Pneumatic fender and mouth piece metal for pneumatic fender

A pneumatic fender comprising:

• a fender bladder including a cylindrical portion and bowl-like hemispherical portions connected to each end of the cylindrical portion;
• a mouth piece metal disposed on at least one of the hemispherical portions,
• the mouth piece metal including:
• a safety valve that, upon an internal pressure of a cavity of the fender bladder reaching a pressure threshold, opens to connect the cavity of the fender bladder to outside air and reduce the internal pressure, and
• a communication passage that connects the cavity of the fender bladder and outside air;
• and
• a bladder open/close valve that opens and closes the communication passage;
• wherein
• the mouth piece metal further includes:
• a receiving chamber that isolates the safety valve from the cavity of the fender bladder,
• a through hole that connects a cavity of the receiving chamber and the cavity of the fender bladder, the through hole being formed on a dividing wall constituting the receiving chamber,
• an open/close valve that opens and closes the through hole,
• a resilient member that constantly biases the open/close valve toward a closing direction of the through hole,
• a receiving chamber communication passage that connects the cavity of the receiving chamber and outside air, and
• a receiving chamber open/close valve that opens and closes the receiving chamber communication passage;
• and
• upon the internal pressure of the cavity of the fender bladder being less than the pressure threshold and greater than a standard pressure, which is a sum of a predetermined initial internal pressure and an allowable pressure, the open/close valve opens, opening the closed through hole.