Fitting with biased locking device for coupling pipes

A pipe fitting connection comprising:

• (a) a pipe having a wall and a plain end portion;
• (b) a wall defining a metal pipe receiving socket having an exterior surface and a pipe cradling interior surface fitted longitudinally onto said pipe plain end portion;
• (c) a first bore having a smooth side wall extended from said exterior surface substantially through said wall and having a termination short of said interior surface, the juncture between said first bore and said exterior surface having a shoulder extending partially over said first bore and including a central aperture coaxial with said first bore;
• (d) a second bore of lesser diameter than said first bore and coaxial therewith extending the remainder of the way through said side wall from said termination to said interior surface;
• (e) a locking device having a shaft for extension through said first and second bores and including a head end generally adjacent said exterior surface and an opposite tip end for extension inwardly of said interior surface and piercing through the wall of said pipe end portion positioned in said socket and a seal retaining flange extending around said shaft generally at a midlength portion thereof, said seal retaining flange having a ring seal thereon engaging said side wall of said first bore and providing a fluid-tight engagement between said shaft and said side wall;
• (f) a retainer normally maintaining said locking device in a ready-to-use position whereby said tip end is spaced from said interior surface;
• (g) a coil spring sleeved on said shaft between said flange and said shoulder, said spring being compressed when said locking device is in said ready-to-use position and urging said tip end against said retainer and whereby, when said tip end is engaged with the wall of said pipe end portion positioned in said socket, said spring biases said locking device toward an extended position locking said pipe end portion to said socket.