Hydraulic directional control valve

A fluid directional control valve for regulating the flow of a fluid under pressure, comprising:

• a. a valve body having formed therein a valve chamber, an inlet fluid flow passageway opening to said chamber for admitting pressurized fluid thereinto, an outlet fluid flow passageway opening to said chamber for exhausting pressurized fluid therefrom, an annular valve seat in said chamber about said outlet passageway defining a circular valve seat opening providing fluid communication between said chamber and said outlet passageway, and a return fluid flow passageway normally at a generally balanced atmospheric fluid pressure;
• b. a fluid reservoir communicating with said return fluid flow passageway and being at said balanced atmospheric pressure;
• and
• c. ball check valve means disposed in said chamber for selective movement toward and away from said valve seat between a closed position seated in said valve seat opening and an open position spaced from said valve seat for respectively preventing and permitting fluid flow from said inlet passageway to said outlet passageway, said ball check valve means including a substantially spherical ball compatibly dimensioned with said valve seat for seated engagement therein and a ball retaining member disposed in said chamber in engagement with said ball in opposition to said valve seat, said ball and said ball retaining member being reciprocally movable substantially in a line perpendicular to said valve seat opening through the center thereof to engage and disengage said ball in said valve seat in said closed and open position, respectively, said ball retaining member including a head portion having a circular engaging surface in sealing contact about said ball substantially centered about said line of movement of said ball and said retaining member and a longitudinal stem portion extending from said head portion oppositely of said ball substantially centered about said line through another wall surface of said chamber generally opposite said valve seat to exposure exteriorly of said chamber in communication with said return passageway, the cross sectional area of said stem portion perpendicularly of said line being less than the cross-sectional area of said valve seat opening along substantially the entire length of said stem portion exposed in said chamber and the cross-sectional area defined by said circular engaging surface being greater than said cross-sectional area of said stem portion, said stem portion and said head portion cooperating with said valve seat opening to leave exposed to pressurized fluid in said chamber only a slightly greater total surface area of said ball and said retaining member facing toward said valve seat opening than facing away therefrom to provide a reduced net effective exposed surface area of said ball and said retaining member for application thereagainst by said pressurized fluid in said chamber of a relatively slight valve closing force sufficient to bias said ball and said retaining member to said closed position to reduce the force required in opposition to said pressurized fluid to open said valve while maintaining said retaining member in sealing contact with said ball to prevent separation thereof, said circular engaging surface of said head portion forming therewithin a ball receiving recess and said stem portion having forced therein a bore opening to said recess at one end thereof and to said return passageway at the other end thereof to relieve any fluid pressure at the location of contact between said circular engaging surface and said ball to permit said pressurized fluid to apply said valve closing force against said net effective surface area to maintain said retaining member in contact with said ball.