Electrical insulator string with bullet-proof protective rings

摘要

A bullet-proof board includes a pair of steel plates of substantially identical thicknesses that sandwich a thick intermediate layer therebetween and a thin surface layer secured to that steel plate surface which faces a striking bullet. The intermediate and surface layers are made of such chemical fiber cloths or synthetic resin plates which absorb energy of a striking bullet. The bullet-proof board may be formed in the shape of a sidewall of a truncated-cone and secured to a suspension insulator for protecting it against gun shooting. A bullet-proof insulator assembly includes an insulator string formed of suspension insulators coupled to each other, bullet-proof rings, one of which is mounted on each of the suspension insulators, each bullet-proof ring having a shape representing a sidewall of a truncated-cone with a minimum inside diameter larger than the outside diameter of the shed portion of the suspension insulator, and holders mounting the bullet-proof rings to the suspension insulators in such a manner that each bullet-proof ring extends away from a longitudinal axis of the insulator string at an angle of 45-70 degrees relative to the longitudinal axis as the bullet-proof ring extends upwardly and that the minimum distance between adjacent bullet-proof rings (L) is longer than the minimum distance between adjacent suspension insulators (l).