Abstract: A disc brake wherein a caliper having a fluid pressure cylinder portion and a reaction portion for urging a pair of pad assemblies onto a disc rotor is shiftably retained by four slide pins. The slide pins are erected from a torque receiving member, one pair on either side of the disc rotor. Respective two slide pins projecting perpendicularly away from the rotor on opposite sides thereof are positioned co-axially to each other. At least one of the four slide pins disposed on the side with the cylinder portion is made into a main slide pin for chiefly regulating the shifting direction of the caliper; and the remaining three slide pins are respectively made into auxiliary slide pins with less capability for regulating the shifting direction than the main slide pin.

Abstract: An alarm device for a brake clearance limit in an air-over-hydraulic brake system wherein air pressure piston drives a hydraulic piston for producing braking hydraulic pressure in a hydraulic brake system, capable of giving a warning at a certain constant brake clearance, irrespective of the height of pressure in the hydraulic brake system. The device comprises a sensor of hydraulic pressure for detecting a hydraulic pressure P in the hydraulic brake system, a sensor of shift amount l of the air-pressure piston after the moment when the permissible limit of brake clearance has been reached and all of the gaps in the hydraulic brake system have been lost, and a warning element which gives a warning signal when a formula l>.alpha..multidot.P is satisfied, wherein .alpha. designates rigidity coefficient of the hydraulic brake system, i.e., a quotient of the increased shift amount of the hydraulic piston divided by the increased amount of the hydraulic pressure.

Abstract: A brake booster consisting of a power cylinder and a hydraulic cylinder in combination and a wear detector for detecting a predetermined extent of wear of a brake lining is disclosed, which comprises the wear detector being formed of a switch operating member provided with a spring at one end and adapted to be moved by the action of a power piston in the power cylinder, a switch to be actuated due to the movement of the switch operating member and means apparatus for exerting a pressure corresponding to the operating pressure of the power piston on the other end of the switch operating member so that the switch operating member can be moved by the action of the power piston through the spring.

Abstract: A safety device for a double-circuit type air brake, wherein compressed air is supplied from one compressor to a pair of air reservoirs, through a check valve in each respective route, featured in inserting a safety device in an upstream portion of the double-circuit brake system, i.e., nearer to the compressor than the check valves.