Gas tube fail-safe device for telephone protector modules

Claim 1

An improved thermally sensitive secondary protection device for use with three-element gas tubes employed for protecting individual telephone subscriber circuits, said gas tube including first and second end electrodes, and a centrally disposed electrode, said centrally disposed electrode having a laterally extending contact thereon; said protective device comprising: a length of resilient conductive material having a principal axis parallel to that of said tube, and having first and second end portions and a medially disposed portion therebetween; said first and second end portions being resiliently engageable with said first and second end electrodes on said gas tube, and having a fusible insulative covering normally preventing electrical current conduction therebetween; said medially disposed portion including means engaging said contact on said center electrode on said gas tube in electrically conductive relation; whereby, the development of a predetermined degree of heat by said gas tube upon the occurrence of a sustained current overload, will cause fusing of said insulative covering on said first and second end portions, causing shorting of said end electrodes to said center electrode; said length of resilient conductive material being in the form of a stamping of planar resilient material, the end portions of which form arcuately shaped recesses for engaging the first and second end electrodes of a gas tube to fix the relative position therebetween, said medially disposed portion including a centrally disposed opening bordered by first and second laterally bent tabs, said tabs resiliently engaging said laterally extending contact.