Time-delayed automatic shut-off means for valves

Claim 1

A liquid-filled, dashpot mechanism, comprising: a. a dashpot housing having a dashpot chamber and a reservoir chamber wherein said liquid is disposed, said dashpot housing having portions of unequal diameters therein with rims thereabout; b. a stem means interposed in said dashpot housing and a portion of said stem means being disposed within said smaller diametered portion in contiguous relationship to said rim of said smaller diametered portion and slidably operable therein and projecting therebeyond; c. means for effecting a fluid sealing relationship between said rim of said smaller diametered portion and stem means; d. a dashpot piston means smaller in diameter than said larger diametered portion and fixedly disposed on said stem means, said dashpot piston means being operably disposed within said dashpot housing and capping said dashpot chamber formed between said smaller diametered portion in said dashpot housing and said dashpot piston; e. flexible flange means disposed about and inbetween said dashpot piston and said dashpot housing, said flexible flange means effecting fluid sealing engagement between said dashpot housing and said dashpot piston means when said dashpot piston means is moved away from said smaller diametered portion and effecting non-fluid sealing engagement when said dashpot piston means is moved towards said smaller diametered portion, thereby functioning as a check valve; f. a reservoir piston means slidably mounted on said stem means between said larger diametered portion and said dashpot piston means and disposed in peripheral, slidable engagement with said dashpot housing, said reservoir piston capping said reservoir chamber formed in said dashpot housing between said dashpot piston and said reservoir piston disposed within said dashpot housing; g. means for effecting fluid sealing relationship between said reservoir piston means and said stem means; h. means for effecting a fluid sealing relationship between said reservoir piston means and said dashpot housing; i. spring biasing means disposed between said reservoir piston means and said dashpot housing adjacent to said larger diametered portion in said dashpot housing for urging said reservoir piston means towards said dashpot piston means thereby maintaining said reservoir piston in full contact with said liquid in said reservoir chamber; and j. a liquid metering passageway through said dashpot piston providing fluid communication between said dashpot chamber and said reservoir chamber, whereby when said dashpot piston is moved towards said smaller diametered portion in said dashpot housing by urging said stem means to move within said smaller diametered portion of said dashpot housing and outwardly therefrom, the liquid in said dashpot chamber is forced through said liquid metering passageway and simultaneously flexes said flexible flange means away from said dashpot housing thereby creating non-fluid sealing engagement between said dashpot piston and said dashpot housing and when said dashpot piston is moved away from said smaller diametered portion in said dashpot housing by urging said stem means to move inwardly into said dashpot housing through said smaller diametered portion in said dashpot housing, the liquid in said reservoir chamber flexes said flexible flange means towards said dashpot housing and into fluid selaing engagement therewith and is forced to pass solely through said liquid metering passageway from said reservoir chamber to said dashpot chamber thereby effecting time-delayed movement of said stem means.