Patent ID: 7963296

Claim:
A fuel cutoff valve that is to be mounted on an upper portion of a fuel tank, for opening and closing a connecting passage that connects between an inside of the fuel tank and outside, the fuel cutoff valve comprising: a casing that forms a valve chamber that connects the inside of the fuel tank and the connecting passage; and a float mechanism that is housed in the valve chamber and includes (i) a float that rises and falls according to a fuel level in the valve chamber and (ii) a valve mechanism that is disposed above an upper portion of the float and opens and closes the connecting passage through rising and falling of the float, wherein the float has a supporting portion disposed on the upper portion of the float for supporting the valve mechanism, the supporting portion having a supporting face, and the valve mechanism includes a first valve unit and a second valve unit, wherein the first valve unit has (i) a first valve main body with a support hole, (ii) a first seat part that is formed on the first valve main body and opens and closes the connecting passage, and (iii) a connecting hole that is formed to pass through the first valve main body and connects the support hole with connecting passage, an area of the connecting hole being smaller than that of the connecting passage; and the second valve unit has (i) a second valve main body that is interposed between the first valve unit and an upper portion of the float and that is housed within the support hole, (ii) a second seal portion that is disposed on the upper part of the second valve main body and opens and closes the connecting hole, and (iii) a supported part of convex shape that is formed on a lower part of the second valve main body wherein the supported part is configured to be supported at a single point on the supporting face, wherein the single point contacts the supporting face when the float is in an opening and closing position, and when the float falls from the closing position towards the opening position and the second seal portion opens the connection hole, wherein the valve mechanism is configured such that a center of gravity of the valve mechanism is set below a support portion, at which the supporting portion supports the supported part under a balance.