Abstract: A friction brake mechanism having a pair of front brake assemblies and a pair of rear brake assemblies receives pressurized fluid at the same time and at the same pressure from a hydraulic control apparatus. Each of the brake assemblies has a brake piston movable in a chamber between a holding position and a releasing position and a plurality of brake plates and a plurality of brake disks interleaved with the brake plates. A first spring system is associated with the pair of front brake assemblies and a second spring system is associated with the rear brake assemblies. The first spring system provides a different force than the second spring system to cause the rear brake assemblies to be engaged a predetermined period of time ahead of the pair of front brake assemblies without any design change in the hydraulic control apparatus.

Abstract: In the very large hauling vehicles (10) it is desirable to provide the front and rear wheels (20,16) with multiple disc brake assemblies (32) that have retarding capabilities. It has long been a problem to route a conduit (34,36) of a size large enough to carry the required volume of cooling oil, between a frame (12) of the vehicle (10) and the front wheels (20). The front wheels (20) present a particular problem in that they usually move vertically along an axis (28) of a suspension strut (22) to which they are mounted, as well as pivoting about the axis (28) for steering functions. A conduit (34,36) that has sufficient length to accommodate the extremeties of the compound motion will often come in rubbing contact with the surrounding structural members which results in wear and premature failure of the conduit.

Abstract: A standard motor vehicle having a pair of driving wheels (8), (9) powered by a drive shaft (10) through a differential (11) can experience difficulties when one of the two differentially driven wheels (8/9) loses traction. The differential (11) directs all of the power to the wheel that is slipping and the wheel with traction remains stationary. Various anti-spin devices have been developed but these often produce an abrupt transfer of all of the driving power to the wheel having traction. The anti-spin apparatus of this invention overcomes this problem and includes an electrical control circuit (24) and sensors (20), (21) for generating a slip signal representing the speed difference between the wheels (8), (9). The apparatus further includes a modulated hydraulic reducing valve (30), (110) for actuating the brake (15/15') on the faster rotating wheel (8/9) and a hydraulic modulating control valve (29) connected to the reducing valve (30), (110) and actuated by the slip signal.

Abstract: A slip control system for vehicles having spaced apart differentially driven wheels (200,202) including means (220) for calculating wheel slip according to the ratio of wheel speeds, means (242,230,232) for entering a slip control mode wherein a braking force is applied to the slipping wheel and incrementally varied on a periodic review basis according to recalculated slip values. If slip increases or holds steady, the brake force is incrementally increased. As slip becomes less, the brake force is incrementally reduced, the particular increments of force reduction being selected in accordance with successive measurements of slip. A drive shaft signal (226) is compared to the high wheel speed signal to identify a wheel speed transducer failure.

Abstract: A spring assembly and a method of assembly therefor are provided wherein one or more longitudinal coil springs are retained between two end caps. Each end cap receives a hollow pin, each pin extending axially inwardly therefrom and abutting the other pin. The pins include axially aligned threaded throughbores which receive a threaded stud whereby the pins are maintained in abutting relation. The spring assembly is assembled by means of assembly tools which serve to rotate the pins to allow the stud to be received therein and to space the stud within the pins.

Abstract: A dual piston brake arrangement for selective holding engagement of a rotatable member of a drive train includes a support structure, a service brake piston axially reciprocably and nonrotatably mounted within the support structure with a fluid passage therethrough, a fluid actuator for biasing the service brake piston toward a brake holding position, a secondary brake piston axially reciprocably and nonrotatably mounted within the support structure and in substantially radially aligned relation within the service brake piston for selective telescopic movement from an abutting to a separated condition therefrom, and a fluid circulating system for delivering a fluid radially outwardly adjacent the rotatable member and the service brake piston for cooling thereof and subsequently along an egress path including flow of the fluid through the fluid passage in the service brake piston.