Holder for a blade-type circuit element

A holder and method of forming a holder for a removable plug-in circuit element is disclosed. The fuse holder comprises an insulated base, an electrical bus member, and a plurality of terminal members which are formed from the same blank of metal as the metal bus member and which were separated from each other after that blank was mounted on the insulated base. The bus member comprises a plurality of branches joined to a common trunk with each branch having at its free end an integral terminal. Each terminal member has at one end an electrical terminal and, at an opposite end, an integral terminal which is aligned to the free end of one lateral branch. In one embodiment of the invention, the holder includes an insulated cover which is carried by the base and which has a plurality of apertures which aligned to the terminals of each branch so as to receive the ends of a removable plug-in circuit element therein.

TECHNICAL FIELD 
This invention relates to holders for removeable circuit elements and fuse 
blocks, in general, and to fuse blocks and holders for replaceable circuit 
elements having blade-type terminals, in particular. 
BACKGROUND OF THE INVENTION 
Plug-in fuses are disclosed in U.S. Pat. No. 3,909,767 and 3,962,782. Such 
a fuse comprises a plug-in fuse element which includes: a blade-like body 
of fuse metal having a pair of laterally spaced terminal blade portions to 
be received by pressure clip terminals in a mounting panel or fuse block; 
current-carrying extensions at the inner end portions of each terminal 
blade portion; and a fuse link portion, generally of reduced thickness and 
small cross-sectional area, for interconnecting the current-carrying 
extensions. These fuses are alternatively referred to as "ATC" fuses (ATC 
is a registered trademark of Cooper Industries, Inc.) and have found 
wide-spread use in electrical systems found in automobiles, motorboats and 
other products. 
Plug-in fuses are used in conjunction with pressure clip terminals which 
are carried in a fuse mounting panel or by a fuse block. Generally 
speaking such a panel or block comprises an insulated base to which are 
attached pairs of terminals, each pair of terminals comprising a fuse 
holder. Usually one side of each fuse holder is connected to a source of 
power and the other side is connected to the electrical device which is 
protected by the fuse. The terminals are, for the most part, individually 
mechanically attached to the insulated base by rivets, screws, threaded 
fasteners and the like. Sometimes, snap-in connections, pressure gripping 
tabs, or heat staking is used to hold the fuse terminal on the base. 
It can be appreciated from the foregoing description that the manufacture, 
construction, and assembly of a fuse block, especially an ATC fuse block, 
is difficult and labor intensive. Since the parts are small, a premium is 
placed on the manual dexterity of the assembler. Thus, the manufacture of 
ATC fuse blocks involves the use of semi-skilled workers. The use of 
multiple, small, dimension sensitive parts also adds to the cost of 
manufacturing a fuse block. 
With the wide-spread acceptance of ATC fuses in mass produced products, 
such as automobiles and pleasure craft, there is a need for a cost-saving 
method of assembling a fuse block for plug-in fuses, a fuse block which is 
easy to assemble, one which is easily adoptable to automated assembly, and 
one which has fewer assembly steps. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, a fuse holder and method of 
forming a fuse holder is disclosed. Specifically, the fuse holder 
comprises an insulated base, an electrical bus member carried by the base 
and a plurality of fuse terminal members which were formed from the same 
blank of metal as the electrical bus member and which were separated from 
each other after that blank was mounted on the insulated base. The bus 
member comprises a plurality of lateral branches joined to a common trunk 
with each branch having at its free end one integral fuse accepting 
terminal. Each fuse terminal member has, at one end, an electrical 
terminal for receiving an electrical connection and, at an opposite end, 
an integral fuse accepting terminal which is aligned to the free end of 
one lateral branch. In one embodiment of the invention, the fuse holder 
includes an insulated cover which is carried by the base and which has a 
plurality of apertures which are aligned to the fuse terminals of each 
branch so as to receive at least the ends of the fuse therein. 
The fuse holder just described is preferably made by: forming from a 
generally flat blank of metal a plurality of generally parallel branches 
which are separated from each other by space distance; forming along one 
edge of each branch a pair of pressure clip terminals which are adapted to 
receive the blade portions of a plug-in fuse; mounting the formed blank of 
metal on an insulated base; and severing each branch at a position between 
the pair of pressure clip terminals, whereby those pressure clip terminals 
of each branch which are joined to the trunk member form a common 
electrical bus. 
From the foregoing description it will be seen that the fuse holder can be 
formed using a minimal number of steps makes economical use of material, 
does not require highly skilled assembly workers, is adapted to automatic 
manufacturing processes, and represents a cost-effective and improved 
method of manufacture. 
Numerous other advantages and features of the present invention become 
readily apparent from the following detailed description of the invention 
and the embodiments thereof, from the claims and from the accompanying 
drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
While this invention is susceptible of embodiment in many different forms, 
there is shown in the drawings and will herein be described in detail 
several embodiments of the invention. It should be understood, however, 
that the present disclosure is to be considered as an exemplification of 
the principles of the invention and is not intended to limit the invention 
to the specific embodiments illustrated. 
Before describing the method to manufacture the fuse holder that is the 
subject of the present invention, the fuse holder resulting from the 
method will be described so as to facilitate an understanding of the 
manufacturing process. 
Fuse Block 
Turning to FIGS. 1, 2, and 3, the fuse holder 10 that is the subject of the 
present invention comprises: an insulated base 12, an electrical bus 
member or terminal plate 14, a plurality of fuse terminal members 16 and 
an insulated cover 18. Each terminal member 16 has at one end an 
electrical terminal 20 and at its opposite end, an integral fuse terminal 
22. The fuse terminal 22 on the fuse terminal member 16 is aligned and 
spaced apart from a corresponding fuse terminal 24 on the terminal plate 
14. In the particular embodiment illustrated in the drawings, the fuse 
terminals are pressure clip terminals comprising trifurcations which are 
adapted to accept the generally flat blade portions of a plug-in fuse. The 
terminal plate 14, in this particular embodiment is adapted to be 
connected to an electrical source 99 by means of a threaded fastener 26 
and the electrical terminal 20 is a spade quick-connect terminal. 
The insulated base 12 is a generally flat structure (See FIG. 3) made from 
thermal plastic by injection molding so as to be suitable for mounting 
thereon the terminal plate 14 and the terminal members 16. The insulated 
base 12 is provided with a series of mounting apertures 30a (See FIG. 2) 
which can be used to mount the base, die-stamp apertures 32, cover 
securing apertures 34a and hardware mounting apertures 35a (See FIG. 8). 
The base member 12 is also provided with a series of pin-like projections 
37a and 39a which are aligned to corresponding securing apertures 37b in 
the fuse terminal members 16 (See FIGS. 18A and 18B) and apertures 39b in 
the terminal plate 14 (See FIG. 4). To facilitate alignment and to insure 
that the fuse terminal members 16 are properly located, a plurality of 
raised recesses 33 are provided on each side of the fuse terminal 
projections 37a (see detail in FIGS. 18A and A8B). 
The cover member 18 is a generally flat, five-sided structure (See FIG. 3) 
which is made from thermal plastic by injection molding and which includes 
a top wall 19, two side walls 21, two end walls 23, and two interior 
barrier walls 25 (see FIG. 17). The top wall 19 has a plurality of fuse 
accepting apertures 28. The side walls 21 have a plurality of securing 
tabs 34b and recesses 36b for the electrical terminals 20, such that the 
electrical terminals of the fuse terminal members 16 are exposed. The fuse 
apertures 28 are aligned with the fuse terminals 22 and 24 carried by the 
insulated base 12. Additional apertures may be provided for electrically 
connecting one end of the terminal plate 14 at a position outside of the 
cover. The inside of the cover 18 (see FIG. 17) has two barrier walls 25, 
tube-like extensions 30b to be received by the base mounting apertures 
30a, and tube-like extensions 37c to receive the fuse terminal projections 
37a. 
Method 
Turning now to FIGS. 9 through 14, the method of forming the terminal plate 
14 will now be described. The terminal plate 14 is die-stamped from a 
generally flat blank of metal or copper alloy 15, such as a long strip of 
electrical grade brass. To each side of a common trunk member 40 (see 
reference line 41) are formed a plurality of generally parallel branches 
42. To simplify the drawings (see FIGS. 10 through 14), branches 42 are 
shown formed only on one side of the trunk number 40. However, it should 
be understood that branches 42' can be formed to each side or to one side 
of the trunk member 40 (See FIGS. 15A through 15F), symmetrically or 
asymmetrically, relative to a base reference line. Moreover, the branches 
need not be parallel or at right angles to the trunk. Each branch 42 is 
separated from the others by spaced distance. Each branch has a relatively 
short free end or distal end 44 and two relatively long edges 46 which 
join the free end to the trunk member 40 (See FIG. 11). Formed along one 
long edge 46 of each branch 42 are two fuse securing terminals 22 and 24, 
each comprising trifurcations. The two fuse terminals 22 and 24 are 
separated from each other by a lateral section 48 of reduced width (See 
FIG. 12). Each terminal 22 and 24 is partially separated from the free end 
44 and the trunk member 40 by two recesses or channels 50. The purpose of 
the reduced width section 48 and the recesses 50 will become apparent from 
the description which follows. At the free end 44 of the branch 42, the 
electrical connecting terminal 20 is formed. In this particular 
embodiment, the electrical terminals 20 at the end of each branch 42 are 
of the well-known quick-connect variety. They provide a complete gripping 
surface and give good engagement strength. A large contact surface also 
affords the highest affordable electrical conductivity. Other electrical 
terminal connecting means may be stamped into each branch, i.e., screw 
connections, trifurcations, box connector, solder connectors, etc. Here 
the electrical terminals 20 are formed approximately 45 degrees to the 
plane of the terminal plate (See FIG. 3). 
Each fuse terminal 22 and 24 is formed generally at right angles (See FIG. 
13) to the plane of the terminal plate 14. The fuse terminals 22 and 24 
are separated from each other by a distance generally equal to the 
distance between the blade portions of the associated fuse 100. Between 
the electrical terminal 20 at the free end of each branch and the adjacent 
fuse terminal 22, a securing aperture 37b is formed. Finally, a plurality 
of apertures 39b are formed on the trunk 40. Proper alignment of the 
formed blank on the insulated base 12 is facilitated by means of 
cooperating projections 37a, and 39a, and apertures 37b and 39b and by 
means of the cooperating raised insulated recesses 33 (See FIGS. 18A and 
18B) and metal recess 50. The apertures 37b and 39b in conjunction with 
projections 37a and 39a on the insulated base 12 facilitate heat staking 
of the two parts, should that become necessary. 
The steps just described are conveniently accomplished using die stamping 
techniques and metal punching methods much as that used in U.S. Pat. No. 
3,140,364. One or more punching steps may be used. FIGS. 9 through 14 are 
illustrative. 
From the foregoing it will also be appreciated that the formed metal blank 
may be of any length (See FIG. 4) and any number of branches may be formed 
therein. Here (See FIG. 1) the finished terminal plate 14 has eight 
branches on each side of a longitudinal reference line "R". 
Prior to mounting the terminal plate 14 on the insulated base 12 one pair 
of lateral branches 42' (See FIG. 4) may be removed. This will allow the 
trunk to extend out of the cover area so as to provide a convenient point 
of attachment to a source of power 99. The reduced width lateral section 
50 at the proximate end of each branch facilitates easy removal. 
Prior to mounting the finished blank on the insulated base 12, a threaded 
fastener 26 may be mounted onto the base (See FIG. 8). Here the hex-head 
35b of a bolt is inserted into a corresponding cavity 35a in the base 12. 
The threaded portion 39c of the bolt is preferably selected to pass 
through a corresponding aperture 39b' in the terminal plate 14. This 
allows good electrical contact for all of the fuse protected loads. Of 
course other means may be used to electrically connect the terminal plate 
14. Moreover, the electrical connection may be made inside the protective 
cover by means of a suitable aperture in one of the end walls 23. 
After the terminal plate 12 is formed, it is mounted on the insulated base 
12. The apertures 39b on the terminal plate 14 are received by the 
projections 39a on the insulated base 12 and the slots 50 at the ends of 
each branch fit within the alignment recesses 33 (See FIG. 18A). When so 
mounted the die stamp apertures 32 are located below the reduced width 
sections 48 between the two fuse terminals 22 and 24 of each branch 42. At 
this point the finished blank may be heat staked in position. 
Once the formed blank is mounted on the insulated base, a die stamping 
machine is used to sever or cut each lateral branch 42 at a position 48 
generally midway between the two fuse terminals 22 and 24. The process of 
die stamping forms a plurality of fuse terminal members 16 and a common 
bus member 14 in one step (See FIG. 14). Heretofore, the fuse terminal 
members and bus member were added to the base serially. Such a process is 
time consuming and requires good manual dexterity if the assembly was to 
be completed without error and with good quality. 
After the fuse terminal members 16 are separated from the common bus 
member, the cover 18 is installed. Here the cover securing tabs 34b are 
forced into the corresponding apertures 34a in the base 12. The tube-like 
extensions 37c, located on the inside of the cover 18, are received by the 
pins or projections 37a on the base, thereby securely holding the fuse 
terminal members in place. The barrier walls 25 reduce the potential for 
arcing between the fuse terminals 22 and 24. In addition, the tube-like 
extensions 30b on the inside of the cover 19 fit within apertures 30a in 
the base 12 (See FIG. 2 detail). 
From the foregoing description, it will be observed that numerous 
variations and modifications may be effected without departing from the 
true spirit and scope of the novel concept of the invention. For example, 
FIG. 14A shows how the terminal plate may be formed to have terminals 22' 
and 24' for accepting a cylindrical type fuse. Of course, a different 
cover would be used. Other fuse accepting terminals (i.e., bifurcations), 
fuses and plug-in circuit elements (e.g., circuit breakers, disconnects, 
jumpers, etc.) may be accommodated. As another example, FIG. 16 depicts an 
embodiment wherein two formed metal blanks are located at opposite ends of 
a common insulated base 12; thus, two or more power sources may be 
protected from the same fuse block. In a similar fashion, FIG. 18B 
illustrates an embodiment wherein the alignment recesses 33' on the 
insulated cover 12 are provided with two oppositely disposed extensions 
which fit within two oppositely disposed recesses 33b in fuse terminal 
member 16'. It should be understood that no limitation with respect to the 
specific apparatus illustrated herein is intended or should be inferred. 
It is, of course, intended to cover by the appended claims all such 
modifications as fall within the scope of the claims.