Tire valve cap for measuring air pressure

摘要

In the state where a tire valve cap body (12) has been fixedly screwed onto a valve mouthpiece, a top cover (14) is pushed to open a tire valve, allowing introduction of a tire air pressure. A piston (23) is slidably incorporated in a cylinder chamber (15D) defined within the top cover (14) and is urged by a return spring (26). Upon the introduction of the tire air pressure, the piston (23) is displaced to a position at which the biasing force of the return spring (26) 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 (23) displaced by the tire air pressure introduced, thereby indicating a measurement value of the tire air pressure.