Shut-off valve for a sprinkler head

A shut-off valve interactive between a sprinkler head having a downwardly directed female threaded opening and a riser pipe having a male threaded uppermost extremity adapted to engage said female threaded opening, said valve comprising:

• a) a coupling sleeve comprised of a rigid sidewall of monolithic construction bounded by interior and exterior circular cylindrical surfaces and defining a hollow interior region elongated upon a straight axis between an upper extremity having external male threading adapted to engage said sprinkler head and a lower extremity having interior female threading adapted to engage said riser pipe, an interior annular shoulder, and an annular frangible zone formed as a recess in said exterior surface between said shoulder and upper extremity,
• b) a washer fabricated of a resilient material having a Shore A Durometer hardness between 40 and 80, said washer disposed within said interior region seated upon said shoulder and having an aperture-centered upon said axis, and
• c) a sealing member moveable upon said axis between uppermost and lowermost positions, and comprised of a head portion disposed below said washer, and shaft portion directed upwardly from said head portion, penetrating said aperture and terminating in a bifurcated upper section having outwardly divergent arms biased into engagement with the interior cylindrical surface of the upper extermity of the coupling sleeve to hold the sealing member in place, said arms with abutment extremities adapted to contact said sprinkler head, said head portion having a sealing section inwardly tapered toward said shaft portion, said sealing member being fabricated of a resiliently rigid plastic which permits said arms to be squeezed together sufficiently to permit passage through said aperture.