Balanced rotary-faced valve

A balanced rotary-faced valve for controlling the flow of pressurized fluid to hydraulic apparatus having extend and retract ports, the valve comprising:

• means for inletting and draining pressurized hydraulic fluid from the valve;
• a valve body portion having a flat land portion and a plurality of recesses adjacent to and opening at the plane of the land portion, the recesses including two opposed pressurized fluid receiving recesses, a retract recess in fluid communication with the retract port, an extend recess in fluid communication with the extend port, and a drain recess in fluid communication with the pressurized fluid drain means;
• pressure port means in fluid communication with the pressurized hydraulic fluid inlet means for providing pressurized hydraulic fluid to a station at the land portion of the body;
• a disk having first and second faces and an axis about which said disk is rotatable, the first face in surface contact with the flat land portion of the body and having pressure-drain coupling recesses and extend and retract recesses capable of registration with corresponding retract and extend recesses in the body portion;
• means defining an annular groove in the second face of the disk;
• means defining a first pair of diametrically opposed passageways between the groove and the first face of the disk, each passageway in fluid communication with a corresponding body portion pressurized fluid receiving recess so that any reaction forces created thereby act in a direction coaxially with the axis of the disk;
• means defining a second passageway through the disk for guiding pressurized fluid from the body portion station to the groove;
• sealing means for preventing the pressurized fluid from flowing out of the groove except through the first pair of passagways, the sealing means having an area in contact with the pressurized fluid thereby creating a predetermined counter force upon the second face of the disk to urge said disk toward the flat land portion, in opposition to any pressurized fluid created force on the first face of the disk;
• means for rotating the disk to neutral, first and second positions so that in the neutral position the pressure-drain coupling recesses in the disk overlays corresponding pressure and drain recesses of the body providing fluid communication therebetween and, thus, the inletted pressurized fluid flows from the pressure recess to the drain recess and so that in a first position the extend recess in the disk overlays the pressure and extend recesses of the body and the retract recess in the disk overlays the drain and retract recesses of the body providing fluid communication therebetween so that an equal amount of fluid entering the extend port exits from the retract port, and so that in a second position the retract recess in the disk overlays the pressure and retract recesses of the body and the extend recess in the disk overlays the drain and extend recesses of the body providing fluid communication therebetween so that an equal amount of fluid entering the retract ports exits from the extend port.