Fuel tank filler cap

Claim 1

A cap for a vertical filler pipe of the fuel tank of a vehicle comprising: an inner shell having a flat portion adapted to extend horizontally across the end of a filler pipe and a peripheral flange to surround and engage with the filler pipe; a first vent passage through said inner shell flat portion for permitting the flow of air into said tank in the normal operation thereof; first valve means for said first vent passage adapted to seal the same upon tilting of said cap a predetermined amount from its normal position; said first valve means comprising a valve member having a stem slidably engaged in said vent passage and a head upon its lower end of larger diameter than said vent passage; a ball positioned beneath said head; and a ball retainer positioned beneath said ball; said ball retainer being cup-shaped with a lowermost center portion concentric with said stem and converging in all directions outwardly from said center portion toward the lower surface of said shell flat portion; the lowermost center portion being spaced beneath said lower surface a distance such that said valve means head, when resting on said ball, is displaced from said lower surface thereby to permit air to flow through said vent passage; said retainer converging toward said lower surface such that, upon tilting of said cap beyond a predetermined angle in any direction, said ball will force said head into engagement with said lower surface; a cover surrounding said inner shell; rib means extending between said cover and the outer surface of said inner shell flat portion to space said cover from said surface and provide an air passage therebetween; said inner shell flange having grooves in the outer surface thereof communicating with said air passage for permitting air to flow between said air passage and the atmosphere; a second vent passage through said inner shell flat portion spaced from said first vent passage; second valve means for said second vent passage adapted to seal the same upon seating therein; said spring means connected between said inner shell and said second valve means for normally seating said second valve means in said second vent passage and allowing said valve means to unseat upon an increase of pressure in said tank beyond a predetermined amount.