Fuel Cartridge For Fuel Cell, Fuel Cell, And Coupler

A coupler, comprising:

• a socket having a first valve element and a first biasing member biasing the first valve element in a closing direction;
• and
• a plug having a second valve element and a second biasing member biasing the second valve element in a closing direction, said plug engaged with and coupled to said socket detachably, wherein the first and second valve elements are released and brought into communication in a state that said socket and said plug are engaged with and coupled to each other;
• and
• wherein in a state that a projecting coupling portion of said plug is coupled to a plug coupling hole of said socket, at least one of said socket and said plug can be slanted and removed with the projecting coupling portion of said plug being located within an interference prevention space, which is a space formed by rotating a virtual circle about said plug, the virtual circle having a center at an outermost peripheral point on a coupling surface of the projecting coupling portion of said plug and a radius from the center to an intersection point of a lower end circumference of the plug coupling hole of said socket and a diagonal position of the center.

A coupler, comprising:

• a socket having a first valve element and a first biasing member biasing the first valve element in a closing direction;
• and
• a plug having a second valve element and a second biasing member biasing the second valve element in a closing direction, said plug engaged with and coupled to said socket detachably, wherein the first and second valve elements are released and brought into communication in a state that said socket and said plug are engaged with and coupled to each other;
• and
• wherein a narrow portion is formed in said plug, and in a state that a projecting coupling portion of said plug is coupled to a plug coupling hole of said socket, when at least one of said socket and said plug is slanted about an outermost peripheral point on a coupling surface of the projecting coupling portion of said plug, the narrow portion prevents interference with an internal cylinder lower end of the plug coupling hole of said socket, the internal cylinder lower end projecting toward said plug side further than the coupling surface of the plug coupling hole of said socket, and at least one of said socket and said plug can be slanted and removed.