Fused resistive electrical protection device

A resistive protection device comprising:

• resistor means capable of fracturing and, thereby, of establishing a physical open-circuit separation therealong when subjected to a specified current-induced overload condition;
• an insulative tubular member for receiving said resistor means therewithin, and having one integral end wall formed with a lead-receiving aperture therethrough, and with a flange portion;
• a movable insulative end wall adapted to substantially enclose the other end of said tubular member, and having a lead-receiving aperture formed therethrough and a flange portion;
• elongated coil spring means coaxially positioned on said tubular member and normally confined between said integral and movable end wall flange portions, and normally maintained under a predetermined degree of compression, and
• a pair of conductive lead respectively and electrically connected to opposite ends of said resistor means, each of said leads extending outwardly through the aperture formed in the adjacent one of said end walls, with an upper end region of both leads immediately adjacent the outer surfaces of the respectively associated end walls being configured such that they function as stops to normally prevent may relative displacement between the assembled end walls normally maintained under mutually opposed spring bias, said leadforming stops, thereby, holding said composite device together until such time that a predetermined overload condition would induce a fracture in said resistor means which would, in turn, result in said spring urging said resistor means into two sections at the point of fracture and, in turn, displacing said end walls and associated lead ends in engagement therewith apart a predetermined distance to establish an open circuit gap in the region of said fracture.

A protective device comprising:

• fusible means capable of at least establishing a weakened physical condition along an electrical circuit-pathdefining dimension thereof when subjected to a specified current-induced overload condition;
• insulative enclosure means for said fusible means including a substantially tubular member having one secured end wall formed with an integral flange portion, and further including an insulative movable end wall formed with a flange portion, and being adapted to normally enclose the end of said tubular member opposite said secured end wall thereof, each of said walls having a central aperture formed therein;
• conductive terminating means respectively secured to the ends of the circuit path-defining dimension of said fusible means and extending through the respectively associated apertures of said end walls, said terminating means being formed to maintain said flange portions normally in a desired spaced relationship, and to allow external connections to be made to said fusible means, and
• spring means mounted on said tubular member and normally maintained under a predetermined degree of compression between said flange portions of said enclosure means, said compressive force being sufficient, in response to said fusible means being subjected to a predetermined overload condition, to physically separate said fusible means into two sections along the resultant weakened region thereof and, thereby, effect an open-circuit gap along the electrical circuit path dimensions thereof, by displaying said flange-forming end walls, together with at least the upper end regions of the conductive terminating means in respective engagement therewith, a predetermined increased distance relative to each other and from their normally spaced relationship, as assembled.