Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BACKGROUND OF THE INVENTI~N
Field of the Invention
The present invention relates to an electronic shorting
device, and more particularly to a leadless electronic shorting
device which has a low resistance and wherein the portions to be
soldered may easily and q~ickly be heated to the solder melting
point.
Description of the Prior Art
A conventional lead-less electronic shorting device
consists of a smaller cylindrical portion with larger cylindrical
end-portions as electrodes, formed integrally with the smaller
cylindrical portion at bo~h ends and made of conductive material.
The larger cylindrical portions are soldered to conductive
patterns bridging a gap between separated patterns on a printed
board, thus the conductive patterns are electrically connected
to one another through the electronic shorting device. Such an
electronic shorting device is generallycall~a "jumper part".
In order to attach the larger pvrtions of the jumper part to the
conductive patterns, solder cream is applied to the larger portions,
followed by the joint heating of them both. However, the time
required to melt the solder cream applied to the larger portions
of the jumper part is longer than the time re~uired to melt the
solder cream applied to other leadless electronic parLs ~uch as
resistors. This is primarily because the jumper part is a
relatively massive device made of metal having a high thermal
conductivity.
Typically, in manufacturing a jumper part, a metal rod
is machined with a lathe. However, an undesira~le whisker-like
projection or burr is formed on the larger portions. The
cQntinuous flow of parts in a part feeder for an automatic mounting
app~ratus is often disturbed by these whisker-like projections.
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5UMMARY O~ THE INVENTION
~ he present lnvention has, accordingly, ~s an object,
the provision of an electronic shorting device which overcomes
the above-described defect of the conventional shorting apparatus.
Another object of this invention is to provide an
electronic shorting device which has a low resistance.
A further object of this invention is to provide an
electronic shorting part which may be easily manufactured.
The resolution of this objective is attained by
~nventively providing an electronic shorting apparatus which
includes a cylindrical porcelain body which is plated with metal;
with conductive end caps fitted to both end portions of the
cylindrical porcelain body.
More particularly, there is provided:
An electronic shorting device which comprises:
a cylindrical, porcelain body;
a layer of an electrically conducting metal coating
said cylindrical, porcelain body; and
a conductive end cap received by and carried upon each
end portion of said cylindrical porcelain body, each end cap
being in electrical contact with said layerO
There is also provided:
An electronic shorting device which compri es:
a cylindrical, porcelain body;
a layer of an electrically conducting metal plated to
said cylindrical, porcelain body comprising:
a first layer of nonelectrolytically applied metal
platinq said cylindrical porcelain body;
a second layer of electrolytically applied metal plat-
0 ing the first layer of metal; anda conductive end cap received by and carried upon eash
end portion of said cylindrical, porcelain body.
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Various other objects, features, and advantages of the
present invention will become readily apparent from the ensuing
detailed description and the novel features will be particularly
pointed out in the appended claims.
BRIEF DESCRIPTION OF ~HE DRAWINGS
Fig. 1 is a perspective view of a conventional electronic
shorting device arranged on a printed board;
Fig. ~ is a cross-sectional view of the conventional
electronic shortin~device of the type as shown in Fig. l; and
Fig. 3 is a cross-sectional view of an electronic
shorting part according to one embodiment of the present invention.
DESCP~IPTION OF THE PREFERR~:D EMBODIMENTS
.
Before proceeding to a detailed description of the
present invention, and in order to enhance the understanding
thereof, a conventional electronic shorti~g devic~ will be
described with reference to Figs. 1 and 2.
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A conventional leadless electronic shorting device
which is a so-called "jumper part", is shown in Fig. 1. The
electronic shorting device 1 consists of larger cylindrical
portions 2 and 3, and a smaller cylindrical portion 4, made of
conductive material. Referring to Fig. 1, conductive patterns 7
and 8 are formed at both sides of a conductive pattern 6 in a
printed board 5. The patterns 6, 7 and 8 are separated from
each other as shown in Fig. 1. The patterns 7 and 8 are
electrically connected to each other through the electronic
shorting device 1 arranged across the pattern 6.
For example, a rod of brass is machined by a lathe
to form the larger cylindrical portions 2 and 3 and the smaller
cylindrical portion 4 of predetermined dimensions. The entire
surface of the produced electronic shorting device 1 is plated
with nickel or 95% of tin and 5% of solder. However, an
undesirable whisker-like projection 9 is often formed on the
end surface of one of the larger cylindrical portions 2 or 3
during the completion of the lathe machining.
Generally, an automatic mounting apparatus is used for
mounting various electronic parts onto a printed board. A part
feeder is provided as a component of the automatic mounting apparatus
~nen the electronic shorting devices 1 are transported in the part
feeder, they are often caught by internal projections and
constructions of the part feeder because of the whisker-like
projections or burrs 9. This of course results in a disturbance
of the smooth flow of parts. Accordingly, a process to remove
the whisker-like projections 9 is required, causing the manufacturin~
cost to increase.
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In the mounting process, the shorting devices 1 and
other electronic parts are provisionally attached to predetermined
conductive patterns with solder cream on a printed board, They
are then heated within a gas furnace or by infrared rays to
melt the solder cream which, after cooling~ firmly attaches
other electronic parts to the predeterm;ned conductive patterns.
However, the time required to melt the solder cream applied to the
larger cylindrical portions 2 and 3 of the jumper part 1 is longer
than the time required to melt the solder cream applied to the
electrode portions of the other electric parts. This
is because the jumper part l is entirely made of metal having a
high thermal conductivity, and therefore heat is rapidly transmitted
away from the metal surface and to the internal portion of the
jumper part 1.
The followin~ is a description of an electronic shorting
device according to an embodiment of the present lnvention with
reference to Fig. 3.
Referring to Fig r 3 ! a jumper part or de~ice 11 lncludes
a cylindrical body 12 made of a ceramic such as porcelain. The
circumferential surface of the cylindrical body 12 are tapered,
for example~ by a barrel polishing method ! as indicated by
reference numerals 12a and 12_. Due to the slants 12a and 12_~
the caps 14 and 15 can be easily fitted to the end portions of
the cylindrical body 12.
The cylindrical body 12 is first plated with metal
such as sil~er or copper by a nonelectrolytic plating method, to
th.e depth of about 2~ ~. Then~ the thus obtained metal layer of
the cylindrical body 12 is plated with,metal such as silver or
copper by an electrolytic plating method, to the depth of about 50
to 60 ~ m. Thus~ the metal layer 13 as shown in Fig~ 3 is formed
~n the cylindrica.l body 12, In order to prevent oxidation, the
~etal layer 13 may be further plated with. nickel~
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The caps 14 and 15 are made of conductive metal such
as brass or iron with a thickness of about 200 ~ m. They are
also plated, using a tin material containing 5 to 10% of solder.
The caps 14 and 15 are fitted to the end portions of
the cylindrical body 12 by a driving-fit or impacting method.
The contact resistance between the metal layer 13 and the caps
14 and lS is satisfactoriiy low.
The following example is for illustrative purposes
and is not to be viewed as limiting the scope of the present
invention.
Thermo-setting resin of an epoxy group or an ultraviolet-
setting resin thereof may be used as the material for the insulating
film 16. The insulatin~ material 16 is coated onto the metal
layer 13 to a depth which is smaller than the thickness of the
caps 14 and 15, for example about 200 /um. The obtained
insulating layer 16 is ~uitar-shaped with bulges adjacent the
caps 14 and 15. It is pre~erable that the height of the enlarged
portions of the insulating film 16 at the edges of the caps 14
and 15 is smaller than 50 ~ m. Dimensions ~ andQ 2 as
shown in Fig. 3 are as follows:
~ - 2.2~m or 2.5mm;
R 1 = 6mm or 8mm; and
2 = 1.5mm.
The internal resistance o the above-described jumper
part 11~ namely the resistance between the caps 14 and 15, can be
a$ low as 4 to 5mQ, Generallyr the internal resistance required
~or a ~umper part is lower than about lOmQ,
The thermal conductiyity o~ the cylindrical body 12
made of ceramics such as porcelain is low. Accordingly~ the time
required to mel~ the ~older c~eam applied to the caps 14 and 15
of the jumper part 11 is shortened in comparison with the
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conventional jumper part 1, and it is comparable to the time
required to melt the soldered cream applied to the electrode
portions of the other electric parts.
A cylindrical body for a leadless carbon resistor may
be used as the cylindrical body 12. The cylindrical bodies for
the jumper part 11 and the leadless carbon resistor may be equal
to each other in shape and size. Accordingly, a manufacturing
apparatus for carbon resistor can be used for the jumper part 11,
and so the jumper part 11 can be mass-produced in economical
manner.
Ceramics such as porcelain are lighter than brass which
is a typical material for the conventional jumper part 1.
Accordingly, the jumper part 11 when provisionally attached to
the printed board, does not fall out as easily from the printed
board when it is overturned as does the conventional jumper
part 1 when it is provisionally attached to the same printed board.
~ hile we have disclosed an exemplary structure to
illustrate the principles of the invention, it should be understood
that we wish to embody within the scope of the patent warranted
hereon all such modifications as reasonably and properly come
within the scope of our contribution to the art.
