Cartridge type directional control valve

A cartridge type directional control valve assembly comprising an elongated housing having a longitudinal bore therein extending from one end of said housing to the other end thereof;

• a series of longitudinally aligned pressure responsive valve units within said bore for controlling the flow of hydraulic fluid when the control valve assembly is incorporated in a hydraulic control system;
• a first valve seat in said bore spaced from said one end of said bore;
• a ball check valve in said bore for controlling flow of hydraulic fluid across said valve seat;
• a first transverse passage extending through the walls of said housing and communicating with said bore;
• a second valve seat in said bore spaced from said first transverse passage and from said ball check valve;
• a flow control valve element in said bore controlling flow of hydraulic fluid across said second valve seat;
• one end of said flow control valve element being spaced from said ball check valve when said ball valve and said valve element are seated;
• a first spring in said bore biasing said flow control valve element towards said second valve seat;
• a second transverse passage extending through the walls of said housing and communicating with said bore;
• said second transverse passage being spaced from said second valve seat and from said first transverse passage;
• an adjustable load sensor changeover piston nested and sealed in said bore and having one end axially aligned with said flow control valve element;
• a plug having an end threaded into said other end of said bore for closing same;
• and a second spring interposed in said bore abutting the plug on one end and said load sensor changeover piston on the other end and urging said load sensor changeover piston against said flow control valve element.