Patent ID: 7478841

Claim:
A rapid coupling comprising: a sleeve having an inner stop and an insertion end; a pipe nipple having an insertion end adapted to be inserted into the sleeve's insertion end and having an outer surface formed with an engagement section; a locking element provided in the sleeve at the insertion end of the sleeve, the locking element, upon engagement with the engagement section, retaining the nipple in the sleeve to constitute a coupled state of the coupling; a compression spring disposed between the inner stop of the sleeve and the insertion end of the nipple wherein the position of the locking element and the engagement section and the strength of the compression spring are such that in an uncoupled state of the coupling, the compression spring pushes the nipple out of the sleeve to such an extent that the engagement section is outside the sleeve; and wherein the engagement section of the nipple is formed as a groove, and a recess is provided in the sleeve, the recess having three successive regions with diameters decreasing in an axial direction toward the insertion end of the sleeve, the diameter of an inner one of the regions being at least equal to the outer diameter of the nipple plus twice the radial thickness of the locking element, and the diameter of a center region corresponding to the diameter of the groove plus twice the radial thickness of the locking element.