US Patent 7048309 Pipe coupling

A coupling for attachment to the end portion of a pipe includes jaw members adapted to slide along an inner end taper in the coupling body so that linear movement of the jaw members toward the end of the inner end taper adjacent an end of the coupling body causes movement of the jaw members radially inwardly of the coupling body against the end portion of the pipe when received in the coupling body. The coupling may include a bell type gasket to function as a spring and the spring action of the gasket may be augmented by installing a springy crib ring around the gasket inside the coupling body.