Patent ID: 7555867
Filing Date: 2009-07-07
Classification: E05F,E05Y

Abstract:
1. A motorized operator for a swing door comprising: a frame; a motor supported on said frame; a coil spring supported on said frame; an elongated shaft connected to a member engaged with said spring at one end of said spring for transmitting forces to and from said spring through said elongated shaft; a gear reduction drive mechanism supported on said frame and drivenly connected to said motor; an output shaft connected to said drive mechanism and having a part configured for connection to said door for moving said door, said output shaft is operably connected to opposed chain runs extending between said output shaft and said elongated shaft; and a link member connected to said elongated shaft and directly connected to said opposed chain runs, such that rotation of said output shaft in a first direction causes one of said runs to become taut and the other run to become slack to compress said spring and store energy in said spring, and said spring is operable to return said energy through said one run to said output shaft to rotate said output shaft in a second direction opposite to said first direction for assisting movement of said door.