Fluid actuated brake safety device

Claim 1

A combined safety device and alarm assembly for use with a pressurized fluid supply line and first and second conduits leading to first and second concurrently operated fluid actuated brake assemblies, said device being of the type that includes a valve body that defines a confined space that is in communication with first and second axially aligned bores and a third bore normally disposed to said first and second bores; a valve body portion that extends into said confined space and has a fourth bore therein that is axially aligned with said first and second bores; first and second plugs mounted in said first and second bores, said first and second plugs having first and second longitudinal bores therein, and the adjacent ends of said plugs defining ring shaped valve seats; an elongate valve member slidably mounted in said fourth longitudinal bore, said valve member having end surfaces that can abut against said valve seats when said valve member moves longitudinally from a first centered position between said plugs to a second position; first and second means for connecTing said first and second conduits to said first and second plugs to be in communication with said first and second bores; third means for connecting said fluid supply line to said third bore; fourth means that at all times tend to maintain said valve member in said first position, said safety device being characterized by: a. radially deformable resilient means so operatively associated with said valve member and plugs that said valve member moves from said first to said second position due to an unbalanced fluid pressure condition arising in said confined space as a result of a leak in one of said first or second conduits or said brake assemblies associated therewith, said resilient means not only seals the longitudinal bore in said first or second plug leading to the defective conduit or brake assembly to prevent any further flow of fluid from said confined space therethrough but locks said second position; b. first and second normally closed fluid pressure actuated electric switches in communication with said first and second conduits; c. a third normally open fluid pressure actuated switch in communication with said supply line; d. electrically operated warning means; e. a source of electric power; and f. an electric circuit so connecting said first, second and third switches, said warning means and said source of power that said circuit is not completed to said warning means when the pressure on fluid in said supply line is increased and said valve member remains in said first position, but said electric circuit to said warning means being completed when said valve member is held in said second position by said resilient means and one of said first or second fluid pressure actuated electric switches does not assume an open position due to there being a leak in said first or second conduit, and said first or second switch is subjected to no fluid pressure as a result thereof, with said warning means continuing to be energized until said circuit is broken or said valve member is moved to said first position.