Abstract: A fuse for operation with both DC and AC currents is disclosed which consists of a composite fuse link contained in a large insulator housing. Located within the housing are first and second foil sections fabricated from a good conducting material. Each foil section is secured to a right and left terminal with its other end coupled to a central link fabricated from zinc. The central link is contained within a smaller cylinder and is surrounded by air, while the foil sections are surrounded by quartz sand or some other suitable filler material dispersed within the large housing.

Abstract: A strip-shaped fusible member is disposed in a slit formed in an electrically insulating member to be not greater than 1 mm in width. Further a granulated electrically insulating material may be charged around the electrically insulating member within an enclosed housing. Alternatively, a plurality of electrically insulating members may alternate in intimate contact relationship fusible member to form a stack. Each fusible member is connected at both ends to two terminal blocks located on the opposite sides of the stack on those portions higher in level than that portion thereof sandwiched between the insulating members while its end portions are slackened.

Abstract: A direct current interrupter comprising a plurality of two-point interrupter units each including a pair of interrupting portions. The interrupting portions of the interrupter units are arranged at regular angular intervals on a circle with the axial line of the interrupter as its center and arranged parallel to the axial line. An input terminal is provided to supply shunted current to one interrupting portion of each interrupter unit. An output terminal is provided to receive the shunted current from the other interrupting portion of each interrupter unit. A first common connecting portion and a second common connecting portion near the axial line. The main current flows through a conductor line from the main current input terminal to the first common connecting portion and shunted.

Abstract: A current limiting fuse is disclosed in which a main fuse element is wound at a given pitch around a fuse spider or mandrel. An auxiliary fuse element for assisting in low current high voltage current limiting operation is wound at generally the same pitch but in a disposition of non-electrical contact on the same fuse spider or mandrel. At the ends of the auxiliary elements, sheaths of flexible glass material of known thickness and dielectric characteristics are disposed for being wound around a predetermined notch in the fuse element for greatly enhancing the flashover or arc transfer characteristic between the main fuse element and the auxiliary fuse element during a fusing operation.

Abstract: A fuse comprises a thin metal strip of constant thickness mounted on an insulating support and having relatively wide portions mutually spaced apart and interconnected by a relatively narrow portion constituting a fusible link which overlies a recess or aperture in the support so that the fusible link is spaced apart from the support surface. Preferably, the strip is folded about one end of the support with the fusible link remote from the fold, the relatively wide portions extending around the fold on each side of the support to constitute tab contacts for mating with a receptacle.

Abstract: An electric fuse for elevated circuit voltages, such as, e.g. 5 to 15 KV. It includes a tubular casing or electric insulating material, terminal elements and a pulverulent arc-quenching filler. It further includes a plurality of equidistantly spaced fusible elements electrically connected in parallel, wound substantially helically in planes defining a prism and forming part of a current path conductively interconnecting the pair of terminal elements.The point of novelty consists in that the fusible elements are formed by a unitary metal stamping. That stamping also includes aligned metal bridges conductively interconnecting all the fusible elements. The preferred number of planes or sides of the aforementioned prism is four and the preferred number of bridges is n-1 for each quarter turn of the fusible elements, wherein n is the number of fusible elements connected in parallel. The bridges are arranged in spaced relation from the edges of the prism.

Abstract: The dual element fuse of the present invention has at least one fusible element and at least one mass of heat softenable material; and that fusible element will respond to a short circuit to fuse and thereby assure opening of the circuit, whereas that mass of heat softenable material will respond to a long-continued relatively-low potentially-hurtful overcurrent to soften and thereby initiate opening of the circuit. That dual element fuse has a shunt element which shunts the mass of heat softenable material and which will fuse after that mass of heat softenable material has initiated opening of the circuit; and hence that shunt element will minimize arcing as that mass of heat softenable material initiates opening of the circuit.

Abstract: A pair of parallel fusible elements is sub-divided, or separated by points of reduced cross-section into two parallel strings of fusible element sections. The pair of fusible elements is supported by a support of electric insulating material including a portion arranged between the pair of fusible elements and extending in a direction longitudinally thereof. The support further includes transverse arms arranged to both sides of the portion of the support that extends in the direction of the pair of fusible elements. These transverse arms are planar and support said planar fusible element sections and consequently the pair of fusible elements. The arms sandwich the planar fusible element sections which are arranged between the arms. If fusible elements of the above kind are connected in parallel into an electric circuit, the fusible elements will fuse sequentially at low currents at one or more points thereof. This process is often referred-to as "triggering".

Abstract: A plurality of ribbon-type fusible elements is arranged in parallel. Each of them includes a plurality of serially arranged points of reduced cross-sectional area. Each of these points is formed by a perforation and two current paths, each to opposite sides of the perforation. Along the plurality of fusible elements, like rungs of a ladder, is arranged a plurality of separate pairs of members of electric insulating material, each covering at least two points of the plurality of points of reduced cross-section. Fastener means project through each of the pairs of insulating members to firmly position the same in relation to the plurality of fusible elements.

Abstract: A fuse having a composite fusible element comprising a plurality of separate, parallel, equidistantly spaced wires. A plurality of bridges of electric insulating material is arranged substantially transversely to the aforementioned wire-like fusible elements at spaced fixed points thereof integrating said plurality of fusible elements into a ribbon-like unitary structure and maintaining said wire-like fusible elements equidistantly spaced at said plurality of points thereof. Said plurality of wire-like fusible elements are wound helically around a prismatic surface in such a way that said plurality of bridges are located between the edges of said surface.

Abstract: A flat safety fuse having a carrier plate fabricated from a synthetic material on which is mounted a sheet metal member with at least one fusible arc. The fusible arc has an inner diameter equal to the distance between parallel inner edges of its supporting bases which are each attached to associated contact surfaces separated from each other by a slot. The sheet metal member is received in a recess provided in a surface of the carrier plate. Preferably, the sheet metal member is secured in the recess by pressure arcs and clamping portions provided on the sheet metal member and by raised clamping portions provided on the carrier plate. Preferably, the sheet metal member has a W-shaped configuration to provide two fusible arcs.

Abstract: An electric fuse having a tubular casing, an arc-quenching filler, a pair of terminal plugs closing the ends of the casing and fusible elements conductively interconnecting said pair of terminal plugs. The thermal duty imposed upon said arc-quenching filler is equalized so that equal amounts of filler are caused to absorb approximately equal amounts of heat. This is achieved by immobilizing the positions of the fusible elements and by giving them such a shape that heat dissipation is substantially equalized. In other words, the position of the fusible elements relative to the casing must be in such a way that they are not displaced when the fuse is filled with pulverulent arc-quenching filler, and the arc path of one of the fusible elements must be separated as much as possible from the arc path of the other fusible element.

Abstract: In fuses exceeding a certain voltage rating it is necessary to establish series multibreaks to interrupt small overload currents. An initial break is formed in the helically wound fusible elements near the center thereof where the temperature is highest. If the arc voltage along this initial break does not exceed the circuit voltage, even after a number of cycles of arcing, secondary or tertiary breaks must be formed in series to the initial break. This is achieved according to the present invention by providing one or more quarter-turns of reduced pitch where the spacing between contiguous groups of windings is reduced and a low temporary current flashover is allowed to occur which results in the formation of secondary and tertiary breaks.

Abstract: In fuses for a sufficiently elevated circuit voltage the single breaks formed near the center of the fusible element at the occurrence of small overload currents does not produce a sufficiently high arc voltage to bring the current down to zero. In such instances it is necessary to produce series multibreaks to achieve interruption of the overloaded circuit.The present invention describes new means to produce series multibreaks. In fuses according to this invention the fusible element is subdivided into a plurality of spaced elements in parallel to reduce the concentration of metal vapors. Each of the element forms a break near the center thereof. This occurs at different times t.sub.1, t.sub.2, t.sub.3, etc. even though the elements are identical. Each break-formation is accompanied by a concomitant increase of current in the remaining fusible elements, and each break-formation is accompanied by a concomitant voltage spike or voltage surge -- L(di/dt).

Abstract: A fuse cartridge has a hollow casing of insulated material having an internal chamber filled with quartz sand and being of a parallelepiped form having two transverse walls and two pairs of longitudinal walls. One of the transverse walls is integral with the housing, and the other transverse wall is removable therefrom and has holes, through which electrically conducting pins extend into the chamber. A partition wall is located in the chamber parallel to a plane of symmetry of a first pair of the longitudinal walls. At least one substantially flat fuse strip is located in the chamber and has two opposite ends, each electrically connected to a respective pin. The fuse strip is U-shaped and has two portions parallel to the second pair of the longitudinal walls and a third portion connecting the two portions of the fuse strip to one another and parallel to the transverse walls.

Abstract: The dual element fuse of the present invention has at least one fusible element and at least one mass of heat softenable material; and that fusible element will respond to a short circuit to fuse and thereby assure opening of the circuit, whereas that mass of heat softenable material will respond to a long-continued relatively-low potentially-hurtful overcurrent to soften and thereby initiate opening of the circuit. That dual element fuse has a shunt element which shunts the mass of heat softenable material and which will fuse after that mass of heat softenable material has initiated opening of the circuit. That shunt element has a current rating which is larger than the current rating of the mass of heat softenable material; and that shunt element has a current-interrupting characteristic which has the same shape as that of the current-interrupting characteristic of the fusible element.

Abstract: The fusible element of a fuse that needs series multibreaks for interrupting small currents is provided with a shunt current path including an arc gap in the center region thereof. That current path does not normally carry any current on account of the presence of the arc gap in it. The shunt current path shunts a portion of the fusible element including a so-called M-effect causing overlay. When that overlay becomes operative it causes formation of an arc gap in the fusible element which, in turn, causes a voltage to appear across the arc gap. When that voltage is sufficiently high the arc gap breaks down. The ensuing arc current is too small to allow formation of series breaks in the fusible element. The fusible element or the above shunt thereof are provided with beads that evolve gases under the action of the arc.

Abstract: An electric fuse having blind metal fusion joints, e.g. solder joints, between the two ferrules and the fusible element, or the fusible elements, thereof. One of these conductive connection joints is situated adjacent the center region of the inner end surface of one of the two ferrules. The other of these conductive connection joints is situated between one of the rims of the casing and the peripheral region of the inner end surface of the other of the two ferrules.

Abstract: A method of making fuses for a record unit comprising providing an electrl circuit pattern on an insulated substrate and then attaching a plurality of fine wires to the circuit pattern. A groove is provided beneath the wires which are encapsulated collectively but not individually.

Abstract: An electric fuse having a plurality of fusible elements connected in parallel. The fusible elements extend from the center region of one of the ferrules to the region of the other of the ferrules coextensive with one of the rims of the casing of the fuse. The ends of the fusible elements are conductively connected to the axially inner end surfaces of the ferrules. The plurality of fusible elements is formed by a self-sustained structural unit adapted to be telescoped in one single operation into the casing of the fuse, thus greatly facilitating the assembly of the fuse.

Abstract: A current limiting fuse and an expulsion fuse are disposed in side by side relationship on a common supporting structure. One terminal of each fuse are interconnected electrically. The other terminals of each fuse are spaced by a predetermined insulating gap. An external circuit which includes a voltage source and a load to be protected is connected in series circuit relationship with the terminals of the expulsion fuse. The current limiting fuse is only disposed in circuit relationship with the external circuit for current limiting purposes when the expulsion fuse blows because of a relatively high value of fault current. This causes gaseous products to be directed from an internal portion of the expulsion fuse to a region between the unconnected terminals of both fuses.

Abstract: The fuse is of the general purpose type having a casing closed at the ends by terminal caps; a core inside the casing; a main fusible element wound about the core and connected between the caps; a pair of arcing clips mounted in spaced relation on the core adjacent the main fusible element; and, an auxiliary element also wound about the core and connecting together the arcing clips. The improvement comprises a nonporous dielectric sheet covering the exposed surface of the clips and being interposed between and in contact with the clips and the main fusible element for determining the arc gap between them.

Abstract: An electric fuse adapted to form multibreaks at the occurrence of small protracted overload currents includes a first fusible element having a relatively small resistance which supports at a predetermined point thereof means for causing formation of a break at the occurrence of small protracted overloads. The fuse includes a second fusible element having a relatively high resistance shunted across said predetermined point of said first fusible element and has ends adapted to initiate arcing at small current intensities at points thereof located immediately adjacent said first fusible element. Blocks of metal are arranged in spaced relation from said first fusible element in the zone of arcing established by fusion of said ends of said second fusible element to increase the contamination of said zone by products of arcing resulting from vaporization of said blocks.A rod member of electric insulating material is arranged parallel to, but spaced from, the axis of the casing of the fuse.