Abstract: A control apparatus for a power transmission of vehicles such as construction machine having at least one work implement actuated by a hydraulic cylinder unit, a transmission gear with hydraulically operated speed-change clutch, and a torque converter interposed between an engine and the transmission gear so as to transmit rotational power of the engine and having a hydraulically operated stator clutch.

Abstract: A hydraulic emergency braking system for a vehicle also having service brakes wherein a hydraulic directional control valve provides input pressure to a dump valve having a pressure outlet to spring apply, pressure-release brake actuators and a dumping outlet to the hydraulic reservoir. Internal conduits in the dump valve housing assure continuous transmission of inlet pressure to the pressure outlet thereby releasing the pressure-release brakes, while preventing reverse flow with a check valve when the directional control valve dumps the inlet pressure to the reservoir to apply the brakes. In the absence of inlet pressure to the dump valve, a spring-biased spool valve connects the pressure outlet to the dumping outlet, thereby immediately dropping the pressure in the brake actuators to the value predetermined by the spring.