U.S. patent application number 10/909958 was filed with the patent office on 2005-01-06 for electronic filter assembly.
Invention is credited to Gould, Jerry M., Tresness, Andrew F..
Application Number | 20050001697 10/909958 |
Document ID | / |
Family ID | 23507396 |
Filed Date | 2005-01-06 |
United States Patent
Application |
20050001697 |
Kind Code |
A1 |
Gould, Jerry M. ; et
al. |
January 6, 2005 |
Electronic filter assembly
Abstract
An electronic filter comprises a housing having input and output
ends. The housing has a body and a connector. The connector is
located at the input end of the housing. A circuit board is located
within the body. A collet assembly is located within the connector
to receive electrical signals and conduct them to the circuit
board. The collet assembly includes an insulator, a conductor, and
an elastomeric sealing member. The insulator is located within the
connector. The insulator contains a generally cylindrical opening
through its length. The conductor extends through the opening of
the insulator. The conductor has an input end adjacent the input
end of the housing and an output end adjacent the circuit board.
The conductor has a hollow interior at its input end. The sealing
member surrounds the insulator in compressed engagement with the
insulator and the surrounding connector.
Inventors: |
Gould, Jerry M.; (Liverpool,
NY) ; Tresness, Andrew F.; (Manlius, NY) |
Correspondence
Address: |
Lawrence P. Trapani
Attorney at Law
2nd Floor, Monroe Building
333 East Onondaga Street
Syracuse
NY
13202
US
|
Family ID: |
23507396 |
Appl. No.: |
10/909958 |
Filed: |
August 2, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10909958 |
Aug 2, 2004 |
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10721492 |
Nov 25, 2003 |
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10721492 |
Nov 25, 2003 |
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09898543 |
Jun 29, 2001 |
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6674343 |
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09898543 |
Jun 29, 2001 |
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09382064 |
Aug 24, 1999 |
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6323743 |
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Current U.S.
Class: |
333/185 ;
333/175 |
Current CPC
Class: |
H01R 13/5213 20130101;
H01R 2103/00 20130101; H03H 7/0115 20130101; H01R 24/42 20130101;
H05K 9/0066 20130101; H03H 2250/00 20130101; H01R 2201/18
20130101 |
Class at
Publication: |
333/185 ;
333/175 |
International
Class: |
H03H 007/01 |
Claims
What is claimed is:
1. An electronic filter assembly of the type that includes a female
terminal cap having a fitting portion and containing a terminal
passage through the fitting portion, and a collet assembly secured
in and substantially closing the terminal passage of said female
terminal cap, wherein said collet assembly comprises: an insulator,
made from a single piece of insulator material, containing a bore
therethrough; a collet terminal extending through the bore of the
insulator; and a seal located inside the terminal passage of said
female terminal cap, between the collet terminal and said female
terminal cap.
2. The electronic filter assembly of claim 1, wherein the collet
terminal has at least one barb which penetrates the insulator
material of the insulator, to help prevent moisture from entering
said filter housing between the bore of the insulator and the
collet terminal.
3. The electronic filter assembly of claim 1, wherein the insulator
of said collet assembly has a substantially cone-shaped nose
portion.
4. An electronic filter assembly of the type that includes a female
terminal cap having a fitting portion and containing a terminal
passage through the fitting portion, and a collet assembly secured
in and substantially closing the terminal passage of said female
terminal cap, wherein said collet assembly comprises: an elongated
insulator, made from a single piece of insulator material,
containing a hole therethrough; a collet terminal extending
substantially through the hole of the insulator, the collet
terminal having a female end surrounded by the insulator and
tightly fitted in the hole of the insulator, such that the female
end is insulated from the fitting portion of said female terminal
cap; and a seal located inside the terminal passage of said female
terminal cap, between the collet terminal and said female terminal
cap.
5. An electronic filter assembly of the type that includes a female
terminal cap having a fitting portion and containing a terminal
passage through the fitting portion, and a collet assembly secured
in and substantially closing the terminal passage of said female
terminal cap, wherein said collet assembly comprises: an insulator,
made from a single piece of insulator material, containing an
axially directed hole therethrough; a collet terminal extending
substantially through the hole of the insulator, the collet
terminal having a female end surrounded by the insulator and
tightly fitted in the hole of the insulator, such that the female
end is insulated from the fitting portion of said female terminal
cap; and a seal located inside the terminal passage of said female
terminal cap, between the collet terminal and said female terminal
cap.
6. An electronic filter assembly of the type that includes a female
terminal cap having a fitting portion and containing a terminal
passage through the fitting portion, a collet assembly secured in
and substantially closing the terminal passage of said female
terminal cap, and a circuit board, wherein said collet assembly
comprises: an insulator, made from a single piece of insulator
material, containing a hole therethrough; a collet terminal
extending substantially through the hole of the insulator, the
collet terminal having a female end and a coupling end, the female
end being surrounded by the insulator and tightly fitted in the
hole of the insulator, such that the female end is insulated from
the fitting portion of said female terminal cap, the coupling end
being coupled to said circuit board; and a seal located inside the
terminal passage of said female terminal cap, between the collet
terminal and said female terminal cap.
7. An electronic filter as recited in claim 6, wherein said
coupling end has a neck-shaped portion.
8. An electronic filter assembly of the type that includes a female
terminal cap having a fitting portion and containing a terminal
passage through the fitting portion, and a collet assembly secured
in and substantially closing the terminal passage of said female
terminal cap, wherein said collet assembly comprises: an insulator,
made from a single piece of insulator material, containing a hole
therethrough; a collet terminal extending substantially through the
hole of the insulator, the collet terminal having a female end
surrounded by the insulator and tightly fitted in the hole of the
insulator, such that the female end is insulated from the fitting
portion of said female terminal cap, the collet terminal having at
least one barb which penetrates the insulator material of the
insulator; and a seal located inside the terminal passage of said
female terminal cap, between the collet terminal and said female
terminal cap.
9. An electronic filter assembly of the type that includes a female
terminal cap having a fitting portion and containing a terminal
passage through the fitting portion, a collet assembly secured in
and substantially closing the terminal passage of said female
terminal cap, and a circuit board, wherein said collet assembly
comprises: an insulator, made from a single piece of insulator
material, containing an axially-directed hole therethrough; a
collet terminal extending substantially through the hole of said
insulator, said collet terminal having a female end surrounded by
said insulator and a coupling end coupled to said circuit board,
said collet terminal further having a barb engaging the insulator
material of said insulator inside the hole of said insulator, the
barb having an inclined side; and a seal located inside the
terminal passage of said female terminal cap, between said collet
terminal and said female terminal cap.
10. An electronic filter as recited in claim 8, further comprising
a circuit board, said collet terminal further comprising a coupling
end which is coupled to said circuit board.
11. An electronic filter assembly of the type that includes a
female terminal cap having a fitting portion and containing a
terminal passage through the fitting portion, and a collet assembly
secured in and substantially closing the terminal passage of said
female terminal cap, wherein said collet assembly comprises: an
insulator, made from a single piece of insulator material,
containing a hole therethrough, the insulator having a
substantially cone-shaped nose portion, a collet terminal extending
substantially through the hole of the insulator, the collet
terminal having a female end and a coupling end, the female end
being surrounded by the insulator and tightly fitted in the hole of
the insulator, such that the female end is insulated from the
fitting portion of said female terminal cap, the coupling end being
integrally formed with said female end and electrically connected
with a circuit board; and a seal located inside the terminal
passage of said female terminal cap, between the collet terminal
and said female terminal cap.
12. An electronic filter assembly of the type that includes a
female terminal cap having a fitting portion and containing a
terminal passage through the fitting portion, and a collet assembly
secured in and substantially closing the terminal passage of said
female terminal cap, wherein said collet assembly comprises: an
insulator, made from a single piece of insulator material,
containing a hole therethrough, the insulator having distal and
proximal ends, said hole axially extending through the insulator
and opening at the distal and proximal ends, the female end of said
collet terminal opening at the distal end; a collet terminal
extending substantially through the hole of the insulator, the
collet terminal having a female end surrounded by the insulator and
tightly fitted in the hole of the insulator, such that the female
end is insulated from the fitting portion of said female terminal
cap; and a seal located inside the terminal passage of said female
terminal cap, between the collet terminal and said female terminal
cap.
13. An electronic filter comprising: a conductive housing having
input and output ends, said housing having a body portion and a
female connector, the female connector being located at the input
end of said housing and having a diameter less than that of the
body portion; a circuit board within the body portion of said
housing; and a collet assembly within the female connector to
receive electrical signals and conduct them to the circuit board,
the collet assembly including an insulator member within the female
connector, the insulator member containing a generally cylindrical
opening through its length, a conductor extending through the
opening of the insulator member, the conductor having an input end
adjacent the input end of said housing and an output end adjacent
the circuit board, the conductor having a hollow interior at its
input end, and an elastomeric sealing member surrounding the
insulator member in compressed engagement with the insulator member
and the surrounding female connector, to provide a moisture seal
between the insulator member and the female connector.
14. The electronic filter of claim 13, wherein the input end of the
conductor is surrounded by the insulator member and is tightly
fitted in the opening of the insulator member.
15. The electronic filter as recited in claim 13, wherein said
female connector is cylindrical.
16. An electronic filter comprising: a conductive housing having
input and output ends, said housing having a cylindrical body
portion and a cylindrical female connector at the input end of said
housing; at least one printed circuit board within the body portion
of said housing; and a collet assembly within the female connector
to receive electrical signals and conduct them to said printed
circuit board, the collet assembly including an insulator member,
the insulator member containing a generally cylindrical bore
through its length, a conductor extending through the bore of the
insulator member, the conductor having an input end adjacent the
input end of said housing and an output end adjacent said printed
circuit board, the conductor having a hollow interior at its input
end, and an elastomeric sealing member surrounding the insulator
member in compressed engagement with the insulator member and the
surrounding female connector, to provide a moisture seal between
the insulating member and the female connector.
17. The electronic filter of claim 16, wherein the insulator member
has a reduced diameter over a portion of its length, and the
elastomeric sealing member surrounds the reduced diameter
portion.
18. The electronic filter of claim 16, wherein the conductor is a
unitary member which extends beyond the length of the insulator
member and is connected to the printed circuit board.
19. The electronic filter of claim 18, wherein the conductor has a
reduced diameter portion beyond the length of the insulator
member.
20. An electronic filter comprising: a conductive housing having
input and output ends, said housing having a cylindrical body
portion and a threaded female connector at the input end of said
housing, a printed circuit board within the body portion of said
housing; and a collet assembly within the female connector to
receive electrical signals and conduct them to said printed circuit
board, the collet assembly including only a single substantially
cylindrical insulator member that extends through at least a
portion of the female connector in close proximity to an interior
surface of the female connector, the insulator member containing a
generally cylindrical bore through its length, a conductor
extending through the cylindrical bore of the insulator member, the
conductor having an input end adjacent the input end of said
housing and an output end connected to said printed circuit board,
the conductor having a hollow interior at its input end, and an
elastomeric sealing member in compressed engagement with the
interior surface of the surrounding female connector to provide a
moisture seal against the interior surface thereof, the insulator
member surrounding at least the input end of the conductor.
21. An electronic filter comprising: a conductive housing having
input and output ends, said housing having a cylindrical body
portion and a cylindrical threaded female connector, said connector
being located at the input end of said housing; and a printed
circuit board within the housing, the threaded female connector
enclosing a cylindrical space that contains only a single
cylindrical insulator member, an elastomeric sealing member, and an
elongated conductor member, the cylindrical insulator member
containing a generally cylindrical bore through its length, the
elongated conductor extending through the bore of the insulator
member, the conductor having an input end adjacent the input end of
said housing and an output end adjacent said printed circuit board,
the conductor having a hollow interior at its input end, the input
end being surrounded by and tightly fitted in the insulator member,
the elastomeric sealing member being in compressed engagement with
the surrounding female connector to provide a moisture seal against
the surrounding female connector.
22. An electronic filter comprising: a conductive housing having
input and output ends, said housing having a body portion and a
cylindrical female connector, said female connector being located
at the input end of said housing and having a diameter that is less
than the diameter of the body portion, a printed circuit board
within the body portion; and a collet assembly within the female
connector to receive electrical signals and conduct them to said
printed circuit board, said collet assembly including a single
insulator member within the female connector, a conductor extending
through the insulator member, the conductor having an input end and
an output end, the input end being adjacent the input end of said
housing, the conductor having a hollow interior at its input end,
the input end of the conductor being surrounded by and in close
contact with the insulator member, and an elastomeric sealing
member surrounding the insulator member in compressed engagement
with the insulator member and the surrounding female connector to
provide a moisture seal between the insulator member and the female
connector.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 10/721,492, filed Nov. 25, 2003, which is a continuation of
U.S. application Ser. No. 09/898,543, filed Jun. 29, 2001, now U.S.
Pat. No. 6,674,343, which is a continuation of application Ser. No.
09/382,064, filed Aug. 24, 1999, now U.S. Pat. No. 6,323,743.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The present invention relates generally to electronic
filters used in the cable television industry, and relates more
particularly to the construction and assembly of such filters.
[0004] 2. Background Art
[0005] Typical electronic filter constructions in the cable
television (CATV) industry involve a considerable number of parts,
such as, for example, one or more circuit boards, connecting wires
or leads, filter circuit components, isolation plates, blocks or
chambers, input and output terminals, moisture barrier seals or
plugs, connector housings, sub-housings or caps, o-rings, outer
housing sleeves, and potting material. This elaborate array of
parts constrains efforts to: minimize the size and weight of the
filters; reduce material and labor costs associated with assembly
of the filters; and simplify and automate the assembly process.
Examples of such filter constructions are shown and described in:
U.S. Pat. No. 5,278,525 to Palinkas; U.S. Pat. No. 4,901,043 to
Palinkas; U.S. Pat. No. 4,701,726 to Holdsworth; U.S. Pat. No.
4,451,803 to Holdsworth et al; U.S. Pat. No. 3,579,156 to Parfitt;
and U.S. Pat. No. 3,065,434 to Calderhead.
[0006] For such CATV filters as highpass and lowpass filters,
diplex filters, windowed highpass filters, and step attenuator (or
return path) filters, tunable filter circuits and shielding between
filter components and circuits are not normally required. Thus, for
these types of filters, an opportunity is presented to simplify
filter components, construction and assembly. U.S. Pat. No.
5,745,838 to Tresness et a. discloses (FIGS. 8-10) a filter
construction for a return path filter called a "step attenuator."
This construction is also shown in FIG. 2 herein, as representing
the prior art construction for this type of filter. While
simplification was achieved in U.S. Pat. No. 5,745,838, the
construction still required two major o-rings around the male and
female terminal caps and an outer housing sleeve (See FIG. 2
herein); and, manual assembly of these parts was still
required.
[0007] Many diplex, windowed highpass, and return path filters
(See, e.g., embodiments shown in FIGS. 1-5 of U.S. Pat. No.
5,745,838), have dual (or "parallel") circuit paths. For example,
FIG. 1, herein, shows a simplified step attenuator circuit 10
containing a forward (or highpass) path 12 and a return (or
lowpass) path 14. Cascaded or elongated circuit board arrangements
such as shown in U.S. Pat. No. 5,770,983 to Zennamo, Jr. et al.,
U.S. Pat. No. 4,901,043 to Palinkas, U.S. Pat. No. 4,701,726 to
Holdsworth, U.S. Pat. No. 4,451,803 to Holdsworth et al., U.S. Pat.
No. 3,579,156 to Parfitt, and U.S. Pat. No. 3,065,434 to
Calderhead, are not optimum platforms for such dual path filters. A
more optimum platform would be to have two circuit boards disposed
in a parallel arrangement.
[0008] U.S. Pat. No. 5,278,525 to Palinkas discloses parallel
circuit boards for a CATV notch filter (or "trap"), rather than for
a dual path filter. The construction includes a considerable number
of extra parts, such as an isolation shield, circuit board
housings, tuning screw housings, o-rings, and an outer housing
sleeve.
[0009] In most CATV applications, the filters are installed
outdoors. Thus, it is important that the filter construction be
moisture resistant. Efforts to make filters moisture resistant have
included enclosing the filter in an outer housing sleeve and
employing o-rings between the filter and the outer housing sleeve.
See, e.g., U.S. Pat. No. 5,745,838 to Tresness et al., U.S. Pat.
No. 5,278,525 to Palinkas, U.S. Pat. No. 4,701,726 to Holdsworth,
and U.S. Pat. No. 4,451,803 to Holdsworth et al. Such an approach
requires the additional parts and expense of o-rings and outer
housing sleeves, and may require manual assembly of such parts.
[0010] A prime path for moisture penetration into the filter is
through the terminal fittings or connectors. While efforts to
prevent moisture penetration through filter connectors (such as
disclosed in U.S. Pat. No. 5,278,525 to Palinkas) have been
satisfactory, there remains a need to improve moisture resistance
through these connector paths.
[0011] Another consideration in CATV filter construction is to
establish a good and reliable electrical ground between the filter
circuit or circuits and the filter housing. Electrical ground has
been established by soldering or fitting isolation shields or
blocks between the circuit boards and the filter housing, or by
soldering wires or leads between the circuit board and housing.
See, for example, U.S. Pat. No. 4,701,726 to Holdsworth. However,
such methods usually require additional components or manual
assembly steps.
OBJECTS AND SUMMARY OF THE INVENTION
[0012] It is therefore an object of the present invention to
provide an electronic filter construction that avoids the limits
and problems associated with the prior art.
[0013] It is another object of the present invention to provide an
electronic filter construction that is more suitable for automated
assembly than previous filter constructions.
[0014] It is a further object of the present invention to provide
an electronic filter construction that requires less parts than
previous filter constructions.
[0015] It is still another object of the present invention to
reduce material and labor costs associated with the assembly of an
electronic filter;
[0016] It is still a further object of the present invention to
reduce the size and weight of an electronic filter; and
[0017] It is still yet another object of the present invention to
provide an electronic filter construction that has improved
moisture resistance.
[0018] These and other objects are attained in accordance with the
present invention wherein there is provided an electronic filter
assembly of the type that includes a female terminal cap and a
collet assembly. The female terminal cap has a fitting portion and
contains a terminal passage through the fitting portion. The collet
assembly is secured in and substantially closes the terminal
passage of the female terminal cap. The collet assembly comprises
an insulator, a collet terminal, and a seal. The insulator is made
from a single piece of insulator material and contains a bore
therethrough. The collet terminal extends through the bore of the
insulator. The seal is located inside the terminal passage of the
female terminal cap, between the collet terminal and the female
terminal cap.
[0019] In a more specific embodiment, an electronic filter
comprises a conductive housing having input and output ends. The
housing has a body portion and a female connector. The female
connector is located at the input end of the housing and has a
diameter less than that of the body portion. A circuit board is
located within the body portion of the housing. A collet assembly
is located within the female connector to receive electrical
signals and conduct them to the circuit board. The collet assembly
includes an insulator member, a conductor, and an elastomeric
sealing member. The insulator member is located within the female
connector. The insulator member contains a generally cylindrical
opening through its length. The conductor extends through the
opening of the insulator member. The conductor has an input end
adjacent the input end of the housing and an output end adjacent
the circuit board. The conductor has a hollow interior at its input
end. The elastomeric sealing member surrounds the insulator member
in compressed engagement with the insulator member and the
surrounding female connector, to provide a moisture seal between
the insulator member and the female connector.
BRIEF DESCRIPTION OF THE DRAWING
[0020] Further objects of the present invention will become
apparent from the following description of the preferred embodiment
with reference to the accompanying drawing, in which:
[0021] FIG. 1 is a schematic diagram of a dual-path filter
circuit;
[0022] FIG. 2 is a longitudinal cross-sectional view of a filter
constructed in accordance with the teachings of the prior art;
[0023] FIG. 3A is a longitudinal cross-sectional view of a filter
constructed in accordance with the present invention;
[0024] FIG. 3B is an enlarged cross-sectional view of the circled
area in FIG. 3A;
[0025] FIG. 4 is an exploded view of the filter shown in FIG.
3A;
[0026] FIG. 5 is an exploded view showing a modification to the
filter of FIG. 4; and
[0027] FIG. 6 is an exploded view showing another modification to
the filter of FIG. 4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0028] The filter assembly of the present invention is especially
suited for dual (or parallel) path filter circuits. As understood
in the art, dual path circuits include at least two separate
circuit paths. Examples of dual path filters are diplex, windowed
highpass, and some step attenuator filters. Referring now to FIG.
1, there is shown a schematic of a dual path filter circuit 10,
having a highpass circuit path 12 and a lowpass circuit path 14.
Circuit 10 is a simplified version of a step attenuator circuit
described in U.S. Pat. No. 5,745,838 to Tresness et al.,
incorporated herein by reference. The present invention is not
limited to filter assemblies for any particular filter circuit.
Circuit 10 is presented only as an example of a dual path circuit.
An understanding of circuit 10 is not necessary for an
understanding of the present invention.
[0029] FIG. 2 shows a sectional view of a conventional filter
construction. The construction includes a female terminal cap 16, a
male terminal cap 18, an elongated circuit board 20, a female
terminal 22, a male terminal 24, o-rings 26 and 28, and an outer
housing sleeve 30. Terminal caps 16 and 18 are soldered together by
way of a solder ring 32. Female terminal 22 is connected to a
female connector assembly 34 which includes a sealing member 36.
Male terminal 24 extends through an internally threaded fitting 38
contained in cap 18. Terminal 24 is tightly fitted through a
sealing wafer 40 secured inside cap 18. The filter shown in FIG. 2
is of the type that does not require shielding or tunable filter
components. As a result, low profile, surface mounted filter
components 44 are used. It is apparent from FIG. 2 that this
conventional construction produces an enormous amount of wasted
internal space, and the elongated shape of circuit board 20
constrains efforts to reduce the length of the filter.
[0030] The conventional filter construction of FIG. 2 is contrasted
markedly by the filter construction of the present invention, shown
in FIG. 3A. FIG. 3A depicts the preferred embodiment of the present
invention. It does not include the outer housing sleeve and
accompanying o-rings. The elimination of these parts simplifies the
assembly and allows the filter manufacturer to adopt a more
automated assembly process.
[0031] The preferred construction will now be described in detail
with reference to FIGS. 3A, 3B and 4. A filter 50 includes a female
terminal cap 52 and a male terminal cap 54. Caps 52 and 54 are
disposed along a longitudinal axis L, in opposing relation to each
other. Caps 52 and 54 are made of any suitable conductive metal
typically used in the filter industry. Cap 52 includes a
cylindrical portion 56 having an extension or crimping sleeve 58.
Cylindrical portion 56 extends to cap 54, and sleeve 58 is crimped
around cap 54, to form a filter housing with an interior volume 60
(FIG. 3A). Cap 54 contains an external circumferential groove 62
(FIGS. 3A and 4). Caps 52 and 54 are sealed together using a solder
ring 64 received in groove 62. A circumferential solder joint is
established with ring 64, by way of induction soldering. The solder
joint also establishes a good electrical ground connection between
caps 52 and 54. Induction soldering is preferred because it can be
implemented as an automated assembly step. As a result of the
above-described crimping and soldering, a secure physical and
electrical connection is established between caps 52 and 54.
[0032] Female terminal cap 52 includes a fitting portion 66
containing external threads 67 and a terminal passage 68. Male
terminal cap 54 includes a fitting portion 70 containing internal
threads 71 and a terminal passage 72. Passages 68 and 72 each
establish a passageway between interior volume 60 and the exterior
of filter 50.
[0033] As shown in FIG. 3A, a pair of filter circuit boards 74, 76
are enclosed in interior volume 60. Circuit boards 74, 76 are
arranged substantially parallel to each other and to longitudinal
axis L. In this disclosure and in the claims, the term "parallel"
is not intended to mean precisely parallel. The term includes
orientations that may produce acute angles between the circuit
boards.
[0034] As best shown in FIG. 4, circuit board 74 includes--(i)
front and rear surfaces 78, 79, (ii) a filter circuit 80 located on
front surface 78, (iii) a pair of ground contacts 82, 83
electrically connected to circuit 80, and (iv) a terminal 84
electrically coupled to circuit 80. Circuit board 76 includes--(i)
front and rear surfaces 86, 87, (ii) a filter circuit 88 located on
front surface 86, (iii) a pair of ground contacts 90, 91
electrically connected to circuit 88, and (iv) a terminal 92
electrically coupled to circuit 88. It is preferred that another,
corresponding pair of ground contacts be located on the rear
surfaces of boards 74, 76, respectively (see corresponding contacts
82a, 83a and 90a, 91a in FIG. 4). These corresponding pairs of
contacts are likewise electrically connected to their respective
filter circuits (80, 88). Circuit 80 is connected to circuit 88 by
way of jumper wires 93a, 93b (FIG. 4), to form a complete filter
circuit (such as shown in FIG. 1). Circuits 80, 88 are preferably
implemented with all surface mounted filter components, including
fixed-tuned chip (ceramic medium) inductors and/or ferrite core
inductors.
[0035] Dual filter circuit 10 (FIG. 1) can be neatly arranged on
circuit boards 74, 76, as indicated by the broken lines in FIG. 1.
As represented in FIG. 1, circuit board 74 contains circuit path 14
which is embodied in circuit 80, and circuit board 76 contains
circuit path 12 which is embodied in circuit 88. These paths are
joined together by jumper wires 93a, 93b (FIG. 1). It is to be
noted that the present invention is not limited to dual path
circuits or to the separation of dual circuit paths on respective
circuit boards. Any operable arrangement may be employed. When we
refer to a "filter circuit" or "circuit" on a circuit board, in
this disclosure and in the claims, it is intended to mean any
arrangement of a circuit component or circuit components, whether
or not constituting a complete or identifiable filter circuit. The
example presented in this disclosure is merely to illustrate the
suitability of the parallel circuit board arrangement to a dual
path circuit.
[0036] Circuit boards 74, 76 are mounted directly to male terminal
cap 54. As best shown in FIG. 4, circuit boards 74, 76 have mating
ends 75, 77, respectively, and the ground contacts are located at
the mating ends. Terminal cap 54 contains two pairs of opposed
notches 94a, 94b and 94c, 94d. For the purpose of this disclosure
and the claims, the term "groove" shall include its normally
intended meanings and, in addition, it shall include notch pairs,
such as notch pairs 94a, 94b and 94c, 94d. Thus, e.g., notch pair
94a, 94b may be properly referred to herein as groove 94a, 94b.
Grooves 94a, 94b and 94c, 94d are configured to receive, in a tight
press fit, the mating ends of circuit boards 74, 76, respectively.
This tight press fit secures the circuit boards in position.
[0037] Circuits 80, 88 are electrically coupled to terminal cap 54
via the ground contacts, and thus establish a common electrical
ground for circuits 80, 88. Ground contacts 82, 82a and 83, 83a are
in registration and direct contact with notches 94a and 94b,
respectively, and ground contacts 90, 90a and 91, 91a are in
registration and direct contact with notches 94c and 94d,
respectively. Each of the ground contacts is coated with solder
when circuit boards 74, 76 are produced. The solder coating ensures
a tight fit between the contacts and the notches.
[0038] In fact, during assembly, the some of the solder is sheared
off during insertion of boards 74, 76 into notches process 94a, 94b
and 94c, 94d. The ground contacts are soldered to the notches by
induction soldering (another automated assembly step). This
arrangement establishes a good ground connection between the
circuit boards and cap 54.
[0039] Terminal 92 is a male connector terminal which extends
through and is operatively supported inside terminal passage 72. A
potting wafer 95, made of low density polyethylene, is inserted
into and substantially closes off terminal passage 72. Wafer 95
contains an open bore through which terminal 92 tightly fits. Once
installed, wafer 95 seals passage 72, substantially preventing
moisture from entering filter 50 through passage 72.
[0040] Terminal 84 includes a female terminal assembly 96 which
extends through and is operatively supported inside terminal
passage 68. Terminal assembly 96 includes a female connector
element or collet terminal 96a, a polypropylene insulator 96b
containing an external o-ring groove 96c (FIG. 4), and an o-ring
96d seated in groove 96c. Assembly 96 is inserted into and
substantially closes off terminal passage 68. Insulator 96b and
o-ring 96d, together, seal passage 68, substantially preventing
moisture from entering the filter between passage 68 and insulator
96b. Insulator 96b contains an open bore through which collet
terminal 96a tightly fits.
[0041] As shown in FIG. 3B, collet terminal 96a has a pair
circumferential (360.degree.), protruding barbs or ribs 98. Collet
96a is press fitted through the bore of insulator 96b, causing
barbs 98 to penetrate and anchor into insulator 96b (FIG. 3B).
"Penetration" of barbs 98 may or may not include breaking into the
insulator material--typically, the barbs will penetrate the
insulator by deforming the insulator material. The barbs, and their
penetration into the insulator, help prevent moisture from entering
filter 50, between the bore of insulator 96b and collet 96a.
[0042] As shown in FIGS. 3B and 4, insulator 96b has a cone-shaped
nose 99, which allows o-ring 96d to be easily slipped over the
insulator and seated in groove 96c. This cone-shape allows o-ring
96d to be installed on the insulator by an automated assembly step.
In some filter constructions, it may be preferable to have collet
96a extend through the insulator to the point where it is flush
with an insulator face 96e (See FIG. 3B). The construction, as
above-described, may eliminate the need for potting material inside
the filter, in most applications.
[0043] Referring now to FIG. 5, there is shown a modification to
the embodiment of FIG. 4. Like parts are indicated by like
reference numbers. The modification concerns the placement of
printed circuit inductors on the rear surface of each circuit
board. As shown in FIG. 5, circuits 180, 188 each include a pair of
printed inductors 180a, 180b and 188a, 188b, respectively, etched
on respective rear surfaces 179 and 187. Inductors 180a, 180b and
188a, 188b may serve, for example, as inductors L3, L4 and L1, L2,
respectively, in the circuit shown in FIG. 1. In this embodiment,
the capacitors of circuits 180, 188 would remain on the front
surfaces of circuit boards 174, 176. The embodiment of FIG. 5 is
otherwise the same as the embodiment of FIGS. 3A, 3B and 4.
[0044] Referring now to FIG. 6, there is shown another modification
of the embodiment of FIG. 4. Like parts are indicated by like
reference numbers. In some applications, it may be desirable to
have a certain degree of electromagnetic shielding between circuit
boards. This can be achieved by locating the filter circuits on the
rear surfaces of the circuit boards and locating ground planes on
the front surfaces of the boards. As shown in FIG. 6, circuits 280,
288 are located on rear surfaces 279, 287, respectively, and ground
planes 281, 289 are located on the front surfaces of boards 274,
276, respectively. The ground planes provide shielding between
circuits 280, 288. Ground planes 281, 289 are grounded by their
direct physical contact with notches 294a, 294b and 294c, 294d,
respectively, when boards 274, 276 are seated in the notches. Thus,
separate ground contacts are not necessary on the front surfaces of
the boards. As shown in FIG. 6, ground contacts 282a, 283a and
290a, 291a are located on the rear surfaces of boards 274 and 276,
respectively.
[0045] A circular opening 281a is contained in ground plane 281 to
allow terminal 284 to be connected to board 274 without shorting to
ground. A similar opening is provided in ground plane 289 for
terminal 292. Openings are also contained in the ground planes to
accommodate jumper wires 293a, 293b. The embodiment of FIG. 6 is
otherwise the same as the embodiment of FIGS. 3A, 3B and 4.
[0046] While the preferred embodiment of the invention has been
particularly described in the specification and illustrated in the
drawing, it should be understood that the invention is not so
limited. Many modifications, equivalents, and adaptations of the
invention will become apparent to those skilled in the art without
departing from the spirit and scope of the invention.
* * * * *