Note: Descriptions are shown in the official language in which they were submitted.
l~ZZOS 9996
The present invention relates to resin coated
electrolytic capacitors having terminal conductors con-
figured to facilitate mounting and engagement with circuit
boards and the like.
Resin coated solid state electrolytic capacitors
are well known to the art and are described in United
States patent 3,646,404 issued February 29, 1972, which
also describes a terminal conductor configuration generally
suitable for circuit board installation. However, the
terminal conductor configuration of this patent, and other
previously known configurations, are not completely satis-
factory in several important aspects e.g. the avoidance of
accidental polarity reversal during installation, retention
prior to soldering, uniformity of installation, and other
aspects.
It is therefore an ob;ect of the present invention
to provide an electrolytic capacitor having terminal leads
which can be readily affixed and which are especially suited
for circuit board engagements.
Other objects will be apparent from the following ~ -
description and claims taken in conjunction with the drawing
in which
Figure 1 shows a cross-sectional elevation view of
an electrolytic capacitor in accordance with the present -
invention.
Figure l(a) shows a bottom view of the capacitor.
Figures 2 through 4 illustrate steps during the
manufacturing of capacitors of the type shown in Figure 1
and
Figures 5(a), 5(b) and 5(c) illustrate certain
terminal lead arrangements adapted for circuit board
engagement which can be substituted for the anode lead
terminal of Figure l(a).
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lO~ZOS
The present invention will be more fully unter-
stood with reference to Figure 1 of the drawing which
shows a sintered capacitor anode 10 made from tantalum,
aluminum or other film forming metal having an attached
metal lead out rod 20. An oxide layer is electrolytically
provided on the surface of anode 10 and a cathode layer,
e.g. silver, is applied on the oxide layer following con-
ventional, known procedures. Anode and cathode terminal
leads, indicated at 30 and 40 respectively, are bonded to -
the capacitor body by welding, as indicated at 35, and
solder, as indicated at 45, and the assembly is enclosed
within a resin envelope as indicated at 50 by conventional
techniques. With further reference to Figure 1, cathode
terminal lead 40 comprises a relatively narrow portion 60
which is arranged to loosely fit in the slightly larger
aperture 62 of the conventional circuit board indicated
at 64. Intermediate lateral portion 66 of cathode lead 40
is in contact with circuit board 64 as is the corresponding
lateral portion 68 of anode lead 30. The longitudinal
portion 70 of cathode lead 40 is bonded by solder to the
cathode of the capacitor as previously described. Anode
lead 30 is formed of a resiliently deformable metal
8uch as "nickel silve~r' which is~we~Idabre~ to ~t-an~alum~
and solderable (typicaL composition:55%Cu,26.75%Zn,18V/ONi,
.2570Mn) and has a relatively wide strip-like portion 72,a : :
transve~e "shou~er" portion 68 at the same ~elas ~e transverse .
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109ZZ05
portion 66.of cathode lead 40, a longitudinal portion 74,
and a transverse portion 76 which i8 welded at 35 to
anode lead out rod 20. As can be seen from Figure l(a),
the relatively wide portion ?2 of anode_lead 30 has an end
portion 78 which, upon entry into aperture 80 of circuit
board 64, is resiliently deformed by the sides 83 of
aperture 80, as indicated at 82, due to the relatively
narrow width of aperture 80. Upon passing through aper-
ture 80, resilient end portion 78 returns to its initial
shape and engages the capacitor to circuit board 64 as
shown at 85 in Figure l(a). The resilient deformation of
locking conf'iguration 78 is facilitated by~ lance cuts, as
indicated'a't 84, in're~'ative'ly'wide''strip-like~ member 72.
Upon insertion of the capacitor into circuit board 64,
as described above, which can be done manually or auto-
matically by machine, the capacitor is firmly held to
circuit board 64 by the engagement of end portion 78 of
arode terminal lead 30,and the c~ntact of lateral portions
66 and 68 of the cathode and anode terminal leads. The - '
capacitor can thus be conveniently joined to conductors : '
86 and 88 as indicated in Figure 1 by solder connections
90 and 92. :
The capacitor body of the present invention i~
engaged to circuit board 64 b.y'aligning the relatively '
narrow strip-like cathode terminal lead 40 with the rela-
tively smaller aperture 62 of circult board 64. End portion
60 of cathode lead 40 is surrounded by aperture 62 but fits~ -
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lOSZ2()S
loosely in aperture 62. The end portion 78 of relatively
wide strip-like anode terminal lead 30 is spaced ~ pre-
determined distance from portion 60 of cathode lead 40
so as to be aligned with ap~-rture 80 of circuit board 64.
The width of aperture 80 is narrower than the overall
width 81 of end portion 78. Thus, end portion 78 is resil-
iently deformed upon passing through aperture 80 and is
returned to its original shape after passing through aper-
ture 80 and thus engages circuit board 64. In view of the
substantially different widths of the anode tenminal lead
30 and cathode terminal lead 40, the likelihood of reversing
the desired polarity upon engagement with circuit board 64
is obviated. In addition to ease of installation, the
capacitor of the present invention is firmly engaged so
that it will not fall free of the circuit board 64 prior
to or during soldering.
- With reference to Figure 2, a thin sheet of
resilient, solderable metal such as previously mentioned
hereinabove, about 0.010 inch to 0.020 inch thick, is
suitabl~ punched to obtain the configuration shown having
a pluralit~ of conductor pairs 100 attached to strip 110.
The configuration of Figure 2 is subsequently subjected ~: -
. to a lancing operation to provide the lance cuts indicated
at 84 in Figure 3, and a progressive die punch press opera- :
~ tion to deform end portion 78 as shown in Figure 3 and 3A.
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Thereafter capacitors 10 are attached as shown in
Figure 4, to anode leads 30 by welding lead out rods
20 thereto as indicated at 35. Subsequently, the
assembly is conventionally dipped in molten solder
to bond the cathode leads 40 to capacitors 10 and
provide the solder coating shown at 45 in Figure 1.
Following the solder-dipping step, the assembly is
conventionally dipped in liquid resin, e.g. epoxy
resin to provide a resin envelope as indicated at 50
in Figure 1 which encloses the capacitor 10, anode
lead out rod 20 and most of the longitudinal portions
of anote terminal lead 30 and cathode terminal lead
40. After forming the resin envelope 50, the conductor
pairs 100 are cut at line 120 to obtain individual
completed capacitors of the type shown in Figure 1.
With reference to Figures 5(a), 5(b) and 5(c), these
figures show different embodiments of end portion or
locking c~nfiguration 78, which can be formed by
conventional metal working techniques. In Figure 5(b),
the embodiment disclosed engages circuit board 64 in a
manner similar to the embodiment of Figure 1, i.e. the
end portion 78" is resiliently deformed and passes
completely through aperture 80" and thereafter returns
:
to its original shape to engage circuit board 64. In
the embodiment of Figure 5(a), end portion 78' is
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lO ~ Z ~ O S 9996
resiliently deformed and compressed and engages circuit
board 64 by being "wedged" in aperture 80' which is
suitably of a circular, rather than elongate cross-
section. In the embodiment of Figure 5(c), end
portion 78 " ' is tapered as shown at 81, suitably
from about 5 to 10, and is wedged in aperture 80 " '
without any substantial deformation of end portion
78 " '. m e slight taper of end portion 78 " ' enables
a firm engagement with circuit board 64, particular~y
when the circuit board material is a thermosetting
resin such as phenolic and glass epoxy materials.
While in the foregoing description, the
anode tenminal lead conductor has been described
as having a relatively wide strip-like portion and
a locking configuration, and the cathode terminal lead
conductor as having a relatively narrow strip-like
portion, it is within the scope of this invention that
this arxangement be reversed. That is, the cathode
lead terminal conductor can have a relatively wide
strip-like portion and locking configuration while
the anode terminal lead conductor has a relatively
narrow strip-like portion.
