U.S. patent number 3,587,028 [Application Number 04/819,873] was granted by the patent office on 1971-06-22 for coaxial connector guide and grounding structure.
This patent grant is currently assigned to International Business Machines Corporation. Invention is credited to Edward C. Uberbacher.
United States Patent |
3,587,028 |
Uberbacher |
June 22, 1971 |
COAXIAL CONNECTOR GUIDE AND GROUNDING STRUCTURE
Abstract
A grid structure is provided defining rows and columns of square
openings therein which when connected to a circuit board provides a
guide means for positively indexing coaxial wire terminals with
contact pins extending from terminals on the circuit board. The
grid structure also serves as a common grounding means for the
shield conductor of each of the coaxial wires.
Inventors: |
Uberbacher; Edward C.
(Poughkeepsie, NY) |
Assignee: |
International Business Machines
Corporation (N/A)
|
Family
ID: |
25229302 |
Appl.
No.: |
04/819,873 |
Filed: |
April 28, 1969 |
Current U.S.
Class: |
439/49;
439/607.08 |
Current CPC
Class: |
H01R
13/6585 (20130101); H01R 24/50 (20130101); H01R
13/506 (20130101); H01R 13/6582 (20130101); H01R
2103/00 (20130101) |
Current International
Class: |
H01R
13/00 (20060101); H01R 13/646 (20060101); H01r
003/06 () |
Field of
Search: |
;339/14,17,18
;52/667,668 ;220/21 ;217/18,29 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Leppink; James A.
Assistant Examiner: Hafer; Robert A.
Claims
What I claim is:
1. A coaxial wire connector guide and shield grounding structure
comprising:
a conductive grid wall structure defining small apertures therein
securely mounted to a unit which has a plurality of contact means
extending therefrom;
each of said apertures surrounding a different one of said contact
means but spaced therefrom so that there is no electrical
interconnection therebetween;
coaxial wire terminators each having a signal wire contact means
for connection to a respective one of said contact means extending
from said unit and each having a shield contact means electrically
connected to the shield conductor of said coaxial wire and
surrounding said signal wire contact means and electrically
insulated therefrom;
each coaxial wire terminator being slightly smaller in width than
said apertures so as to be guided therein to positively mate with
said contact means; and
a grounded grid wall contact means on at least one of said grid
walls adapted to complete an electrical circuit through said shield
contact means when said coaxial wire terminator is inserted within
said aperture in said grid wall structure.
2. Apparatus according to claim 1, wherein said grid structure is
made of strips of material having slits extending halfway through a
width thereof, said slits being spaced from one another at a
distance defining an aperture width;
a cutout portion of the same width as said slit located below said
slit in the other half of the width of said strips; and
a pair of opposing retaining lobes extending into each of said
slits, whereby said strips may be interconnected by inverting one
with respect to another and interconnecting via said slits, the
lobes being dimensioned and located along the length of said slits
to fit into said cutout portions of the interconnected strip.
3. Apparatus according to claim 2, wherein both surfaces of the
strips are alternately gold plated and tin-lead plated in stripes
extending from the top to bottom thereof across the width along the
entire lengths, each tin-lead stripe including one of said slits
and cutout portions, the gold stripes forming said grounded grid
wall contact means.
4. Apparatus according to claim 3, wherein the joints between said
interconnected strips are soldered by causing the tin-lead plated
stripes to rise above their melting temperature whereby they form a
solder joint between the contiguous edges of the interconnected
slits, cutout portions and the retaining lobes.
5. Apparatus according to claim 3, wherein said grounded grid wall
contact means includes a finger cut from the strip in the area of
each of said gold plated stripes except for one end so that they
can be bent into said apertures to form a good pressure contact
between said shield contact means of each coaxial wire terminator
inserted in said apertures and the grounded grid wall.
6. Apparatus according to claim 3, wherein said shield contact
means of said coaxial wire terminator includes at least one
outwardly spring biased portion for contacting a gold plated stripe
of a wall of the aperture to form a good pressure contact
electrical connection between the shield conductor of said coaxial
wire and the grounded grid wall.
7. Apparatus according to claim 1, wherein said electrical unit is
a circuit board and said contact means are male contact terminals
extending vertically from said board and arranged in a
predetermined pattern to be compatible with the aperture locations
in said grid structure.
8. Apparatus according to claim 1, wherein said coaxial wire
terminator comprises a receptacle attached at one end to the center
conductor of said coaxial wire and adapted to receive a male
contact;
insulation means surrounding said receptacle;
said shield contact means comprising a shield potential sleeve
surrounding said insulator and being connected to the shield
conductor of said coaxial wire; and
said sleeve being shaped the same as said apertures and being of a
size to fit snugly therein.
Description
This invention relates to a coaxial connector guide and grounding
structure and more particularly to a grid structure for guiding
coaxial wire terminating contacts into engagement with
complementary contacts and for providing a common ground for the
shield conductors of the coaxial wires.
With the continuing trend toward miniaturization of electronic
components and circuits, it has become necessary to provide a
greater number of electrical connections in a very small space. For
example, it has become desirable to be able to make connections to
a circuit board on 0.050-inch centers. The usual way of making such
connections is to make a solder connection to a contact pin
extending from a terminal on the circuit board. These contact pins
are extremely small and delicate. It has become extremely difficult
to make a connection to these closely packed pins without some more
positive guide means. The problem is especially critical in
connection with coaxial wires which require separate termination to
two pins on the board. The center conductor must be connected as
well as the shield conductor. For example, a coaxial line connector
is shown in U.S. Pat. No. 3,179,914, which shows two separate
contacts 38 and 28. One of these contacts is the center conductor
or signal conductor contact while the other is the shield or braid
conductor contact. It will be readily appreciated that separate
contact means are needed to engage each of the contacts of the
connector to complete the connection.
Accordingly, it is the main object of the present invention to
provide a coaxial wire connector means which can be terminated to a
circuit board through one contact pin.
It is another object of the present invention to provide a coaxial
connector guide means for guiding a coaxial cable terminator into
positive engagement with a complementary contact.
It is a further object of the invention to provide a coaxial
connector guide means which also serves as a common grounding
structure for the shield conductors of the coaxial wires.
It is another object of the present invention to provide a coaxial
connector guide means and common grounding structure which is
constructed of strips which are easily engageable into a locked
grid structure and which are manufacturable economically utilizing
known mass production techniques.
The invention includes a combination of a coaxial wire connector
guide and shield grounding structure having a grid structure which
defines small equal size apertures therein. The grid structure is
connected to an electrical unit which has a plurality of contact
terminals extending therefrom. Each of the apertures in the grid
structure surrounds a different one of the contact means extending
from the unit but is spaced therefrom so that there is no contact
therebetween. Coaxial wire terminators having signal wire contact
means are provided for connection to respective contact terminals
on said electrical unit. The coaxial wire terminators each include
a shield potential sleeve forming the outer wall of the terminator
and being slightly smaller in width than said apertures so as to be
guided therein into positive engagement with a contact terminal of
the electrical unit. At least one of the grid walls of each of said
apertures is electrically conductive and connected to ground. A
further contact means is provided between the coaxial wire
terminator shield potential sleeve and one or more of the
electrically conductive grid walls of the aperture.
The foregoing and other objects, features and advantages of the
invention will be apparent from the following more particular
description of a preferred embodiment of the invention, as
illustrated in the accompanying drawings.
FIG. 1 is a perspective expanded view of a grid structure, circuit
board and coaxial wire terminator.
FIG. 2 is a perspective view of strips out of which the grid
structure is formed and illustrating their interconnecting
means.
FIG. 3 is a cross-sectional view of an aperture in the grid
structure showing the male contact and the coaxial cable terminator
to be plugged therein.
FIG. 4 is a perspective view of a cable terminator showing spring
biased contact means for contacting the walls of the aperture.
FIG. 5 is a perspective view of a strip made of an insulative
material showing predetermined interconnections by printed circuit
means.
Referring to FIG. 1, there is shown a printed circuit board 10
which has a number of closely spaced circuit termination contacts
12 extending therefrom. These contacts are pins and are located on
0.050-inch centers. It will be appreciated that such close spacing
provides a great number of circuit terminations in a small space. A
grid structure 14 is provided which fits over the contact pins 12
of the circuit board 10 such that each pin extends into the middle
of an aperture of the grid 14. The grid structure 14 is connected
rigidly to the circuit board 10, or the like, thus preventing any
possibility of short circuiting the contact 12 to the walls of the
aperture. Utilizing pin contacts 12 that are only 15 mils in
diameter and 6.5 times their diameter in length, approximately 400
terminations per square inch can be made. The strips, 16, 18 from
which the grid structure 14 is formed, are made of thin sheets of
electrically conductive spring material such as phosphor bronze.
Thus, when the grid structure 14 is rigidly connected to the
circuit board 10, the apertures formed therein provide a guide
means for a coaxial cable terminator 20 so that positive indexing
of the terminator with the male contact 12 located in the center of
the aperture is obtained and a grounding means is provided.
The strips 16, 18, from which the grid structure 14 is formed, are
shown in FIG. 2. Each strip 16, 18 is identically manufactured with
slits 22 extending halfway through the width thereof. Below each
slit there is a short cutout portion 24 of the same width as the
slit. In each slit 22, there is a pair of facing retaining lobes 26
which engage the respective cutout portion 24 of an interconnected
strip to hold the strips in place. The interconnection is performed
by inverting one of the strips 16, 18 with respect to the other so
that the slits 22 fit within each other and the retaining lobes 26
fit into the cutout portions 24 below each of the slits. The slits
22 and cutout portions 24 are surrounded by a stripe 28 of tin-lead
plating extending the entire width of the strips on both sides of
the strips. The stripes 28 of tin-lead plating are separated by
stripes 30 of gold plating. The gold plated stripes 30 include a
finger 32 of the strip material 16, 18 which is cut therefrom but
attached at one end and biased away from the surface of the strip
16, 18. As will be explained later in more detail, the gold plated
spring finger 32 serves as a contact to electrically interconnect a
coaxial cable terminator 20, inserted into the apertures, with the
grid structure 14.
Once the strips 16, 18 have been interconnected by means of the
slits 22, cutouts 24 and retaining lobes 26, heat is applied, for
example, by placing the unit in an oven or blowing hot air
thereover, so that the stripe 28 of tin-lead plating melts and
collects in the joints between the joined strips 16, 18. It has
been found that this soldering prevents the strips 16, 18 from
moving relative to one another and thus adds structural strength to
the grid structure 14.
Coaxial wire generally consists of an inner signal conductor which
is surrounded by an insulation material which in turn is surrounded
by an outer shield or braid which serves as the outer conductor.
This outer conductor is sometimes referred to as the ground shield.
In connecting coaxial wire to a circuit board, the signal conductor
is generally connected to a circuit pin and the shield or braid is
connected to a separate ground pin. It will be readily appreciated
that twice as many pins are required for making connections to a
circuit board from coaxial wires.
The coaxial wire terminator 20 of the present invention consists of
a forwardly extending receptacle 34 which is attached at its rear
end to the signal wire 36, for example, by soldering. This
receptacle 34 has a slit 38 running lengthwise from the front
toward the rear across the diameter thereof which allows the
receptacle 34 to give a little in receiving the pin 12 and thus
forms a good tight contact therebetween. The receptacle 34 is
surrounded by insulation material 40 to prevent shorting except for
a portion in the front which serves as an opening 42 to receive the
pin 12. This opening 42 is funnel-shaped with the narrow end
extending towards the front of the receptacle 34 to more easily
receive and guide the pin 12 into the receptacle. The insulation 40
is surrounded by a conducting sleeve 50 which is electrically
connected to the shield conductor 46 of the coaxial wire. The
connection can be made by pretinning the portion of the shield 46
and the conductor sleeve 50 portion to be connected and then
applying heat to cause the portions to solder together. Thus, the
signal wire 36 is connected to the terminal on the circuit board by
connecting to the pin 12 while the outer conductor or braid 46 is
connected by means of contact elements 48 between the aperture
walls and the outer conductive sleeve 50 of the coaxial terminal
20.
The contact arrangement between the outer conductive sleeve 50 of
each of the coaxial terminals 20, and the walls of the respective
aperture in the grid structure 14, can take many forms. As shown in
FIG. 2, a cut is made in each gold plated stripe 30 of each strip
16, 18 which outlines a finger 48 but is left attached near one of
the side edges of the strip. The end at which the finger 48 is left
attached or the direction in which the finger points depends upon
whether the strip is to be inverted or not for interconnection. The
finger 48 is connected at the end away from the slit 22 for the
strip 16 which is shown inverted with respect to strip 18. The
finger 48 is connected near the edge where the slit 22 starts on
the strips 18 which are shown not inverted for interconnection with
strip 16. Thus, the fingers 48 extend or point into the apertures
on all the walls. The fingers 48 are bent away from the plane of
the strips 16, 18 so that they are displaced into the plane of the
strip by a terminal 20 as it is inserted into the aperture into
which the finger 48 is bent. Since the finger 48 is cut from a
spring material, it will press against the terminal 20 because of
the spring bias, thus insuring a good electrical contact between
the wall and the shield sleeve 50 of the terminal 20. The spring
fingers 48 are bent away from the plane of the strips 16, 18 in
alternate directions. The strips 16, 18 are interconnected so that
one pair of opposite walls of each aperture will have their fingers
48 bent into the aperture. Accordingly, the other opposite pair of
walls will have their fingers 48 bent out of the aperture forming a
contact for the aperture into which they are bent. Each aperture,
therefore, contains two contacting fingers 48 each of which is on
an opposing wall for connecting the shield conductor sleeve 50 of a
coaxial terminal 20 to ground. It will be appreciated that each of
the coaxial cable shields 46 can be grounded in this way to the
common grid structure 14 which is connected to the circuit board by
a grounding pin, if desired. Of course, grounding of the grid
structure 14 can be accomplished by other means. The contact means
between the coaxial terminator 20 and the grid structure 14 can
also be made by a contact 54, extending from the coaxial terminal
20, as shown in FIG. 4 for electrically connecting the outer
conductor 46 of the coaxial wire 55 to ground. The contact 54
extends from at least one side of the coaxial terminal 20 and is
preferably spring biased outward such that when the terminal 20 is
inserted into the respective aperture of the grid structure 14 the
contact 54 will be pressed inward but yet maintain sufficient force
outward to give a good electrical connection along the conductive
plated stripe 30 of the adjacent wall of the aperture. Thus, the
contacts 54 replace the contacting fingers 48 of the previously
described embodiment. Once the coaxial terminals 20 are in place in
the grid structure 14, each of the shield conductors 46 of the
coaxial wire 55 are connected to the walls within the aperture.
Thus, each of the conductive sleeves 50 of the terminals 20 are
essentially interconnected by the strips 16, 18 of the grid
structure 14 and thus the grounded grid structure 14 serves as a
common ground means for each of the coaxial wires 55.
If it is desired to terminate the shields 46 of coaxial cables 55
to different grounds of different potentials, this can be
accomplished by utilizing nonconductive grid strips 57 as shown in
FIG. 5. That is, the strips 57 can be made of an electrical
nonconductor such as epoxy. Each of the conductive stripes 56, to
make the electrical connection between the coaxial terminal 20 and
the strip 57 of the grid structure, are isolated from the tin-lead
plated areas 58. This can be accomplished by copper plating 59 the
epoxy wall 57 so that the plating of conductive material 56 such as
gold and the tin-lead plating 58 can be applied. The tin-lead
plating 58 is applied only adjacent the edges of the slit 62 and
cutout portion 64. Once the tin-lead plating 58 and the conductive
plating 56, such as gold, are applied, the copper portion 59
between the conductive coating 56 and the tin-lead coating 58 can
be easily removed. This isolates the conductive coating 56 from the
tin-lead coating 58. It will be appreciated, that the isolated
conductive areas 56 can be interconnected by printed circuitry 66
and grounded as desired. Using an arrangement of this type, pairs
of adjacent parallel strips 57, for example, can be connected to
one ground where other pairs of adjacent parallel strips can be
connected to a separate ground of a different desired potential. Of
course, the strips forming the walls between the respective pairs
will have to be nonconductive in such an arrangement. It will be
appreciated that opposite sides of the same strip may be connected
to different ground potentials. As a matter of fact, each
conducting surface 56 could be connected to a separate ground or
any electrically connected surface 56 can be connected to a
particular ground potential.
The grid structure 14 serves not only as a guide means for
positively indexing the coaxial wire terminator 20 with the male
contact pin 12 of the circuit board 10 but also serves as a
grounding structure for the shield conductor 46 of the coaxial wire
55.
While the invention has been particularly shown and described with
reference to a preferred embodiment thereof, it will be understood
by those skilled in the art that various changes in form and detail
may be made therein without departing from the spirit and scope of
the invention.
* * * * *