Compressed air coupling

In a compressed air coupling comprising a socket, a valve sleeve displaceable in the socket, said socket having a compressed air inlet means releasably to lock the sleeve in a first position in the socket, a nipple insertable into the sleeve, a ball catch carried by the sleeve releasably to lock the nipple in the sleeve, means defining a first passage for flow of compressed air from said compressed air inlet through the socket and sleeve and into the nipple in said first position of the sleeve, the sleeve being movable relative to the socket to a second position upon release of said locking means, in said second position said ball catch releases the nipple, and resilient means urging the sleeve in a direction from said first position toward said second position;

• the improvement in which the sleeve with the nipple locked therein is movable to a position intermediate said first and second positions, said sleeve in said intermediate and said second positions cooperating with a first inner surface portion of said socket to block the first passage to prevent flow of compressed air from said compressed air inlet of said nipple, means defining an open passageway from the interior of the nipple to a region outside the coupling in said intermediate position, the socket having on a second inner surface portion, in the direction the resilient means urges the sleeve, a cylindrical surface followed by a radially inwardly extending shoulder followed by a radially outwardly extending first ball groove, the nipple having on an outer surface a second ball groove having an inclined side surface, said cylindrical surface maintaining said ball catch in said second groove in said first position of the sleeve, said inclined surface camming said ball catch partially out of said second groove and against said shoulder in said intermediate position of said sleeve when compressed air in the nipple forces the nipple in said direction, the sleeve urging the ball catch against said shoulder to cam the ball catch into said second groove in said intermediate position in the absence of compressed air in said nipple thereby to permit said resilient means to move said sleeve to said second position after compressed air in said nipple has been exhausted through said open passageway, and said inclined surface camming said ball catch into said first groove in said second position of the sleeve upon movement of the nipple relative to the sleeve in said direction thereby to permit withdrawal of the nipple from the sleeve.