Dashpot mechanism for self-closing plumbing valves

Claim 1

A fluid-filled dashpot mechanism comprising: (a) housing means having a passageway therein; (b) stem means reciprocally disposed in said passageway; (c) pushbutton means secured to one end of said stem means for operably displacing said stem means; (d) a pair of rolling diaphragms disposed in face-to-face relationship in said passageway and operably coupled in fluid sealing relationship to said housing means and said stem means so as to form an enclosed chamber within said housing means for containing said fluid therein; (e) piston means dividing said chamber into two portions and reciprocally operable therein for displacement of said fluid in said chamber; (f) means for operably associating said stem means with said piston means for reciprocation therewith; (g) fluid communication means for providing continuous fluid communication between said chamber portions; (h) check valve means operably associated with said stem means so that when said stem means is operably displaced in one direction said fluid flows from one chamber portion to the other through said check valve means and said fluid communication means, thereby allowing a reltively rapid displacement of said fluid between said chamber portions and effectuating relatively rapid displacement of said piston means and said stem means, and when said stem means is operably displaced in the opposite direction said fluid flows from said other portion to said one chamber portion through said fluid communication means thereby allowing a relatively slow displacement of said fluid between said chamber portions and effectuating relatively slow displacement of said piston means and said stem means; and (i) stop means for limiting the stroke of said stem means, wherein said stop means for operably limiting the stroke of said stem means includes threaded rod means one end of which is threadably disposed in said pushbutton means and the other end extending beyond said pushbutton means towards said housing means, the distance between said other end of said rod and said housing means determining the stroke of said piston means by limiting the axial displacement of said stem means.