Pipe coupling

A pipe coupling for a pipe having cylindrical end without a flange and which is made of one of plastic or ductile iron, the coupling comprising a coupling sleeve having an enlarged end for receiving the end of the pipe and an interior surface for defining a seal cavity between the surface of the pipe end and said interior surface of said enlarged end of said coupling sleeve, a tightening ring having a slanted radially interior surface portion and positionable over the pipe end and being relatively movable with respect to the pipe end, a slide ring and a gripper ring, said gripper ring having a radially inner surface provided with a plurality of gripping members extending radially inwardly, said gripper ring having a slanted radially outer surface for engaging the slanted interior surface portion of said tightening ring, said slide ring having an end for engaging a seal ring placed around the pipe end and an opposite end for engaging said gripper ring so that when said tightening ring is moved toward said enlarged end of said coupling sleeve, said gripper ring will be moved by said tightening ring to move said slide ring against said seal ring to compress said seal ring in said seal cavity and against the surface of the pipe end and to move at least some of said gripping members into the surface of the pipe.