Note: Descriptions are shown in the official language in which they were submitted.
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Thls inventlon relates to a solderles~ termlna-
tion system. In partlcular, lt relates to the type o~ such
systems where a wlre ls engaged and held by blades or ~aws.
In further particularJ lt relateæ tothe type o~ such æy~tems
adapted for insulatlon pierclng as well as engaging and
holding a wire.
Electrlcal termlnation systems are known ln myriad
forms and slzes. The type o~ system of intere~t in the
present desoriptlon provldes, as a means for retalning a
wlre, a pair of ~aclng blades or Jaws whlch may be, be~ore
insertlon of a wlre, ln contact or approprlately spaced
apart. Conventionally, blades are adapted to grip a wire
between them for mechanical and electrlcal contact. Often,
a lead-ln portion is provided where the contact portlon of
the blades opens to provlde convenient positioning and
gradual gripping o~ the wlre. Such structures as are ~hown
in the prior art may also enable the inæulatlon ~urround-
ing the wlre to be plerced as lt ls lnserted between the
blades. Common appllcation~ of such termlnatlon systems
are in spllcing wlres and in the wire termlnatlng end of
connectors.
mere are a number o~ factors and problems
lmportant in an aaceptable insulatlon plerclng solderless
termlnation system. Some of these factoræ and problems
are more pronounced wlth regard to so-called minlature
terminatlon systems or high den~lty ~ystems where elements
are quite close together.
- One of the mo~t lmportant (1~ not the most
lmportant) performance ~a¢tors relates to contact resis-
30 tance. More accurately, thls factor relates to the changein contact resistance between the termlnated wire and the
terminating system a~ter belng sub~ect to tlme and hostlle
envlronments.
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The physlcal strength and durabllity o~ the con-
nectlon between the wire and the terminatlon system is al30
important.
Other ~actors relate to manufacturablllty and
withln that general sub~ect, to the level o~ confldence
~ound for terminations passing the various acceptance
tests. It should be understood that with hlgh volume
productlon, the number o~ faulty pieces should be small and
predlctable with a high level of con~idence.
The termlnation system descrlbed below has been
~ound to perform very well under a variety of physical and
electrical performance conditions and to meet the needs
~or manu~acturablllty. In terms of change in contact re-
slstancel under hostile environments and use tests, excel~
lent results have been obtained.
It is further notable that termination systems
of the type hereln descrlbed have both civilian and mili-
tary w es and are particularly used in telephone ~ystems.
Productlon and utilization volumes are high and rella-
blllty requirements withln the per~ormance parametersspecl~led by users are very strlngent. In one exemplary
applicatlon, the crlterlon set is that, under the de~lned
test conditlons, no more than 1 out of 10,000 termlnations
may exceed a change in contact resistance of .25 mllllohms
at the 95~ confldence level.
The invention comprlses an electrlcal terminatlon
sy~tem in which the wire recelving portlon is de~ined by
spaced apart sldes for receiving a wlre between them and
at least one palr of ~ormed-in ~aws in the sides. The
30 ~aws are formed opposlte each other presenting a narrowed~
space between them. The formed-in Jaws are lntegral with
the ~ldes at each o~ their lateral extremitles. In a
~urther aspect, a lead-in portion is prov$ded by notching
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the sides at the jaws establishing an angle to the upper edge
of the jaws to aid in locating the wire and directing it
into the jaws. In the area which contacts the wire, the
lead-in edge desirably has a transition portion which comprises
a coined edge in order to present to an entering wire a
smoothly angled embossing surface. In addition, the jaws
may be freed at their lower ends.
Figure 1 is a perspective view of a preferred
embodiment of the termination system of the invention.
Figure 2 is a perspective view of another
preferred embodiment of the termination system of the inven-
tion as embodied in a ribbon type contact element.
Figure 3 is a perspective view of the contact
element of Figure 2 installed in a high aensity connector
body.
Figure 4 is a partial top view of the preferred
embodiment of the invention.
Figure 5 is an enlarged partial sectional end view
-of the preferred embodiment of the invention through V-V
of Figure 4.
Figure 6 is a sectional end view through VI-VI
of Figure 4 of the termination system with a wire installed,
and illustrating in phantom the wire prior to installation.
Figure 7 shows a top view of the invention
employed for splicing parallel wires.
Figure 8 shows a top view of the invention
employed for butt splicing.
Fig. 9 is a reproduction of a photomicrograph of a
longitudinal cross-section of 24 gauge wire inserted in the
- 30 termination system. The insulation is not shown.
Fig. 10 is a reproduction of a photomicrograph of a
right-angle cross-section of 24 gauge wire inser~ed in the
termination system. The insulation is not shown.
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In the drawings, ln Figure l, the termlnation
system ~s lllustrated without reference to any speclflc
application. In Figures 7 and 8 the terminatlon system is
schematically illustrated as employed as a splicing means
for parallel wires and buttlng wires, respectively.
In Figures 2 and 3, the system is illustrated as
employed as a termination or wire receivlng end of a ribbon
type contact element l. Figure 3 shows how such a contact
element may be used in a high density connector system.
By thls, it should be evldent that the inventlon
has wide utili~y as a terminating system. However, lt is
emphasized that the greatest advantages are seen when lt
is used in a miniaturized appllcation where there is re-
quired strength, reliability and manufacturabillty of very
small parts made ~rom otherwise relatively weak materlals.
Referring to Figure l, the termlnatlon system
illustrated has spaced apart generally parallel sides 2 and
a bottom 3 forming an elongated wire receiving channel.
Pairs of opposltely facing formed-in ~aws 4, 4a are formed-
20 in and lntegral with ~ach of the sides 2. T~o pairs of~aw~ 4, 4a are shown although one pair or more than two
palr could be used. By formed-in, it is meant that the
metal of the sides is not cut or otherwlse interrupted
but is, rather, stretched and/or bent and ~ormed into the
continuous curved ~aws attached to and lntegral with the
sides 2 at each of lts lateral extremities. Thus, the ~aws
4, 4a present laterally smoothly curved opposing formations
havlng working faces 5, 5a as shown.
In order to best explain the lead-in portion 6,
6a of the termlnatlng system, it is helpful to describe
some of the steps in maklng the system. Basically, lt is
punched, bent and fo~med from flat sheets. The lead-ln 6,
6a ls preferably made by punching a V-shaped notch prior
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to the forming-in of the jaws (and also before bending
up the sides) so that after the jaw is formed, the upper
edge 7, 7a of the sides extends angularly downward and
inward following the plan of the jaw and as best seen in
Figures 4, 5 and 6.
As shown in Figure 1, slots 8, 8a are formed in
the sides 2 in order to free the lower end of the jaws 4,
4a from the sides. As shown in Figures 2, 4 and 5 the
slot ~j 8a is a piece of the sheet removed at the bend in ~
the ch~*~ between the sides 2, 2a and the bottom 3. With
the partlc~u~ar embodiment shown here involving a 90 bend
and the ~tom 3 being very close to the lower end of the
jaws, it ~ very important to free the lower end of the
jaws in order to prevent excessive stretching and random
formations of the metal. It may be possible, where more
free area is available below the jaw, to omit freeing it,
although the freeing is still preferred.
Referring to Figure 5, in order to
facilitate such a smooth distortion, the lead-in
portion has a transition area 9, 9a to change the angle
of the edge to present an angled embossing surface ~- -
to the wire at the upper edge of the jaw in the working
area. It may be formed by a coining operation in the
formation of the piece where the edge 7, 7a has its angle
changed to follow the shape of the lead-in portion 6, 6a
as seen in Figure 5. This transition area 9, 9a is so
designated because it is an area of transition from con- -
tact, by a wire being insert~d, with the upper edge 7, 7a
of the jaw to contact with its working face 5, 5a. Thus,
the transition area is formed at the innermost area of
the jaw defined by the working face 5, 5a of the jaw. The
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transitlon area, presenting an angled embosslng surface,
tends to cause compresslve ~orces on the wlre, aiding ln
the desirable relatively smooth dlstortlon of the wlre
when lt ls eventually fully inserted. Without the transi-
tion area~ a sharp corner at the upper edge of the ~aw
over the working faces 5, 5a would be presented to a wire
which would tend to shear and sharply shape the wlre.
The lead-in area 6, 6a includlng the coined
transltion portion is preferably at about a 45 angle to
horizontal. It may be pre~erable to make the transition
area present an even steeper angle to a-wlre between the
upper edge and the worklng face of the ~aw in order to
enhance lts transition effect. Other methods may be
employed to ~orm the ~ransitlon area 9, 9a such as by
~j forming the V notch of the lead-ln area with an angled
- edge lnstead of a square cut edge. It ls lntended to de-
~lne the transition area there~or as e~fecting a smooth
continuation of the upper edge and into transltlon to the
working face of the ~aw.
It is for many applications lmportant to provlde
some strain relief in combinatlon with thls termination
system. A strain relief means sultable with the present
termination system shown at 13 ln Figure 2 and 3.
In the preferred commercial embodiment, such as
illustrated ln Flgures 2 and 3 ~or a rlbbon type contact
element, the contact element may be formed from o.oo6 inch
cadmlum bronze sheet. The contact will usually be gold
plated either in its entirety or selectively on the mating
portion, or both fully and selectively plated. In a
primary use in telephone systems employing 24 gauge and/or
26 gauge solld lnsulated wlre, the space between the ~aws
can be about .007 inch.
The tab 14 is provided to hold the contact element
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in place in the insulating connector body. A similar tab
15 is formed up in the butt splicing embodiment of Figure
8 to hold the part in place in an associated body member.
Figure 3 shows part of a 50 contact polarized
r~bbon type connector. This is a type of high density
connector commonly used in rack-and-panel and cable-to-
cable applications in telephone systems. In an exemplary
case, the contact elements are on .085 inch centers. The
contact elements 1 are mounted in two parallel rows in the
insulator 10 between the ribs 11. The contact elements 1
reside in channels defined, at the wire termination end,
by ribs 11. The ribs 11 provide support for the sides 2, -~
2a of the termination systems, serving to rigidly back
the sides 2 in order to prevent their spreading apart when
a wire is inserted.
To use the connector, the completed connector is - - -
held fimrly and wires inserted either singly or multiply,
one into each contact element.
The wire 12 is positioned as shown in Figure 6
over the channel and, with a tool designed to do so,
evenly pushed down into the channeI.
As can be appreciated, the smoothly angled con-
figuration of the upper edge 7, 7a of the jaw will contact
the insulation on the wire and, as the wire is pushed
downward, will tear through the insulation. As the wire
progresses downward and the metal of the wire itself con-
tacts the jaws past the transition area 9, 9a and to the
working faces 5, 5a, it ~ill be deformed to eventually
mate intimately with the jaw working faces 5, 5a. The
primary distortion of the wire is an inwardcompression
or embossing with some upward displacement of metal.
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In an intensive series of tests involving a
variety of hostile environments, thermal cycling, thermal
shock, thermal aging and physical strength and durability
the termination system performed well according to cri-
teria relevant to telecommunications applications.
While the above description relates to certain
embodiments now known to and preferred by the inventors,
it is possible for persons skilled in the art to make
certain additions, changes and modifications. It is in-
tended by the appended claims to cover such additions,changes and modifications as fall within the scope and
spLrit of the inventlon.
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