Note: Descriptions are shown in the official language in which they were submitted.
5~
~ACKG~OU~D OF T11E I1~1JTIO1~
The present invention is directed to a multi-
conductor electrical cable ~ermination and, moxe paxticularly,
to a relativ~ly permanent termination for a flat ribbon-like
multiconductor electrical cable ~ith mass termination insulation
displacement and solder connections for the contacts and cable
conductors.
Since individual manual connection of each
conductor in a multiconductor electrical cable, which usually
has more than three conductors and as many as fifty or more
conductors therein, would be a difficult and tedious task, a
number of specialized connectors have been developed for
simultanQously connecting each of the plural conductors
to tho~se of another multiconductor electrical cable via
anot11er connector, for example, to a plural signal input
terminal of a computer or the like, to conductive paths on
printed circuit board or the like, etc. Typically these
specialized conn2ctors include multiple housing parts between
whic11 the cable is clamped, and usually before or during that
clamping the ~ultiple contacts of the connector puncture the
electrical insulation of the cable to connect with
respective conductors therein. Tho housing parts are mechanically
secured in clamping engaqement ~ith th~ cable, and strain relief
is usually provided by the clamping strength and/or by th~
terminal parts of the contacts pierced through the cable
insulation.
In U.S. Patent 4,030,799 is disclosed a multiconductor
electrical cable termination formed as an integral structural
combination of the multiconductor electrical cable, the plurality
of electrical contacts, and a housing part that is molded about at
least a portion of ~ach of the contacts and a portion of the cable.
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~2~573~ii
Each contac~ forms a junc~ion with a respective co~ductor
of the cable~ and the integral housing part ~s mDlded under
eleYated temperature and pressure conditions so tha~ each of
the junctions is substantially fully encapsul.~ted ~y at least
one of the cable insluation and the molded-~ody part and, ~hus,
maintained relatively free o f moisture and oxygenO The
contacts and tl~e conductors, therefore, may be of dissimil~r
metals, which will not corrode, oxidize or undergo any electrolysis-
like activity due to the lack of moistuxe or oxygen at the
ju~ctions. Furthermore, the molded housing part preferably
is of a material compatible with that of ~he electrical
insulation of the cable so as to bond chemically there~it} to
provide an e~ective strain relief for the termination and
also to insure the integrity of ~e encapsulation of the
junc*ions. Tl~e terminal portion of each electrical contact
preferably extends fully through the ca~le insulation, and
openings pro~ided in the molded housing part offer access
to the ends of those terminal portions for test probing thereof.
It will be appreciated that the contactin~ portion of each
electrical contact, i.e. the portion beinq intended for elec-
trical connection to a ~evice other than th~ cable of the
termination, may b~ of various desi~ns for connection, for
example, with pin contacts, femal~ contacts, e.gO fork contacts;
conductive paths on a printed circuit board, etc.
Such cable termination may be formed using a mass
termination techni~ue known as insulation displacement connection
(IDC) whereby the contacts, preferably a plurality of them
simultaneously, pierce the cable insula~ion to engage cable
conductors before the integral hou~ing body part is molded.
Such IDC mass termination approach is relatively inexpensi~e
and expeditious.
BRIEF SU~MARY OF THE INVENTION
According to the invention, a solder connection of
the contacts of the cable termination and the conductors
of the cable being terminated is provided while also retaining
the manufacturing and cost efficiency characteristics of
a mass termination IDC connector device. A solder connection
can provide added integrity of the junction of the contact
and cable conductor while also assuring a minimum of impedance
at such junctions. The solder connection preferably is formed
using induction heating of the otherwise complete connector~
cable termination to re-flow solder.
Such solder connection is provided by employing con-
tacts that have been pre-coated, e.g. by electro-plating
with a solder material at the IDC part thereoE and after
the IDC connection oE the contacts and cable conductors has
been made providing heat to the solder material to re-flow
the same thereby forming a solder connection with respective
cable conductors. Preferably the solder connection is so
formed after the integral housing part has been molded about
the IDC connection of the contacts and cable conductors
by applying sui-table source of heating energy to re-flow
the solder.
Advantages of the aforesaid approach include main-tain-
ing the solder connection area clean from contaminant and
the confining of the solder to assure re-flowing in the cor
rect areas of the contacts and especially the conductors
while minimizing the amount of solder required for the pur-
pose. Another important advantage is the avoiding of a spur-
ious short circuit between an incorrect contact and cable
conductor because during the soldering operation the indi-
vidual contact andconductor pairs are isolated from the other
such pairs by the molded housing part and the cable insula-
tion.
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~2'~
On the other hand, if desired, it is possible that
the solder connections may be formed by applying heat and
re-flowing the solder on the contacts prior -to the molding
step or possibly during the molding step.
~ ith -the foregoing in mind, it is a primary object
of the invention to provide a multi-conductor electrical
cable termination improved in the noted respects.
Another object is to provide advantages of a mass
termination multiconductor cable termination while also
achieving the integrity and other characteristics of a solder-
connection junction.
Another object is to achieve both the mass termination
IDC cable termina-tion cost and manufacturing efficiencies
and to utilize the same to facilitate making solder connec-
tions in a mu]ticonductor cable termination device.
Another object is to facili-tate the formation of
plural solder connections of a mass termination cable termi-
nation device especially using induction heating, and,
further, especially by effecting such induction heating and
re-flowing of the solder material to form the solder connec-
tions after the cable termination device is otherwise already
complete or substantially complete in manufacturing.
Another object is to maintain the junctions between
the terminals and conductors of a multi-conductor electrical
cable termination substantially free of moisture and oxygen.
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~2~ 73~
~n additional object of the inven~ion i~ to
pn~Yide integral molded strain relie~ for a multiconductor
electrical cable termination.
A further obiect of the invention is to provide
for test probing or ~le like of the electrical circui~s in a
multi-conductor electrical cable termincltion and especially
to provide such ability while the termination i5 ~onnected
to anoth~r d2vice.
Still another object of the invention is to
10 provide for the termination of a multi-conductor electrical
cable having a plurality of closely positionod, electrically
insulated conductors.
Still an additional object of ths invention is to
terminate in a facilQ manner a multi-conductor elec~rical
cable and especially a flat, ribbon-like multi-conductor
electrical cable.
These and other objects and advantages of the
present invention will ~ecome more apparent as the
following description proceeds.
To the accomplishment ~ the foregoing and related
ends, the invention, then, compri,ses the features hereinafter
fully d scribed and particularly pointed out in the claims,
the following description and the annexed drawing setting
forth in detail a certain illustrative embodimen~ of the
invention, this being indicativQ, however, of but one of
the various ways in which the principles of the invention
may be employed.
BRI~F DESCRIPTION Ol Tli~ DR~ING
In the anne~ed drawinq:
Fig. 1 is an ~xploded isom~tric view o:E th~ multi
conductor electrical cable ternlination in accordance with the
invention;
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~5~5
~ig. 2 is a bottom view of the mDlded housing part
of the multiconduc~r electrical cable term.ination looking
in the direction of ~he arrows 2--2 of Fig. l;
Fig. 3 is an end elevation view of th~ multi-
conductox electxical cable termination looking in the direction
of the arrows 3-~3 of Fig. l;
Fig. 4 is a partial se~tion view at two relatively
spaced apart generally vertical planes of ~he multiconductor
alectrical cable termination looking in ~he direction of the
stepped arrows 4--4 of Fig. l;
Fig. 5 is a partial section view at a test probe
opening of the multiconductor el~ctrical cable t~rmination
looking in the direction o~ th~ arrows 5--5 of Fig. 4;
Fig. 6 is an ond elevational section ~i~w of tha
housing cover of the multiconductor el~ctrical cable
termination looking in the direction of the arrows 6-~6 of
Fig. l;
Fig. 7 is a partial side elevation view, mostly
in section, o~ the housing cover looking in th~ ~irection of
the arrows 7--7 of Fig. 6;
ir ln. a i5 an enlaraed plan view of a contact rl~1ted with
soldr?l~ act:ol-dino to tne preser-~t invention;
Fiy. 9 is an enlarged sectiQn view simil2.r to Fia. 4 showing
the sulrder conrlection of a tvpic~l contact ~nd condLIctor in a
multirondLIctor cable termination according to the present
i nvent i on; ~nd
Fig. 1(1 is a schematic view of ar~ induction ne~tlnu method
and ,:;poaratLl, in ~ccc:,rdance with the pr-esent inventioll emploved
to effect rompletion rf solder conr)ecti~ns in the cable
tei-mination assembly by i~e--f lowina solder upun appl lc~tion of
i l-, d ~ lc ~ , e c~ ~ 1 r~
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3~
DESCRIPTIOI~ OF THE PR~FERRE~ E~ODIMENT
Referring no~ more specifically to th~ drawing,
wherei~ like referenc~ numerals designat:e like parts in the
several figures, and initially to Figs. 1 through 5, a
multiconductor electrical cable termir~ation is generally
indicated at la. Th~ fundamental parts of the terrr.ination 10
include a multi-conductor _lectrical cable 11, a plurality
of 21ectrical contacts 12 for connection a~ respectiv~ junctions
to the respective conductors 13 of the cabl~, and a housing 14
having a base body part 15 molded about at least a portion of
eacn of the contacts and a portion of the cabl~ to an integral
structure therewitll.
-4a-
In the illustrated preferrea embodiment of the
inv~ntion the housing 14 also includes a cover 16
adapted to fi~ onto the base 15 at a poripheral ~tep 17 of
the latter for appropriate containment of the c:ontactinq portions
18 of the el~ctrical contacts 12; however, it will ~ appre~iated
that the form of the cover 16 and its possible elimi~ation will
depend on the particular style of the contacting portions lB.
For example, if the contacting portions 18 were simply poin~s
to bQ soldered in plated through op~nings of a printed circuit
board or ~le like rather than of the illustrated fork-like
style, the cover 16 can be eliminated from the termination :L0~
Preferably, the composition of the material of which
the base 15 is form~d and th~ composition of the electrical'
insulation 19, which maintains the conductors 13 in parallel spac~d-
apart locations, are similar or compatible so that when the base
15 is molded it will chemically bond to the insulation 19
further to increase the integrity of th~ structure of the
termination 10 and at the same tim~ to provide a mol~d strain
relief that precludes separation of the contact terminal
portions 20 from their respective junctions 21 with the
conductors 13, which are seen most clearly in Fig. 4.
As shown in Fig. 4, the junctior,s 21 are e~capsulated
by the insulation 19 and the ~olded body of the base lS, and in
the preferred form of the invention the body 15 is molded about
portions of the electrical contacts 12 and cable 11 under the
elevated temperatures and pressur~s used in an injec~ing molding
maclline, ~her~by any moisture and~or oxygen at thC~ junction 21
is substantially eliminated during the molding proc~ssO Therefore,
the ma~erial o which the electrical contacts 12 are formed and the
material of which th~ conductors 13 ar~ formed may b~ d~ss~ilar
, ~
without encountering corrosion, o~:idation or cl~ctroly~is--l;ke
activity at the junctions 21, which t~ill re~ain efective
cl~ctrical connectionS between the electrical contacts and the
respective conductors regardless of the ~xternal environment
to whic~ the termination 10 is subsequently subjected, Moreover,
since ~che base material and the insulation material chomically
bond during m~lding of the base, the integrity of the encapsulatio~.
at each junction is further enhanced. T~erefore, th~ relatively
~xpensiv~ copper or plated conductors 13 may be ef fectively
terminated, for example, by less expensiv~ al~minum ~lectrical
contacts 12.
The texminal portion 20 of each electrical contact
12 pr~ferably includes a pair of elongate prong-lik~ arms 22
commonly supported from a base portion 23 and d~fi~ing a relatively
narrow slot ~4 ~hsr~twee~. Th~ ends of ~ anms 22 r2mote
from the base portion 23 prefsrably are tapered or chamfered
to define an entranceway into the narrow slot 24 and to form
g~n_rally pointed tips 25 to pierce easily through the c~ble insu-
lation 19. The width of the narrow slot 24 is preferably narrower
than the normal diameter of the conductor 13. Th~refore, as a
typical electrical contact 12 is joined with the cable 11
by urging th~ t~Jo toward ~ach oth~r, the pointed tips 25
pierce through the insulation 19 while the wide chamfer~d entrance-
way guides ~he conductor 13 into the narro~ slot 24. As the con-
~uctor 13 enters the slot, it is somewhat flattened to provide
a relatively ~anlarged surface area of engagement or conn2ction
~ith the two arms 22.
35i
To maximize the efficiency of the insulation displace
ment connections (IDC) a plurality of the conductors and
contacts make connections simultaneously, for example, by
loading the contacts into a holder and pressing the same
simultaneously through the cable insulation into the afore-
noted engagement with respective cable conductors. Such
simultaneous mass termination of respective cable conductors
is extremelycost and time efficient.
With the contacts in place in the cable, thebase body
is molded about part of the contacts, cable conductors
and cable insulation forming an integral structure therewith,
for example, using a plastic injection molding machine.
Although such rnolded plastic fills a large portion of any
voids formed in the area of slo-t 24 of the respective con-
tacts, a-t least small open areas remain exposed wl-thout
molcled plastic there, and this is especially true at areas
of the contact directly engaged with and very proximate to
the cable conductor 13. Moreover, preferably the cable con-
ductor 13 is a stranded conductor, for example a seven strand
conductor. A stranded conductor has good signal carrying
properties and also is easily distorted to make a good con-
nection with the edges of the contact 12 on opposite sides
of the slo-t 24. An added advantage of the stranded conduc-
tor used in the present invention is that the spaces between
the strands generally do not fill with plastic during the
plastic molding step mentioned above; therefore, such spaces
or areas are available for the flowing of solder therein
during the soldering process described further below. Further-
more, during the insulation piercing by the contact arms
22 and tips 25 (the
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i;'73~
insLIlation displa~ement step in the process of ~nufac~uring the
connector/cable termination 10 ~f the invention~ the c~ble
insul~tion m~y wip~ closely ~gainst the sLIrface 9~ the co~tact
~nd remain at l~t in part about the conductor 1~ such as o~er
p~rt of the latter which is ~Jithin the slot 24~ and! thus~ suc~
insul~tion l~y f~rther chielcl p~rt of the c~ble ~nd contact ~rDm
plastic being molded ~irectly into engage~ent therewith in order
tD prDvi~e sp~ce ~or s~ld~r to be re-~low~-d in formino ~ solder
connecti~r) betweer\ respective contact~ and cable conductors.
The terminal portion 20 of each electrical contact
12 is in the same plane and is offset with respect to the
contacting portion 18 thereof, as can be seen most clearly
in Figs. 1 and 4~ ~s seen particularly in Fig. 1, the el~ctrical
contacts 12 in the fon~ard row 26 have ~leir te.rminal portions
offset to the left with respect to their contacting portions, and
the electrical contacts in the rear~ard row 27 have their
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3~
texminal portio~s offset to the right wi~h respect to the
contacting portions. This offset configuration ~f th~
electrical contacts 12 allows them ~o be o xeasonabie size
and strength while ~h_ contacting psrtion of each contact in one
row is dircc~ly aligned with ~he co~tacting portion of
an opposite contact in the other row and with each ~f the
relatively c10s21y positioned parallel co:nductors li 3 bei ng
connected to only a single respecti~e contact 12. It will be
appreciated that al~ough the illustrated invention utilizes
10 two rows of contacts, the principles of the inv~ntion
may be, of course, employed in terminations having one
row or more than two such rows of contacts or any ot~her arran~e-
ment th~reof.
Each of ths contact terminal arms 22 is
preferably sufficiently long to extend fully through the
cable 11 with a portion, for example, including the
pointed ends 25, being exposed beyond the plane of the cable, as
is illustrated most clearly in Figs. 3 and 4. ~hen the base body
15, then~ is mold~d about portions of the contacts and cable,
openings or holes 2~, which are seen most clearly in Figs . 2
through 5, are formed in the bas~ to allow those portions of
the arms 22 to remain e~posed. Th~refore, wh~n the multiconductor
electrical cable t~rmination 10 is connectod, for example, to ~-
another connector, to a computer, to a printed circuit board
or the like, with the conductors 13 operativ~ly carrying
r~spective 21ectrical sisnals, each of the circuits in ~hich ~e
respective conductors 13 are connect~d may be tested, for
example, by insertion of a probe ~rom a t~st instrument or the li~e
in the r~spective openings 28 to en~ag~ment ~ith the exposed
arms 72. Also, during the molding of ~he bas~ body 15 l~d~es
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~ 3~
29 are fonmed be nd each of the arms 22 ~o pre~ent such an
insert~d probe from separating the arms and disturbing ~he
sealed encapsulated and electrical integrity of ~he
junction 210
As illustrated in Fig. 1, for example, each of
the electrical contacts 12 is of the fork contact type whereby
each of the contact portions 18 comprises a pair of generally
parallel elongate arms 30 adapted for electrical and mechanical
connection with a pin contact, for example, inserted there-
between. The housing cover 14, which is illustrated in Figs.1, 6 and 7, preferably is also injection m31ded as a separate
part of dielectric material such as, for example, plastic ~ith
chambers 31 th~rein for containment of the arms 30. The
cover 16 has an outer wall 32 opon at the bottom 33 to
recelve respective pairs of elongate contacta~ns 30 in the
respective cha~bers 31, which arQ ~efined by the outer wall 32
and by internal walls 34, 35. In the cover top 36 are a plurality
of apertures 37 for guidin~ respective pin contacts or the like
into the respective cham~ers 30 between
the t~Jo arms 30 of the respectivo el2ctrical contacts
12 for mechanical and electrical engagement ~erewith.
The opening at the cover bottom 33 is also stepped for joining
at the step 17 of the base 15.
--8--
~5~35
In addition to the above express and implied advan-
tages of the multiconductor electrical cable termination
10 of the present invention, the termination may be produced
relatively more efficiently~than the prior art clamping type
specialized connectors previously used to terminate flat
multiconductor ribbon-like cable, for example, by inserting
the electrical contacts 12 in the cable 11 and moldiny the
base body 15 of the housing 14 thereabout at the same work
station of an injection molding machine substantially to
complete the formation of the termination in a single step.
Thereafter, if the housing 14 is to include a cover 16, the
latter may be easily fitted to the base 15 at the step 17
and secured thereto, for example, by acoustical or ultra-
sonlc welding techniques.
I'urning now to Fig. 8, a contact 12 employed in the
present invention is shown in enlarged plan view. Preferably
the arms 22 and part of the contact base 23 are electro-plated
with a relatively copious amount of solder material 40, and,
if desired, some flux material may be provided there as well.
In the preferred embodiment flux is employed and may be
applied direc-tly to the contacts as par-t of or as a separate
step as is the solder 40, for example. The flux is not
separately identified in the drawings but may be construed
as being part of the solder 40 that is shown. The solder
40 is shown about the outer edges and especially about the
inner edges 41 of the arms 22 bounding the slot 24. If
desired, the solder may be applied to the contact by means
other than electro-plating and may be applied in a more res-
tricted area than that shown in the drawings.
The cable rDnciuctors 1~ preferably are Dt the stranded type
noted above and also are preferably formed of a mater-ial that
will form a satisf~ctory solder connection with the solder and
the ~ontacts 1~ with good r~liability of the elec~rical
connection so formed. In the preferred embodiment and best mode
of the invention~ the cable conductors 1~ are formed of tinned
copper material.
~ ccording to the preferred embodiment and best mode~ too~
the solder 40 is re-~lowed to forn~ the solder connection 42 shown
in Fig. 9 after the body 15 has ~een molded int place and~ if
usedl after the cover 16 has been put in place e~nd preferably
ultrasor,ically welcied to the body 15. To effect such re-flowin~
of the c,older~ hr-at is applied to the soltier~ Such hr~?at
application may be bv laser~ heatinq in an oven. or other
technique. For e~mple~ a laser mav be ~ocust:~d ~nto the opentng
?8 onto the e~posed contact arMs 8; ~nri heat fr-om the laser may
be transmitted thruugh the metal of the cQntact to re-flow the
soler thereon~ especie~lly in the area of the desired lunction Df
the contact and cable conductor l_. ~ltern~-tively. if the
material uf which the bodv 15 and cover or aap 1~ are. cornpried
is of the thern~osetting type or is capable after beina molded of
withstanding the tell)peratLIre required to re-flow the solder, in
is possible ~o place the conr-ector 1~:) in an oven to heat the
eiolder to r~e--flcw the -,ame without ti,:-trlm-entall~ iectin~? the
bndy 15 or- the cover 16~
~ ccor-ding to the prefer-reri r-mttodin,ent and ~est ~)ode of the
invention~ as is illustrated in Fia. lC)o induction heatil-)g is
~Ised tu re-flow the solder- 4l:). Specificallv~ a power s~lpply 5
pr-ovides electrical po~Jer to an ind-lctior- heatin~ COl 1 ~1 Yi a
electr-ical leads 5'~ 57~. T~-,e induction tteatina cull 51 is
adequatelY laYge to receive the completed connector/cable
terrrlination ll:) therewithin. Ur~orl ~pF~lication of suitable
electrical erer91~atlQrl to the coll 51 th-- Cc~me eftects heaLinrJ
--10--
'73~
of the contacts within the connectDr $0 andJor of the ~older 40
caucjing -the latter- to re-flow over at least part of the contacts
and respective cDnductors associ~ted therewith. The flowing
solder 4C~ preferably ~akes a good solder connection 4~ by flowing
into the in~erstices between the str~nds of the c~ble conductor
13. Thus! such induction heating process facilitates further ~h~
manu4acturing of the c~ble termination 10 according to the
invention achieving both ~irect engagement and solder connection
integrity of the individual iunctiQns of respective contacts l2
and conductors l~. The use of indL(ction he~ting. too. avoids the
s~lbiecting of the other pcarts of the corl)lector 10 to heat that
maY be otherwise disadvantageoLIsly affecting sa~.e~ while also
enablincl colnpleting of ll the or a plur~litv of the solder
connections in the conrlectcr in a simultaneou~ manner.
7'hu~ it will be appreciat~d that the presi?nt invention
providec~ t:or the cernlinatino of a mLIlticor)ductor cable achieving
the lhbor~ cr~t, arld time effiLiencv of a mass termination
connE~ctor~ especlally of th_ IDC type while also adding the
reli~bility r~f a sulder connectinn. Moreov_r! due tv the ability
to effect the solder- re-~lowinL3 within a confined .area after
molding of the body 15~ such ~oldering step may be effected
r~pidly and efficientlY, e.g~ in terms of cost. labor~ time~
materi~ls and equipment.
UFon rompletlnc~ the tormatlon and~or- as~embl~ ot ~he oulti-
conductor- electrical cable termination lO~ it m~y be easily
connecterd to another electrical ronnector~ a plural signal input
terminal ol a computer-! conducLive paths on a print~d circuit
~c3ard! or- the like to cor~nect the conductors 13 in respective
circuits~ 'l'hr- ccntacts 1~, cilthough described as female
Lontacts~ n,ay be of the male type or of other scecialtv type fDr
connectinr~ the condoctors 13 l~ith other respecti~e circuits~
cond~ctc~rs~ etc.
3 ~
~ reov2r~ w~ile the in~ention is illustratod and described
above with reference to multiconductor electrical rable termination
10 located at ~n end of the multiconductor el~ctrical conductor
11, it Wlll be apparent that Cuch a termination also may be
pro~ided in accordanc~ the invention at a location on a
multic~nductor electrical ca~le intermediate the ends ~hereof.
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