| 摘要 |
PURPOSE:To immediately announce the abnormality of the air pressure of a tire occurred during running and prevent accident by providing a lamp which is controlled by the fluctuations in the air pressure of the tire of automobiles and providing a photodetector and an alarm device on the body side. CONSTITUTION:A light projecting circuit A is formed by connecting a lamp, for example, an infrared lamp 3, via a pressure switch 2 opened and closed by the fluctuations in the air pressure of a tire, to a generator 1 which generates electricity by the running of a vehicle. A photodetecting circuit B provided on the body side is provided with a photodetector 4 which catches the light from the lamp 3 in correspondence to the projecting circuit A, and is provided on the body side near the outside circumference of a wheel. An alarm circuit C is so arranged that when no light enters the photodetector 4 the electric power is conducted to sound a buzzer, thereby announcing the abnormality of the air pressure to the driver. Hence, when the wheel is punctured during running and the air pressure of the tire drops down to below a constant value, the pressure switch 2 operates to extinguish the lamp 3 and no more light enters the photodetector 4, so that the anormality is announced to the driver by the buzzer. |
