Patent ID: 7341282

Claim:
A detachable plug coupling with a locking element for the connection of liquid lines comprising: a coupling housing with an accommodating space adapted for insertion of a tubular insertion part having a circumferential retaining rib; an enlarged housing head formed on the coupling housing for receiving a retaining element; wherein the retaining element includes elastically opening retaining edges oriented radially into the accommodating space, and said retaining edges are operative to engage behind the retaining rib after the insertion of the insertion part into the accommodating space; a transversely displaceable locking element secured to the housing head, wherein the locking element includes two lateral walls positioned adjacent the housing head, a U-shaped transverse wall disposed between the two lateral walls, a front plate connected to an uppermost edge of each of the two lateral walls and the transverse wall; and inwardly pointing stop edges located on a lowermost edge of each of the two lateral walls that operatively engage a head edge of the coupling housing after transverse movement of the locking element between an open position and a closed position; wherein the front plate, when in an open position, includes a first semicircular recess adapted to correspond to an external diameter of the retaining rib and a second semicircular recess adapted to correspond to a diameter of the tubular insertion part, and the second semicircular recess extends from a base of the first semicircular recess towards the transverse wall; and an arc-shaped support bar formed on the front plate, adjacent an outer edge of the first semicircular recess, before the transition to the second semicircular recess and extending into the accommodating space; wherein the support bar includes a support surface that ends with an engagement plane of the retaining edges when the locking element is in the closed position, and the locking element is adapted to be connected to the housing head, and is operatively displaced transversely in an insertion direction to retain the retaining rib, after engagement of the tubular insertion part in the retaining element.