One-Piece Female Blade Fuse With Housing

The present invention relates generally to electrical fuses. More particularly, this invention relates to female electrical fuses which are designed for connection into a fuse block having male terminal connections.

Automobile and other female fuse assemblies commonly comprise a two-piece assembly heretofore having a box-like housing and an all metal one-piece female fuse secured therein. The female fuse has a pair of spaced apart female terminals which are accessible from one end of the housing where male terminal openings are placed in the housing to correspond to male blade-type terminals. The male blade-type terminals or conductors recently, typically extend from a mounting panel or male fuse block, as there has been a shift in the automotive industry toward the use of male terminal blocks. The female terminals are commonly closely encompassed by the housing walls. The female fuse also includes a fuse link extended, usually unsupported, between the female terminals. The connection or transition between the female terminals and the fuse link begins at the center of one female terminal and extends linearly, from a side view, to the other female terminal. At the top of the fuse link, the width of the fuse link, from a top view, is narrowed to create a fuse blowing portion.

Some female fuses use an additional component with the fuse link, such as a ceramic member, for heat conduction purposes to achieve a desired fuse characteristic. The fuse link and additional component are commonly spaced close to the housing side walls for a reduced volume of used material. The above identified two-piece female fuse assembly, with a one piece fuse, is generally disclosed in U.S. Pat. Nos. 4,570,147 , (Ebi), 4,751,490 (Hatagishi), 4,869,972 (Hatagishi), and 4,871,990 (Ikeda et al.). However, there are numerous disadvantages with these and other fuses of this type based on the heretofore mentioned female fuse configurations.

Specifically, when the width of the fuse link is narrowed by cutting into the fuse link, it is very difficult to achieve a width which is consistent across the full length of the fuse blowing portion. The consistency of this width is significant because the width of the fuse blowing portion can be used to control the time delay of the fuse. In addition, the use of a linear fuse link, which starts at the center of the female terminals, limits the length of the fuse link. When linear bends are added to increase the length of the fuse link, a substantial amount of surface area is discarded during manufacture, as disclosed in Ebi listed above. The length of the fuse link is significant, as the length can be used to control the resistance and ,thus, the current rating of the fuse. However, the configuration in Ebi wastes a significant amount of metal during manufacture in order to increase the fuse link length. Furthermore, the use of an additional component with the fuse link, such as a ceramic member, for heat conduction purposes, increases the cost of the materials, and increases the amount of steps of the female fuse assembly.

The present invention is provided to solve these and other problems.

The present invention is a female fuse assembly. The fuse assembly, among other things, allows for a longer effective length of the fuse link and allows for a uniform reduction in the thickness of the fuse link, for controlling the resistance and time delay of the fuse while at the same time avoiding the above and others problems of previous one-piece female fuses. Generally the female fuse assembly will interrupt a current flowing through a circuit upon certain high current conditions. The circuit will include male terminals that have opposed contact surfaces which connect to female fuse assembly to conduct current through the circuit.

The female fuse assembly includes a female fuse and a housing. The female fuse includes a first and a second female terminal portion each having a face portion which includes a first end, a second end, a first side, and a second side, includes a first clamping arm and a second clamping arm. The female fuse also includes a first bracing arm and a second bracing arm connected to the respective first and second ends of the face portion of first and second female terminal portions. The female fuse further includes a fuse link having a first terminal extension and a second terminal extension connected to the respective first and second female terminal portions. The fuse link has a skived region connected between the first and second terminal extensions at a first transition point and a second transition point, respectively, for controlling the resistance between the first and second female terminal portions. The fuse link further includes a fuse-blowing portion and requires no additional structure for heat insulating the female fuse.

The fuse link further includes a first terminal bend and a second terminal bend. The first terminal bend is positioned substantially toward the second end of the face portion of the first female terminal portion, or vice versa. The second terminal bend is positioned substantially toward the first end of the face portion of the second female terminal portion, or vice versa. This positioning allows for increased length of the fuse link.

The connection between the first female terminal portion and the first terminal extension of the fuse link is positioned substantially toward one end of the face portion of the first female terminal portion. Similarly, the connection between the second female terminal portion and the second terminal extension of the fuse link is positioned substantially toward one end, but not limited to the other end, of the face portion of the second female terminal portion. The present invention can be configured in both a back-to-back or face-to-face arrangement while, at the same time, capturing the features and advantages set forth herein.

Other features and advantages of the invention will be apparent from the following specification taken in conjunction with the following drawing.

FIG. 1 is a front view of one embodiment of the female fuse assembly of the present invention.

FIG. 2 is a bottom view of the embodiment from FIG. 1 of the present invention.

FIG. 3 is a left-side view of the embodiment from FIG. 1 of the present invention.

FIG. 4 is top view of the embodiment from FIG. 1 of the present invention.

FIG. 5 is an exploded perspective view of the embodiment of FIG. 1 of the present invention.

FIG. 6 is a top view of the female fuse embodiment of FIG. 1 of the present invention, in a preformed sheet configuration.

FIG. 7 is a front view of the preformed sheet configuration of the female fuse embodiment from FIG. 6 of the present invention.

FIG. 8 is a front view of the female fuse from the female fuse assembly of FIG. 1 of the present invention.

FIG. 9 is a left-side view of the female fuse from FIG. 8 of the present invention.

FIG. 10 is top view of the female fuse from FIG. 8 of the present invention.

FIG. 11 is a top view of a separate female fuse embodiment of the present invention, in a preformed sheet configuration, similar to FIG. 6.

FIG. 12 is a front view of the preformed sheet configuration of the female fuse embodiment from FIG. 11 of the present invention.

While this invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail, a preferred embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspects of the invention to the embodiment illustrated.

FIGS. 1 through 5 show a female fuse assembly for interrupting current flowing through a circuit upon certain high current or over current conditions. Numerous occurrences can cause these types of conditions, as is well known in the art. The female fuse assembly is typically placed within a circuit to perform these functions. Specifically, the circuit includes male terminals (not shown) which typically are a part of a male terminal block or fuse block (not shown) for inserting the female fuse assembly onto the male terminal block. Each male terminal has opposed contact surfaces for conductively connecting the female fuse assembly to the rest of the circuit, as will be further described below.

The female fuse assembly of FIGS. 1 through 5 generally includes a fuse housing 2 and a female fuse 4. The female fuse 4, more clearly shown in FIGS. 6 through 10, is made from one continuous sheet of metal, preferably a copper alloy, and several manufacturing steps cuts out and otherwise forms the metal sheet into the embodiment in FIGS. 1 through 5 as will be described further below. The female fuse 4 includes a first female terminal portion 6 and a second female terminal portion 8. The first female terminal portion 6 includes a first face portion 10 and the second female terminal portion 8 includes a second face portion 12. The first and second face portions each include a first end 14, 16, a second end 18, 20, a first side 22, 24, and a second side 26, 28, respectively.

The first side 22 of the first face portion 10 of the first female terminal portion 6 includes a first raised portion 30. The first raised portion 30 is formed by pressing out a rectangular shape into the second side 26 of the first face portion 10. Likewise, the first side 24 of the second face portion 12 of the second female terminal portion 8 includes a second raised portion 32. The second raised portion 32 is again formed by pressing out a rectangular shape into the second side 28 of the second face portion 12. The first and second raised portions 30, 32 are provided on the first and second face portions 10, 12, respectively, for creating a secure engagement with the male terminals. The raised portions are also provided for creating a large surface area of contact between the face portions 10, 12 and the male terminals, to reduce resistance between the female terminal portions 6, 8 and the male terminals.

The female fuse 4 further includes a first clamping arm 34 connected to the first end 14 of the first face portion 10, a first clamping arm 36 connected to the first end 16 of the second face portion 12, a second clamping arm 38 connected to the second end 18 of the first face portion 10, and a second clamping arm 40 connected to second end 20 of the second face portion 12, of the respective first and second female terminal portions 6, 8. The first clamping arm 34 of the first female terminal portion 6 includes a first contact edge 42, and the first clamping arm 36 of the second female terminal portion 8 includes a first contact edge 44. Likewise, the second clamping arm 38 of the first female terminal portion 6 includes a second contact edge 46, and the second clamping arm 40 of the second female terminal portion 8 includes a second contact edge 48. Each of these contact edges 42, 44, 46, 48 generally face and extend toward the respective first side 22, 24 each of the respective first and second female terminal portions 6, 8, after the female fuse 4 is formed during manufacture. These contact edges 42, 44, 46, 48 are provided to engage the male terminals when the male terminals are inserted into the female terminal portions 6, 8. When the male terminals are inserted, the contact edges 42, 44, 46, 48 press against one side of the male terminals, and force the male terminals into effective contact with the respective first and second raised portions 30, 32.

To achieve an effective contact between the male terminals and the respective raised portions 30, 32, each clamping arm includes a semi-circular portion formed at a proper bend, and made of a sufficient resiliency. Specifically, the first clamping arm 34 of the first female terminal portion 6 includes a first resilient semi-circular portion 50, and the first clamping arm 36 of the second female terminal portion 8 includes a first resilient semi-circular portion 52. Likewise, the second clamping arm 38 of the first female terminal portion 6 includes a second resilient semi-circular portion 54, and the second clamping arm 40 of the second female terminal portion 8 includes a second resilient semi-circular portion 56. FIGS. 6, 7, 11, and 12 do not show these semi-circular portions 50, 52, 54, 56 as these portions are created by bending the respective clamping arms 34, 36, 38, 40 toward the first sides 22, 24 of the respective first and second faces 10, 12 of the first and second female terminal portions 6, 8.

The female fuse 4 further includes a first bracing arm 58 connected to the first end 14 of the first face portion 10 of first female terminal portion 6, and a first bracing arm 60 connected to the first end 16 of the second face portion 12 of second female terminal portion 8. Likewise, the female fuse 4 includes a second bracing arm 62 connected to the second end 18 of the first face portion 10 of first female terminal portion 6, and a second bracing arm 64 connected to the second end 20 of the second face portion 12 of second female terminal portion 8. The first bracing arm 58 of the first female terminal portion 6 includes a first bracing edge 66, and the first bracing arm 60 of the second female terminal portion 8 includes a first bracing edge 68. Likewise, the second bracing arm 62 of the first female terminal portion 6 includes a second bracing edge 70, and the second bracing arm 64 of the second female terminal portion 8 includes a second bracing edge 72. The first and second bracing arms, 58, 60, 62, 64 of the respective first and second female terminal portions 6, 8 are arranged substantially perpendicular to the respective first and second face portion 10, 12 of the first and second female terminal portions 6, 8. Thus, the first and second bracing edges 66, 68, 70, 72 extend away from, and perpendicular to, the respective first side 22, 24 of the first and second face portion 10, 12 of the respective first and second female terminal portions 6, 8. The bracing arms 58, 60, 62, 64 and bracing edges 66, 68, 70, 72 are provided for bracing and stabilizing the female fuse 4 within the housing 2, as will be described in greater detail below.

The female fuse 4 additionally includes a fuse link 80. The fuse link 80 includes a first terminal extension 82 and a second terminal extension 84. The first terminal extension 82 is connected to the first female terminal portion 6, and the second terminal extension 84 is connected to the second female terminal portion 8. The fuse link 80 further includes a skived region 86 connected between the first and second terminal extensions 82, 84 at a first transition point 88 and a second transition point 90. The skived region 86 is provided for controlling the resistance between the first and second female terminal portions, as the resistance will vary by changing the thickness of the fuse link 80. During manufacture, skiving takes place before the female fuse 4 is formed. Specifically, the thickness is reduced in a specified area along a full sheet of metal before the sheet of metal is cut or stamped into the female fuses. The reduction of thickness takes place through known reduction techniques, such that the reduced area, or skived regions has a substantially uniform thickness. Skiving creates a more uniform thickness, and thus, a more reliable opening time characteristic as well as other advantages, than does casting, stamping, coining, or other reduction technique.

The fuse link 80 also includes a fuse-blowing portion 92. The fuse-blowing portion 92 includes a ring 94 that has a first branch 96 and a second branch 98, which together form a plug hole 100. A plug (not shown) is placed within the plug hole 100. As described in U.S. Pat. No. 4,635,023 (Oh), entitled "Fuse Assembly Having a Non-Sagging Suspended Fuse Link," which is incorporated herein as a part of the present specification by reference, the fuse-blowing portion 92 of the fuse link 80 includes a hot spot portion or ring 94, and a fuse-blowing current-reducing material or plug (not shown) placed within the plug hole 100. The material used to reduce the opening current within the plug hole 100 is preferably tin, while the overall female fuse 4 is preferably a copper alloy. In addition, the fuse link 80 configuration alleviates the need for any heat conduction member, and requires no additional structure for heat insulating the fuse link 80 or the female fuse 4.

The formed fuse link 80 further includes a first terminal bend 102 and a second terminal bend 104. In one embodiment, the first terminal bend 102 is positioned substantially toward the first end 14 of the first face portion 10 of the first female terminal portion 6, and the second terminal bend 104 is positioned substantially toward the second end 20 of the second face portion 12 of the second female terminal portion 8. In another embodiment of the present invention, the first terminal bend 102 is positioned substantially toward the second end 18 of the first face portion 10 of the first female terminal portion 6, and the second terminal bend 104 is positioned substantially toward the first end 16 of the second face portion 12 of the second female terminal portion 8. The placement of the bends 102, 104 within the female fuse 4 increases the length of the fuse link 80 without requiring the use of any additional volume of metal material to create the female fuse 4. Moreover, increasing the length of the fuse link 80 in this fashion, and in the embodiments described below, actually reduces the amount of material which is discarded during manufacture.

Other configurations for the connections between the female fuse terminals 6, 8 and the terminal extensions 82, 84, will achieve a lengthened fuse link 80 without increasing the volume of material used, as well. Specifically, another embodiment of the present invention includes that the connection between the first female terminal portion 6 and the first terminal extension 82 of the fuse link 80 is positioned substantially toward the first end 14 of the first face portion 10 of the first female terminal portion 6, and includes that the connection between the second female terminal portion 8 and the second terminal extension 84 of the fuse link 80 is positioned substantially toward the first end 16 of the second face portion 12 of the second female terminal portion 8. Another embodiment of the present invention includes that the connection between the first female terminal portion 6 and the first terminal extension 82 of the fuse link 80 is positioned substantially toward the first end 14 of the first face portion 22 of the first female terminal portion 6, and includes that the connection between the second female terminal portion 8 and the second terminal extension 84 of the fuse link 80 is positioned substantially toward the second end 20 of the second face portion 12 of the second female terminal portion 8. Another embodiment of the present invention includes that the connection between the first female terminal portion 6 and the first terminal extension 82 of the fuse link 80 is positioned substantially toward the second end 18 of the first face portion 10 of the first female terminal portion 6, and includes that the connection between the second female terminal portion 8 and the second terminal extension 84 of the fuse link 80 is positioned substantially toward the second end 20 of the second face portion 12 of the second female terminal portion 8. Another embodiment of the present invention includes that the connection between the first female terminal portion 6 and the first terminal extension 82 of the fuse link 80 is positioned substantially toward the second end 22 of the first face portion 10 of the first female terminal portion 6, and includes that the connection between the second female terminal portion 8 and the second terminal extension 84 of the fuse link 80 is positioned substantially toward the first end 16 of the second face portion 12 of the second female terminal portion 8.

One feature which most embodiments have in common is that the fuse link 80 is non-linear. Previous fuses used a fuse link which extended linearly from the first female terminal to the second female terminal when viewed from the side of the fuse (facing a face portion). No lateral curves or bends existed in these previous fuse links from a side view. The present fuse 4 has at least two lateral curved portions 150 which break the linearity of the fuse link 80, for increasing the length of the fuse link 80 without using any additional fuse material during manufacture.

After the female fuse 4 is formed, generally in the shape of the female fuse 4 from FIGS. 1 through 5, and 8 through 10, the female fuse is placed within the housing 2, as shown in FIGS. 1 through 5. The housing 2 includes a main portion 106 and a cap 108. The fuse housing 2 is made of electrically insulating material, such as a synthetic polymer or plastic. The main portion 106 includes a first interior wall 110, a second interior wall 112, a third interior wall 114, and a fourth interior wall 116, a divider 118 extended between the third and the fourth interior walls 114, 116, all defining a space therein. The divider is provided for partially dividing the space, and includes a first interior cut-out portion 120 and a second interior cut-out portion 122. The first interior cut-out portion 120 includes and is defined by a first cut-out side wall 124 and a first cut-out upper wall 126. The second interior cut-out portion 122 includes and is defined by a second cut-out side wall 128 and a second cut-out upper wall 130.

For the purpose of securing the female fuse within main portion 106 of the housing 2, the first female terminal portion 6 includes a first lance 132. The first lance is defined by a first lance cut-out portion 136 on the first face portion 10 of the first female terminal portion 6, and is substantially centered between the first and second ends 14, 18 of the first face portion 10 of the first female terminal portion 6. The first lance 132 includes a first lance edge 140. Likewise, the second female terminal portion 8 further includes a second lance 134. The second lance 134 is defined by a second lance cut-out portion 138 on the second face portion 12 of the second female terminal portion 8, and is substantially centered between the first and second ends 16, 20 of the second face portion 12 of the second female terminal portion 8. The second lance 134 also has a second lance edge 142. When the female fuse 4 is inserted into the main portion 108 of the housing 2, the first lance edge locks into the first interior cut-out portion 120, and engages with the first cut-out upper wall 126. Likewise, the second lance edge 142 locks into the second interior cut-out portion 122, and engages with the second cut-out upper wall 130. The cap 108 of the housing 2 is preferably transparent, and locks into the main portion 108 through well known techniques.

On additional specific embodiment of the present invention is shown in FIGS. 11 and 12, and has generally already been described above. However, FIGS. 11 and 12 include reference to several common element numbers with a single prime designation instead.

It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof, including, but not limited to, the orientations of the invention elements herein to achieve the above identified and other advantages. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.