Abstract: A brake valve (45) is disclosed of the type which permits communication from a source (11) of pressurized fluid to a brake actuator (47) in response to manual movement of a valve spool (57) from a neutral position (FIG. 2) to a power brake position (FIG. 5). In the power brake position, the valve spool permits fluid communication between a work port (53), which communicates with a brake actuator, and a brake load signal chamber (87), the brake load signal controlling the fluid output of the source. As the valve spool moves toward a manual brake position (FIG. 6) communication between the work port and the brake load signal chamber is blocked. In the manual brake position, movement of the valve spool causes a large piston (63) to displace fluid from its piston bore (73) into a piston bore (75) in which is disposed a small piston (61), the small piston being operable in response to movement of the valve spool to build brake pressure in the work port (53).

Abstract: An automatic hitch mechanism that permits a tractor driver to connect and disconnect an implement without leaving the cab of the tractor. The hitch includes a tractor drawbar equipped with a power-driven slide member, hook member, and power coupling assembly all interconnected for coordinated movement so that during a hitching operation the hook member first swings into operative engagement with the latch ring of an implement and then, in a continuous sequence of automatic steps, the hook member is locked in its operative position, the power coupling assemblies of the tractor and implement are joined together, the jack supporting the implement tongue is retracted, and one of the coupling assemblies is de-stabilized so that thereafter the tractor and implement may execute turns and traverse uneven terrain without damaging or disengaging the coupling assemblies. Automatic unhitching of the tractor and implement involves a reversal in the direction and order of such steps.