Patent ID: 7124579

Claim:
A hydraulic control system including a source of pressurized fluid having a load pressure responsive means for varying the fluid delivery of said source; a fluid pressure operated actuator defining a pair of actuator ports; and a main control valve having an inlet in fluid communication with said source, and a pair of control ports in fluid communication with said actuator ports by means of first and second conduits; said main control valve defining a main variable flow control orifice which closes to prevent fluid flow through said main control valve when said main control valve is in a neutral condition, and including means operable to generate a load pressure representative of the hydraulic load on said actuator; and a pressure spike suppression valve having first and second ports connected to said first and second conduits, respectively, said pressure spike suppression valve including a valve member moveable between a first position blocking fluid communication between said first and second ports, and a second position permitting fluid communication between said first and second ports; characterized by: (a) said pressure spike suppression valve defining a spring chamber including a compression spring biasing said valve member toward said first position; (b) said pressure spike suppression valve defining a load signal passage to communicate said load pressure to a load signal chamber also to bias said valve member toward said first position; and (c) said pressure spike suppression valve defining a pressure chamber in fluid communication with said source of pressurized fluid, fluid pressure in said pressure chamber biasing said valve member toward said second position.