. Specification 490,591 also is referred to.