Protector device for telecommunications circuits

An electrical device located at the interface between an incoming wire pair and an outgoing wire pair for diverting to a ground structure excessive current and voltage and arranged to provide two electrical test points, one of said test points bridging one of said incoming wires and the other of said test points bridging the complementary wire of said pair, comprising in combination:

• an adjacent pair of heat coil assemblies inserted in series between said incoming and outgoing pairs, each of said assemblies comprising
• a heat coil mechanism movable from a first position spaced-apart from said ground structure to a second position proximate to said ground structure in response to heat generated by said excessive current including:
• a spool having a first conductive flange at one end;
• a second conductive flange mounted on said spool and being electrically isolated from said spool and said first flange;
• windings of resistance wire about the outer surface of said spool with one wire end connected to said second flange and the other end to said spool;
• a conductive rod affixed to the inner surface of said flange by a thin coating of solder;
• and an electrically conductive coil spring having one end contacting one of said outgoing wires and the other end contacting said second flange for pushing said second flange from said first to said second position along said bar whenever heat melts said solder so as to bring said first flange into contact with said ground structure to divert said excessive current to ground, said spring axially aligned with said spool and containing said spool and said windings within the helix of said spring;
• an elongated, electrically conductive body having a transverse bend at one end providing a projection, a tab transverse to said body at an intermediate point along its length for supporting said rod, and a transverse bend at the other end providing a test land to serve as one of said test points, wherein said projection, said tab, and said land are disposed in the same transverse direction;
• and an electrically conductive pin affixed to said projection for connecting one of said incoming pairs to said device;
• an adjacent pair of spark gap arresters, axially aligned with said pair of heat coil assemblies, each of said arresters electrically in shunt with one of said incoming wires and comprising
• a first carbon block;
• a second carbon block contacting said bar;
• and an insulated holder, axially aligned and abutting said first carbon block and partially surrounding said second carbon block for holding said second block in a predetermined, spaced-apart relation to said first block,
• a conductive shield encasing adjacent pairs of said first and second carbon blocks except for the free faces of said second blocks, said shield having an end face having one surface contacting the free faces of said first carbon blocks and the other surface contacting said ground structure and a sleeve portion encompassing said holders and said first blocks;
• said ground structure comprising
• a conductive top plate contacting a substantial portion of said sleeve on one of its outer surfaces;
• a side plate disposed transversely to and joined with said top plate for contacting the outer surface of said end face;
• and a member emanating from said top plate for contacting external ground;
• and
• a generally rectangular-shaped housing having a pair of apertures in the back wall, each of said apertures aligned for accessing said test land, and means affixed to said back wall for facilitating accessing and handling of said device.