The field of the invention relates generally to fuse holders, and more specifically to modular fuse holders having terminal stud connections.
Fuses are overcurrent protection devices for electrical circuitry, and are widely used to protect electrical power systems and prevent damage to circuitry and associated components when specified circuit conditions occur. A fusible element or assembly is coupled between terminal elements of the fuse, and when specified current conditions occur, the fusible element or assembly melts or otherwise structural fails and opens a current path between the fuse terminals. Line side circuitry may therefore be electrically isolated from load side circuitry through the fuse, preventing possible damage to load side circuitry from overcurrent conditions.
Some known fuse holders are provided in modular form that may be assembled into larger fuse blocks. A pair of terminal studs are sometimes provided in each of such modular fuse holders for electrical connection to line side and load side circuitry, with a fuse completing a circuit path between the pair of fusible studs. Bus bars, which may be sold with the modular fuse holders or separately provided, are sometimes desirable to connect one power supply, for example, across a number of fuse holders while providing separately fused output power connections. Known fuse holders of this type are subject to certain difficulties and improvements are desired.
Non-limiting and non-exhaustive embodiments are described with reference to the following Figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.
Exemplary embodiments of modular fuse holders and assemblies are described herein that overcome numerous disadvantages in the art.
The body 102 is fabricated from a known insulative or nonconductive material using known processes. In one embodiment, the body 102 may be fabricated from an injection molded, heavy duty plastic material. It is understood, however, that other suitable processes and materials are known in the art and may likewise be utilized to fabricate the body 102. In the embodiment shown, the body 102 is generally rectangular in form and includes diametrically opposed mounting lugs 108, 110 allowing the body 102 to be mounted on, for example, a chassis of a vehicle or other supporting structure. Additionally, and as shown, the exemplary body 102 includes one or more projections 112 and slots 114 that allow multiple bodies 102 to be coupled or ganged together to form a larger fuse block as shown in the examples of
The body 102 further includes first and second terminal studs 116 and 118 projecting therefrom and arranged as a pair opposing one another. One of the studs 118 may be electrically connected to power supply circuitry, sometimes referred to as a line side connection, and the other stud 116 may be electrically connected to electrical loads and circuitry receiving electrical power from the line side, sometimes referred to by those in the art as a load side connection. The fuse 106 may be connected to the line and load side terminal studs 118, 116, respectively as further described below to provide fusible protection for circuitry completed to the studs 116, 118. The line side and load side connections may be established in a known manner using, for example, ring terminals and the like coupled to the studs 116, 118. The body 102 including the studs 116, 118 is provided as a module that may be used alone or in tandem with other modules as desired to provide one or more fused power connections in, for example, a vehicle electric power system or other electrical power system. Any number of modules may be assembled to form a larger fuse block as shown in the examples of
The bus bar 104, as shown in the example depicted, may be a generally flat and planar element fabricated from a conductive material such as metal (e.g., copper or another metallic material familiar to those in the art) or a conductive alloy familiar to those in the art and utilizing known processes. The bus bar 104 in the illustrated embodiment is provided with a plurality of equally sized (i.e., equal diameter as shown) and spaced apart holes 120 (three of which are visible in
While a bus bar having four holes 120 is shown in the exemplary embodiment, it is understood that the bus bar 104 may alternatively be provided with greater or fewer numbers of holes 120 to accommodate a greater number (e.g., seven in another embodiment) or a fewer number of modular fuse holders including a body 102 and the terminal studs 116 and 118. A wide variety of differently configured fuse blocks having varying numbers of modular fuse holders may therefore be provided in addition to those shown in
The fuse 106 in the illustrated embodiment is a known overcurrent protection fuse such as AMI fuse or AMG fuse of Cooper Bussmann, St. Louis Mo., although it shall be understood that other fuses of various other manufactures may likewise be utilized. The fuse 106 includes a nonconductive housing 124 and conductive terminal elements 126, 128 extending from opposed ends of the housing 124. A fuse element, fusible link or fuse element 130 (
In abnormal operating conditions, however, the fuse element, link or assembly 130 is constructed to structurally fail and open the current path between the fuse terminals 126, 128. The fuse element, link or assembly 130 can be strategically selected to fail at a predetermined location in the housing 124 when predetermined current conditions occur via weak spots in a fuse element or other features known to those in the art. The predetermined current conditions causing the fuse element 130 to fail is typically selected to be a current level that is below an amount that would result in damage to downstream circuitry, devices or components in the load side circuitry. The predetermined current conditions causing the fuse element, link or assembly 130 to fail also corresponds to the rating of the fuse. Various ratings are possible and the fuse element, link or assembly 130 may be designed for different voltages and current conditions appropriate for the line and load side circuitry. As the fuse element, link or assembly 130 structurally fails when specified conditions occur, the fuse element, link or assembly 130 becomes incapable of conducting current and an open circuit between the fuse terminals 126 and 128 results. The line side circuitry connected to the terminal stud 118 is consequently electrically isolated from the load side circuitry connected to the stud 116. Potential damage to load side circuitry from excess currents in the line side circuitry is therefore reliably avoided.
As shown in the embodiment of
The presence of a bus bar on one side of the assembly 100 (sometimes referred to as the bus side), but not on the other side of the assembly 100 (sometimes referred to as the non-bus side) can present certain problems in fuse holders of this kind. Specifically, the thickness T (
One potential solution to such concerns is to develop somewhat customized and specifically designed modular fuse holders for use with or without bus bars. For example, fuse holders designed specifically for use with bus bars may include modified insulative bodies so that the bus bar sits lower on the bus side. Incidentally, if such a specialized fuse holder designed for use with a bus bar is (intentionally or unintentionally) used without the bus bar, similar issues to those described above will result because the fuse will again sit at an undesirable angle to the terminal studs. In such a case, instead of the fuse terminal on the bus bar side sitting higher than the opposite fuse terminal as discussed above, the fuse terminal on the bus bar side would sit lower than the fuse terminal on the non-bus bar side.
Specifically designed fuse holders for use with and without bus bars tends to increase production costs of providing the fuse holders, as well as presents a possibility of human error when selecting or installing them. Proper inventories of modular fuse holders and bus bars must be inventoried and distinguished by manufacturers, distributors, and installers. If a fuse holder of one type (e.g., one designed for use with a bus bar) is ordered, supplied or installed by mistake and actually used without a bus bar, it can be difficult to detect and somewhat costly to correct after the fact, especially if such mistakes are repeated throughout one or more electrical systems. Installation of the fuse holders can become more costly and time consuming if the proper fuse holders and bus bars are not present when needed in the field.
The difficulties noted above are overcome with the fuse holder assembly 100, as will now be explained in relation to the sectional view of
As
The openings 132, 134 (
The anchor portion 156 (
The planes of the bus bar receiving surfaces 162 and the fuse terminal receiving surfaces 158 are spaced apart in a direction parallel to the axes 150 of the studs 116, 118 by an amount approximately equal to the thickness T (
The openings 120 (
As shown in the exemplary embodiment of
It is contemplated that the flared anchor portion 156 as shown and described, while believed to be beneficial for the reasons stated, may be entirely omitted in another embodiment if desired. In one such embodiment the bus bar receiving portion 154 may be further extended and attached to the insulative body 102, or as another example the anchor portion may be present but have a constant diameter (possibly even a reduced diameter) relative to the bus bar receiving portion 154 in each stud while still attaching to the insulative body 102.
In an exemplary but non-limiting embodiment, the holes 120 in the bus bar holes may be about 8 mm in diameter, while the openings 132, 134 (
Further, and also advantageously, because the openings 120 in the bus bar are equally sized, the bus bar 104 is substantially universal and the input stud 122 may be received in any of the openings 120 of the bus bar. That is, the input terminal stud 122 may be used with the bus bar in multiple positions in the larger block when coupled to other modular fuse holders as described, while the bus bar receiving portions 152 in the terminal studs 116, 118 substantially fill the other openings 120 in the bus bar 104. Specifically, the input terminal can be positioned in an end position as shown in
It should now be evident that the three modular fuse holders including the terminal studs 116 and 120 and the body including the input stud 122 renders it possible to arrange them in many different combinations, at least four of which include the input stud 122 being located in a different location on the block. As more fuse holders are included, the benefits of having multiple combinations and options for positioning the input stud are perhaps even more pronounced. It is also contemplated that other types of modules may further be provided and combined with modular fuse holders as described to provide even more options.
The benefits and advantages of the invention are now believed to amply demonstrated in connection with the exemplary embodiments described above. It is contemplated, however, that further variations are possible, and the basic concepts and methodology disclosed could be expanded to other types of bodies 102, bus bars 104 and fuses 106. For example, other shapes and configurations of housings may be utilized with other shapes and configurations of bus bars within the scope and spirit of the invention. As another example, the bus bar openings 120 need not be round, and other shapes and geometries may be utilized with complementary shapes and profiles in the bus bar receiving portions 154 of the studs 116, 118 within the scope and spirit of the invention. Those in the art would no doubt envision still other modifications and variations achieving substantially similar structure, functionality and/or resultant benefits in a substantially similar manner.
An embodiment of a modular fuse holder assembly has been disclosed including at least one insulative body, and first and second studs projecting from the body in a spaced apart and generally parallel relationship to one another. Each of the first and second studs includes a threaded terminal portion having a first outer diameter, and a bus bar receiving portion having a second outer diameter larger than the first diameter. The bus bar receiving portion defines a generally planar fuse terminal receiving surface proximate one end of the terminal portion.
Optionally, each of the fuse terminals may further include an anchor portion attached to the insulative body, and the anchor portion has a third outer diameter larger than the second outer diameter. The anchor portion may define a generally planar bus bar receiving surface spaced from and generally parallel to the fuse terminal receiving surface. A bus bar may also be provided, with the bus bar having a thickness, and the bus bar receiving surface and the fuse terminal receiving surface being spaced by an amount substantially equal to the thickness of the bus bar. The third outer diameter may not be constant along an axis of the anchor portion. The fuse terminal receiving surfaces of the first and second terminal studs are generally coplanar to one another.
Also optionally, the at least one insulative body may further be configured to receive a fuse between the first and second stud terminals. The fuse may include a nonconductive housing and first and second conductive terminal elements extending from the nonconductive housing. Each of the first and second conductive terminal elements may include an aperture having an outer diameter substantially equal to the first outer diameter, and the aperture in the first and second conductive element may be fitted over the respective first and second terminal stud with the terminal elements being seated upon the fuse terminal receiving surface when the fuse is installed. The first and second conductive terminals elements may each be generally planar, and may even be generally coplanar in an exemplary embodiment.
As still another option, a bus bar may be provided having a plurality of spaced apart holes extending therethrough, and each of the holes may be substantially equally sized and having an outer diameter substantially equal to the second outer diameter. The bus bar has a thickness, and the bus bar receiving portion in each of the first and second studs may extend for an axial distance approximately equal to the thickness. The bus bar may be a generally planar element. Another insulative body having a power input stud attached thereto may also be provided and ganged with the at least one insulative body, with the power input stud having an outer diameter approximately equal to the second diameter.
Optionally, the at least one insulative body may include a plurality of insulative bodies ganged together. Each of the plurality of insulative bodies may include first and second terminal studs, and the first terminal studs in each respective one of the plurality of bodies may be received in one of the holes in the bus bar. The insulative body having the power input stud may be ganged with the plurality of insulative bodies in any position relative to the plurality of insulative bodies wherein the power input terminal is receivable in one of the spaced apart holes in the bus bar. The second terminal stud in each respective one of the plurality of bodies may not be associated with a bus bar.
Another embodiment of modular fuse holder assembly has also been disclosed including a plurality of insulative bodies configured to be ganged to one another in a side-by-side arrangement to form a fuse block. One of the insulative bodies includes a power input stud attached thereto and the other of the insulative bodies each having a pair of terminal studs attached thereto. The power input terminal in the one insulative body has a first outer diameter and each of the pair of terminal studs in the other of the insulative bodies have threaded portions with a second outer diameter smaller than the first outer diameter. Each of the pair of terminal studs in the other of the insulative bodies further includes a bus bar receiving portion having an outer diameter approximately equal to the first outer diameter of the power input stud. The bus bar receiving portions each define a fuse terminal receiving surface spaced from the respective insulative bodies, whereby a fuse may be connected between each pair of terminal studs in the other of the insulative bodies with opposed terminal elements of the fuse maintained in contact with the fuse terminal receiving surface in spaced relation to the other of the insulative bodies.
Optionally, the fuse holder assembly may further include a bus bar having a plurality of spaced apart holes. The spaced apart holes may have an outer diameter approximately equal to the first diameter of the power input stud, and the power input stud may be received in one of the spaced apart holes and one of each of the pairs of the threaded stud terminal may be received in the other of the spaced apart holes. The bus bar may have a thickness, and the bus bar receiving portions of the terminal studs may extend for an axial distance in the terminal studs that is approximately equal to the thickness. The bus bar may be substantially planar.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.