Fuel tank cap and fuel filler device for a vehicle

1 . A fuel filler device adapted to be connected with a fuel filler pipe, comprising:

an adaptor securely connected with the fuel filler pipe, said adaptor including a surrounding wall extending longitudinally, and two engaging protrusions projecting radially from an inner peripheral surface of said surrounding wall and radially spaced apart from each other, said engaging protrusions extending circumferentially and being angularly spaced apart from each other by two access slots, each of said engaging protrusions having a guiding portion which extends from one of said access slots toward another one of said access slots, and a retaining portion which projects downwardly from said guiding portion adjacent to said another one of said access slots, said guiding portion having a guiding surface which faces downwardly and which is inclined upwardly from an end adjacent to said retaining portion toward another end distal from said retaining portion; and

a fuel tank cap removably and longitudinally insertable into said adaptor, said fuel tank cap including a gripped cap body which is disposed on said adaptor to cover an upper opening of said surrounding wall, an insert portion which extends downwardly from a bottom surface of said gripped cap body to be rotatably inserted into said surrounding wall, and two retained protrusions which project radially from an outer peripheral surface of said insert portion and are diametrically opposite to each other, said two retained protrusions being moved longitudinally with said insert portion to respectively pass through said access slots, each of said retained protrusions having a press-fit surface which faces upwardly, and a first retained slot and a second retained slot which are recessed from said press-fit surface and angularly spaced apart from each other, wherein said fuel tank cap is operably rotated relative to said adaptor between an opened position, where said retained protrusions are aligned with and disposed downwardly of said access slots, and a closed position, where said press-fit surface of each of said retained protrusions abuts upwardly against said guiding surface of a corresponding one of said engaging protrusions, and said retaining portion of each of said engaging protrusions is engaged downwardly in either said first retained slot or said second retained slot of a corresponding one of said retained protrusions.

2 . The fuel filler device of claim 1 , wherein said first retained slot of each of said retained protrusions extends downwardly from said press-fit surface through a lower surface of said retained protrusion.

3 . The fuel filler device of claim 1 , wherein said second retained slot of each of said retained protrusions extends downwardly from said press-fit surface through a lower surface of said retained protrusion.

4 . The fuel filler device of claim 1 , wherein each of said engaging protrusions further has a stop portion which projects downwardly from said guiding portion and is located between said another one of said access slots and said retaining portion, said stop portion having a first abutting surface which faces said retaining portion, and a second abutting surface which is opposite to said first abutting surface, wherein each of said retained protrusions abuts against said second abutting surface when said fuel tank cap is in the opened position, and abuts against said first abutting surface when said fuel tank cap is in the closed position.

5 . A fuel tank cap mountable on an adaptor of a fuel filler device, the adaptor including a surrounding wall extending longitudinally, and two engaging protrusions projecting radially from an inner peripheral surface of the surrounding wall and radially spaced apart from each other, the engaging protrusions extending circumferentially and being angularly spaced apart from each other by two access slots, each of the engaging protrusions having a guiding portion which extends from one of the access slots toward another one of the access slots, and a retaining portion which projects downwardly from the guiding portion adjacent to the another one of said access slots, said fuel tank cap being removably and longitudinally insertable into the adaptor, and comprising:

a gripped cap body which is mountable on the adaptor to cover an upper opening of the surrounding wall;

an insert portion which extends downwardly from a bottom surface of said gripped cap body to be rotatably inserted into the surrounding wall; and

two retained protrusions which project radially from an outer peripheral surface of said insert portion and are diametrically opposite to each other, said two retained protrusions being moved longitudinally with said insert portion to respectively pass through the access slots, each of said retained protrusions having a press-fit surface which faces upwardly, and a first retained slot and a second retained slot which are recessed from said press-fit surface and angularly spaced apart from each other, wherein said fuel tank cap is operably rotated relative to the adaptor between an opened position, where said retained protrusions are aligned with and disposed downwardly of the access slots, and a closed position, where said press-fit surface of each of said retained protrusions abuts upwardly against the guiding portion of a corresponding one of the engaging protrusions, and either said first retained slot or said second retained slot of each of said retained protrusions is in longitudinal engagement with the retaining portion of the corresponding one of the engaging protrusions.

6 . The fuel tank cap of claim 5 , wherein said first retained slot of each of said retained protrusions extends downwardly from said press-fit surface through a lower surface of said retained protrusion.

7 . The fuel tank cap of claim 5 , wherein said second retained slot of each of said retained protrusions extends downwardly from said press-fit surface through a lower surface of said retained protrusion.