Abstract: In a connector provided with a coupling ring for the pipe coupling of a high-pressure cleaning apparatus, the pipe coupling comprising a coupling sleeve with a conical sealing surface, a circular-cylindrical sealing surface adjacent thereto, and an outer thread for the coupling ring of the connector, with a cylindrical nipple carrying a ring seal and sealingly positionable at the circular-cylindrical sealing surface of the coupling sleeve, and a convex sealing shoulder for sealing abutment on the conical sealing surface of the coupling sleeve, the coupling ring being mounted on the connector so as to be freely rotatable and essentially immovable in the axial direction, in order to improve the mechanical protection of the coupling parts against damage, it is proposed that the coupling ring protrude in the axial direction over the free end of the nipple, and that the ratio of the length of the nipple to the outer diameter thereof be between 0.4 and 0.3.