Balanced valve coupling

In a fluid coupling for interconnecting pressurized fluid systems comprising, in combination, a first part having an axial passage having an inner end connected to a first fluid system and an open outer end, a second part having an axial passage having an inner end connected to a second fluid system and an outer end adapted to be received within said first part passage outer end, a tubular sleeve concentrically mounted upon said first part for axial displacement thereon between first and second positions, said sleeve having an open end located adjacent said first part's open end at said sleeve's first position and drawn into said first part at said sleeve's second position, a plurality of radially movable detents mounted on said sleeve adjacent said open end thereof, an annular detent retainer mounted on said sleeve in radial alignment with said detents axially displaceable between detent locking and detent release positions, a spring defined on said sleeve biasing said detent retainer toward said detent locking position, said second part outer end being receivable within said sleeve open end and having an annular groove defined therein for receiving said detents when said retainer is in said detent locking position, a manual actuator mounted upon said first part operatively connected to said sleeve for displacing said sleeve between said first and second positions, an expansible motor chamber defined in said first part, a piston defined on said sleeve within said motor chamber, said chamber selectively communicating with said first part first fluid system whereby the pressure thereof augments movement of said sleeve from said first position to said second position, said second part being connected to said sleeve at its first position and drawn into said first body at said sleeve's second position, a first valve within said first part passage, a second valve within said second part passage, said first valve including an annular axially reciprocal booster piston within said first part passage for axially biasing said first valve toward said second valve to open said second valve when said sleeve is in said second position and said parts are fully coupled.