Abstract: A steering control system for applying brakes to engine powered vehicles having power-shifting hydraulic fluid transmissions. An interface value is provided to sense a pressure signal of hydraulic fluid that is proportional to ground speed movement of a vehicle. A control value transforms the signal generated by fluid pressure into associative structure for applying vehicle brakes in a manner proportional to vehicle ground speed, either in a forward or reverse direction. Dual pressure regulating valves are provided wherein one value is set at a higher pressure than the other values for eliminating a need for two sources of pressure and/or a pressure accumulator.

Abstract: A vehicle hydraulic system wherein there is provided a primary pump coupled to a steering control valve through which steering of the vehicle is effected. A main priority valve is used to meter the flow of pressurized hydraulic fluid from the primary pump to either the steering control valve or an implement valve which is utilized to effect operation of auxiliary equipment, in accordance with the priority demands of the steering system. An auxiliary ground-drive pump provides a source of pressurized hydraulic fluid at all times the vehicle is in motion and is coupled to the steering control valve to provide a source of pressurized fluid when necessary or circulates the pressurized fluid to sump. The application of the output from the ground-drive pump is controlled by a secondary priority valve coupled to the output from the ground-drive pump to direct the output to the steering control valve or to sump.

Abstract: A valve for controlling the flow and pressure of fluid in a fluid operated system in which a hollow, ported control valve spool is movable in response to selective operation of a manually actuated actuator valve spool to effect modulation of a first fluid flow through the valve. One end of the hollow, ported control valve spool engages a plug portion of a freely floating piston movable in response to fluid pressure from a second fluid source to close a normally open port in the hollow control valve spool.