US Patent 11105136 Regulating valve

A regulating valve for activating a strike function of a hydraulic door, gate, or window drive, in particular a hydraulic door closer, which is arranged in a hydraulic channel via which hydraulic fluid can flow, comprises a valve member which is axially displaceable in a valve bore between a closed position and an open position, is acted on in an opening direction by a spring unit, is acted on by the pressure in a pressure chamber in the closing direction and can be transferred into the open position thereof by the spring force of the spring unit when there is a drop in pressure in the pressure chamber below a predeterminable limit pressure.