Abstract: The invention concerns overvoltage arresters and its basic objective is to combine a carbon air gap device with a novel and improved surge voltage gas tube, the combination also including a fusible element and a coil spring. The coil spring becomes effective upon melting of the fusible element to connect the transmission line to ground so as to short out both the carbon air gap device and the gas tube thereby preventing overheating of the same. The carbon air gap device and the gas tube are so combined as to obtain the advantages of both, namely the long life advantages of the gas tube and the reliability of the carbon air gap device. The two devices are combined in such a manner whereby the carbon air gap device is a back-up for the surge voltage gas tube.

Abstract: The overvoltage arrester disclosed in the drawings employs a surge voltage gas tube in combination with a fusible element and also unique and novel means for effecting a metallic connection between the transmission line and ground in the event the fusible element is caused to melt. One element of the unique and novel means for effecting the metallic connection includes a coil spring having encircling relation with part of the gas tube. As a result of the metallic connection which includes the coil spring, the gas tube is shorted and overheating of the said tube is effectively prevented.