Underwater timer and release device

Claim 1

A combination timing-and-float-marking device, comprising: a cylindrical housing having an upper wall and a removable lower end wall, wherein there is defined an enlarged compartment; a buoyant mass releasably attached to one end of said housing; means for releasably securing said mass to said housing, wherein said means is disposed therebetween; a piston means slidably disposed within said compartment, whereby the movement thereof operates said releasably securing means, said piston means comprising: a piston head having a rod secured thereto, one end thereof extending upwardly through said upper wall and downwardly through said lower end wall, a valve means disposed in said pistoN head to permit flow of fluid in one direction therethrough, a fluid-flow-regulating means disposed in said piston, whereby fluid flow is metered therethrough for controlled movement of said piston, and a biasing means operably disposed within said compartment between said upper wall and said piston head, thereby biasing said piston head in a direction whereby fluid is forced to flow through said regulating means; and wherein said compartment includes: a primary chamber formed in said compartment between said upper wall and said piston head, and a secondary chamber formed in said compartment between said lower end wall and said piston, and wherein said valve means comprises a one-way check valve so arranged within said piston head as to permit fluid flow from said primary chamber to said secondary chamber, and wherein said fluid-flow-regulating means permits fluid to flow into said primary chamber from said secondary chamber at a predetermined rate.