Abstract: A fusible element for electric fuses including a core or layer of copper, an outer layer of silver plating, and an M-effect overlay on the silver layer of a low fusing point metal, e.g. tin, capable of severing the current path through the plating of silver and the core of copper by a metal diffusion process.The M-effect overlay is arranged in spaced relation in regard to the point of the fusible element where the highest temperature prevails to maximize the temperature difference, or temperature gradient, between the M-effect overlay and the hottest point of the fusible element when the latter is carrying current.

Abstract: This invention relates to electric fuses meeting the requirements of Underwriter's RK1 classification. It includes a high-current interrupter in the form of a fusible element having serially arranged points of reduced cross-section and a low-current interrupter in the form of a plunger soldered to the high-current interrupter. The plunger is spring biased, and when the solder joint softens, the plunger separates under the action of the spring from the fusible element leaving a large gap between them. The separation of the plunger from the fusible element is allowed to be particularly large on account of the fact that the plunger may be allowed to move into a special fuse cap, known as a cap having a rejection feature as described, for instance, in U.S. Pat. No. 2,943,295 to V. N. Stewart; June 28 1960 for REJECTION TYPE FUSE CLIP and in many other patents.

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: A regulating transformer including a base winding and a plurality of auxiliary windings adapted to be connected in whole, or in part, to said base winding. The ends of each auxiliary winding and a point between its ends are passed through a bushing to a change-over switch arranged outside the transformer tank. The base winding of the transformer is connected to the movable contact of a first change-over switch. The movable contacts of continuous change-over switches are interconnected. The movable contact of the last change-over switch is connected to an outgoing line. Each change-over switch has a movable contact that can be selectively engaged with either of a pair of fixed contacts. One of the fixed contacts is connected to one of the ends of an auxiliary transformer winding. The other of the fixed contacts is connected to a point, or tap, between the ends of the auxiliary winding.

Abstract: A two terminal solid state device for voltage limitation comprises a controllable current path and a control electrode for the control thereof. A series arrangement of one or more diodes is connected with one of the ends thereof to said control electrode and with the other end thereof to one of said two terminals of the device. The latter is adapted to operate above the combined threshold voltages of said controllable current path and that of said one or more diodes.

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 welded composite fusible element utilizing weld joints, or welded hinges, to interconnect the component parts of it. The above referred-to weld joints or hinges interconnect portions of a fusible element which are fragile and easily damaged with portions of the fusible element which are rugged and which involve little or no danger of damage in the process of assembly. The function of stress relieving hinges or weld joints according to this invention is to protect the delicate component of the composite fusible element.

Abstract: An electric fuse, in particular an electric time-lag fuse, comprising a tubular casing, a pair of terminal elements, a granular arc-quenching filler, and a pair of parallel fusible elements inside the casing interconnecting the pair of terminal elements. Each of the pair of fusible elements has a plurality of juxtaposed points of reduced cross-section. Juxtaposed points of reduced cross-section support an M-effect causing overlay thereon. Each of the M-effect causing overlays extends from a pair of juxtaposed points of reduced cross-section in opposite directions longitudinally of said pair of fusible elements. A substantially E-shaped member of a solid gas-evolving material having three arms is associated with said pair of fusible elements. One of said three arms is interposed between said pair of fusible elements at the region thereof where the juxtaposed points of reduced cross-section are located.

Abstract: A composite fusible element for electric fuses comprising a pair of spaced drawn wires substantially circular in cross-section, at least one pair of spaced plates of sheet metal in contact with said pair of wires, and electrical bonds conductively connecting each of said pair of wires and one of said pair of plates. The pair of wires is preferably of silver, and the pair of plates is preferably of copper. A fuse according to the invention includes a fusible element as described above.

Abstract: A composite fusible element of silver and copper includes an inlay of silver and a base formed by a thicker strip of copper than the inlay of silver. The strip of copper is severed by a pair of juxtaposed incisions, so that the entire current is carried at this particular point only by the strip of silver. Moreover, the incisions penetrate into the strip of silver, producing in it a point of reduced cross-section. The strip of copper is preferably provided with a concave groove. The strip of silver is preferably convex and fits into the concave groove of the strip of copper. The composite fusible element may include several parallel strips of silver in a joint base of copper.

Abstract: A fuse having a high cycling ability combined with a high arc-extinguishing ability due to the presence of a gas-evolving material. The fuse includes a pair of fusible elements having end portions and intermediate portions arranged between the end portions and converging in opposite directions, so as to form a pair of wedge-like structures. The pair of fusible elements is composed of planar portions and portions where these planar portions meet. The fusible element has points of minimized cross-section which are spaced from any bent in the fusible element. The improvement comprises a rectangular plate of gas-evolving material inserted into the gap, or space, defined by the pair of parallel fusible elements. The terminal elements of the fuse and its casing form abutments for the plate of gas-evolving material in longitudinal and in transverse direction so that no additional means are required for maintaining the gas-evolving plate in position relative to the pair of fusible elements of the fuse.

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: The process of circuit interruption by an electric fuse can be initiated either by a protracted overload, or by a major fault current of large proportions. This invention is concerned with the latter kind of fault currents.A substantially U-shaped gas-evolving structure is inserted between parallel rows of fusible elements. The two parallel arms of that structure are positioned close to the terminal elements of the fuse. A tie member interconnecting the two arms is positioned substantially out of the arcing zone and parallel to a generatrix of the fuse casing. On occurrence of a major fault current, the gas evolved from the arms protects the terminal elements of the fuse. It also tends to quench the follow current, i.e. the current which flows through the hot fulgurite after a successful interruption of a major fault current.

Abstract: A fuse for elevated circuit voltages having a blown fuse indicator. The fuse is characterized by its great simplicity of design. Virtually all its components, or constituent parts, form a sub-assembly capable of being inserted as a unit into the fuse tube or casing. One terminal of the fuse is formed by a plug contact that defines a heating chamber for heating one end of the restraining wire for the blown fuse indicator above all other points thereof. The other terminal of the fuse is formed by a ferrule, or terminal cap, conductively connected to a perforated metal disk, or metal plate, arranged immediately adjacent thereto. That disk or plate performs four functions, namely (1) to help support insulating rods around which the fusible element is helically wound, (2) to form one of the terminals of the fusible element and of the restraining wire for the blown fuse indicator, and (3) to provide a large aperture through which the fuse is easily filled with arc-quenching filler.

Abstract: A fusible element for electric fuses capable of combining time-lag in the range of overload currents with current-limiting action for currents in the range of short-circuit currents. The fusible element comprises a relatively wide perforated center section and axially outer heat dam sections. The center section has points of reduced cross-section imparting to it a predetermined fusing i.sup.2 .multidot.t. The center section of the fusible element is folded in a direction longitudinally thereof to effect mutual heating of the portion, or portions, thereof to different sides of the fold, or folds. This allows to increase the mass of the center section and results in an increase of time-lag. Relatively narrow heat-dam-strip sections extend from the ends of said center section. The fusing i.sup.2 .multidot.

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: A dual element fusible device is provided utilizing a plurality of separate arc quenching fillers disposed in layers within the fuse casing and being effectively separated from one another by an electrically insulative material which is introduced into the casing in a fluid state so that regardless of the configuration of the internal workings of the fuse, it establishes a continuous and impermeable barrier between the respective layers.

Abstract: A force balance instrument providing precision control of pneumatic actuators in response to command pressure signals independent of external forces on the actuator shaft. The instrument includes a high gain signal detection circuit in combination with one or two pilot operated output valves. In the case of two output valves inverse "push-pull" control of a double acting pneumatic actuator is provided. Full supply pressure differential can be developed across the piston of the actuator, permitting to minimize the size of the actuator for any specified output force.The positioner proper controls the position of valve actuator system through a stem connector arm and a feed-back spring. A force balance condition is initially established between the feedback spring and the force of a rolling diaphragm controlled piston assembly for the range of signal pressure P.sub.1 to be used. Any change in this force balance condition because of a change in signal pressure P.sub.

Abstract: A shaft sealing precluding fluid from moving in a direction longitudinally of the shaft. At the same time the shaft sealing allows a motion of the shaft in axial direction, an inclination of the shaft, and may also allow a rotary motion of the shaft relative to its sealing means. The sealing means is a rolling diaphragm including a clamping flange on one end of the rolling wall thereof. The other end of the rolling diaphragm is provided with a cylindrical elastomeric member having a projection conforming substantially with the shape of a portion of reduced diameter of the shaft and engaging under pressure said portion of reduced diameter. The rolling diaphragm includes an elastomeric ply and a fabric reinforcement of the ply.