This invention relates in general to the manufacture of a line of fuses having large numbers of component parts, and more particularly to the manufacture of high speed fuses.
Fuses are widely used as overcurrent protection devices to prevent costly damage to electrical circuits. Fuse terminals typically form an electrical connection between an electrical power source and an electrical component or a combination of components arranged in an electrical circuit. A fusible link or fuse element assembly is connected between the fuse terminals, so that when electrical current flowing through the fuse exceeds a predetermined limit, the fusible link melts and opens the circuit through the fuse to prevent electrical component damage.
Many different types of fuse constructions exist, and large inventories of different types of fuses are typically required to meet a full range of circuit protection needs. It would be desirable to provide a lower cost fuse constructions and to reduce fuse inventory issues.
Embodiments of the present invention provide a relatively low cost yet highly adaptable fuse construction that may substantially reduce cost, space and complexity issues associated with having to stock and maintain large inventories of different types of fuses as has been conventionally done.
As one illustrative example, high speed fuses have been used to protect or isolate equipment having power semiconductor devices such as, for example, variable speed drives. There is very little safety factor in these semiconductor devices and they can fail quickly when subjected to overcurrents. Therefore, a fuse designed to protect semiconductor devices must open quickly. High speed fuses have very little thermal capacity, and in general open in the order of 0.001 to 0.004 seconds when interrupting short circuits.
Over time, high speed fuses have been developed to meet the needs of specific applications and devices, resulting in a large number of different fuses made in different sizes, shapes and connecting terminals to satisfy the voltage and amperage ranges expected to be encountered. Consequently, many different parts and subassemblies for these fuses, numbering in the hundreds, may be required to manufacture fuses for different customer and different applications. Maintaining an inventory stock for manufacturing a complete line of such fuses is challenging.
Typically, the fuses are completely assembled, including any terminal or connecting elements to couple the fuse to circuitry to be protected, by the manufacturer at a centralized manufacturing facility and the fuses are shipped to distributors and retailers for acquisition by customers. In part because of the large variety of such fuses, it is impractical for distributors to maintain large inventories of all the potential types of fuses. Locating a replacement fuse in an existing inventory can therefore be difficult. If it is necessary to order a replacement fuse from a manufacturer, some delay will be incurred to manufacture the fuse and and/or ship it from the manufacturer through the distribution chain to the customer. Such delay in restoring the downed circuitry and equipment is undesirable.
According to an exemplary embodiment of the invention, and as explained in detail below, a universal fuse engine is provided that is configured to accept modular end fitting elements to provide various fuse configurations. Fuses may therefore be manufactured and assembled using a reduced number of parts that need to be stocked in order to manufacture a complete line of high speed fuses, and further to more quickly provide replacement fuses to customers.
The fuse engine may be manufactured in bulk at the manufacturer level, and in an exemplary embodiment includes an insulative fuse body, conductive end closure elements coupled to the fuse body, a contact piece and a fuse element assembly. The fuse element assembly extends between one of the end closure elements and the contact piece and defines a conductive path therebetween. The fuse engine therefore includes the operative components of the fuse, and is configured to readily accept and be attached to the modular end fittings at a later stage of assembly.
One of the end closure elements and the contact piece are configured to receive separately provided modular end terminal elements. Protective elements are attachable to the respective end closure elements until the end fittings are installed. With the protective elements attached, contact portions of the end closure elements are sealed and protected from damage and environmental exposure so that the fuse engines may be shipped to another location, while reliably establishing electrical contact with the end fittings after the guards are removed and replaced with the end terminal fittings.
The modular end fittings are each provided with a standard mounting base that is compatible with the end closure element and the contact piece of the fuse engine, and a terminal element extends from the standard mounting base in each of the modular end fittings. In various embodiments, the terminal configurations may conform to various standards, requirements, and connection schemes for various applications when the end fittings are connected to fuse engines. For example, “French style” end terminals, various types of DIN end terminals, flush mount terminals, and “U.S. style” terminals may all be provided with the standard mounting base and interchangeably used with the fuse engine.
Advantageously, the modular end fittings may be stocked at the distributor level, together with an inventory of the fuse engines from the fuse manufacturer, so that the distributor may quickly assemble the end fittings to the fuse engines to quickly fill a customer order for replacement fuses. By mass producing the fuse engines and separately providing modular end fittings for installation at a later time in a non-manufacturing installation, manufacturers can reduce their parts count and associated inventory management difficulties in manufacturing fuses, while still offering a full line of fuses, and while more quickly filling customer orders and requests.
Multiple fuse engines and accompanying modular end fittings may be provided and assembled to provide fuses having varying voltage and current ratings and different dimensional package sizes.
Turning now to the Figures,
While the invention is believed to be particularly advantageous for the manufacture of high speed fuses, which until now have required a large number of parts to provide a full line of fuses, it is understood that other types of fuses could benefit from the principles of the present invention, and the following description is therefore provided for illustrative purposes only.
In an exemplary embodiment, the fuse engine 100 may include a nonconductive fuse body 102, conductive end closure elements 104 and 106 coupled to opposing ends of the fuse body 102, and protective elements or guards 108 attached to the end closure elements 104 and 106. The fuse engine 100 may be assembled by the manufacturer and shipped to a non-manufacturing site to be completely assembled for use in a circuit having, for example, semiconductor components that are sensitive to overcurrent conditions. Fuses may therefore be manufactured and assembled at different times and locations using a reduced number of parts that need to be stocked in order to manufacture a complete line of high speed fuses, and further to more quickly provide replacement fuses to customers.
The fuse body 102 in an illustrative embodiment may be manufactured into a generally square configuration having rounded corners, although it is appreciated that the body 102 could be fabricated into other shapes in alternative embodiments of the invention. The body 102 defines a cavity or opening therein (shown in
The guards 108 may be removably attached to the closure elements 104, 106 as described below, and are in abutting contact with outer surfaces of the end closure elements 104, 106 to protect contact portions of the closure elements, as explained below, for shipping and transit from a manufacturer, for example, to a distributor.
Body mounting apertures 126 are provided in the end plate 104 adjacent the corners thereof to secure the end plate 104 to one end of the fuse body 102, and the apertures 126 may be threaded to receive fasteners (not shown in
When the end plate 104 is attached to the body 102 (
The contact piece 122 may be fabricated in an exemplary embodiment into an annular or disk shape having a round flange portion 140 and an inset mating portion 142 extending from the flange portion 140. The mating portion 142 may be raised or elevated from the top surface 144 of the flange portion 140, and the mating portion includes an outer periphery 146 having a clover leaf shape that is complementary to, but slightly smaller than, the shape of the central opening 130 of the end plate 104. The mating portion 142 of the contact piece 122 may therefore be inserted into the central opening 130 of the end plate 104 with the flange portion 140 of the contact piece abutting an underside 148 of the end plate 104. A round central opening 150 extends through each of the mating portion 142 and the flange portion 140 of the contact piece 122.
While a disk shaped contact piece 122 is illustrated in
The flange portion 140 of the contact piece 122 may include end plate mounting apertures 152 for attaching the contact piece 122 to the end plate 104, and the apertures 152 may be threaded to receive fasteners. When the contact piece 122 is assembled to the end plate 104, the end plate mounting apertures 152 align with the contact piece mounting apertures 134 of the end plate 104. The mating portion 142 of the contact piece 122 may further include pairs of end fitting mounting apertures 154 for attachment of an end fitting, described below, to the contact piece 122. The end fitting mounting apertures 154 may be threaded to receive fasteners.
Body mounting apertures 162 are provided in the end plate 106 adjacent the corners thereof to secure the end plate 106 to the fuse body 102, and the apertures 162 may be threaded. A central recessed area 164 may be provided in the middle of the end plate 106, and may define, for example, a circular contact area that is depressed relative to the top surface 166 of the plate 106 adjacent the end edges 160.
Unlike the end plate 104 (
While the embodiment described thus far includes the end closure assembly 120 on one side of the fuse engine 100 and the end plate 106 on the other side of the fuse engine 100, it is contemplated that in other embodiments the end closure assembly 120, or alternatively the end plate 106, may be used on both sides of the fuse engine 100 while still achieving the benefits of the invention.
The plug portion 182 may extend generally perpendicular to the flange portion 180 and may include an outer diameter that is dimensioned for insertion into the central opening 150 of the contact piece 122 (
The guards 108 may be coupled to the end plate 106 and the contact piece 122, respectively. The flange portions 180 of the guards 108 are in abutting surface engagement with the recessed area 164 (
The arc quenching material surrounds the fusible elements 200 in the cavity 202, and in one embodiment is solidified or cured to a solid form according to known techniques, such as a silication technique. The channels 186 in the guards are plugged or blocked after the arc quenching media is introduced.
The end fitting 220 may further include an end terminal portion 226 extending upwardly and away from the mounting base 222. The end terminal portion 226 is configured for connection to terminals of circuitry to be protected, and as shown in
As such, the mounting base 222 is sometimes referred to as a standard base, and the end fittings 220, 240, 242, 244, and 246 including the standard base 222 are therefore interchangeably used with one another on the fuse engine 100 to assemble a variety of fuses having different end terminal configurations. While some exemplary end terminal configurations are shown in
With the engine 100 fabricated from a standard set of parts, and the modular end fittings 220 that can be assembled thereto, manufacturers can reduce their parts count and associated inventory management difficulties while still providing a complete line of fuses, and while delivering replacement fuses with minimal delay. Fuses may therefore be manufactured and assembled at different times and locations using the modular end fittings 220 and the modular fuse engine platform. The universal fuse engines 100 and the modular end fittings 220 may be supplied in kits for ready assembly to meet needs as they arise.
Multiple fuse engines and accompanying modular end fittings may be provided and assembled to provide fuses having varying voltage and current ratings and different dimensional package sizes.
By way of example,
Having now described some exemplary embodiments of the fuse engine and modular end fittings with standardized mounting bases, it is believed that the versatility of the invention has now been demonstrated and the advantages of the invention are now apparent. Furthermore, the methodology of the present invention could be applied beyond the application of high speed fuses as herein presented.
An inventory of modular end fittings of different types or styles is also provided and maintained 304 that may be used in combination with the inventory of fuse engines in an interchangeable manner as described above. As used herein, “inventory” shall include one or more sets of modular end fittings, and preferably multiple sets of different styles of fittings. The number of end fitting sets in the end fitting inventory may be the same or different from the number of fuse engines in the fuse engine inventory. The inventory of end fitting may include, without limitation, any of the aforementioned end terminal configurations and other terminal configurations as desired. The fuse engine inventories and the end fitting inventories may be fabricated, provided and inventoried in the same or different location.
When an order for a fuse is received 306 from a customer or other party, either for an original fuse or for a replacement fuse, appropriate end fittings are selected 308 from the end fitting inventory of step 304 to fill or satisfy the order. Orders may be received in any manner, from human entry to automated systems known in the art, and the selection 308 is made from the available types and styles of end fittings of different configurations, which as described above includes exemplary styles of selected from the group of a French style fitting, a DIN style fitting, a flush mount fitting, a US style fitting, or other types of fittings and combinations of fittings as desired. The selection 308 may be made automatically or manually in different embodiments.
After selecting 308 the appropriate end fittings for a customer order, a fuse engine is obtained 310 from the inventory 302 and the guards are removed 312 to expose the contact areas of the fuse engine described above, which are kept clean and protected during shipping and handling of the engine. The guards may be removed 312 at a location separate, such as a distribution facility, from a manufacturing facility for the fuse engine. The guards may be removed in an automated manner or in a manual manner.
Once the guards are removed 312, the selected end fittings may be mounted 314 to the fuse engine in mating contact with the clean contact areas protected by the guards prior to their removal. When the end fittings are mounted 314 to the engine, a fuse assembly ready for connection to a circuit is provided 316 to the customer for use.
The method 300 provides for assembly of a variety of fuses with different terminal structures from a relatively small number of parts. That is, each of the fuse engine inventory and the end fitting inventory may be relatively small, while meeting a relatively large number of different customer orders for different types of fuses in relatively little time in comparison to known fuses and conventional construction and assembly methods of fuses. Because all of the end fittings are installed in the same way by virtue of the standard mounting base, the fuse assemblies of different types may be installed with equal ease and speed, and fuse assemblies from the inventoried components can be provided in a matter of minutes.
Further, the inventories of fuse engines and end fittings may be optimized to meet anticipated needs while minimizing the amounts of components actually inventoried. For example, certain types of end fittings that are frequently ordered may be maintained in a larger inventory than other types of end fittings that are less frequently ordered.
As embodiment of a fuse assembly is disclosed herein that comprises a fuse body defining a cavity and a first end in fluid communication with the cavity. A first end closure element is coupled to the first end of the fuse body, and the first end closure element comprising an opening exposing a portion of the first end. At least one fuse element is situated in the cavity, and a removable guard substantially closing the opening for shipping and transit of the fuse assembly.
Optionally, the first end closure may comprise an end plate. The fuse body may be generally square. The guard may include a plug portion extending through the opening and extending inwardly into the cavity, and the guard may include a channel defining a flowpath extending from an exterior of the cavity to the interior of the cavity. A contact piece may be separately provided from the first end closure element and may be attached to the first end closure element. The at least one fuse element may be electrically connected to the contact piece The opening in the end closure element may be non-circular, and may have a clover leaf shape. A plurality of modular end fittings of different types may be separately provided from the first end closure element, with each of the modular end fittings configured to connect to the fuse assembly when the guard is removed. The end fittings may be selected from the group of a French style fitting, a DIN style fitting, a flush mount fitting, a US style fitting, and combinations thereof. The modular end fittings may comprise a base portion and a terminal portion, with the base portions of the modular end fittings configured for interchangeable mounting of the modular end fittings to the first end closure element.
Another embodiment of a fuse assembly is also disclosed. The assembly comprises a fuse body defining a cavity and opposite ends in fluid communication with the cavity. First and second end closure elements are coupled to the first end of the fuse body, with each of the first and second end closure elements comprising a central opening extending therethrough and exposing a portion of cavity. At least one fuse element is situated in the cavity and electrically connected to one of the first and second end closure elements, and first and second removable guards extend over each respective central opening in the first and second end closure elements.
Optionally one of the first and second end closure elements comprises a plate, and one of the first and second end closure elements may comprise a recessed contact area surrounding the central opening. One of the guards may include a flange portion and a plug portion extending inwardly into the cavity, with the flange portion having a shape complementary to the central opening. One of the guards may include a channel defining a flowpath extending from an exterior of the cavity to the interior of the cavity. An optional contact piece may be coupled to one of the end closure elements, the contact piece defining a contact area, and one of the first and second removable guards covering the contact area.
An embodiment of a fuse assembly is disclosed wherein a fuse body defines a cavity and opposite ends in fluid communication with the cavity. First and second end closure elements are coupled to the first end of the fuse body, with each of the first and second end closure elements comprising a central opening extending therethrough and exposing a portion of cavity. The central openings of the first and second end closure elements are different from one another, and a contact piece is coupled to the first end closure element. The contact piece has a flange portion and a mating portion, the mating portion having a complementary shape to the central opening of the first end closure element and being insertable therein. At least one fuse element is situated in the cavity, the fuse element having first and second ends, and the fuse element electrically connected to the contact piece at the first and to the second end closure element at the second end. A plurality of interchangeable modular end fittings of different types are provided, and each of the modular end fittings configured to be interchangeably mounted to one of the contact piece and the second end closure element.
Optionally, first and second removable guards extend over each respective central opening in the first and second end closure elements. One of the first and second end closure elements may comprise a recessed contact surface, the assembly further comprising a guard comprising a flange portion and a plug portion, the flange portion in abutting contact with the recessed contact surface. A removable guard may be in abutting contact with one of the first and second end closure elements, the guard defining a flowpath extending from an exterior of the cavity to the interior of the cavity.
A kit for assembling a fuse is also disclosed. The kit comprises a universal fuse engine comprising a body, a fuse element within the body, and end terminal end closure elements; and a plurality of interchangeable end fittings mountable to the universal fuse engine, the plurality of end fittings comprising different terminal configurations extending from a standard mounting base compatible with the universal fuse engine.
Optionally, the fuse engine may comprise a high speed fuse element. The standard mounting base may be non-circular, and may be clover shaped. Guards may be provided and configured to removably engage the fuse engine prior to installation of the modular end fittings The universal fuse engine may comprise opposite end closure elements coupled to the body and a contact piece, with the fuse element extending between one of the end closure elements and the contact piece.
A method of assembling a fuse from an inventory of components including at least one universal fuse engine and a plurality of separately provided modular end fittings of different configurations is disclosed. The universal fuse engine may be provided with removable guards attached to end closure elements, and the method comprises removing the guards from the fuse engine; selecting a first and second end fitting from the plurality of modular end fittings of different configurations; and mounting the first and second end fittings to the fuse engine where the guards were installed prior to removal.
Optionally, selecting the first and second end fittings comprises selecting the first and second end fittings from the group of a French style fitting, a DIN style fitting, a flush mount fitting, a US style fitting, and combinations thereof. Removing the guards may comprise removing the guards at a location separate from a manufacturing facility for the fuse engine. The method may further comprise maintaining an inventory of substantially identical universal fuse engines; maintaining an inventory of the modular end fittings; receiving a customer order for a replacement fuse; selecting the first and second end fittings to fill the order; and providing one of the universal fuse engines and the selected modular end fittings to the customer.
A modular fuse system is also disclosed, the system comprising: a plurality of modular end fittings having modular end fittings with a standard mounting base and various terminal configurations; and a universal fuse engine, separately provided from the modular end fittings, configured to accept any of the modular end fittings via the standard mounting bases thereof.
Optionally, the universal fuse engine comprises a body, a fuse element within the body, and end closure elements, wherein the mounting bases are attachable to the end closure elements. The universal fuse engine may include a high speed fuse element.
A modular fuse system is also disclosed. The system comprises means for packaging operative components of a fuse into a stand alone assembly for shipping and transit. A means for connecting the means for packaging to a circuit is also provided. The means for connecting provides a variety of connecting options for the means for packaging, and the means for connecting is separately provided from the means for packaging. The means for connecting is interchangeably used with the means for packaging.
While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
This application claims the benefit of U.S. Provisional Application Ser. No. 60/687,832 filed Jun. 6, 2005, the entire disclosure of which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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60687832 | Jun 2005 | US |