Test element, mounted on the wheel of a motor vehicle, for monitoring the internal pressure of a tyre

摘要

The invention relates to a reliable, durable test element which is cost-effective to manufacture and low in weight and can be mounted on the inside of the rim of a tyre of a motor vehicle in order to monitor the internal pressure of the tyre and is provided with an electric switch via which the circuit of a display device or warning device is connected. If the internal pressure of the tyre drops below a threshold value which can be reproduced well, this switch opens. It contains a contact rivet provided on the floor of the housing of the test element, with which rivet a spring contact element interacts, the said contact element having a support face, which is as large as possible, for a cover film of the housing. This cover film is stressed by the high pressure of the air inside the tyre, a portion of which being however compensated by the pressure of the external atmosphere.