Coupling for plastic pipe

Claim 1

A coupling for use with pipe formed of resin material, the coupling comprising adjacent pipe sections each having its end externally beveled, a coupling sleeve receiving the beveled ends of the adjacent pipe sections and having internal grooves for sealing rings, and sealing rings in said grooves cooperating with the pipe sections, the sleeve having abutments formed on the internal surface thereof for limiting assembly movement of the pipe sections into the sleeve, the abutments for the respective pipe sections comprising annular ridges in the sleeve and each having an annular inclined abutment face decreasing in diameter inwardly of the sleeve, the diameters of the ends of the adjoining pipe sections and of said inclined abutment faces providing for engagement of the beveled ends of the pipe sections with the inclined abutment faces intermediate the regions of maximum and minimum diameter of the inclined faces, the angle of inclination of the abutment faces providing freedom for advancement of the pipe ends into the sleeve with resultant compressive distortion of the end portions of the pipe sections when the pipe sections are forced into the sleeve under the influence of expansion of the coupled pipes, and the abutment ridges being spaced from each other to provide an intervening space therebetween of diameter greater than the minimum diameter of the ridges and thereby accommodate inward advancement of the pipe ends beyond said ridges.