Abstract: An electric fuse having a support for helically wound fusible element or elements. The support includes a plurality of rods which are supported at their opposite ends adjacent the fuse end terminal by rod supports each of which is made from a pair of angularly arranged sheet-metal channels. The channels have a U-shaped cross-section and are arranged with their open ends facing the center of the fuse housing. Centrally positioned sections of the channels are flattened to facilitate rigid attachment of the channels to one another. The ends of the rods are received in and attached to interior portions of the U-shaped channels. A sub-assembly comprising the rods, rod supports and the wound fusible elements is pre-assembled and, when placed in a fuse housing, the ends of the channels cooperate with the inside walls of the housing to properly position the entire assembly.

Abstract: A blade type fuse whose blades project through the end surfaces of the caps which close the tubular casing. Thus the blade contacts project from the outside of the casing into the inside thereof. There are a plurality of fusible elements inside the casing, all having substantially the same resistance. Some of the fusible elements inside the casing that interconnect the aforementioned blade contacts have a relatively small spacing from the plane defined by the pair of blade contacts. Others of the fusible elements that interconnect the aforementioned blade contacts have a relatively large spacing from the plane defined by the pair of blade contacts. All fusible elements are approximately equally distributed across the cross-section of the casing. This involves for some of the fusible elements a relatively large, and for others of the fusible elements a relatively small, spacing from the plane of the blade contacts to which their ends are attached.

Abstract: An electric fuse having a fuse tube or casing into the ends of which plug terminals are plugged. The plug terminals are conductively interconnected by a plurality of fusible elements, the number of which may change depending upon the desired current-carrying capacity of the fuse. Each plug terminal is provided with a recess in the center thereof. Each recess receives an insert member having a wide flange at right angles to the longitudinal axis of the insert member. A small gap is left between the axially outer end surfaces of the pair of flanges and the axially inner end surfaces of the plug terminals. The fusible elements are held in position by radial slots in the aforementioned flanges into which they are inserted, and their ends are bent 90 degrees and inserted into the aforementioned gap. A solder joint is placed in each slot containing a fusible element conductively connecting the bent ends of the fusible elements, the aforementioned flanges and the plug terminals.

Abstract: Electric fuses according to this invention aim to increase the ratio between current-carrying capacity and i.sup.2 .multidot.t values. This means, in other words, to increase the current-limiting action for any given current rating.The fusible element of such fuses comprises an axially inner substantially planar portion of silver having at least one short-circuit neck adapted to initiate circuit interruption when said neck reaches approximately the fusing temperature of silver. The fusible element of such fuses further comprises a pair of non-planar axially outer portions of copper each having a larger width and a larger surface than said axially inner portion. The axially inner portion and the axially outer portions are conductively interconnected.

Abstract: A current-limiting fuse including a fusible element that comprises a relatively long portion of sheet copper and one or two end portions of sheet silver. The portions of sheet silver are each shorter than the portion of sheet copper. The portion of sheet copper is perforated, establishing points of reduced cross-section. The portion or portions of sheet silver are likewise perforated. The points of reduced cross-section established by the perforation, or perforations, in the portion or portions of sheet silver have a considerably smaller cross-section than the points of reduced cross-section in the portion of sheet copper.

Abstract: A fusible electric cable protector has a casing that defines a first internal space containing the fusible elements and a granular arc-quenching filler. At least one of the pair of terminal elements closing the casing is conductively connected to one connecting element that extends axially outwardly from the aforementioned terminal element and whose purpose is to connect the cable protector into an electric circuit. That connecting element has a cylindrical outer surface and is hollow, thus defining a second internal space filled with a granular arc-quenching filler. The aforementioned first internal space and the aforementioned second internal space are in communication by a passageway in one of the pair of terminal elements. A plug normally closes the open end of the cylindrical connecting element.

Abstract: An electric fuse having plug terminals. The fusible elements are connected to the plug terminal by the intermediary of metal strips having three sections. One section is inserted into the grooves of the plug terminals and conductively connected with the latter. Another section is arranged in a plane parallel to, but spaced from, the plane defined by said first mentioned section. A third section of the metal strips conductively interconnects the first section and the second section thereof.

Abstract: An electric fuse including blade contacts projecting through the terminal caps into the casing. The axially inner ends of the blade contacts are conductively connected by electroconductive elements to the axially outer ends of the fusible element. The electroconductive elements each comprise a first planar arm conductively affixed to one end of the fusible element, a second planar arm arranged parallel to and spaced from said first planar arm and conductively affixed to one end of the blade contact, and tie means integral with said first and said second arm conductively connecting the axially outer end of said first arm to the axially inner end of said second arm.

Abstract: Fuses having different ratings, all of which comply with the Standard for Class L fuses of the Underwriters Laboratories Inc.The fusible elements of the fuses have identical points of reduced cross-section which fuse simultaneously on major fault currents, except one point of reduced cross-section which fuses ahead of the others.A relatively large temperature gradient prevails between the aforesaid points of reduced cross-section that fuse on short circuit current and the M-effect low fusing point overlay of the copper links that severs the current path through the latter by a diffusion process. The M-effect overlay metal may just reach its fusing point, while the immediately adjacent points of reduced cross-section may have a much higher temperature, e.g. 300.degree. to 400.degree. C. Thus the fusing M-effect metal will flow to the point of higher temperature and a rapid severing of the latter will take place.

Abstract: A solderless pressure contact between a cap or ferrule of a fuse and the end of a fusible element that has been bent around the rim of the casing of the fuse from the space inside the casing to the outer surface thereof. A normal ferrule is used, i.e. a ferrule having a planar end surface rather than one having an end surface projecting into the casing of the fuse. The side wall, or lateral wall, of the ferrule is provided with a tab being hingedly supported at the axially inner end thereof by the lateral wall of the ferrule. The aforementioned tab slants from its point of support by the lateral all of the ferrule, or from the axially inner end thereof, axially outwardly and radially inwardly into firm engagement with the end of the fusible element on the outer surface of the casing. This pressure contact requires the use of casings which are electically deformable according to Hooks law, or have a memory, i.e. tend to assume their original shape after having been deformed.

Abstract: An electric fuse has rod supports for the helically wound fusible element which are of a laminate of glass cloth and a synthetic resin. This is a material which is slightly gas evolving. The rods have inserts of a material which is highly gas evolving, and they provide a substantial spacing between the path of the fusible element--and the arc path--and the surface of the rod supports for it. The limited gas evolving capacity of the rods combined with the large gas evolving capacity of the inserts and combined with the spacing between the arc path and the surface of the rods allows proper operation of the fuse in the absence of any ceramic insulators or ceramic supports for the fusible element.

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: An electric fuse having a support for the helically wound fusible element or elements. The support includes a plurality of rod-like supports each made of one uniform material. Some of the plurality of rod-like supports consist solely of a non-gas-evolving material, while at least one of the plurality of rod-like supports consists solely of a gas-evolving material.

Abstract: A time-lag fuse of the type including a fusible element proper, and heat dams formed by strips of sheet metal folded in a direction transversely to the direction of the fusible element proper impeding the axially outer heat flow from said fusible element proper. The fusible element proper has several straight edges extending parallel to the axis of the casing of the fuse. Points of the heat dams engage the inner surface of the casing of the fuse and thus ensure correct positioning of the fusible element proper, i.e. in such a way that its edges extend always parallel to, and are equidistantly spaced from, the axis of the casing. The heat dams engage the inner surface of the casing at discrete points only, to minimize the area of engagement between said heat dams and the inner surface of the casing and to thus minimize direct heat flow from one to the other.

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: 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: Load-break switches and current-limiting fuses are often serially connected and placed one above the other. This arrangement is relatively bulky, and involves in particular relatively large requirements in respect to height.The present invention concerns an arrangement of parts wherein the load-break disconnect and the current-limiting fuse are electrically connected in series, but wherein they are arranged spatially in parallel, substantially in coaxial relation, the load-break switch or some of its constituent parts being arranged inside of the current-limiting fuse; or the load-break switch and the current-limiting fuse may be provided with contact means common to both of them.

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: An electric fuse suitable for motor-starting, i.e. having a considerable time-lag in the range of motor starting currents, and at the same time having a current-limiting action in the high fault current range, characterized by extremely small peak let-through currents and extremely small clearing I.sup.2.multidot. t values. To be more specific, fuses emboyding this invention have considerably smaller maximum peak let-through currents and considerably lower clearing I.sup.2.multidot. t values than Underwriter Laboratories Class RK5 fuses, and meet the maximum acceptable peak let-through current values and clearing I.sup.2.multidot. t values of Underwriter Laboratories Class RK1 fuses. This is achieved by combining specific time-lag means involving a minimum of mass with parallel current paths of greatly increased number and greatly decreased size.

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.