Single-adjustment, dual-null pressure setting for an electrohydraulic valve pilot stage

An electrohydraulic valve for controlling differential hydraulic fluid pressure, comprising,

• a housing,
• a first inlet capable of connection to a first pressurized fluid supply,
• a second inlet capable of connection to a second pressurized fluid supply,
• a horizontal baseplate mounted within the housing,
• first and second spaced upstanding vertical nozzles having fluid outlet ports at upper ends thereof mounted on the baseplate and being fluidly connected to the first and second nozzles, respectively,
• a support member on the baseplate midway between the first and second nozzles,
• an elongated transversely extending pivot pin rotatably mounted with respect to the support member and adapted for vertical movement therewith,
• an elongated magnetic flapper member pivotally mounted with respect to the pivot pin in a normally horizontal position and extending over the fluid outlet ports of the nozzles in spaced relation thereto, and being adapted to pivot in a vertical plane,
• resilient restraining means in the housing connected to the flapper member for normally holding the flapper member in a horizontal position,
• a vertically disposed adjust pin mounted in the housing for vertical movement and having a lower end in contact with the pivot pin for adjusting the space between the flapper member and the fluid outlet ports of the nozzles, and
• magnetic means in the housing for selectively pivoting the flapper member to effect a distance variation between the flapper member and the outlet ports of the nozzles to create a differential fluid pressure therebetween.