Tire valve cap for measuring air pressure
AssigneeFuji Univance Corporation
InventorsTouji Takemura, Hirohisa Maki
Life of this patent
Estimating the term…
Abstract
In the state where a tire valve cap body has been fixedly screwed onto a valve mouthpiece, a top cover is pushed to open a tire valve, allowing introduction of a tire air pressure. A piston is slidably incorporated in a cylinder chamber defined within the top cover and is urged by a return spring. Upon the introduction of the tire air pressure, the piston is displaced to a position at which the biasing force of the return spring balances with the force of the introduced air pressure. An indication mechanism is provided to indicate, through an indication window formed in a cylinder member, a position of the piston member displaced by the tire air pressure introduced, thereby indicating a measurement value of the tire air pressure.
Claims16
A tire valve cap intended to be mounted on a tire valve mouthpiece for measuring air pressure within a tire, the tire valve cap comprising:
- a body fixedly screwed onto said tire valve mouthpiece;
- a cylindrical bottom cover secured to said body;
- a cylindrical top cover axially slidably received in said bottom cover with its extremity protruding through an outside opening of said bottom cover, said top cover being operable to be pushed at the time of measuring a tire air pressure;
- a cylinder member accommodated within said top cover and including a cylinder chamber formed in its interior for introducing therein an air pressure from said tire, said cylinder member being provided with a push rod located at its extremity having an air inlet port opening into said cylinder chamber, said push rod pushing a valve member of said tire valve to open said tire valve to thereby introduce the tire air pressure into the interior of said cylinder member;
- a retainer spring for retaining, together with said top cover, said cylinder member to its initial position at which said cylinder member protrudes outward from said opening of said bottom cover;
- a piston member slidably received in said cylinder chamber in such a manner that said piston member is biased by a return spring, said piston member being displaced, upon the introduction of said tire air pressure, to a position at which the biasing force of said return spring balances with the force of introduced air pressure;
- and
- an indication mechanism for indicating a position of said piston member displaced by said introduced tire air pressure in an indication window formed in said cylinder member, to thereby indicate a measurement value of said tire air pressure.
Dependencies are inferred from the claim text.