Note: Descriptions are shown in the official language in which they were submitted.
-`` 111537t
CRIMPED STRANDED WIRE MICROPIERCE
TERMINATION SYSTEM
TECHNICAL FIELD
The present invention is directed generally to
solderless electrical connections andg more partlcu-
larlyg to a novel electrical connector including a con-
tact for forming a crimped/ insulation-piercing ele¢tri-
cal connection and a termination tool used to effect
such a connection.
BACKGROUND OF THE PRIOR ART
In recenk yearsg increasing numbers of applica-
tionæ have developed in the communications, data process-
ing and transportation industries requiring electrical
connectors which provide reliable solderless intercon-
nections wlth insulated electrlcal conductors. Thisdemand has perhaps been greatest in the telecommunica-
tions industry where miniaturizedg high contact density
ribbon connectors are used extensively. Connectors of
this general type are dlsclosed in United States Patent
Nos. 3g8679005g 3g902gl54; and 3g926g498~ Because of the
great number Qf individual conductors terminated in
these connectors and because of the close spaclng be-
tween the individual contactsg reliable solder termina-
tions are dlfficult to achieveg as well as time consuming
and costly to maintain and serviceO For these reasons
lnsulation-piercing contacts have been developed for use
in ribbon connectors and have met with ~ide acceptance
when used to terminate insulated conductors having solid
wire cores. Un~ortunatelyg due to the demanding stan-
dards in the industry requiring almost negligible changein contact reslstance~ the insulation-piercing type
rlbbon connectors have proven unacceptable when used
with stranded wire core conductorsO Experience has
shown that tensile forces applied to the conductorsg as
well as the cold flow of the insulation surrounding the
coreg cause~ tlle individual strands of the wire core to
move and reposition within the insulation-plercing con-
tacts, causing changes in contact resistance. Thus,
solder ter~ination ribbon connectors are still used with
standard core insulated conductors.
. ~ . .
,: ' ~ ,' ' ' - .
li~53~7 1
Accordingly, a need exists for a ribbon connector
which provides a satisfactory solderless termination to
stranded core insulated conductor, and preferably both stranded
and solid core conductors. In addition, in order that the
conDector be commercially practicable, the termination must be
performed with the electrical contact premounted within the
connector.
BRIEF SUMMARY OF THE INVENTION
The present invention, therefore, is directed to
an electrical connector including means to effectively and
reliably terminate both solid and stranded wire core insulated
conductors in an insulation-piercing contact, without the need
for any soldering operation, and while the contacts are
assembled within the connector.
In accordance with one embodiment of the invention,
the electrical connector generally comprises a dielectric
insert, including a plurality of contact receiving cavities;
a plurality of electrical contact members each having a terminal
portion with opposed sidewalls disposed within one of the
cavities; and access means formed in the dielectric insert
: providing access to the sidewalls, said sidewalls e~tending
into said access means, whereby a crimp tool may be inserted
into the access means to deform the portions of the sidewalls
adjacent the access means to secure the conductors in ter-
minated position within the contact terminal portions
The present invention also provides a method for
terminating an electrical conductor to a contact member
premounted in an electrical connector, said contact member
having a terminal portion including at least one conductor
engaging element, said method comprising the steps of:
inserting the conductor into the contact member to seat the
conductor within said terminal portion and make electrical
~ -2-
111'.37:1
engagement between the conductor and said element; and
thereafter crimping a segment of the contact member terminal
portion other than said element onto said conductor to
mechanically retain said conductor in electrical engagement
with said contact members.
BRIEF DESCRIPTION OF THE D~?AWINGS
... . _ . ..
The novel features which are believed to be chara-
cteristic of the invention are set forth in the appended
claims. The invention itself, however, together with further
objects and attendant advantages thereof, will be best under-
stood by reference to the following description taken in con-
nection with the accompanying drawings in which: -
-2a-
~11.1537i
FI&URE 1 is a side elevational view of an electri-
cal connector embodylng the features of the present invention
and showing the individual conductors of a multi-conductor
electrical cable terminated therein;
FIGURE 2 is a fragmentary perspective view of the
connector of FI&URE 1 with portions broken away to illustrate
the crimp-pierce termination obtained with the present inven-
tion;
FIGURE 3 is a fragmentary cross-sectional view
illustrating the sequence of steps performed to obtain the
desired crimp-pierce termination;
FIGURE 4 is a perspective view illustrating a pre-
ferred termination tool made in accordance with the present
invention;
FIGURE 5 is a plan view of the terminal portion of
a preferred contact member used in the connector illustrated
in FIGURE l; and
FIGURE 6 is a perspective view of the contact member
of FIGURE 5,
DETAILED DESCRI~TION OF THE INVENTION
With reference to the drawings, and specifically
FIGURE 1, an electrical conductor 10 is shown with individual
insulated conductors 12 terminated to each of the connector's
electrical contacts. The connector 10 is a ribbon connector
and comprises a dielectric insert 14, a plurality of electrical
contacts 16 mounted in the ~nsert, and a metal skirt 18 which
houses the insert and contacts subassembly. A detailed de-
scription of the structure and function of ribbon connectors
and their components is provided in U.S. Patents Nos.
3,867,005
B _3_
l~lS371
~nd 3,926,498, The insert 14 includes a plurality of elongated
contact-receiving cavities 20 and an access passageway in the form
of a slot 22 extending transversely to the cavities 20. The slot
22 provides access to the electrical contacts 16 to permit crimp-
pierce termination of the conductors 12 as described in greater
detail below.
Referring now to FIGURE 2, the subassembly comprising
insert 14 and contacts 16 is shown in greater detail. The insert
includes a plurality of partitions or upstanding barriers 24 which
form the sides of the contact-receiving cavities 20. Each of the
contacts 16 has an active contact portion 26 adapted to electri-
cally engage a compatible contact and a terminal portion 28 for
electrically and mechanically engaging the insulated conductors ~-
12. In the illustrated embodiment, the terminal portion 28 of
each contact is channel-shaped, having a bottom wall 30 and op-
posed side walls 32 and 34, and includes insulation-piercing means
which serve to provide the electrical and mechanical engagement
with a conductor inserted and pressed into the channel.
In accordance with the present invention, the insert 14
is designed to permit crimping of the terminal portion 28 while
the contacts 16 are mounted in place in the connector. To accom-
plish this end, the slot 22 is formed in each barrier 24 to pro-
vide access for a crimping tool. The slot 22 need not extend to
the base of cavity 20 but must terminate at a point below the top ;~
of the side walls 32 and 34 of the contact terminal portion 28.
In other words, the side walls 32 and 34 extend upwardly into the
slot 22 As shown in FIGURE 3 the crimp tool is inserted into
the cavity 20 along a path of travel generally perpendicular to
the terminal portion 28 and acts to deform a portion of the side
walls 32 and 34 coinc~de~ wl~ th~ 81~t ?2 to hold the conductor
12 in final terminated 4~S~ t~.
A preferred configuration for the terminal portion 28
is illustrated in FIGURES 3, 5 and 6. In accordance
~ ~.rr,
~ - 4 -
371
with this embodimeilt~ the side walls 32 and 34 lnclude
conventional insula~:~on-piercing protuberances or de-
tents 36 whose structure and function are well known in
the art. In addition~ the terminal portion 28 of the
contact includes a further insulation-piercing extrusion
in the bottom wall 30. In the illustrated embodiment~
the extrusion is an upstanding cone 37. The side walls
also include lnwardly extendingg offset upper edges 38
which form a lead-in for the crimp tool. The detents 36
are pos~tioned longitudinally on the sidewalls 32 and
34 remote from the slot 22 of insert 14 and their
function and operation remain substantially the same as
in prior art connectors. The cone 37 and edges 38 are
positioned coincldent with the slot 22 and serve to
improve both the mechanical and electric characteristics
of the termination. As the conductor is pressed into
the terminal portion of the contact, the cone 37 pierces
the conductor's insulation and engages the conductor
core. Likewiseg as the walls 32 and 34 are deformed by
the crimp tool~ the edges 38 pierce the conductor's
lnsulation and also engage the conductor core. Thus, in
the illustrated embodiments electrical contact is made at
the sidesg top and bottom of the conductor via the de-
tents 36, cone 37 and edges 38. In additiong mechanical
retention o~ the conductor within the contact is en-
hanced~ and the opportunity for movement of even stranded
core conductors is thereby minimized. -
A preferred termination tool is lllustrated in
FIGURE 4 and includes a bifurcated terminatlon head 40
3 havlng separate insertion and crimping members, 42 and
449 respectively. The insertion member 40 has a g~ner-
ally planar end face ~6 for engaging and pressing the
conductor into electrical engagement with the terminal
portion 28 of the contact 16. The crimplng member 44
has a specially configured end face 48 including means
for cutting portions of the contact's side walls 32 and
34 and means for crimping or folding these cut portions
inwardly onto the conductor. In the ~llustrated embodi-
ment, the cutting means are curved edges 50 which shear
:
~.
~ 111.~37~
the side walls of the contact as the tool is inserted
into the c~vlt~ 20, and the foldin~ means are the curved
surfaces 52 which meet at a central apex 540 It will be
appreciated that as the insertion tool is inserted into
cavity 20 to the ~ull extent~ the surfaces 52 will direct
the cut portions of side walls 32 and 34 over and into
the conductorg thereby crimping the contact and conductor
in a fixed lnsulation-piercing termination.
In a conventional ribbon connector as many as
twenty-five conductors wil,l be terminated to twenty-five
separate contacts on each side ~ the connector, Each
o~ the conductors ~ aligned adjacent the terminal por-
tion of a respective contact and then terminated by
means of a suitable termination tool. The sequence of
steps employed to effect a crimp-pierce termination with
the connector and tool of the present invention are
illustrated in FIGURE 3. After the conductors have been
aligned adjacent the appropriate contact terminal por-
tions 28, the tool carrying head 40 presses each con-
ductor into the terminal portion and then crimps thecontact o~to the conductor. Since the tool moves rela-
tlve to the connector (right to left in FIGURE 3) with
each insertion~ the insertion member 42 flrst seats the
conductor within the contact and properly positions the
conductor for the subsequent insertion of the crimping
member 44. As can be clearly seen in FIGURE 3 the crimp-
lng member 44 extends latera~ly beyond the side walls
32 and 34 of the contact~ thereby necessitating the
access passageway or slot 22. The slot 22 must have a
3 depth suf~icient to allow full insertion of the crimping
member 44 to properly sheer the side walls 32 and 34
and completely crimp the sheered portions over and into
the conductor.
Of course~ it should be understood that various
changes and modifications to the preferred embodiments
described herein will be apparent to those skilled in
I the art. Such changes and modifications can be made
; without departing ~rom the spirit and scope of the pres-
ent inventlon and without diminishing its attendant
` ~
..~
11~537~l
,
-7-
advantages. It isg thereforeg intended that such changes
and modif~cations be covered by the ~ollowing claims.
-~ . '
