Patent ID: 7784634

Claim:
A fuel filler cap comprising: an inner cap of a substantially cylindrical member; and an outer cap of a cover member mounted on said inner cap: wherein the outer cap includes an upper face portion having a circular shape, a skirt portion integrally extending downward from an outer circumference of the upper face portion, and a plurality of a wedge-shaped projection having a triangular section formed circumferentially intermittently on an inner face of the skirt portion; wherein a pressing plate is a member having a circular shape, as viewed in a top plan, and having a smaller diameter than the internal diameter of the skirt portion; wherein the inner cap includes a supporting plate having a circular shape, as viewed in a top plan, and having an annular slant formed radially downward by chamfering a peripheral edge of an upper face thereof, a seal ring fitted between a lower face of the supporting plate and an outer face of an inner cap body, and an annular groove defined by a lower face of the pressing plate laid over the supporting plate and by the annular slant of the supporting plate and to thereby form into a sectional shape corresponding to a sectional shape of the wedge-shaped projection; wherein the outer cap and the pressing plate are provided with a cap engagement means for engaging in a closing direction of the fuel filler cap; and wherein the pressing plate and the supporting plate are provided with a plate engagement means for turning integrally in opening/closing direction of the fuel filler cap and for releasing an engaged state of the pressing plate with the supporting plate when a releasing load is applied upward to the pressing plate.