Patent Description:
Fuses are current-sensitive devices designed to be the intentional weak link in an electrical circuit. Fuses come in a variety of form factors, including bolt-down fuses. Bolt-down fuses feature a fuse body with two terminals extending therefrom, where one or more of the terminals is bolted down to a surface, such as a busbar or printed circuit board (PCB).

Some fuses are contained in a fuse holder, which is a generally airtight housing for the fuse. The fuse holder may have busbars or PCBs therein, with cables extending from the fuse to the circuit(s) to be protected. More extensive fuse holders may include low-voltage power distribution modules and high-voltage power distribution units, which house relays in addition to fuses.

The housing of the fuse holder may be a clam-shell type, with a cover portion already connected to the housing, or the fuse holder may have a separate cover, due to the fact that the fuse holder needs to be accessed when changing the fuse. Occasionally, the fuse holder will also house one or more spare fuses. The typical arrangement is to have the spare fuses bolted down to the housing, which necessitates that the housing be sized to accommodate the particular fuse size. There is also the possibility that the bolts will get lost during the fuse change operation. The fuse housing may also have a plug-in arrangement for holding spare fuses, which does not successfully accommodate fuses of different sizes.

The document <CIT> discloses a fuse holder according to the preamble of claim <NUM>.

This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended as an aid in determining the scope of the claimed subject matter.

An exemplary embodiment of a fuse holder in accordance with the present disclosure may include a housing, a clip, and a cover. The housing is for a fuse, and the fuse is to be connected to and protecting a circuit. The clip includes a base, a pair of shafts, an overhead, and an underhang. The base is for seating a spare fuse. The pair of shafts are on and perpendicular to the base. The overhead is located on and supported by the pair of shafts. The underhang is beneath the overhang and deforms in response to the movement of the spare fuse along the base toward the shaft. The cover is placed over the housing to form an enclosed space around the fuse and the clip.

An exemplary embodiment of a clip in accordance with the present disclosure, not part of the invention, may include a shaft, an overhead, and an underhang. The shaft is located on and perpendicular to a base. The overhead is on and supported by the shaft and is triangular prism-shaped. The underhang is attached to the overhead. The underhang and the base secure a spare fuse.

A fuse holder for holding working fuses features a spare fuse holder inside the housing of the fuse holder. The spare fuse holder includes a clip that has an elastic underhang for exerting pressure on the fuse as it is slid into place in the clip. The clip also has a base with some angled surfaces, two shafts orthogonal to the base for providing structural support, and, between the shafts, a fuse release for enabling ease of removal of the spare fuse. The spare fuse holder is suitable for bolt-down fuses with various current ratings. Unlike the bolt-down type, the spare fuse holder does not use bolts for holding the spare fuse. Unlike the plug-in type, the spare fuse holder successfully holds fuses of different fuse body sizes, terminal sizes, and current ratings.

For the sake of convenience and clarity, terms such as "top", "bottom", "upper", "lower", "vertical", "horizontal", "lateral", "transverse", "radial", "inner", "outer", "left", and "right" may be used herein to describe the relative placement and orientation of the features and components, each with respect to the geometry and orientation of other features and components appearing in the perspective, exploded perspective, and cross-sectional views provided herein. Said terminology is not intended to be limiting and includes the words specifically mentioned, derivatives therein, and words of similar import.

<FIG> is a representative drawing of a fuse holder <NUM> (perspective view) for holding fuses and spare fuses, according to exemplary embodiments. The fuse holder <NUM> includes a housing <NUM> to hold two fuses 102a and 102b (collectively, "fuses <NUM>"). In exemplary embodiments, the fuses <NUM> are bolt-down fuses. The fuse holder <NUM> also features a busbar <NUM> which is distributed in several locations in the fuse holder <NUM>. The fuses <NUM> are each connected at one end to the busbar <NUM>. Bolts 106a-c (collectively, "bolts <NUM>") enable connections to be made between the fuse holder <NUM> and one or more cables or other busbars (not shown). Clamps 112a-d (collectively, "clamps <NUM>") enable a cover to be attached to the housing <NUM>, thus ensuring that there is a somewhat air-tight seal for the contents inside the fuse holder <NUM>. Mounting brackets 114a-b (collectively, "mounting brackets <NUM>") include apertures for bolting the fuse holder <NUM> to a surface, although the mounting brackets may be attached to the surface in another way, as this is a non-limiting example.

In exemplary embodiments, the fuse holder <NUM> features a spare fuse holder <NUM>, shown in the dashed circle. As will be shown, the spare fuse holder <NUM> overcomes the deficiencies of the prior art by accommodating fuses of different sizes. In exemplary embodiments, the spare fuse holder <NUM> holds bolt-down fuses, although the design is not limited in this respect. As will be shown, the spare fuse holder <NUM> is flexible enough to accommodate a variety of different fuse types and shapes.

<FIG> are representative drawings of fuse holders and bolt-down fuses, according to the prior art. <FIG> is a perspective view of a first fuse holder 200A, <FIG> is an overhead view of a second fuse holder 200B, and <FIG> are perspective views of bolt-down fuses 20a-c (collectively, "spare fuse holders <NUM>" and "bolt-down fuses <NUM>"). For simplicity, the fuse holders <NUM> do not include the fuses, busbars, bolts, and clamps that characterize typical fuse holders, as these drawings are intended to show and describe the spare fuse holder portion of these devices.

A fuse 202a is disposed in the fuse holder 200A (<FIG>), fuses 202b and 202c are disposed in the fuse holder 200B (<FIG>), and fuses 202d (<FIG>), 202e (<FIG>), and 202f (<FIG>) are shown (collectively, "fuses <NUM>"). Each fuse <NUM> includes a fuse body and two terminals, with fuse 202a having terminal 210a, fuse body 212a and terminal 210b (<FIG>), fuse 202b having terminal 210c, fuse body 212b, and terminal 210d, fuse 202c having terminal 210e, fuse body 212c, and terminal 210f (<FIG>), fuse 202d having terminal <NUM>, fuse body 212d, and terminal <NUM> (<FIG>), fuse 202e having terminal 210i, fuse body 212e, and terminal 210j (<FIG>), and fuse 202f having terminal <NUM>, fuse body 212f, and terminal <NUM> (<FIG>) (collectively, "terminals <NUM>" and "fuse bodies <NUM>").

The fuse holder 200A features a housing 208a with a location for placing the spare fuse 202a. The fuse holder <NUM> holds the spare fuse 202a using bolts 204a and 204b (collectively, "bolts <NUM>"). The fuse holder 200A is thus a "screwing design" of fuse holder since the bolts <NUM> are screwed into the housing 208a to secure the spare fuse 202a. With such a design, the housing 208a would be assembled with the specific dimensions of the fuse 202a in mind. Further, to access the fuse 202a (to replace a blow fuse), a screwdriver would be needed to remove the bolts <NUM> and there is some risk that the bolts would be lost during this process. Further, having the bolts will result in additional assembly time including the process of securing the spare fuse.

The fuse holder 200B features a housing 208b with a fuse receptacle <NUM> suitable for holding the two fuses 202b and 202c. The fuse holder 200B is thus a "plug-in design" of fuse holder, since the fuses 202b and 202c are simply plugged into the fuse receptacle <NUM> (no bolts are needed). The fuse receptacle <NUM> includes four terminal holders 216a-d (collectively, "terminal receptacles <NUM>"), one for each terminal <NUM> of the two fuses. The terminal holders <NUM> are designed to clamp the terminals <NUM> so that the fuses <NUM> stay in place in the fuse receptacle <NUM>.

The fuse 202b is larger than the fuse 202c and, due to a difference in current rating between the two fuses, the terminals 210c and 210d are longer and thicker than the terminals 210e and 210f. Although able to hold both fuses 202b and 202c, the terminals holders <NUM> of the fuse receptacle <NUM> are all the same size. Thus, the fuse receptacle is sized for the larger fuse 202b and the terminal holder 216a successfully clamps the terminal 210c of the fuse 202b while the terminal holder 216c successfully clamps the terminal 210d of the fuse 202b. The same is not true for the fuse 202c, as the terminals 210e and 210f may not be fully clamped by respective terminal holders 216b and 216d of the fuse receptacle <NUM>. The smaller fuse 202c may fall out of the fuse receptacle <NUM>, such as when a cover (not shown) is removed from the housing 208b of the fuse holder 200B, which is not a desired outcome.

The fuse receptacle <NUM> of the fuse holder 200B could be designed differently. That is, the terminal holders 216b and 216d could be made smaller, for fuses of lower current rating. This, however, limits the fuses that can be accepted by the fuse receptacle <NUM>, which is also not a desired outcome.

The three bolt-down fuses 202d, 202e, and 202f of <FIG> may be suitable for either the screwing design fuse holder 200A or the plug-in design fuse holder 200B. Although similar in shape, there are some differences between the bolt-down fuses 202d, 202e, and 202f. For example, the terminals 210i and 210j (of bolt-down fuse 202e) and the terminals <NUM> and <NUM> (of bolt-down fuse 202f) each have apertures, with terminal 210i having aperture 214b, terminal 210j having aperture 214c, terminal <NUM> having aperture 214d, and terminal <NUM> having aperture 214e. In contrast, for the bolt-down fuse 202d, terminal <NUM> has an aperture 214a (collectively, "apertures <NUM>"), but terminal <NUM> has no aperture. Thus, the bolt-down fuse 202d would not be suitable for the fuse holder 200A, as the spare fuse is affixed to the housing 208a using two bolts <NUM>. Further, the bolt-down fuses 202d, 202e, and 202f are different sizes and have different current ratings. Thus, the bolt-down fuses 202d-f may not be suitable for the fuse holder 200B.

<FIG> are representative drawings of the fuse holder <NUM> of <FIG>, according to exemplary embodiments. <FIG> is a perspective view and <FIG> is a close-up cross-sectional perspective view of the fuse holder <NUM>. The fuse holder <NUM> is an improvement over the prior art fuse holders <NUM> in several respects. The fuse holder <NUM> features a special clip design to hold spare fuses. Compared with the legacy bolt-down and plug-in fuse holders, the fuse holder <NUM> is more versatile, as the special clip design can support a variety of types of bolt-down fuses. In exemplary embodiments, the fuse holder <NUM> can support bolt-down fuses having different sizes and current ratings, as well as supporting bolt-down fuses having single-aperture terminals such as the bolt-down fuse 202d (<FIG>). Further, in some embodiments, the fuse holder <NUM> can support fuses other than bolt-down fuses.

The spare fuse holder <NUM> introduced in <FIG> is shown in <FIG>. The fuse <NUM> which is not a replacement fuse, but is a fuse being used to protect a circuit connected to the fuse holder <NUM>, is also shown in <FIG>. The position of the spare fuse holder <NUM> may differ from what is shown in <FIG>, <FIG>, in a non-limiting embodiment. A cover <NUM> is placed over the housing <NUM> to form an enclosed spaced which encapsulates both the fuse <NUM> and the spare fuse holder <NUM>. In exemplary embodiments, the housing <NUM> and cover <NUM> are plastic.

In some embodiments, the fuse holder <NUM> includes a seal <NUM> which surrounds the perimeter of a top portion of the housing <NUM>. Alternatively, the seal <NUM> may surround the perimeter of a top portion of the cover <NUM>. In exemplary embodiments, the seal <NUM> is elastomeric and provides an airtight enclosed space for the fuse <NUM> and the spare fuse holder <NUM>.

The spare fuse holder <NUM> includes a clip <NUM> and a fuse <NUM>. The fuse <NUM> is shown as a rectangular cube to represent a generalized shape of the body of a fuse, such as one of the fuse bodies <NUM> shown in <FIG>. In exemplary embodiments, the clip <NUM> is capable of holding any thickness of fuses tightly. The fuses are easy to load and unload and are particularly more convenient than the bolt-down spare fuse holders. In exemplary embodiments, the spare fuse holder <NUM> is capable of holding a fuse having a fuse body of up to <NUM> with stability. Further, the design of the spare fuse holder <NUM> can be scaled for larger fuses, including high-voltage fuses, in some embodiments.

<FIG> are representative drawings of the spare fuse holder <NUM> that is part of the fuse holder <NUM> of <FIG>, according to exemplary embodiments. <FIG> is a side cross-sectional view of the spare fuse holder <NUM> before the fuse is installed (clip is in a resting state), <FIG> is a side view of the spare fuse holder after the fuse is installed (clip is in holding state), <FIG> is a perspective view of the spare fuse holder with the fuse installed, <FIG> is a perspective view of the clip without the fuse, <FIG> is a cross-sectional perspective view of the clip, and <FIG> is a side view of the spare fuse holder with the fuse installed (clip is in holding state). Once a cover is placed over the housing which holds the clip <NUM> and spare fuse <NUM>, an enclosed spaced is formed which encapsulates both the fuse <NUM> and the clip.

In exemplary embodiments, the clip <NUM> features a base <NUM>, a pair of shafts 406a-b (collectively, "shafts <NUM>"), and an overhead <NUM>, with both shafts being visible in <FIG>. The base <NUM> is for seating the spare fuse <NUM> and the shafts are orthogonal (perpendicular) to the base and support the overhead. The overhead <NUM> has three sides <NUM>, <NUM>, and <NUM> which form a triangular prism. From the side, such as in the views of <FIG>and <FIG>the overhead <NUM> resembles a right triangle, with a first side <NUM> (bottom, horizontal side) being an extension of the shaft <NUM>, a second side <NUM> (vertical side) being perpendicular to the first side, and the third side <NUM> (right-angled side) being angled. In a non-limiting embodiment, the third side <NUM> is at a <NUM>° angle relative to the first side <NUM> and the second side <NUM>. The overhead <NUM> further has an opening <NUM> that cuts away the central part of the first side <NUM> and the third side <NUM>, exposing an inner portion of the second side <NUM>. Thus, instead of being a solid triangular prism-shaped structure, the overhead <NUM> is a hollowed out triangular prism.

An underhang <NUM> is disposed beneath and attached to the overhead <NUM>. As shown particularly in the cross-sectional view of <FIG>, the underhang <NUM> extends downward from the side <NUM> of the overhead <NUM>, and is curved so that, except for the end connection to the overhead, is substantially parallel to the side <NUM> in its resting state. In exemplary embodiments, the underhang <NUM> is an elastomeric material having the ability to deform its shape in reaction to pressure, e.g., the pressure coming from the top of the spare fuse <NUM>, which causes the underhang <NUM> to compress toward the overhang <NUM>, e.g., in an upward direction. In other embodiments, both the underhang <NUM> and the overhead <NUM> are elastomeric.

Beneath the third side <NUM> of the overhang <NUM> and disposed between the shafts <NUM> is a fuse release <NUM>. The fuse release <NUM> is most visible in <FIG>, as only the shaft 406b is visible. The fuse release <NUM> extends downward from the side <NUM> of the overhead <NUM>. In a non-limiting embodiment, the fuse release <NUM> has an angular side that juts out from the back of the clip <NUM>, making it easy to push the fuse release, and a second curved side opposite the angular side that pushes against the fuse body <NUM> when the fuse release <NUM> is pushed (depressed) toward the region in between the two shafts <NUM>. In exemplary embodiments, the fuse release <NUM>, with contact, pushes the spare fuse <NUM> away from the pair of shafts <NUM>, causing the spare fuse to be released from the clip <NUM>. In exemplary embodiments, the fuse release <NUM> is an elastomeric material having the ability to deform its shape in reaction to pressure. By being pressed, the fuse release <NUM> moves toward the installed spare fuse <NUM>, which causes the spare fuse <NUM> to move out from under the clip <NUM>.

In exemplary embodiments, the base <NUM> consists of three surfaces, a surface 420a, a surface 420b, and a surface 420c (collectively, "surfaces <NUM>"). Although substantially planar to one another, the surfaces 420a and 420b are angled slightly, to facilitate leading the spare fuse <NUM> to the clip <NUM>. Extending across the surfaces, <NUM> are two tracks 408a and 408b (collectively, "tracks <NUM>"). The tracks <NUM> are rectangular cutouts which are perpendicular to the surfaces <NUM>, are disposed adjacent two opposing sides ends of the base <NUM>, and have a depth that is slightly less than the height, h, of the base <NUM>. Each track <NUM> has a fuse clip, with track 408a having fuse clip 418a and track 408b having fuse clip 418b (collectively, "fuse clips <NUM>"). The fuse clips <NUM> are close to the side of the tracks <NUM> that are adjacent the shafts <NUM>. The fuse clips <NUM> have an angled tip portion <NUM> (<FIG>) that, when pressed, will cause each fuse clip to move into the cavity (channel) of its respective track <NUM>. In the illustrated embodiments, the movement of each fuse clip <NUM> would be downward into the respective tracks <NUM>. A close-up view of the angled tip portion <NUM> is shown in <FIG>, below. In exemplary embodiments, the depths of the tracks <NUM> are slightly greater than a height, h<NUM>, of the angled tip portion <NUM> of the fuse clips <NUM> (see <FIG>). Like the underhang <NUM> and the fuse release <NUM>, the fuse clips <NUM> are elastomeric, in exemplary embodiments.

In exemplary embodiments, the base <NUM>, the shaft <NUM>, the overhead <NUM>, the underhang <NUM>, the fuse release <NUM>, and the fuse clips <NUM> are made of a thermoplastic material using injection molding operations. In some embodiments, the overhead <NUM>, underhang <NUM>, the fuse release <NUM>, and the fuse clips <NUM> are impregnated with an elastomeric material, thus allowing the clip <NUM> to be both flexible in the impregnated regions and rigid in the other, non-impregnated regions. In this way, the base <NUM>, shafts <NUM>, and overhead <NUM> are a support structure for the spare fuse <NUM>.

In exemplary embodiments, the spare fuse <NUM> is a bolt-down fuse, which has a fuse body <NUM> and terminals 410a-b (collectively, "terminals <NUM>"), with the fuse body having three portions 424a-c (collectively, "portions <NUM>"). In exemplary embodiments, the track 408a is a distance, d, from the track 408b, where the distance, d, is larger than the width, w, of portions 424a and 424c of the fuse body <NUM>, as the width of portion 424a is substantially similar to the width of portion 424c (see <FIG>). The portion 424b is wider than the portions 414a and 424c (see <FIG>), such that, when the spare fuse <NUM> is moved into the clip <NUM>, the portion 424b slides over the tracks <NUM> but the portions 424a and 424c do not slide over the tracks. In exemplary embodiments, as the spare fuse <NUM> is slid across the base <NUM>, the portion 424b pushes against the angled tip portion <NUM> of respective fuse clips <NUM>, causing the fuse clips to move downward into respective tracks <NUM>. Being narrower in width than the portion 424b, the portion 424a does not contact the fuse clips <NUM>. Then, when the portion 424b slides across the tracks <NUM>, the portion 424b does contact the fuse clips <NUM> and pushes them down into the tracks <NUM>. Finally, when the spare fuse <NUM> is flush against the shafts <NUM> of the clip <NUM>, the portion 424b of the fuse body <NUM> moves past the fuse clips <NUM> and the fuse clips move again upward from the tracks <NUM>. In exemplary embodiments, by moving back upward to their original positions, the angled tip portion <NUM> of the fuse clips <NUM> act as a stop to the spare fuse <NUM>.

Where the spare fuse is shaped differently than the standard bolt-down fuse, with the three portions described above, the fuse clips <NUM> may remain in the down position within the tracks <NUM>, in some embodiments. Because the underhang <NUM> is exerting downward pressure thereon, the spare fuse will nevertheless remain in place within the clip <NUM>. The length of the fuse clips <NUM> or the size and shape of the angled tip portion <NUM> may be adjusted to support a spare fuse having a different fuse body than the fuse body <NUM> of the spare fuse <NUM>.

<FIG> are representative drawings of the spare fuse holder <NUM> of the fuse holder <NUM> of <FIG>, according to exemplary embodiments. <FIG> are side views of the spare fuse holder <NUM>, with <FIG> showing a first fuse insertion point (clip is in resting state), <FIG> showing a second fuse insertion point (clip is in activated state), and <FIG> showing a third fuse insertion point (clip is in holding state), and <FIG> is a detailed perspective view of the fuse clip position at the third fuse insertion point. In <FIG>, the overhead <NUM> and underhang <NUM> include cross-hatching to indicate a flexion or pressure-based deformation due to the sliding of the spare fuse <NUM> toward the shaft <NUM> of the clip <NUM>. The clip <NUM> is in a resting state when the underhang has not been deformed; the clip is in an activated state when the underhang is deformed and the fuse clips have been pushed into the respective tracks <NUM>; and the clip is in a holding state when the underhang is deformed and the fuse clips are no longer pushed into the respective tracks but have returned to an original position.

In <FIG>, the spare fuse <NUM> is adjacent, but not yet under the overhead <NUM> and underhang <NUM> of the clip <NUM>. Thus, there is no cross-hatching of the overhead <NUM> and underhang <NUM>, as these elements of the clip <NUM> are undisturbed. The portion 424a does not touch the angled tip portions <NUM> of the fuse clips <NUM>, so the fuse clips remain undisturbed as well. Nevertheless, the slanted surfaces 420a and 420b of the base <NUM> are slightly angled, allowing the spare fuse <NUM> to readily move toward the shafts <NUM> of the clip <NUM>.

In <FIG>, the spare fuse <NUM> is moved toward the shaft <NUM> of the clip <NUM>, and the underhang <NUM> deforms upward, as the spare fuse is compressing the underhang <NUM> toward the overhead <NUM>. At this stage, the portion 424a of the fuse body <NUM> is fully under the underhang <NUM> and the portion 424b is partially under the underhang. Further, the portion 424b is pushing against the angled tip portion <NUM> of the fuse clips <NUM>, causing the fuse clips to move downward into their respective tracks <NUM>. Both the underhang <NUM> and the overhead <NUM> are cross-hatched, indicating some flexion in response to the movement of the spare fuse <NUM> along the base <NUM> toward the shaft <NUM>. Although the overhead <NUM> flexes a little, the shaft <NUM> of the clip <NUM> remains rigid, in some embodiments.

In <FIG>, the spare fuse <NUM> is fully engaged with the clip <NUM>, with portion 424a being flush against the shafts <NUM>. Once the portion 424b moves past the angled tip portion <NUM> of the fuse clips <NUM>, the fuse clips move from a downward position inside the tracks <NUM> back to the original position. The backside of the angled tip portion <NUM> is flush against the portion 424b of the fuse body <NUM>.

Claim 1:
A fuse holder (<NUM>) comprising:
a housing (<NUM>) for a fuse (<NUM>), the fuse to be connected to and protecting a circuit;
a clip (<NUM>) comprising:
a base (<NUM>) to seat a spare fuse (<NUM>);
a pair of shafts (<NUM> a-b) disposed upon and orthogonal to the base;
characterised by
an overhead (<NUM>) disposed upon and supported by the pair of shafts; and
an underhang (<NUM>) disposed beneath the overhead, the underhang to deform in response to a movement of the spare fuse along the base toward the pair of shafts; and a cover (<NUM>) placed over the housing to form an enclosed space around the fuse and the clip.