Current-limiting fuse having arc chutes in which arcs are formed to cut extensions of the current-limiting elements

Claim 1

IN A CURRENT-LIMITING FUSE INCLUDING: AN ELONGATED INSULATED HOUSING WITH END TERMINALS, AN INTERMEDIATE TERMINAL IN SAID HOUSING INSULATED FROM SAID END TERMINALS, CURRENT CALIBRATED FUSIBLE ELEMENT MEANS INTERCONNECTING ONE END TERMINAL AND SAID INTERMEDIATE TERMINAL, AND A PLURALITY OF CURRENT-LIMITING FUSIBLE ELEMENTS EMBEDDED IN A GRANULAR FILLING IN SAID HOUSING AND CONNECTED IN PARALLEL CIRCUIT RELATION BETWEEN SAID INTERMEDIATE TERMINAL AND THE OTHER END TERMINAL, THE IMPROVEMENT COMPRISING: A MINOR PORTION OF EACH CURRENT-LIMITING FUSIBLE ELEMENT ADJACENT SAID INTERMEDIATE TERMINAL CONSITUTING AN EXTENSION OF A MAJOR PORTION THEREOF, MEANS INDIVIDUAL TO EACH EXTENSION PROVIDING AN ARC BLAST CHUTE IN WHICH THE EXTENSION IS LOCATED, AND MEANS PROVIDING A SPARK GAP INDIVIDUAL TO EACH CURRENT-LIMITING FUSIBLE ELEMENT IN THE RESPECTIVE ARC BLAST CHUTE, ONE TERMINAL OF EACH SPARK GAP BEING CONNECTED TO THE JUNCTION BETWEEN THE RESPECTIVE EXTENSION AND THE MAJOR PORTION OF ITS CURRENT-LIMITING FUSIBLE ELEMENT, THE OTHER TERMINAL OF EACH SPARK GAP INCLUDING CONDUCTOR MEANS CONNECTED TO SAID ONE END TERMINAL THEREBY PLACING SAID SPARK GAPS IS SHUNT CIRCUIT RELATION TO THE GAP FORMED ON BLOWING OF SAID CURRENT CALIBRATED FUSIBLE ELEMENT MEANS ON FLOW OF FAULT CURRENT THERETHROUGH.