FLAP DOOR LIFTING DEVICE

PROBLEM TO BE SOLVED: To provide a flap door lifting device capable of lifting a flap door in an opening degree state according to various situations and holding the opening degree state with simple constitution. SOLUTION: The flap door lifting device 5 has a piston 12 arranged in an axially movable manner in a sealed cylinder 6 filled with a pressure fluid, to divide the inside of the sealed cylinder 6 into first and second working chambers 14, 15. A piston rod 7 is mounted to one side of the piston. The piston rod 7 is led outside from the second working chamber 15 while maintaining the sealed state at one end face of the cylinder 6 and hinge-connected to the flap door or a fixed structure part. The other end face of the cylinder 6 is hinge-connected to the fixed structure part or the flap door. The piston 6 is provided with a port 17 leading to the second working chamber 15 from the first working chamber 14, and openable and closable, or either openable or closable. The port 17 can be at least either opened or closed by an electric control valve. COPYRIGHT: (C)2008,JPO&INPIT