Pneumatic retard having stroke-accelerating valve
AssigneePotter Electric Signal Company, LLC
InventorDavid M. Ward
Life of this patent
Estimating the term…
Abstract
A pneumatic retard, of the type used to achieve time-delayed actuation of water-flow alarms or other devices, has a pneumatic chamber from which air is slowly discharged under the pressure applied by a spring-driven plunger. The chamber has an air discharge valve, which also serves as an inlet valve. When the actuating plunger has been released and has traveled to a position at which much of the air has been exhausted, the discharge valve is opened, releasing the remaining air pressure. This releases the plunger to travel from that point onward with a rapid actuating stroke.
Claims2
A combined check valve and pressure dump valve for a gas whose pressure may range from below to above an ambient pressure, comprising
- a walled chamber having gas passage means whereby to communicate gas pressure and having in addition thereto a gas conducting opening,
- a flexible rubber-like check valve mounted in said opening, said check valve there having a circumferential mounting flange by which it supported, and a mouth portion including lip portions extending therefrom and whose inner surfaces taper from said mouth portion toward each other for normal flatwise presentation againsteach other,
- whereby to part and thereby permit gas flow into said chamber on a deficiency of pressure therein below such ambient gas pressure and to seal together on excess of chamber pressure over such ambient pressure, in combination with
- a release pin whose cross section is sufficiently small, relative to the size of said lip portions, to distend and part them from each other without sealing about said pin, and
- means to insert said pin from outside the pressure chamber through the mouth portion of said check valve and inwardly between the tapering inner surfaces of said lip portions,
- whereby to distend and part same, thereby to suddenly dump and discharge any excess of chamber pressure over ambient pressure.
Dependencies are inferred from the claim text.