U.S. patent number 3,864,012 [Application Number 05/444,809] was granted by the patent office on 1975-02-04 for electrical connector.
Invention is credited to John M. Cutchaw.
United States Patent |
3,864,012 |
Cutchaw |
February 4, 1975 |
ELECTRICAL CONNECTOR
Abstract
A connector for electrically coupling flat ribbon type cables to
the edge contacts of printed circuit boards. The connector includes
a housing into which the edge of the circuit board having the cable
held in proper registry therewith is inserted for engaging a
tension band having a cam assembly mounted thereon and causing it
to exert a compressive force on the cable and a circuit board to
form electrical interconnections therebetween. The connector may
also be employed for splicing flat ribbon type cables by using a
spacer for holding the cables in proper registry with each other
and inserting the spacer and cables into the housing.
Inventors: |
Cutchaw; John M. (Scottsdale,
AZ) |
Family
ID: |
23766448 |
Appl.
No.: |
05/444,809 |
Filed: |
February 22, 1974 |
Current U.S.
Class: |
439/493; 439/260;
439/951 |
Current CPC
Class: |
H01R
12/87 (20130101); H01R 12/79 (20130101); H05K
3/365 (20130101); Y10S 439/951 (20130101) |
Current International
Class: |
H05K
3/36 (20060101); H01r 013/54 (); H05k 001/07 () |
Field of
Search: |
;339/75MP,176MF,176MP,17LM,17M |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lake; Roy
Assistant Examiner: Bicks; Mark S.
Attorney, Agent or Firm: Haynes, Jr.; Herbert E.
Claims
What I claim is:
1. A connector for electrically interconnecting flat multiconductor
elements such as a printed circuit board having edge contacts upon
which the conductors of a flexible ribbon cable are aligningly
positioned, said connector comprising:
a. a housing having at least one connection chamber formed therein
and having an elongated slot formed in one wall thereof which opens
into the center of the chamber and through which the portions of
the multiconductor elements to be electrically interconnected are
insertable;
b. a tension band of elastic material mounted within the chamber of
said housing and positioned to present one surface in facing
coextensive relatinship with the slot of said housing;
c. tension means within the chamber of said housing for
deflectively contacting said tension band to apply a tension
preload to said band and to form it into a substantially U-shaped
cross-sectional configuration with the bight portion thereof
aligned and coextending with the slot formed in said housing and
the leg portions thereof forming a diverging included angle
therebetween which extends from the bight portion toward the slot
of said housing, the extending ends of the leg portions being
secured to said housing so that movement of the bight portion away
from the slot is produced by deflective engagement of the
multiconductor elements when they are inserted therein which will
increase the stress of said band and reduce the included angle
between the legs of said band by moving the legs toward each other;
and
d. cam means mounted on said tension band and positioned thereon so
that a portion of said cam means is disposed on each of the leg
portions of said band and movable therewith for applying a
compression force to the multiconductor elements when they are
inserted into the chamber of said housing, the compressive force
resulting from the stress of said band and movement of the leg
portions which decreases the included angle therebetween.
2. A connector as claimed in claim 1 wherein said housing is
provided with a plurality of connection chambers each separated
from its adjacent chambers by a first shelf extending from one wall
of said housing and nestingly aligning in a non-contacting
relationship with a second shelf extending from the opposite wall
of said housing to provide a gap communicating between each of the
connection chambers so that said tension band may be formed of a
continuous sheet strung through said gaps to present a segment of
said tension band within each of said chambers, said tension band
being secured along its length to each of said first shelves to
operationally isolate each of the segments from its adjacent
segments.
3. A connector as claimed in claim 2 wherein said housing is formed
of hingedly connected housing halves, a first one of said housing
halves having said first shelves formed therein and a second one of
said housing halves having said second shelves formed therein, and
further including means for securing said housing halves
together.
4. A connector as claimed in claim 1 wherein said tension means
includes a pair of shelves formed on the wall of said housing in
which the slot is formed, said shelves are positioned in a spaced
apart parallel relationship on opposite longitudinal sides of the
slot and are coextensive therewith, said shelves extending into the
connection chamber for deflectively contacting said cam means to
apply a tension to said tension band and form it into the U-shaped
configuration.
5. A connector as claimed in claim 1 wherein said tension means
comprises a tension spring connected to the bight portion of said
tension band and to said housing for biasing said tension band into
the U-shaped configuration.
6. A connector as claimed in claim 1 wherein said cam means
comprises a pair of cylindrical cams each having a longitudinally
disposed slot formed therethrough through which said tension band
is inserted to assemble said cams in a spaced apart parallel
relationship thereon.
7. A connector as claimed in claim 6 wherein said cam means further
comprises a flexible web interconnecting said pair of cams.
8. A connector as claimed in claim 6 wherein each of said pair of
cams have an alternating series of lands and recesses formed in at
least a portion of its longitudinally disposed peripheral
surface.
9. A connector as claimed in claim 6 wherein the slot formed in
each of said pair of cams is offset with respect to the
longitudinal axis of said cam and formed into a substantially
V-shaped in cross-sectional configuration.
10. A connector as claimed in claim 6 wherein each of said cams is
provided with a coating of compressible resilient material.
11. A connector as claimed in claim 6 wherein each of said cams is
provided with an elongated pad insert of compressible resilient
material mounted on its longitudinally disposed peripheral
surface.
12. A connector as claimed in claim 6 wherein each of said cams has
at least one cam profile formed on its longitudinally disposed
peripheral surface.
13. A connector for electrically interconnecting flexible flat
multiconductor elements comprising:
a. a rigid spacer element upon which the flexible multiconductor
elements are overlappingly positionable so that the exposed
conductors of one of the flexible elements is aligningly contacting
the exposed conductors of the other flexible elements;
b. a housing having at least one connection chamber formed therein
and having an elongated slot formed in one wall thereof which opens
into the center of the chamber and through which the portions of
the multiconductor elements to be electrically interconnected are
insertable;
c. a tension band of elastic material mounted within the chamber of
said housing and positioned to present one surface in facing
coextensive relationship with the slot of said housing;
d. tension means within the chamber of said housing for
deflectively contacting said tension band to apply a tension
pre-load thereto and form said band into a substantially U-shaped
cross-sectional configuration with the bight portion thereof
aligned and coextending with the slot of said housing and the leg
portions thereof forming a diverging included angle which extends
from the bight portion toward the slot of said housing, the
extending ends of the leg portions being secured to said housing so
that movement of the bight portion away from the slot is produced
by deflective engagement of the multiconductor elements when they
are inserted therein which will increase the stress of said band
and reduce the included angle between the legs of said band by
moving the legs toward each other; and
e. cam means mounted on said tension band and positioned thereon so
that a portion of said cam means is disposed on each of the leg
portions of said band and movable therewith for applying a
compression force to the multiconductor elements when they are
inserted into the chamber of said housing, the compressive force
resulting from the stress of said band and from movement of the leg
portions toward each other.
14. A connector as claimed in claim 13 wherein said spacer element
comprises:
a. a rigid body of generally rectangular configuration;
b. a handle formed on one of the side edges of said body; and
c. a notch formed in the opposite side edge of said body.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to electrical connectors and more
particularly to a connector for forming electrical interconnections
between the edge contacts of printed circuit boards and the
conductors of a flat multi-conductor flexible cable, and for
splicing flat cables.
2. Description of the Prior Art
With the ever increasing complexity of modern day electronic
equipment systems, it is often necessary to provide interconnection
between a great number of printed circuit boards and their
components with other related elements of the over-all electronic
system. The present techniques employed require that these printed
circuit boards may be easily removable from their electrical
connectors and mounting devices for rapid change as necessitated by
failure of components or over-all circuits and for servicing and
testing purposes.
To accomplish these purposes, the systems generally require a
number of separate subsystems united into a single unit. Of primary
importance is the electrical connector itself which is required to
connect individual wires to the conductors of the printed circuit
boards leading to the components thereon. These connectors are
usually found to have spring loaded fingers to affect the
connection between the wires and the conductors of the printed
circuit boards. The connectors themselves must be individually
wired to the input-output cables or suitably connected to wires of
other power and signal supplying means. Due to the trend towards
miniaturization of components and related elements, the amount of
spacing available in the connectors for such coupling and/or wiring
is extremely limited and great care must be taken so as to prevent
shorts and other destructive practices with respect to the
connector.
In addition, a framework must be provided for supporting the
circuit board and this framework must allow the circuit board to be
easily removed and re-inserted into the connector with no
destruction to the connector itself. It has been found in practice
that the continual insertion and removal of such printed circuit
boards often leads to the weakening of the spring loaded fingers of
the connectors such that intermittent connections may occur, and
sometimes results in complete failure of the connector.
Recent attempts have been made to eliminate as much as possible,
the individual wiring associated with this type of connection, and
to eliminate the spring loaded type of finger contacts. These
attempts have emloyed a rather recent development in the art, that
is, flat ribbon type flexible cables. These cables generally
include a flexible insulative backing having a pattern of flat
electrical conductors which are formed by an etching process or the
like. Another type of cable employing this basic principle is
formed with circular conductors imbedded in insulative ribbon type
material. These types of cables have several advantages over
conventional wiring such as requiring less room and providing a
much easier method for matching of impedances which is necessary
with todays' high speed electronic equipment.
The flat cables may be coupled directly to the edge contacts of the
circuit board and are held in conductive contact by various types
of connectors. These prior art connectors are designed to retain
the cable in a manner so that the edge connectors of the circuit
board may be positioned in abutting contact therewith. Means
associated with the connector exerts a compressive force on the
cable and the board to hold their respective conductors in
electrical contact.
In general, these prior art connectors have proven unsatisfactory
for various reasons among which are expense and complexity. Some of
these connectors were unable to exert an evenly distributed force
over the plural contacts, while others resulted in problems of
insertion and removal of the boards.
Therefore, there exists a need for a highly simplified and
efficient means to make connections between the ribbon-type cables
and circuit boards and for splicing of cables. Solution to this
need is basic to the production of truly low cost computers and
other electronic devices.
SUMMARY OF THE INVENTION
The present invention overcomes many of the difficulties noted with
respect to the prior art by providing a simple unitary structure
which accomplishes the function of electrically interconnecting
multiconductor elements such as one or more flexible ribbon cables
with one or more printed circuit boards and/or splicing of the flat
cables. The connector also provides a supporting member for holding
the circuit boards in the operating position and provides mounting
means to retain the boards in the desired position and yet allow
easy removal thereof when desired.
The connector is designed to bring into direct operative
relationship the individual conductors of a multiconductor printed
circuit board with the individual conductors of a flexible ribbon
cable thus eliminating the need for individual wiring of the
connector. In the operating position compressive pressure is
brought to bear so as to hold the individual conductors of the
flexible ribbon cable in contact with the aligned conductors of the
printed circuit board to assure intimate contact therebetween, and
may provide the same function for splicing of flat cables.
Briefly, the connector of the present invention is provided with a
housing which may be fabricated to accommodate one or more printed
circuit boards. The printed circuit board is provided with a notch
on the side edge which contains the normal edge contacts. The
flexible ribbon cable is registered within this notch so that the
conductors of the printed circuit board are aligned with the
conductors of the ribbon cable. This edge of the printed circuit
board having the flexible cable positioned thereon is inserted into
an opening formed in the connector housing and upon entering
therein will engage a tension band. The tension band is held in a
U-shaped configuration and has a pair of movable cams mounted
thereon. When the circuit board-ribbon cable assembly contacts the
tension band, the cams will move towards each other and contact the
upper and lower surface of the circuit board adjacent to the edge
on which the edge contacts are disposed. The movement of the cams
exerts a compressive force which forms electrical interconnections
betwen the ribbon cable and the circuit board. The same connector
may be employed for splicing flat ribbon type cables by providing a
spacer element upon which the cables are placed in an overlapped
aligned relationship so that the spacer element and cables may be
inserted into the connector in the same manner as the circuit
board-ribbon cable assembly.
Accordingly, it is an object of the present invention to provide a
new and useful electrical connector interconnecting multiconductor
elements.
Another object of this invention is to provide a new and useful
connector for electrically coupling a flat ribbon type cable to a
printed circuit board.
Another object of the present invention is to provide a new and
useful connector for splicing flat ribbon type cables.
Another object of this invention is to provide a new and useful
connector into which one or more printed circuit boards may be
plugably inserted for electrical interconnection with one or more
flat ribbon type cables.
Another object of this invention is to provide a new and useful
connector for electrically coupling at least one flat ribbon type
cable to at least one printed circuit board, the connector having a
housing which contains the connecting elements and also provides
supporting structure for the printed circuit boards.
Still another object of the present invention is to provide a new
and useful connector of the above described character in which the
conductors of the flat cable are held in conductive contact with
the edge contacts of the printed circuit board by cam means mounted
on a tension band which exert a compressive force on the contacts
when movably activated by engagement thereof by the circuit
board-cable assembly.
The foregoing and other objects of this invention, as well as the
invention itself, may be more fully understood when read in
conjunction with the following drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary side elevation partially broken away to
illustrate the various features of the present invention as being
applied to electrically couple flat ribbon type cables to printed
circuit boards.
FIG. 2 is a sectional plan view of the connector of the present
invention taken on the line 2--2 of FIG. 1.
FIG. 3 is an enlarged sectional view illustrating a modification of
the connection elements of the present invention.
FIG. 4 is an enlarged sectional view illustrating one embodiment of
the connection elements of the present invention in their
disengaged and workpiece engaging positions.
FIG. 5 is a view similar to FIG. 4 illustrating a second embodiment
of the connection elements of the present invention.
FIG. 6 is a fragmentary side elevation of one embodiment of the cam
element of the present invention.
FIG. 7 is a sectional view taken along the line 7--7 of FIG. 6.
FIG. 8 is a sectional view similar to FIG. 7 and showing a
modification of the cam element of the present invention.
FIG. 9 is a sectional view similar to FIGS. 7 and 8 showing another
modified cam element of the present invention.
FIG. 10 is a sectional view similar to FIGS. 7, 8, and 9 showing
yet another modification of the cam element.
FIG. 11 is a fragmentary side elevation similar to FIG. 1 but
showing the connector of the present invention as being employed
for splicing flat ribbon type cables.
FIG. 12 is a perspective view of a spacer element employed to
splice the cables.
FIG. 13 is a fragmentary perspective view of one type of flat
ribbon type cable.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring more particularly to the drawings, FIGS. 1 and 2
illustrate a connector 10 of the present invention having a printed
circuit board 11 and a flat ribbon type cable 12 inserted therein
and held in interconnecting conductive contact as will hereinafter
be described in detail.
The printed circuit board 11 is of the conventional type and has
the usual rigid insulative backing 14 which upon one or both
surfaces thereof is provided the usual conductors 16. The
conductors 16 are employed to interconnect the usual components 17
mounted on the board as is well known in the art. The board 11 is
also provided with a plurality of edge contacts 18 by which power
and signals are coupled thereto.
Although the circuit board 11, as thus far described, is of
conventional construction, two modifications may be performed
thereon which will enhance its operation with the connector 10 of
the present invention.
The first of these modifications is to form a notch 20 in the side
of the circuit board which is adjacent to the edge contacts 18.
This is accomplished so that when the cable 12 is to be coupled to
the board 11, proper alignment thereof is assured.
The second of the modifications which may be performed on the
circuit board 11 is to form, such as by drilling, a pair of
apertures 21 (one shown in FIG. 2) adjacent to opposite side edges
22 and 23 of the board 11. This modification is accomplished to
provide mounting means such as pins 25 by which the board 11 may be
removably mounted to the connector 10 in the proper operational
position.
The ribbon type cable 12 illustrated is but one type of several
varieties currently being employed, therefore, it should be
understood that the connector of the present invention may be used
with any of the cables currently known.
Briefly, the cable 12 as seen in FIG. 2, includes an insulative
flexible backing 24 upon which a plurality of conductors 26 are
formed such as by the well known etching process. The conductors 26
of cable 12 are formed in predetermined patterns and have the
distances between centers determined by corresponding distances
between the edge contacts 18 of the board 11. This is accomplished
not only for alignment purposes but to match impedance of the
boards with the cables.
The connector 10 as seen in FIG. 1 is provided with a housing 28
which may be fabricated to interconnect a single circuit board with
a ribbon cable or may be fabricated to accommodate a plurality of
such interconnections.
The housing 28 is formed in two halves 30 and 32 which are normally
held in a closed position such as by screws 34 that interconnect
abutting flanges 33 formed on the housing halves 30 and 32. The
housing halves 30 and 32 may be easily opened for assembly and/or
servicing purposes by means of a conventional type of piano hinge
35. Also, the housing 28 may be provided with mounting flanges 37
by which the connector 10 is mounted to a structural member 39.
The chambers 36 are separated from each other by a first shelf 38
which extends from the wall 40 of the housing half 32 into the
interior of the housing 28 and nestingly aligns with but does not
contact, a second shelf 42 which has a U-shaped channel 43 in its
extending end. The second shelf 42 extends from the wall 44 of the
housing half 30.
The wall 44 of the housing half 30 is provided with an elongated
slot 46 through which the circuit board and ribbon cable, to be
electrically interconnected, are inserted into the chamber 36. It
will be noted that there is one slot 46 for each chamber 36, and
such slots are located equidistant between the shelves 38 and 42
which separate the chambers.
Each of the elongated slots 46 are formed with an outwardly
extending flange 48 to which is fitted a sealing grommet 50. The
grommets are formed of resilient material such as rubber and will
close the slots 46 when chamber 36 is not in use for preventing
contamination thereof such as by moisture, dirt and the like.
The grommets 50 are formed with an elongated slit 52 so that the
circuit board and ribbon cable assembly may be inserted through the
slit 52 and by doing so will deflect the lips 54 thereof and create
a contiguous engagement between the lips and the circuit
board-ribbon cable assembly thus sealing the chamber 36 against
contamination.
An elongated ribbon-like tension band 56 is suitably secured on its
opposite ends 58 (one shown) to the interior of housing half 32
such as by a retainer plate 60 held in place by screws 62. The band
56 is fabricated of an elastic material such as rubber and is
mounted so that it presents one surface facing the slots 46 and is
coextensive therewith.
The band 56 is positioned so that it passes through a gap 64
between each of the nestingly aligned shelves 38 and 42, and
contacts the extending ends of each of the shelves 38. The band 56
is suitably secured to each of the shelves 38 at the point of
contact such as by screws 66. Thus it may be seen that the band 56
is attached in spaced increments along its length to provide a
series of segments 68, each of which is disposed within a different
one of the chambers 36. It should also be noted that by mounting
the band 56 in this fashion, each segment 68 may be stressed
independently and thus will operate independently from its adjacent
segments as will be fully described.
A tension pre-load is applied, as will be described, to each
segment 68 of the band 56 to form the segments into a substantially
U-shaped in cross section configuration with the bight portions 70
thereof being aligned and coextensive with the slots 46 and the leg
portions 72 and 73 being divergent with respect to each other. Thus
a circuit board-ribbon cable assembly entering into the chamber
will contact the bight 70 and force it toward the wall 40. This
movement will cause the legs 72 ad 73 to move toward each other,
i.e., the included angle becomes smaller, and also causes a
stretching of the segment which increases its stress.
A cam means 76 is affixed to each segment 68 adjacent to the bight
portion 70 thereof. The cam means 76 as will be described, performs
two functions, the first being to assist in the application of the
tension pre-load on its segment 68 and the second is the
application of a compressive load on the circuit board-ribbon cable
assembly for electrical interconnection thereof.
The cam means 76, in one embodiment thereof, includes a pair of
cylindrical cams 78 and 80 interconnected in a spaced apart
relationship by a web 82. Each of the cams 78 and 80 are provided
with a longitudinal slot 84 as best seen in FIG. 4. The tension
band 56 is threaded through the slots 84 of the cams 78 and 80 so
that the cam means 76 is centrally located along the length of the
segment 68. In this position, the web 82 will overlay the bight
portion 70 of the segment 68 and thus locate the cam 78 on the leg
72 and the cam 80 on the leg 73.
As seen in the connecting chamber identified as 36a in FIG.1, no
circuit board-ribbon cable assembly has been inserted therein,
therefore the segment 68 will be urged, due to tension on the
segment, toward a straight line position between the ends of the
shelves 38. However, the cams 78 and 80 prevent complete
straightening of the segment by contacting a tension means which in
this embodiment is the extending ends 86 of the second shelf 42.
Therefore, it may now be easily seen that the cam means 76
cooperates with the second shelf 42 to pre-load the segment 68 into
the substantially U-shaped configuration.
An alternate tensioning means for pre-loading the segments 68 is
illustrated in FIG. 3, wherein the web 82 of the cam means 76 is
provided with one or more spacedly positioned tabs 88 which extend
through apertures 90 formed in the segment 68. A spring 92 is
coupled from each of the tabs 88 to similar tabs 94 provided on the
wall 40 thus biasing the segment into the pre-loaded U-shaped
configuration as previously described.
The second function performed by the cam means 76 is best described
with reference to FIG. 4 of the drawings in which the circuit
board-ribbon cable assembly is shown in solid lines at a position
of initial contact with the cam means 76, and is shown in dashed
lines at a position of full contact or in a working position.
The initial contact position shown in FIG. 4 illustrates the points
of contact A and B as occurring on the radiused leading edge 96 of
the circuit board-ribbon cable assembly. It will be noted that the
distance between points A and B is somewhat less than the thickness
dimension of the circuit board-ribbon cable assembly. Movement of
this assembly in the direction of arrow 98 will simultaneously push
the bight portion 70 of the segment 68 and cam means 76 toward the
dashed line position and will separate the contact points A and B
causing them to ride up in a sliding movement over the radiused
edge 96 until they arrive at the contact positions identified as
points A' and B'. Due to the separation and pushing movements
exerted during insertion of the circuit board-ribbon cable
assembly, an increase in the stress of the bight portion 70 and of
the leg portions 72 and 73 will occur. The force vectors applied by
these portions of the tension band 56 produces a resultant vector
which exerts a compressive force on the circuit boardribbon cable
assembly to form electrical interconnection between the conductors
26 of the cable 12 and the edge contacts 18 of the circuit board
11.
A modified form of the cam means 76 is illustrated in FIG. 5 and is
identified as cam means 76a. In this embodiment, the cam means 76a
is seen to be made up only of a pair of cylindrical cams 100 and
102 which are not interconnected by a web such as was the case
previously described with reference to the cam means 76. The cams
100 and 102 of cam means 76a are assembled to the tension band 56
by a threading operation in the same manner as previously
described, however in this case the cams must be attached to the
band 56 to prevent them from sliding along their respective legs 72
and 73 when separating force is applied thereto. The cams 100 and
102 are each provided with a longitudinal slot 104 formed therein
which are for the same purposes as were the slots 84 of cams 78 and
80. It will be noted that the slots 104 are V-shaped in
cross-sectional configuration to increase the surface friction
between the cams and the band 56. This same cross-sectional
configuration could be employed with the cams 78 and 80, but is not
as essential in that embodiment.
To ensure that the cams 100 and 102 will not slide along their
respective legs 72 and 73, the cams may be fixidly secured in the
proper positions by the application of a bonding agent 106 such as
epoxy cement.
The cam means 76a will react to the forces applied in a somewhat
different manner than that previously described for cam means 76
due to the absence of the web 82.
As seen in FIG. 5, wherein the initial contact is shown in solid
lines, an intermediate contact position is shown in dashed lines
and a final position is shown in dotted lines, the initial contact
points C and D are in the same location as the initial contact
points A and B in that they occur on the radiused leading edge 96
of the circuit board-ribbon cable assembly and are spaced apart a
distance somewhat less than the thickness dimension of this
assembly. Movement of the circuit board-ribbon cable assembly in
the direction of the arrow 108 will cause the cams 100 and 102 to
roll up over the radiused surface 96 in a movement which did not
occur to any great extent in the cam means 76 due to the restraint
applied by the web 82. This rolling movement may be a combination
of rolling and sliding movement with the determining factors being
interfacial friction of the cams and radiused edge 96 and stress of
the band. As seen in the dashed line intermediate position of FIG.
5, the cams 100 and 102 have moved so that the contact points are
now located at the points identified as C' and D'. In doing so, it
will be noted that the bight 70 of segment 68 has been considerably
stretched thus increasing the force applied to the cams by the
bight portion. Also, the same movement of the segment 68 and
connector 76a in the direction of the arrow 108 will stretch the
legs 72 and 73 and decrease the included angle therebetween.
Continued movement of the circuit board-ribbon cable assembly
toward the dotted line final position will again decrease the
included angle between the cams 100 and 102 and elongate the legs
72 and 73 still further, also this movement will change the bight
portion 70 from a straight line between the cams to an angular
disposition. Thus, it may now be seen that the force vectors
applied by the legs 72 and 73 and by the bight portion 70 will
produce a substantially perpendicular resultant vector which urges
the cams toward the circuit board-ribbon cable assembly.
It should be noted that the slots 84 and 104 of the cams 78, 80,
100 and 102 do not pass through the longitudinal axis of the cams
but are cords when considered with respect to the cross-sectional
configuration of the cams. Placement of the slots in this offset
location with respect to the axis of rotation will supplement the
compressive forces applied by the cams on the circuit board-ribbon
cable assembly.
FIG. 6 illustrates one of the cams in detail and will be identified
as cam 100 for descriptive purposes. It should be noted that the
detailed description of cam 100 and the modifications thereof,
which will hereinafter be described in detail, do not apply to cam
100 only, but also apply to cams 78, 80, and 102.
In the preferred embodiment shown in FIGS. 6 and 7, it will be seen
that the cam 100 includes an elongated cylindrical body 110 in
which the elongated slot 104 is formed with an angular
crossectional configuration. A portion of the periphery of cam 100
is formed with an alternating series of land areas 112 having
recessed areas 114 interposed therebetween. The distance between
the center lines of the lands 112 and their width dimensions are
selected to correspond to the dimensions of the edge contacts 18 of
the circuit board 11 and the conductors 26 of the ribbon cable 12,
so that the compressive force applied by either cam means 76 or 76a
will not be unnecessarily dissipated by being applied to areas
where no contact is needed.
As seen in FIG. 7, the cam 100 has an outer coating 116 of
insulative compressible resilient material such as rubber which may
be applied thereto by any number of well known techniques. The
coating 116 is applied so that the cam 100 will have a high
coefficient of friction to enhance the rolling movement and retard
the sliding movement as previously described. The coating will also
compensate for a dimensional deviation in the thickness of the
circuit board-ribbon cable assembly to ensure an even distribution
of the forces across all the contacts to be interconnected.
FIG. 8 illustrates a modified cam 100a wherein the coating 116 has
been replaced with an elongated pad insert 118 of material similar
to that of the coating 116.
FIG. 9 illustrates a cam 100b which is similar to the embodiment
illustrated in FIG. 7 except that the periphery of the cam is
provided with a cam profile 120 which is designed to increase the
tension applied to legs 72 and 73 and the tension applied to the
bight portion 70 of the segment 68.
FIG. 10 illustrates yet another modified cam 100c in which a double
cam profile 122 and 124 is formed on the periphery to provide a
double point of contact and a snap action during insertion of the
circuit board-ribbon cable assembly into the connector 10.
Reference is now made to FIGS. 11, 12, and 13 wherein the elements
and operation of the connector 10 will be described with relation
to the splicing of a pair of ribbon cables 126 and 128.
As seen in FIG. 11, the connector 10 is identical to that
previously described and has the cam means 76a mounted therein. In
order for the connector 10 to function in its capacity as a cable
splicer, there is provided a spacer element 130. The spacer 130 has
a flat rigid body 131 of generally rectangular shape with a handle
portion 132 on one of its relatively long ends and its opposite end
is provided with a notch 134 for the purpose of assuring and
maintaining alignment between the cables 126 and 128 to be spliced.
The spacer 130 is also provided with mounting means in the form of
a pair of apertures 136, one being drilled or otherwise formed
adjacent to each of the side edges 138 and 140 of the spacer 130.
The removable mounting of the spacer 130 to the connector 10 is
identical to that previously described for mounting of the circuit
board to the connector 10 and therefore will not be repeated.
It should be understood that any of the well known types of
ribbon-like flat cable may be spliced by the connector 10 of the
present invention. However, a detailed description of the splicing
of a particular type of cable is deemed appropriate.
The cables 126 and 128 are of the shielded type well known in the
art and are seen in FIG. 13, wherein the cable 126 is shown, to
include a backing 144 of insulative material. Also, an upper ground
plane 146 and a lower ground plane 148 are provided which have the
conductors 150 interposed therebetween. This type of cable is
particularly well suited for applications which require, among
other things, impedance matching.
The cable 126 has been prepared for splicing in the connector 10 of
the present invention by cutting away portions of the insulative
backing 144 to expose the conductors 150 and the laterally disposed
surfaces 145 of the upper ground plane 146.
It should be understood that this stripping operation may be
performed on a terminal end of the cables as shown or may be in the
form of a window (not shown) at any desired location along the
length of the cables.
The cable 128 is stripped in an identical manner, and the cables
126 and 128 are positioned in an overlapping relationship as shown
in FIG. 11. The compressive forces exerted by the cam means 76 or
76a will electrically interconnect the conductors 150 of the cables
126 and 128 and will also electrically couple the surfaces 145 of
the ground planes 146 of cables 126 and 128 to each other.
While the principles of the invention have now been made clear in
an illustrated embodiment, there will be immediately obvious to
those skilled in the art, many modifications of structure,
arrangements, proportions, the elements, materials, and components
used in the practice of the invention, and otherwise, which are
particularly adapted for specific environments and operation
requirements without departing from those principles. The appended
claims are therefore intended to cover and embrace any such
modifications within the limits only of the true spirit and scope
of the invention.
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