US Patent 7694935 Automatically shut off water faucet

A water faucet includes a receptacle engaged into a housing and having a passage communicating with a water outlet of the housing, a valve stem slidably engaged through the passage of the receptacle and having a valve member for controlling the water to flow from the water inlet to the water outlet of the housing, and a piston attached to the valve stem and slidably engaged in a compartment of the receptacle, the valve stem includes one or more orifices and one or more apertures for controlling a fluid to flow between the compartment of the receptacle and a cavity of the valve stem, and a valve element may adjust the flowing of the fluid into and out of the cavity of the valve stem.