Quick action self-locking pipe fittings

Claim 1

A quick action, lockable and releasable fitting for connecting a pipe or tube to a coupling body, said fitting comprising a hollow body having at least a nipple, said nipple having an internal truncated cone surface with the major base facing towards the external opening of said nipple making a leakproof seal with an end of a pipe when the latter is pushed inside said nipple, and an external cylindrical surface provided with at least a collar and terminating in a rim; an elastic anchoring washer placed on said rim of said nipple and provided with a plurality of claws projecting radially inward from its inner circumference and long enough to be elastically flexed towards the interior of the coupling by said pipe and to abut against the external surface of said pipe preventing it from being pulled out; a sleeve having a seat in the internal surface thereof and adapted to be forceably snapped-on said nipple until said collar on said nipple is received in said seat, the internal surface of said sleeve being further provided with a first step blocking said elastic washer against said rim of said nipple, and with a second step; a plug having a crown and a tubular appendix terminating in a collar and having a central cylindrical hole of diameter sufficient to permit passage of said pipe through the plug, said plug by means of said appendix being forceably snapped into said sleeve by forcing said collar of said tubular appendix beyond said second step of the internal surface of said sleeve a distance such that the crown of the plug remains outside the sleeve; cooperating means in said plug and in said sleeve for allowing or preventing an axial displacement of said plug with respect to said sleeve by rotating the plug, by means of said external crown, between at least two distinct angular position in such a way that, when in a first angular position, said plug may advance towards the interior of said sleeve until the rim of said tubular appendix flexes elastically the claws of said washer further towards the interior of the fitting parting said radially projecting claws and freeing said pipe so that it may be pulled out, and, when in a second angular position, said plug is backed out and prevented from being pushed further inside said sleeve and said claws abut against the external surface of said pipe at an angle such as to prevent withdrawal of said pipe.