Abstract: A compressor unloader controller for placing a compressor in an unloaded condition when the compressor is being started. A compressor inlet valve, movable between a normally open and a closed position, admits fluid flow to the compressor when the valve is in the open position. A pressure reservoir contains pressure sufficient to bias the inlet valve into the closed position. A starter valve applies pressure from the pressure reservoir to the inlet valve only when the compressor is in a starting mode. The inlet valve may also be actuated, during normal compressor operation, by a pressure regulating device which is connected to a compressor outlet line.

Abstract: Limiting of hoist overload is accomplished by applying the brake of a pneumatically powered hoist. The brake release signal is interrupted by means of directly sensing the load being lifted by means of this invention, causing the brake to be applied and thus halting the drive mechanism. This device can be applied to any load bearing member such as chain or cable anchors, hooks, connections to trolleys, or other suspension.