Gate valve

A gate valve having an air-tight chamber with an aperture, comprising:

• a valve plate provided in the air-tight chamber, for opening and closing the aperture of the air-tight chamber and sealing the aperture by tilting with respect to the aperture;
• a valve rod having one end to which said valve plate is fixed, said valve rod being supported to be movable in a predetermined straight movement direction for opening and closing the aperture, said valve rod being able to tilt around a predetermined tilting axis;
• a sealing means for sealing a portion between said valve rod and said air-tight chamber;
• a restriction means for restricting a straight movement in such a direction that the aperture of said valve plate is closed at a closed position where the valve plate closes the aperture;
• a tilting cam mechanism which converts straight moving force into tilting force, and tilts said valve rod of which the straight movement is restricted at said closed position around said tilting axis in such a direction that said valve plate seals the aperture;
• a seal-releasing cam mechanism provided independently of said tilting cam mechanism for tilting said valve rod around said tilting axis in such a direction as to release the sealing of said valve plate in the state of sealing the aperture by supplying the straight moving force in such a direction as to open the aperture;
• and
• an actuating means for supplying the straight moving force to said tilting cam mechanism and said seal-releasing cam mechanism.