Fused resistive electrical protection device

Claim 2

A protective device comprising: fusible means capable of at least establishing a weakened condition along an electrical circuit-path-defining dimension thereof when subjected to a specified current-induced over-load condition: biasing means; insulative enclosure means for said fusible means including a substantially tubular member having one fixedly secured and apertured end wall, and being adapted to provide an abutment for one end of said biasing means, and further including a movable apertured end wall adapted to normally substantially enclose the end of said tubular member opposite said secured end wall thereof, and to confine said biasing means between said movable end wall and said abutment of said tubular member; and conductive terminating means respectively secured to the ends of the circuit-path-defining dimension of said fusible means, and being adapted to pass through the apertures of, and to be brought into firm engagement with, the outer surfaces of the respectively adjacent secured and movable end walls such that said movable end wall is normally positioned against te adjacent end of said tubular member, in opposition to a predetermined degree of compressive force imparted thereagainst by said biasing means, but with said latter force being sufficient, in response to said fusible means being subjected to a given overload condition, to physically separate said fusible means into two sections along the resultant weakened region thereof by displacing said movable end wall, together with that portion of the associated terminating means in engagement therewith, and that section of the sub-divided fusible means associated therewith, a predetermined increased distance relative to said tubular member.

Claim 3

A protective device in accordance with claim 1 wherein said secured end wall comprises an integral part of said tubular member, wherein said abutment comprises an integral peripheral flange portion of said end wall, wherein said movable end wall is formed with a flange portion, and is of insulative material, and wherein said biasing means comprises a coil spring coaxially positioned on said tubular member and confined between said integral and movable flange portions.

Claim 4

A protective device in accordance with claim 2 wherein said fusible means comprises a resistor of the type capable of fracturing and, thereby, of establishing a physical separation along its axis length when subjected to a predetermined current-induced overload condition, and wherein said condition terminating means comprises a pair of conductive leads axially secured respectively to opposite ends of said resistor.

Claim 5

A protective device in accordance with claim 3 wherein outer terminating end regions of said resistor leads are bent into parallel extending relationship in a direction substantially perpendicular to the axis of said tubular member so as to facilitate the mounting of said device on a circuit board.

Claim 6

A protective device in accordance with claim 4 wherein intermediate portions of said leads that extend beyond the respectively associated end walls are formed with offset bends to provide respective stops for spacing said device above a circuit board.

Claim 7

A protective device in accordance with claim 1 wherein said integral abutment comprises an integral flangelike portion of said tubular member located along an intermediate region thereof, and being circumferentially disposed.

Claim 8

A protective device in accordance with claim 6 further including a metallic end cap coaxially mounted on an end region of said tubular member between said flange-like abutment and said fixedly secured end wall, said end cap being adapted to be received within a spring clip, and having an aperture therethrough that is aligned with the aperture in said fixedly secured end wall, with the adjacent one of said conductive terminating means extending through both of said aligned apertures and conductively engaging the outer surface of said end cap for both device securement and electrical continuity.

Claim 9

A protective device in accordance with claim 7 wherein said fusible means comprises an elongated resistor of the type capable of fracturing and, thereby, of establishing a physical separation along its axial length when subjected to a specified overload condition, and wherein said conductive terminating means comprises oppositely directed and axially secured resistor leads, and wherein said end wall apertures allow passage of the respectively adjacent leads therethrough, with said leads being configured along upper end regions thereof immediatly adjacent the respectively associated outer end wall surfaces such that the configured regions constitute securement means that cooperated to normally hold said composite protective device together, with said spring means normally being maintained under the desired degree of compression between said flange-like abutment and said moveable end wall.

Claim 10

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.

Claim 11

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.

Claim 12

A resistive protective device in accordance with claim 9 wherein said upper end configured region of each lead comprises a sharp right angle bend that positions a segment of each lead firmly against the mating outer surface of said associated end wall, and wherein the corresponding terminating end portions of said leads are oriented so as to be not only in substantially parallel relationship, but substantially perpendicular to said tubular member so as to allow the insertion of said terminating lead portions into aligned apertures of an associated circuit board.

Claim 13

A resistive protective device in accordance with claim 10 wherein a section of each lead intermediate the configured region and the terminating end portion is formed with at least two offset bends so as to provide a stop region therebetween that is adapted to normally rest on the upper surface of a circuit board and, thereby, provide a predetermined spacing between said circuit board and the tubular member of said protective device.

Claim 14

A resistive protective device in accordance with claim 11 wherein said resistor is of the carbon type, and wherein said tubular member and movable end wall are made of an insulative plastic material exhibiting excellent arc quenching and fire resistant properties.

Claim 15

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.

Claim 16

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.

Claim 17

A protective device in accordance with claim 13 whereinsaid fusible means comprises an elongated metallic member having an intermediate region of reduced cross-section that is capable of being weakened to such an extent in response to a predetermined overload condition, that the tensional force normally imparted thereagainst by said spring means will effect a separation of said elongated member into two sections.

Claim 18

A protective device in accordance with claim 13 wherein said conductive terminating means comprises a pair of oppositely directed wire-like elements, and wherein this fusible means comprises a normally secured connection between overlapping free ends of said wire-like elements, with the interfaces thereof being of predetermined dimensions and secured together by a metallic material capable of at least softening to such an extent in response to an overload condition, that the tensional force normally imparted thereagainst by said spring means will effect a separation of the free ends of said wire-like elements.

Claim 19

A protective device in accordance with claim 13 wherein each of said conductive means includes a wire lead, with a wire segment secured thereto immediately adjacent the outer surface of thee associated end wall, and extending at least a short distance therealong.