Patent ID: 6031450
Filing Date: 2000-02-29
Classification: B60C

Abstract:
A tire pressure alarm system comprising a tire pressure sensor and radio transmitter circuit mounted on a circuit board and installed in a tire to detect the pressure of the tire, and to send the detected tire pressure value to a radio receiver and alarm circuit by radio, and a radio receiver and alarm circuit adapted to receive the detected tire pressure value, wherein:said tire pressure sensor and radio transmitter circuit comprises a power supply circuit, said power supply circuit comprising a power source, and a power switch, said power switch comprising a first metal contact and a second metal contact respectively connected to positive and negative terminals of said power source, a metal spring member having a fixed end connected to said first metal contact and a free end spaced from said second metal contact at a distance, and a weight connected to the free end of said metal spring member; when said tire is rotated at a speed over a predetermined level, a centrifugal force is produced and acted at said weight, and the free end of said metal spring member is forced by said centrifugal force to turn with said weight in one direction and to contact said second metal contact, causing said power switch to be switched on for enabling said tire pressure sensor and radio transmitter circuit to detect the tire pressure of said tire and to send the detected tire pressure value to said radio receiver and alarm circuit by radio.