Flat tire indicating device

A flat tire indicating device for indicating when a tire has lost at least a predetermined air pressure, said tire having a rim and a tire valve with an externally threaded valve stem having an axis, said flat tire indicating device comprising

• a substantially elongated housing having an internally threaded part threadedly coupled to the valve stem of a tire, said housing extending substantially perpendicularly to the axis of the valve stem and substantially symmetrical thereto whereby said housing is positioned along the rim of the tire;
• battery means in the housing;
• audible alarm means in the housing;
• radio transmitter means in the housing;
• air-operated switch means in the housing and in operative proximity with the valve stem having an open condition when the tire pressure is above the predetermined air pressure and a closed condition when the tire pressure is reduced to one below the predetermined air pressure, said switch means having movable electrical contact means controlled in position by the pressure of air in the tire and spring biasing means for adjustment to the predetermined air pressure;
• circuit means electrically connecting the battery means, alarm means, transmitter means and switch means in a circuit whereby when the switch means is moved to its closed condition the battery means actuates the alarm means and transmitter means;
• and
• radio receiver means for receiving a signal transmitted by the transmitter means thereby indicating that the tire is flat.