Pod opener

A pod opener for placing a container, storing cassettes supporting substrates and stacked vertically, at a predetermined position and allowing the substrates supported by the cassettes to be accessible by a substrate holding member of a transportation device, comprising:

• an elevating mechanism elevating the stacked cassettes in a vertical direction;
• a first hook member engaging with an engagement means of a certain first cassette among the stacked cassettes and supporting the first cassette;
• a second hook member engaging with an engagement means of a second cassette disposed immediately below the first cassette supported by the first hook member and supporting the second cassette;
• a forward and backward movement mechanism moving the first hook member and the second hook member forward so as to be closer to the cassettes when engaging with the engagement means of the first and second cassettes and moving the first hook member and the second hook member backward so as to be away from the first and second cassettes when releasing the engagement from the engagement means of the first and second cassettes;
• an urging member urging the second hook member upward;
• and
• an atmosphere maintaining device maintaining an internal space having the cassette disposed therein in a predetermined atmosphere,
• wherein the second hook member is displaced upward by an urging force of the urging member when the second cassette is not supported and is displaced downward by a weight of the second cassette against the urging force of the urging member when the second cassette is supported.