Small-size piping coupling joint

Claim 1

A small-size pipe coupling joint comprising: a cylindrical retainer member having an opened coupling end, an opposed bottom wall and a circumferential wall extending therebetween the bottom wall having a pipe insertion hole passing centrally therethrough, the opened coupling end defining a socket receiving recess extending to the bottom wall, the circumferential wall being circumferentially continuous adjacent the coupling end of the retainer member but comprising at least one engaging hole intermediate the ends; a cap member having an annular portion engaged over the opened coupling end of the retainer member and having at least one locking claw wall projecting through said at least one engaging hole slantingly toward the bottom wall of the retainer member; a socket member having a rear end, a forward end and a flow hole extending therebetween, portions of said flow hole adjacent the forward end defining a stepped expanded chamber, the forward end being disposed in the socket receiving recess of the retainer member and adjacent the bottom wall thereof, an outer circumferential portion of said socket member being characterized by an engaging groove disposed in the socket receiving recess and being lockingly engaged by the claw wall for securely retaining the socket member in the socket receiving recess of the retainer member; a pipe having a coupling end and an annular swelling wall, the pipe passing through the pipe insertion hole of the retainer member such that the annular swelling wall and the coupling end thereof are engaged intermediate the bottom wall of the retainer member and the expanded chamber of the socket member; and seal means provided in the expanded chamber of the socket member and adjacent the annular swelling wall of the pipe, whereby the continuous circumferential wall portion of the retainer member adjacent the coupling end thereof prevents accumulation of foreign matter at the engagement of the claw wall with the engaging groove of the socket member for ensuring secure retention of the pipe, the retainer member and the socket member in locked engagement with one another.