Abstract: Dual master cylinders are arranged to apply hydraulic pressure to a single set of vehicle brakes through a double check valve and single brake fluid conduit. A first of the master cylinders is actuated by compressed air in response to manipulation of an operator's service brake control, while the second master cylinder is actuated to a lesser extent by compressed air responsive to an operator's retarder control. A modulatable emergency brake control may independently and simultaneously actuate both master cylinders together with a third master cylinder coupled to separate brakes. Thus, braking capacity remains available if the service brake system or the retarder brake system or both should fail, or if the emergency system should itself fail while either the service system or the retarder system remains functional.

Abstract: A control system for a spring-applied service brake which can also be used as a parking brake. Pressure from the vehicle hydraulic system is normally used to release the brakes. In the event of a loss of the primary pressure from the hydraulic system, the control system switches automatically to use of secondary pressure from the vehicle compressed air system to release the brakes, while maintaining the ability of the operator to apply the brakes by normal operation of the service and parking brake controls.

Abstract: An outer bearing race is mounted in a bore defined in a support member and an inner bearing race is universally mounted in the outer race to form a ball and socket connection therebetween. An annular retainer is secured in the bore on each side of the outer race to retain an annular lip seal therebetween. A flexible lip of the seal extends radially inwardly into sealing contact with a convex spherical surface formed on the inner race.

Abstract: A strain-limiting fastening apparatus for containing a source of potential energy in entrapped relation between a pair of axially separable members includes a plurality of fasteners securable to one of the members for substantially axially holding the other member thereto in opposition to the source of potential energy, and a plurality of stops on the other member for limiting the degree of maximum axial adjustment of an individual fastener to a predetermined incremental amount until all of the fasteners have been adjusted to this amount, to thereby limit the degree of cocking of the other member during the assembly or disassembly thereof in order to minimize unequal loading of the fasteners by the source of potential energy.