U.S. patent number 3,879,103 [Application Number 05/342,554] was granted by the patent office on 1975-04-22 for coaxial cable connector for circuit board.
This patent grant is currently assigned to Tektronix, Inc.. Invention is credited to Richard F. Guarnero, Ronald W. Peltola.
United States Patent |
3,879,103 |
Peltola , et al. |
April 22, 1975 |
COAXIAL CABLE CONNECTOR FOR CIRCUIT BOARD
Abstract
Connector apparatus for connecting a coaxial cable to a strip
transmission line on an etched circuit board is described including
a resilient socket member mounted on the circuit board and a plug
member attached to the end of the cable. The plug includes a
tubular inner eyelet crimped onto the jacket of the cable and
surrounded by an outer eyelet which clamps a portion of the outer
conductor of the cable between such two eyelets by an interference
fit. One end of the inner conductor of the coaxial cable extends
out of the eyelets and is inserted into a hole in the circuit board
which may contain a separate tubular inner socket member for
connection to the signal conductor of the strip line. An outer
socket member in the form of a split sleeve having a plurality of
legs attached to the circuit board is connected to the ground
conductor of the strip line and resiliently holds the plug member
inserted therein.
Inventors: |
Peltola; Ronald W. (Beaverton,
OR), Guarnero; Richard F. (Lake Oswego, OR) |
Assignee: |
Tektronix, Inc. (Beaverton,
OR)
|
Family
ID: |
26790411 |
Appl.
No.: |
05/342,554 |
Filed: |
March 19, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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95627 |
Dec 7, 1970 |
3742425 |
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Current U.S.
Class: |
439/581 |
Current CPC
Class: |
H01R
24/50 (20130101); H01R 9/0515 (20130101); H01R
2103/00 (20130101) |
Current International
Class: |
H01R
13/00 (20060101); H01R 9/05 (20060101); H01R
13/646 (20060101); H05k 001/02 () |
Field of
Search: |
;339/17,177,276,217S,125,126,128,127,217R |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1,300,611 |
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Jun 1962 |
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FR |
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1,007,053 |
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Oct 1965 |
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GB |
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1,164,120 |
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Oct 1958 |
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FR |
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911,743 |
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Nov 1962 |
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GB |
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811,589 |
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Apr 1959 |
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GB |
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Primary Examiner: Frazier; Roy D.
Assistant Examiner: Lewis; Terrell P.
Attorney, Agent or Firm: La Rue; Adrian J.
Parent Case Text
This is a division of application Ser. No. 95,627, filed Dec. 7,
1970.
Claims
I claim:
1. A coaxial cable connector for terminating an end of a coaxial
cable having an inner conductor surrounded by a sheath of
insulation with an exposed section extending outwardly from the
insulation and an outer conductor surrounded by a sheath of
insulation with an exposed section of the outer conductor extending
outwardly from the sheath of insulation, comprising:
a first ferrule means positioned on the sheath of insulation
surrounding the outer conductor and a second ferrule means
telescopically positioned on said first ferrule means, both of said
ferrule means electrically connected by capturing the exposed
section of the outer conductor therebetween, whereby both of said
ferrule means and the inner conductor so assembled define a plug
means;
a first connector means resiliently connected only to the exposed
section of the inner conductor thereby terminating the inner
conductor and a second connector means resiliently connected to the
second ferrule means thereby terminating only the outer conductor,
whereby both of said connector means are independently connected to
the coaxial cable and so assembled define a socket means mated to
said plug means to terminate the end of the coaxial cable.
Description
BACKGROUND OF THE INVENTION
The subject matter of the present invention relates generally to
electrical connectors for cables and, in particular, to connectors
for connection of a coaxial cable to a strip line type transmission
line on an etched circuit board.
The coaxial cable connector of the present invention includes a
resilient outer socket member in the form of a split sleeve having
legs which are soldered to the circuit board, and a plug member
including two tubular eyelets attached to the end of the outer
conductor of such cable. The plug member is inserted into such
outer socket member which acts as a guide so that the end of the
inner conductor of the cable extending out of the plug member is
also inserted through a hole in the circuit board which may contain
a separate inner socket member. The circuit board may have a strip
line type transmission line formed thereon with a uniform
characteristic impedance equal to that of the coaxial cable, and
includes a signal conductor and a ground conductor, respectively
connected to the inner socket member and the outer socket member.
As a result of its simplified construction, the coaxial connector
apparatus of the present invention is inexpensive to manufacture
and is provided with an extremely high frequency response as well
as a low standing wave ratio due to the fact that the
characteristic impedance of the cable is maintained throughout the
entire length of the connector which minimizes signal
reflections.
The connector apparatus of the present invention is especially
useful for connecting the signal input of a wide band cathode ray
oscilloscope to its vertical amplifier.
Previous coaxial cable connectors for connecting to etched circuit
boards have employed a plug member including a pin connected to the
inner conductor of the cable and a resilient outer shield connected
to the outer conductor of such cable which mate with corresponding
inner and outer socket members joined together by solid dielectric
material, as shown in U.S. patent 2,869,090 of Johanson, granted
January 13, 1959. In addition to being simpler and less expensive
in construction due in part to the use of a split sleeve socket
member and the use of a bare end portion of the inner conductor of
such cable as the inner plug member, the connector apparatus of the
present invention also has a higher frequency response and a lower
standing wave ratio than such prior apparatus.
It is therefore one object of the present invention to provide an
improved cable connector apparatus of simple and inexpensive
construction.
Another object of the invention is to provide such a connector
apparatus for connecting a coaxial cable to a strip transmission
line on a circuit board in which the characteristic impedance of
the cable is maintained through the entire length of the connector
apparatus to provide a higher frequency response and a lower
standing wave ratio.
An additional object of the invention is to provide such a
connector apparatus with a plug means which may be attached to the
cable and a socket means which may be mounted on the circuit board
by automatic assembly.
A further object of the present invention is to provide such a
connector apparatus with a socket member in the form of a split
sleeve which resiliently engages a rigid plug member attached to
the cable and guides the insertion of a bare end portion of the
cable into a hole in the circuit board for easy reliable connection
operation.
Still another object of the present invention is to provide such
connector apparatus in which the socket means includes an inner
socket member mounted in the hole in a circuit board and separate
from the split sleeve socket member for releasable connection of
the cable to the circuit board while enabling a permanent
connection merely by replacing the inner socket member with a
soldered connection.
A still further object of the present invention is to provide such
a connector apparatus in which the plug means is formed by a pair
of tubular eyelet members clamping the shield wires at one end of
the outer conductor of such cable therebetween to form a connector
of short length so that the cable can extend parallel to the
circuit board a short distance therefrom for less mounting
space.
An additional object of the invention is to provide an improved
electrical connector socket in the form of a split sleeve member
having a polygonal cross section with flat sides and mounting legs
extending from such sides to provide good mechanical contact with a
plug member of circuit cross section inserted into such socket.
A further object of the invention is to provide such a connector
socket with a lower inductance to ground by providing one of the
leg portions with a shorter length extending substantially
perpendicular to the main body of the socket and by providing a
slot in such main body extending longitudinally along its full
length.
Other objects and advantages of the present invention will be
apparent from the following detailed description of the preferred
embodiment thereof and from the attached drawings of which:
FIG. 1 is a side elevation view of the connector apparatus of the
present invention with a portion of the circuit board broken away
for clarity;
FIG. 2 is a front elevation view of the connector apparatus of FIG.
1 with the plug shown removed from the socket;
FIG. 3 is an exploded view of the connector apparatus of FIGS. 1
and 2;
FIG. 4 is an enlarged horizontal sectional view taken along the
line 4--4 in FIG. 1;
FIG. 5 is an enlarged plan view of the inner socket member taken
along the line 5--5 of FIG. 2;
FIG. 6 is a horizontal sectional view taken along the line 6--6 of
FIG. 5;
FIG. 7 is a plan view of the circuit board taken along the line
7--7 of FIG. 1; and
FIG. 8 is an enlarged vertical section view taken along the line
8--8 of FIG. 1.
DESCRIPTION OF PREFERRED EMBODIMENT
The electrical connector apparatus of the present invention is
shown in FIGS. 1 and 2 and includes a socket 10 mounted on an
etched circuit board 12 and a plug 14 attached to one end of an
electrical cable 16. The cable 16 may be a coaxial cable including
an inner signal conductor 18 and an outer shield conductor 20
separated by solid dielectric material 22 of a suitable plastic
material, and a protective jacket 24 of plastic material provided
over the outer conductor 20.
The outer conductor 20 may be in the form of braided wire strands
woven together along its entire length except for shield wires 26
at one end thereof which, as shown in FIGS. 3 and 8, are separated
and bent back along the cable over an inner plug member 28. The
inner plug member is in the form of a tubular metal eyelet having
an outer flange portion 30 extending outwardly from the side of the
eyelet one end thereof, such eyelet being crimped onto the jacket
24 of the cable. An outer plug member 32 in the form of a second
tubular metal eyelet is forced over the inner eyelet 28 to clamp
the shield wires 26 between such eyelets. Thus, the inner diameter
of eyelet 32 is just slightly larger than the outer diameter of
eyelet 28, in order to provide the proper spacing for a good
friction fit when the shield wires 26 are between such two eyelets.
The outer eyelet 32 is also provided with a flange 34 extending
radially outward at one end thereof. Flange 34 engages the flange
30 on the inner eyelet and during assembly such flanges shear off
any excess length of shield wires 26 which may extend between
them.
The plug means 14 also includes a bare end portion of the inner
conductor 18 which extends out of the eyelets 28 and 32 after some
of the dielectric 22 is trimmed off in the region where the shield
wires have been removed. This bare end of the inner conductor is
inserted through an opening in the circuit board as hereafter
discussed.
The socket means includes an outer socket member 10 in the form of
split sleeve of spring metal having a slot 36 extending
longitudinally through one side of the sleeve to provide a
resilient socket member. Three mounting legs 38, 40 and 42 extend
from one end of the sleeve into holes through the circuit board and
are soldered to a ground conductor strip 44 on the bottom of such
circuit board. An inner socket member 46 may also be provided to
form a releasable connection with the bare end of the inner
conductor 18. The inner socket member 46 is a tubular member
separate from the outer socket member 10, and is mounted in an
opening extending through the circuit board by soldering to metal
plating 47 on the walls of such opening as shown in FIG. 6. A
signal conductor strip 48 is provided on the bottom of the circuit
board uniformly spaced from the ground conductor 44 to form a strip
line type transmission line having a uniform characteristic
impedance equal to that of the coaxial cable 16, as shown in FIG.
7. The inner socket member 46 is connected to one end of the signal
conductor 48 by its soldered connection. Thus, the inner conductor
18 of the coaxial cable is connected to the signal conductor 48 of
the strip line through the inner socket member 46, while the outer
conductor 20 of the cable is connected to the ground conductor 44
of such strip line through the outer socket member 10 and plug
eyelet 32. It should be noted that the inner socket member 46 can
be eliminated and the bare end of the inner conductor 18 soldered
in the plated hole 47 to form a permanent connection to the signal
conductor strip 48. Also, a ground plane 49 and an annular
soldering tab 51 spaced therefrom may be provided on the top of the
circuit board for shielding the strip line and to facilitate
soldering of the socket members.
As shown in FIG. 4, the outer socket member 10 is of a polygonal
cross sectional shape which may be an octagon including four flat
side portions 50 which engage the outer eyelet 32 of the plug at
point contact areas since such eyelet has a circular cross section
whose outer diameter is slightly larger than the distance between
two opposed flat side portions 50. The three mounting legs 38, 40,
and 42 extend from three of the four flat sides 50 while the fourth
flat side is divided by the slot 36. As a result, it is easier to
form the leg portions merely by bending flat sheets of metal
extending from the main body portion of the socket.
The two opposed legs 38 and 42 each extend at an acute angle of
approximately 45.degree. to the side of the main body portion of
the socket member 10 at a point mid-way down such sides as shown in
FIG. 2. Legs 38 and 42 are formed by providing notches 52 in the
main body portion on opposite sides of such legs extending
approximately half the length of such body portion as shown in FIG.
1. The third leg 40 extends substantially perpendicular to the side
of the main body portion of the socket member 10 at a point on its
bottom end so that such leg is of a shorter length than the other
legs 38 and 40 in order to reduce its inductance and provide good
electrical ground for the socket member to the ground plane 49 on
the circuit board. The other two legs, 38 and 40 primarily serve as
the resilient mounting legs which resiliently urge the flat side
portions 50 of the socket 10 into engagement with the outer eyelet
member 32 of the plug 14. The longitudinal slot 36 in the socket
member 10 not only enables it to resiliently engage the plug with a
springlike action but also reduces the inductance of such socket
member.
As shown in FIG. 3, each of the legs 38, 40 and 42 are each
provided with a pair of shoulders 54 which act as stops for
engagement with the surface of the etched circuit board. The legs
also each include a tab portion 56 projecting from such shoulders
through the mounting hole in the printed circuit board to enable
soldering to the conductive surface of such printed circuit board.
In addition, while not shown, such tabs 56 can be made sufficiently
long to enable the end of the tab portion on the opposite side of
the circuit board from the shoulder 54 to be bent over for
preliminary attachment of the socket to the etched circuit board
before soldering. In any event, the socket members 10 and 46 are
automatically machine assembled on the circuit board and dip
soldered.
As shown in FIGS. 3 and 4, the inner eyelet 28 of the plug is
crimped onto the jacket 24 of the coaxial cable 16 at three crimp
areas 58 on the eyelet about mid-way along its length, such crimp
portions projecting inwardly into frictional engagement with such
jacket.
As shown in FIGS. 5 and 6, the inner socket member 46 includes a
conventional spring insert member 60. The spring insert 60 may be
in the form of a strip of spring metal having a plurality of slits
therein to provide separate strips, alternate ones of which are
bent inwardly toward the axis of the socket member 46 and act as
leaf springs.
The inner socket member 46 and the outer socket member 10 are both
flared outwardly at the top end of such socket members to enable
easier insertion of the inner conductor 18 and the outer eyelet 32
of the plug. Also, during insertion, the outer eyelet 32 of the
plug engages the outer socket member 10 first and guides the inner
conductor 18 into the inner socket member 46 upon further
insertion.
It will be obvious to those having ordinary skill in the art that
many changes may be made in the details of the preferred embodiment
of the present invention without departing from the spirit of the
invention. For example, two wire cables may be employed rather than
coaxial cables merely by attaching the ground wire between the two
eyelets and using the signal wire as inner conductor 18. Therefore,
the scope of the present invention should only be determined by the
following claims.
* * * * *