Note: Descriptions are shown in the official language in which they were submitted.
l~V~686
TRANSMISSION CABLE MASS
TERMINATION METHOD
TECHNICAL FIELD
The present invention is directed generaliy to electrlcal
connection assemblles ~nd, more particularly, to an assembly for
term7nating a flat electrical cable having a plurality of electrtcal
transmission or signal conductors and ground conductors arranged in a
closely-spaced array wlthin a strlp of insulative material.
BACKGROUND OF PRIOR ART
In recent years flexible, flat multiconductor cable has
been used with increasing frequency in the communicatlons, data proces-
sing and transportation industries. Flat cable is partlcularly well
suited for electrlcally connecting high density banks of circuit
elements used in modern computers. To effect these connections
rapidly and economically, a variety of dlfferent conductors, connector
assemblles or mass terminatlon systems have been developed. Con-
ventional solder and crimp type terminations and, more recently, insula-
tion-piercTng terminations have been satisfactorily employed in these
assem~lies to terminate the conductors of the flat cable with the
connector.
Although these prior art termination assemblies have met
with some commerclal success, they all suffer from the disadvantage
that they are not suitable for use with cable having very closely spaced
conductors. For example, insulation-piercing terminations used in the
prlor art are useful only with cable havlng conductors spaced at inter-
vals of about 0.050 inch or more. When the conductors are spaced at
intervals of about 0.030 inch or less, conventional insulation-
piercing termination devices are susceptible to shorting which is,
of course, unacceptable.
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Accordingly, all known connection assembl1es used with flat
cable having very closely spaced conductors employ solder-type termin-
ations and arrangements of components which effect a greater spacing
between the conductors to facilitate the soldering operation. These
assemblies are not only relatively expensive, but the soldering oper-
ation is labor intensive, thereby increasing their installation cost.
BRIEF SUM~iARY OF INVENTION
The present invention, therefore, is directed to a mass
termination system for flat cable having very closely spaced con-
ductors which overcomes the problems and disadvantages associatedwith prior art devices. The termtnation system or assembly of the
present invention may be used to terminate a cable with conductors
spaced at about 0.015 inch intervals and may In some applications
employ conventional connectors including those presently adapted for
the 0.050 inch conductor spacing found in most standard flat cable.
Moreover, the assembly may employ insulation-piercing terminations
without the danger of shorting between adjacent transmission con-
ductors.
The invention finds particular application for termin-
ating flat cable having electrical transmission or signal conductorswlth ground conductors disposed therebetween and generally comprises
connector means, isolation means and bridging means. The connector
means inçlp4e$ ~rm~nal means for slectrically engaging the signal
conductors and active contact means in electrical communications with
the terminal means for electrically interconnecting the signal con-
ductors to an associated electrical component. The isolation means
breaks the electrically conducti~e path between the connector means
and the live ground conductors and may comprise apertures in the cable
which sever the ground conductors, resulting in "dead" ground con-
ductors along the length of cable where the termination is effected.The brTdging means comprises a conductive member which electrically
joins the live portion of the ground conductors to a ground terminal
within the connector.
BRIEF DESCRIPTION OF THE DRAWINCS
The novel features which are believed to be characteristic
of the invention are set forth in the appended claims. The invention,
itself, however, together with further obiects and attendant advantages
thereof, will be best understood by reference to the following
39 description taken in connection with the accompanying drawings in which:
1104686
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FIGURE I T 5 a perspective view t11ustrating the termination
assembly of the present invention and showing the arrangement of a pre-
ferred connector means isolation means and bridging means wTth a flat
cable;
FIGURE 2 is an enlarged cross-sectional view taken along
llne 2-2 of FIGURE I and showing in detail an insulation-piercing
terminal means and an active contact means;
FIGURF 3 Is an enlarged cross-sectlonal vlew taken along
line 3-3 in FIGURE I showing one preferred brtdging means and wlth
one of the terminal members of the bridging means In the open
posttion;
FI~URE 4 is a view similar to that of ~IGUi~E 3 illus-
tratlng a preferred surface configuration for the flat cable used
with the present Invention;
FIGURE 5 is an enlarged fragmentary plan vlew illustrattng
further detatls of the termination assembly shown in FIGURE l; and
FIGURE 6 is a cross-sectional view taken along the line
6-6 of FIGURE 5.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIGURE 1 the mass termination assembly
of the present invention designated generally as 10 is illustrated
In one of its preferred embodiments terminating a flat cable 20. The
assembly 10 Includes a connector means 12 isolation means comprising
a serles of apertures 14 In cable 20 and bridging means 16.
The illustrated cable 20 Is particularly well suited for use
wlth the termination assembly of the present invention and comprises
a plurality of slgnal or power carrying conductors 21 and a plurality
of ground conductors 23 one or more of the ground conductors being
interposed between adjacent signal conductors. The conductors 21 and
23 are spaced by as little as O.OIS inch and accordlngly it is
d1fficult to tenminate the signal conductors 21 by use of conventlonal
insulatlon-pterclng terminals without shorting to adjacent ground con-
ductors 23.
The connector means 12 may be any one of a variety of dif-
ferent connectors well known to those skilled in the art for use interminating flat cable. Generally the con~ector means 12 includes
two-piece ho~sing having a base 18 and a co~er portion 19 made
from dielectric material and which support and enclose a plurality of
39 contacts 22. The contacts 22 comprise a terminal portion 24 for
llQ46~36
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electrlcally engaging an Tndtvidual signal conductor of the cable 20
and an active contact portion 26 which mates w7th an electrical com-
ponent to be interconnected with the cable. In the illustrated
embodlment, the contacts 22 comprise an insulatlon-piercing terminal
5 portion and a multl-tine socket, active contact portion. Of course,
the use of insulatlon-piercing contacts greatly facilitates the term-
lnation operation, and, as described in greater detail below,. the
present invention enables the use of such termination means even with
the cable 20 having very closely spaced conductors 21 and 23.
The isolatlon means comprises, in the preferred embodTment,
a series of apertures 14 which sever the ground conductors 23 so that
along the portion of the cable 20 cooperating wlth the connector 12
the conductors 23 are dead and do not act as a ground path. Accord-
lngly, along this portion of the conductor the spacing between active
15 conductors is actually the interval between adjacent signal conductors
21. In cable 20, the conductors 21 are at 0.050 inch intervals and,
therefore, conventional flat cable connectors can be used to effect
the termination.
In order to provide a ground path to and from the connector,
20 the bridging means 16 is utilized to electrically couple each of the
ground conductors 23 to a single ground conductor 23 which may be
convenlently located at one edge 20 of the cable 20. The bridging
means illustrated in the drawings comprises an elongated clip 3û which
may be easily fabricated from sheet metal by conventional stamping
25 and forming operations. The clip 30 includes a plurality of U-shaped
terminat7On members 32, each having a bight portion 34 passing through
an aperture 14 and leg portions 36 and 38 which overlfe the opposed
surfaces of the cable. The free ends of each leg portion are formed
into flange-like, insulation-piercing terminal means 40 and 42, and
30 at least one of the terminal means is positioned and configured to
make electrical contact with the ground conductors 23. As most
clearly seen in FIGU~<ES 5 and 6, the clip 3C includes a terminal
member 44 which extends over and is folded under the lateral edge 20
of the cable. The member 44 has a termination flange 46 at its distal
35 end which engages conductor 23, the live ground path into the con-
nector 12. The members 32 are ~oined to each other and to terminal
member 44 by a strip or web 48, forming a unitary ground clip and,
thus9 a continuous ground path from each ground conductor 23, through
39 terminal 44 and conductor 23, into the connector 12. ()f course, in
llQ466?6
5--
those instances where the flat cable continues to a further con-
nector or other electrical components, another ground clip may be
installed in a similar manner on the ".'own stream" side of con-
nector 12.
FIGURE 4 illustrates a preferned external configuration
for the cable 20, having spaced longitudinal grooves 50 positioned
to assist the proper orientation and penetration of the termTnal
means 40 and 42 into the cable and conductors 23. The grooves
are particularly useful when the insulation used in the flat cable
is very hard and might have a tendency to deform or misdirect the
piercing tips of the terminal means.
Installation of the termination assembly of the present
invention Is simple and may be completed in a very short time.
The connector means 12 is assembled ~o the cable 20 in an entirely
conventional and well known manner, and the apertures 14 may be
formed with a hand punch or tool specially designed for this purpos~.
The clip 30 is then assembled to the cable by inserting the legs 38
through the apertures 14 and crimping each terminal member 32 to pierce
the Tnsulation of the cable and eiec~r;cally engage the ground con-
20 ductors 23. The terminal member 44 is then folded over edge 20~ and
crimped to the cable to electrically engage conductor 23~. For pre-
determi~ned installations, the cab!e may be prepunched and the clip
30 assembled to the cable 20 in the factory to eliminate these oper-
ations In the field.
Of course, it should be understood that various changes and
modifications to the preferred embodiment described herein will be
apparent to those s'~illed in the art. Such changes and modiflcations
can be made withGut departing from the spirit and scope of the present
invention and without diminishing its attendant advantages. For example,
other structures and configuratio:s may be used for the clip 30 and
terminal members 32 and 44. In addition, other isolation means may
be employed In place of apertures 14. Finally, the Isolation means
and bridging means need not be located adjacent the connector means
as shown, but may be remote from the ccnnector where such an arrange-
ment will ease and facilitate installation or service and maintenance.It is fherefore intended that all such changes and modifications be
covered by the following claims~
