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Description  |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an electrical connection device using a terminal
connector for establishing an electrical connection between tab or
tab-shaped terminals.
2. Description of the Prior Art
A terminal connector is used hitherto for electrically connecting a bus bar
to a male tab terminal of a fuse, a relay or the like in an electrical
junction box. Such a terminal connector is disclosed in, for example,
JP-A-58-27845 (UM).
The disclosed terminal connector is formed of a thin planar member of an
electrical conductor which is bent at its both sides into the form of an
arch thereby forming a pair of arch-shaped resilient contact strips
opposing an electrical contact base.
A bus bar is bent at right angles at one of its end portions to form a
tab-shaped terminal. This tab-shaped terminal of the bus bar is inserted
from one direction into the space between the electrical contact base and
the arch-shaped resilient contact strips of the terminal connector, and a
mating male tab terminal of, for example, a fuse is inserted from the
opposite direction into the internal space of the terminal connector to
establish an electrical connection with the tab-shaped terminal of the bus
bar. Because the tab-shaped terminal of the bus bar makes direct
electrical contact with the male tab terminal of the fuse, a satisfactory
electrical connection therebetween is established.
However, in the prior art terminal connector having the structure described
above, the size (the width) of the male tab terminal of the fuse inserted
into the space between the electrical contact base and the arch-shaped
resilient contact strips of the terminal connector must necessarily be
selected to be smaller than the width of the terminal connector.
Therefore, the prior art terminal connector has been defective among
others in that it is difficult to use this terminal connector in common
to, for example, a blade type fuse and a fuse of the type standardized by
the International Organization for standardization (ISO).
In an attempt to overcome the defect of the terminal connector referred to
above, another terminal connector has been proposed. Such a terminal
connector is disclosed in, for example, JP-B2-60-11588 (UM).
The disclosed terminal connector is formed of a thin planar member of an
electrical conductor which is bent at about the middle to provide a
generally U-like structure. This U-like structure is bent inwardly at one
of its end portions to form a resilient contact strip, and its other end
portion providing an electrical contact base is bent at its both sides
inwardly to form a pair of arch-shaped contact strips similar to those of
the prior art example described already.
A male tab terminal of, for example, a fuse and a mating tab-shaped
terminal of a bus bar are inserted between the resilient contact strip and
the electrical contact base and between the electrical contact base and
the arch-shaped resilient contact strips of the terminal connector,
respectively.
The latter example of the prior art terminal connector is advantageous over
the former example in that the width of the male tab terminal of the fuse
can be freely selected. However, in the latter terminal connector, the
male tab terminal of the fuse is electrically connected with the mating
tab-shaped terminal of the bus bar through the electrical contact base of
the terminal connector. Therefore, the latter terminal connector has been
defective in that, when those terminals do not make sufficient electrical
contact with the electrical contact base, an undesirable increase in the
contact resistance accompanying generation of considerable heat occurs,
resulting in impossibility of establishing a satisfactory electrical
connection.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an electrical
connection device which minimizes an undesirable increase in the contact
resistance accompanying generation of heat and in which the type, that is,
the size (the width) of a connectable tab terminal of a fuse or the like
can be freely selected.
In accordance with the present invention which attains the above object,
there is provided an electrical connection device comprising a terminal
connector including a terminal guide, a resilient strip formed continuous
to the terminal guide to be located opposite to one of the surfaces of the
terminal guide, and a terminal support located opposite to the other
surface of the terminal guide; a tab-shaped terminal of a bus bar to be
electrically connected with the resilient strip; and a tab terminal of a
fuse to be electrically connected with the terminal support, the
tab-shaped terminal of the bus bar being formed with at least one
electrical-contact purpose surface projection projecting toward the
terminal guide of the terminal connector, and the terminal guide of the
terminal connector being formed with a cutout for receiving the surface
projection and permitting outward protrusion of th surface projection
toward the terminal guide, whereby the surface projection of the
tab-shaped terminal of the bus bar makes direct electrical contact with
the tab terminal of the fuse.
In the electrical connection device of the present invention having the
structure described above, the electrical-contact purpose surface
projection formed on one of the terminals projects from the cutout of the
terminal guide to make direct electrical contact with the other terminal.
Therefore, an undesirable increase in the contact resistance accompanying
generation of heat can be minimized in the electrical connection device of
the present invention.
Also, because the terminal guide is disposed between the resilient strip
and the terminal support, two terminals having different sizes, that is,
different widths can be inserted into the gap between the resilient strip
and the terminal support to be directly electrically connected with each
other. Therefore, the size of these two terminals need not be limited.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view showing the structure of an
embodiment of the electrical connection device according to the present
invention.
FIG. 2 is a longitudinal sectional view of the electrical connection device
to show the state of electrical connection between two terminals inserted
into the terminal connector.
FIG. 3 illustrates that one of the two terminals to be electrically
connected with the other terminal in the terminal connector may have a
width different from that of the latter terminal.
FIGS. 4, 5 and 6 are exploded perspective views of other embodiments of the
electrical connection device according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is an exploded perspective view of an embodiment of the electrical
connection device according to the present invention. In FIG. 1, a
terminal connector generally designated by the reference numeral 1a is
shown in a state before a tab terminal 12a or 12a' of a fuse is inserted
from its upper opening, and a mating tab-shaped terminal 10a of a bus bar
9 is inserted from its lower opening.
Referring to FIG. 1, the terminal connector 1a is formed of a flexible thin
planar member 2a of a metal or a synthetic resin. The flexible thin planar
member 2a is bent into a generally U-like shape at about the middle of its
length.
One end portion of the U-like bent member 2a is bent inwardly, and the free
end portion of the inwardly bent portion is further folded back to form a
resilient strip 3a. The other end portion of the U-like bent member 2a is
bent to extend upright in parallel to the resilient strip 3a to form a
terminal guide 4a opposing the resilient strip 3a. Side walls 5 and 5'
extending at right angles from both sides of the terminal guide 4a are
provided, and the side wall 5 is then bent at right angles and extended to
be coupled to the other side wall 5' thereby forming a terminal support
6a. The combination of the terminal guide 4a and the terminal support 6a
constitutes a terminal holder. A gap permitting insertion of the two
terminals 12a or 12a' and 10a is defined between the terminal holder and
the resilient strip 3a, and the upper and lower ends of this gap provide
the terminal insertion openings respectively.
The terminal guide 4a is formed with a cutout 7a extending in the
longitudinal direction from its lower end. A pair of reinforcing strips 8
are provided adjacent to the lower end of the terminal guide 4a.
A bus bar 9 has its inserting end portion bent at right angles to form the
tab-shaped terminal 10a. This tab-shaped terminal 10a is formed with a
rectangular surface projection 11a shaped as by pressing with a press so
as to make electrical contact with the mating tab terminal 12a or 12a' of
the fuse.
FIG. 2 is a longitudinal sectional view of the electrical connection device
to show that the tab-shaped terminal 10a of the bus bar 9 is inserted from
the lower insertion opening of the terminal connector 1a.
The height H of the surface projection 11a of the tab-shaped terminal 10a
of the bus bar 9 is selected to be larger than the distance H' between the
inner surface of the terminal support 6a and the surface 4' of the
terminal guide 4a opposing the resilient strip 3a, so that the surface
projection 11a of the tab-shaped terminal 10a of the bus bar 9 inserted
from the lower insertion opening of the terminal connector 1a can make
direct electrical contact with the tab terminal 12a of the fuse inserted
from the upper insertion opening defined between the resilient strip 3a
and the terminal guide 4a.
FIG. 3 illustrates that either of the tab terminal 12a of the fuse of, for
example, the blade type having a width L.sub.1 and the tab terminal 12a'
of the fuse of, for example, the type meeting the ISO standards and having
a width L.sub.2 (L.sub.2 >L.sub.1) is applicable to the terminal connector
1a used in the device embodying the present invention.
This is because any obstacle obstructing free insertion of either the tab
terminal 12a or the tab terminal 12a' is not present in the terminal
insertion space 13 between the resilient strip 3a and the terminal guide
4a of the terminal connector 1a. Therefore, the electrical contact part 14
of the tab terminal 12a' having the larger width L.sub.2 can be smoothly
inserted to be directly electrically connected with the tab-shaped
terminal 10a of the bus bar 9, although the tab terminal 12a' protrudes
partly to the outside of the terminal connector 1a due to its large width
L.sub.2.
FIGS. 4, 5 and 6 are exploded perspective views of other embodiments of the
electrical connection device according to the present invention.
A terminal connector 1b used in the device shown in FIG. 4 is formed by
bending a thin planar member 2b. When this terminal connector 1b is
developed on a plane, the shape of the thin planar member 2b before being
bent is generally analogous to a T. That is, the initial shape is
analogous to the state when a man extends his both arms. Arm-like strips
15 correspond to the both arms, and a cutout 7b is provided in the middle
of a terminal guide 4b which is connected between these arm-like strips
15. The arm-like strips 15 are bent toward each other into the form of
generally triangular prisms thereby forming a pair of resilient terminal
supports 6b. A curved guide strip 15' projects from the upper end of the
terminal guide 4b.
The body portion 16 of the thin planar member 2b is bent at right angles
with respect to the terminal guide 4b thereby forming a connection strip
17. The substantial portion of this connection strip 17 is then bent in
parallel to the terminal guide 4b, and the free end portion of the bent
portion of the connection strip 17 is then folded back into the form of a
U thereby forming a resilient strip 3b.
In FIG. 4, a bus bar has a tab-shaped terminal 10b, and two surface
projections 11b are formed in parallel to each other on the tab-shaped
terminal 10b for making electrical contact with a tab terminal 12b of a
fuse.
In FIG. 4, the tab-shaped terminal 10b of the bus bar 10 is inserted
between the terminal guide 4b and the terminal supports 6b until the
electrical-contact purpose surface projections 11b fit in the cutout 7b,
so that the tab-shaped terminal 10b of the bus bar makes direct electrical
contact with the tab terminal 12b of the fuse inserted between the
resilient strip 3b and the terminal guide 4b.
According to the embodiment shown in FIG. 4, the two terminals 10b and 12b
make firm electrical contact with each other because the terminal supports
6b have a resiliency similar to that of the resilient strip 3b.
In a terminal connector 1c used in the device shown in FIG. 5, one end
portion of a terminal guide 4c having a cutout 7c is bent into the form of
a U, and its bent portion is then folded back to form a resilient strip
3c, and a pair of parallel or opposing terminal supports 6c extend from
both sides of the other end portion of the terminal guide 4c. These
terminal supports 6c extending in the longitudinal direction make right
angles with respect to the terminal guide 4c and have a resiliency in the
direction of the terminal guide 4c.
The embodiment shown in FIG. 5 differs from those shown in FIGS. 3 and 4 in
that a tab-shaped terminal 10c of a bus bar is inserted between the
resilient strip 3c and the terminal guide 4c, while a tab terminal 12c of
a fuse is inserted between the terminal guide 4c and terminal supports 6c.
A terminal connector 1d used in the device shown in FIG. 6 is a
modification of the terminal connector 1c shown in FIG. 5. That is, the
structure of the terminal supports 6c in FIG. 5 is modified.
Referring to FIG. 6, the other end portion of a terminal guide 4d is
connected with one end portion of a terminal support 6d extending in
parallel to the terminal guide 4d, and the free end portion of the
terminal support 6d is bent outwardly to form a guide 18. As in the case
of the embodiment shown in FIG. 5, the terminal support 6d has a
resiliency in the direction of the terminal guide 4d. Therefore, even when
the thickness of a tab terminal 12d of a fuse and that of a tab-shaped
terminal 10d of a bus bar may slightly deviate from the standard
dimensions, the resiliency of the terminal support 6d ensures satisfactory
electrical contact between the two terminals 12d and 10d.
In all of the aforementioned embodiments, the surface projections 11a, 11b,
11c and 11d for electrical contact purpose are provided on the tab
terminals 10a, 10b, 10c and 10d respectively of the bus bars. It is
apparent however that these surface projections 11a, 11b, 11c and 11d may
be provided on the tab terminals 12a, 12b, 12c and 12d respectively of the
fuses or may be provided on both of the bus bars and fuses. The essential
requirement is that a surface projection having a height larger than the
thickness of each of the terminal guides 4a, 4b, 4c and 4d is to be
provided on each of the tab terminals 10a, 10b, 10c and 10d so as to
ensure direct electrical contact with each of the tab-shaped terminals
12a, 12b, 12c and 12d respectively.
It will be understood from the foregoing description that the present
invention provides an electrical connection device using a terminal
connector in which a cutout is provided in a terminal guide, while at
least one surface projection for electrical contact purpose is provided on
one of two terminals, and this surface projection is received in the
cutout so as to ensure direct electrical contact with the other terminal.
Therefore, an undesirable increase in the electrical contact resistance
accompanying undesirable generation of heat can be minimized thereby
improving the reliability of the electrical connection between the two
terminals.
Further, the electrical connection device of the present invention, in
which the terminal guide is interposed between a resilient strip and a
terminal support, is advantageous in that it is applicable to a variety of
kinds of tab-shaped terminals having different widths.
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