Abstract: An improved telephone line protection device including means for grounding excessive currents and voltages. The disclosed embodiment includes temperature-actuated resilient means for shorting excessive currents directly to a source of ground potential, without passing such currents through the elements normally present for protecting against excessive voltage surges, which are damaged by carrying excessive currents.

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: A current limiting fuse and an oil expulsion or weak link type fuse are connected in series with each other and with a transformer primary winding and a grounded element having a part disposed adjacent one end of the expulsion fuse is arranged so that an arc drawn upon operation of the expulsion fuse is directed to the grounded element in such manner as to cause the current limiting fuse to operate and interrupt the flow of current through the primary winding. The system is applicable to single phase or multiple phase arrangements.

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.

Abstract: A line protector includes a body having first and second end terminals and an intermediate terminal for connection to a ground potential. End caps are mounted on the end terminals and have peripheral edges maintained spaced from the intermediate terminal by means of a displaceable element responsive to excessive currents in the line being protected. High currents will cause the end caps to move toward the intermediate terminal and provide a short circuit therewith to ground to protect telephone equipment connected thereto. The intermediate terminal is mounted in a clip which has centering means formed therein to maintain the mechanical and electrical spacing of the intermediate terminal with respect to the end caps equal to one another. The protector assembly is mounted with a standard housing and base structure to be interchangeable with existing central office plug-in protectors.

Abstract: A circuit interrupting device comprising a vacuum fuse having an evacuated envelope wherein one or more fusible elements electrically connect spaced open ends of aligned tubular electrodes which have respective sealable ends external of the envelope and provide means for facilitating assembly and processing of the fuse.

Abstract: A gas tube arrester subassembly for use in a modular component type telephone central office protection system includes a gas tube arrester having a spacer tube with an electrode at each end. One of the electrodes is insertable into an open end of a generally cylindrical shell portion of the gas tube arrester subassembly with parts of the shell portions at the open end being swaged to form securing members to maintain the one electrode in the shell portion. The other end of the shell portion is closed with a generally rectangular slot therein. Removably mounted in the slot is a conductive U-shaped spring member such that the spring member has one leg extending along the inner surface of the closed end. Disposed between the one leg and the one electrode is a conductive disk-shaped contact member to couple the one electrode to the spring member.