Patent ID: 7695025

Claim:
A coupling for metal, plastic material or multilayer tubes, the coupling comprising: a coupling body comprising a hollow cylindrical neck on at least one end thereof, said coupling body forming a sealed housing for one end of a pipe, said hollow cylindrical neck comprising at least two longitudinal recesses spaced at an angle with respect to each other and at least two radial lugs, said at least two radial lugs being arranged on a free end of said hollow cylindrical neck; a tightening nut assembled and turning around the hollow cylindrical neck of said coupling body; and a plurality of jaws, each of said jaws having an external thrust surface and one or more serrated gripper teeth facing radially inward, each of said jaws being movable in a radial direction of said neck such that each of said jaws moves between an extended release position and a contracted locking position, said contracted locking position being defined by locator steps on at least two lateral sides of each recess, said tightening nut comprising inner cam thrust surfaces, said cam thrust surfaces interacting with said external thrust surface of the jaws such that each jaw moves from the expanded release position to the contracted lock position in response to a partial turn of said tightening nut on the neck of the coupling body, said tightening nut comprising a head portion, said head portion comprising anti-release indents, said anti-release indents interacting with said radial lugs such that said anti-release indents and said radial lugs stop said tightening nut from turning in a release direction once said tightening nut has been locked.