US Patent 7146824 Valve plug and valve provided therewith

A valve plug is threadedly engaged with a valve stem so as to be inserted from an open end of a passage for charging with and/or releasing from a compressed fluid, toward an inner part of the passage, thereby closing an inner smaller diameter portion. The valve plug includes a threadedly engaging member threadedly engaging a portion of the passage located nearer to the open end side than the smaller diameter portion, and a turn head turnably connected to an end of the threadedly engaging member and having a distal end inserted into the smaller diameter portion so as to adhere closely to an open edge of the smaller diameter portion.