Note: Descriptions are shown in the official language in which they were submitted.
This invention relates to electrical connector apparatus,
and is more particularly concerned with a strain relief adapter
~or an electrical connector.
Strain relief apparatus for an electrical connector
which employs a plurality of insertion blades which have a two-
fold purpose has been disclosed. First of all, blades are em-
ployed as a tool for engaging and forcing insulated conductors
into respective insulation-piexcing contact portions of an elec-
trical connector. Secondly, the blades are carried on a common
member which also supports a comb-shaped member which receives
the individual conductors between the teeth of comb to provide
strain relief as the structure is snapped about the rear portion
of the electrical connector. Two such adapters may be mounted on
opposite sides of an elongate electrical connector and a common
hood may be slid over the adapters to provide additional positive
retention of the adapters.
~ primary object of the invention is to provide an impro-
ved strain relief adapter which may be installed on the rear por-
tion o~ an electrical connector which has already had conductors
electrically connected to the contacts of the connector. Another
object of the invention is to provide an improved strain relief
adapter which is more suitable than prior adapters for use in
connection with termination tools.
Another object of the invention is to provide an impro-
ved strain relief adapter constructed o~ two identical one-piece
molded structures which may be mounted on opposite sides of an
electrical connector and which are inter-engageable with each
other to clamp not only to the connector, but to each other.
Another object of the invention is to provide a strain
relief adapter which provides strain relie~ on the incoming lead
side and on the outgoing lead side of an electrical connector
which constitutes a tap in a bundle o~ conductors.
~ 'Y:~
Another object o~ the invention is to provide a strain
relief adapter which includes an integral diversion structure ~or
preventing dislodgement of the conductors from their electrical
contacts in respo~se to tensile ~orces applied on the outgoing ;
leads.
According to the invention, a strain relie~ adapter ~or
insulated conductors electrically connected to contact portions
supported spaced apart by an electrical device, comprises a plu~
rality of pressure members spaced apart corresponding to the
spacing of the contact portions ~or engaging and pressing against
first portions of the insulated conductors in the contact area,
conductor clamping means spaced from the pressure members for
receiving and clamping second portions o~ the ~nsulated conduc-
tors along lines parallel to the ~irst portions of the conductors, :`.
and force diversion means spaced ~rom the pressure members and
from the-conductor clamping means for receiving the conductors
and preventing dislocation o~ the first portions in response to
the application of tensilP forces to the conductors.
More specifically, the invention provides a strain re-
~o lief adapter for insulated conductors which are pressed into insu-
lation-piercing contact portions supported spaced apart in respect-
ive channels in parallel rows on opposite sides o~ an electrical
connector, the adapter comprising a pair o~ identical inter-enga-
geable molded parts for opposite sides of the electrical connector
and each of the parts including a plurality o~ blades for enter-
ing the respective channels and pressing against the insulation-
pierced portions of the conductors3 a comb-shaped edge opposite
the blades having constricted openings for receiving the insula-
ted conductors to clamp the outgoing lead portions of the conduc-
tors, and a comb-shaped member parallel to and extending away
from, the blades and the constricted opening comb clamping struc-
ture for receiving the individual conductors between the teeth
.
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thereo~ as ~ mealls ~or diverting laterally and upwardly applied
forces to pxevent dislocation of the conductors from the insula-
tion-piercing contact portions.
The application of pressure to the conductors by the
blades provides additional strain relief in that the blades fill
the channels straightening any channel barriers which were de-
formed during conductor insertion and creating frictional forces
against the sides of the barriers as additional protection
against loosening of the conductors.
Other objects, features and advantages of the invention,
its organization, construction and operation will be best under-
stood from the following de-tailed description of a preferred em-
bodiment of the invention taken in conjunction with the accompa-
nying drawings, on which:
FIG. 1 is a perspective view of an elongate electrical
connector which may advantageously be provided with strain relief
according to the invent.ion;
FI&. 2 is a fragmentary enlarged view of a part of the
rear portion of the electrical connector of FIG. 1 specifically
~O showing a suitable structure for an insulation-piercing contact
portion;
FIG. 3 is an elevation of the inner side of a strain
relief adapter constructed in accordance with the present inven-
tion;
FI&. 4 is a perspective view of a strain relief adap-
ter according to the invention, specifically illustrating the
outer side and one end of the strain relief adapter;
FI&. 5 is an enlarged fragmentary view of a portion of
the elevation of FIG. 3 to more specifically show the structure of
the pressure members and the relationship between the pressure mem~
bers and the structure provided for force diversion;
FIG. 6 is a partial fragmentary sectional view taken
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substantially alon~ the parting line VI-VX o~ FIG. 5;
FIG. 7 is an end view taken in the direction VII-VII
o~ FIGS. 3 and 4;
FIG. 8 is a sectional view, taken substantially along
the line VIII-VIII of FIG. 9 illustrating a pair o~ -the adapters
of FIG. 4 mounted on an electrical connector and covered with a
hood assembly which provides additional strain relie~;
FIG. 9 is a complementary sectional view taken substan-
tially along the parting line I~ of FIG. 8 illustrating an
adapted connector ~mounted in one shell o~ the hood assembly, spe-
cifisally showing the hood assembly features ~or providing an in~ ~:
coming bundle clamp and outgoing conductor distribution;
FIG. lO is a perspective view of the hood assembly o~
FIGS. 8 and 9 specifically illustrating a latching structure for
releasably locking the housing shells together; .
FIG. ll is an elevation of a housing shell with an elec~
trical connector mounted therein, specifically showing the shell
adapted for receiving and clamping incoming and outgoing bundles ``:
of conductors;
FI&. 12 is a completed housing assembly, with a connec-
tox mounted therein, similar to FIG. ll additionally showing a
narrow slot for distributing a portion of the conductors; and
FIG. 13 is an elevational view of the apparatus of
FIG. 8 as viewed in the direction XIII-XIII.
Referring to FIG. 1, an electrical connector is general-
ly illustrated at 10 as comprising a forward portion 12 which, as
is well known in the art, is mateable with a complementary connec-
tor unit, and a rear portion 14 which carries the contact portions
for connection to individual conductors of a bundle or cable. Con-
nectors of this type may advantageously be provided with insula-
tion-piercing contact portions~ one type of which will be discussed
below. . .
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~3`~P~
The connector 10 also comprises means for mounting the
connector to a supporting device or surface, depending on its
particular application, and in the particular connector illustra-
ted in FIG. 1 a pair of flanges 16 and 18, including respective
mounting holes 20 and 22 are illustrated as one type of such
mounting means.
The rear portion 14 of the connector 10 is usually mold-
ed from a plastic material as a structure which includ0s a plura-
lity of spaced vertical ribs 24 defining a plurality of channels
26 therebetween on each side of the connector. The inner portion
of each channels 26 includes a cons-tructed opening 28 ~or receiving
a conductor and providing a certain amount of strain relief.
The rear portion 14 of the connector 10 includes a pair
of recesses 30 and 32 at each end thereof which, as will be under-
stood ~rom the description below, aids in locating and aligning
the strain relief adapter.
It should be mentioned here that although reference may
be made to specific directions and relationships, such as vertical,
horizontal, above and below, these directions and relationships
arP utilized for clarity only with respect to the particular orien-
tation of the apparatus as illustrated on the drawings. It will
be appreciated that these terms are only limiting in their sense
of relationship with respect to each other in that an electrical
connector may be oriented in an almost limitless number of posi-
tions~ as is well known to those versed in this art.
Referring to FIG. 2, an enlarged view of part of the
rear portion of the connector 10 of FIG. 1 is illustrated in an
enlarged view to more clearly show that the ribs 24 define channels
which have insulation-piercing contact portion 38 supported there-
in, each of the contact portions 38 including one or more insula-
tion-piercing notches 40 formed by a pair of opposed sharp edge
portions 42. ,The ~hannels 26 extend upwardly to form notches 36
.
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: .
to receive and have the conductors dressed therein prior to ac-
tual electrical connection to the insulation piercing contact
portions 38. Although this specific structure is illustrated
herein, it is only typical of many suitable contact structures
which may be utilized in an electrical connector and wh.ich may
be supplemented, with respect to strain relief, by a strain re-
lief adapter constructed in accordance with the invention.
~ eferring to FIGS. 3-7, a strain relief adapter cons-
tructed according to the invention is illustrated at 44 as com-
prising a genexally rectangular, elongate element, preferablymolded of plastic material, and which comprises an upper surface
46 having a shallow edge recess 48 which presses against -the in- :
coming portions of the conductors above the constricted notches
28 to increase the strain relief at the incoming portions of the
conductors.
The recess 48, as can be seen in FIG. 6, is carried on
a ledge member 50 which, when mounted on the connector, rests on
the upper ends of the vertical ribs 24.
A plurality of pressure members, in the form of blades
52 which are similar to conductor insertion blades, are to be
received in the channels to engage and press against the conduc-
tors which have already been electrically contacted by the contact
portions. Each of the blades 52 comprises a first narrow portion
54 to engage the respective conductor adjacent its entry into $he
connector strain relie~ mechanism, second and third narrow por
tions 58 and 60 for engaging the conductor adjacent the insulation- :
piercing notches 40, and a spur or projection 62 which extends
beyond the distal edge of the blade proper to slightly dig into
the insulation of the conductor and provide additional securement
within the contact portion 38. The plurality of insertion blades
52 have been given the collective reference numeral 64 and consti-
tute a means for engaging and urging each of the conductors into
-- 6 --
th~ respective insulation-piercing contact portion. The vertical
ribs 24 constitute barriers between the contact portivns 38 which
may be pushed apart by an insertion tool or oversize conductors
causing decreased pressure on the conductors and -the possibility
of decreased electrical reliability. The insertion blades 5Z
therefore provide several advantages including addi-tional pressure
on the conductors, realignment of the barriers in those cases
where the barriers have been deformed, and filling of the barriers
to provide additional frictional forces between the barriers, the
contact portions and the insulated conductors via the blades 52
for a tighter and more reliable assembly.
The strain adapter 44 is also provided with a force di-
version means 66 which comprises a downwardly projecting member
68 having a lower edge formed in the shape of a comb having a plu-
rality of tseth 70 and spaces 72 between the teeth 70. It will be
apparent from FIG. 5 that each o~` the spaces 72 is aligned with
a pressure blade 52, and as such receives a conductor therein, the
conductor being subsequently bent upwardly so that the conductor
at least partially wraps about the force diverter.
A wire clamping means 74 is provided opposite the recess
48 and the upper portions of the blades 52 and is constituted by
a comb-shaped edge having a plurality of shaped teeth which form
a plurality of complementary shaped constricted openings 80. Each
of the openings gO is aligned with a xespective opening 72 of the
force diverter to receive and hold the outgoing portion of the
conductor in a position generally parallel to the electrically
contacted portion of the conductor.
A pair of strain relief adapters is utilized for pro-
viding additional strain reli~f on each side of the rear portion
of an electrical connector. Advantageously, each o~ the strain
relief adapters is identical to the other and asymmetrically com-
plementary when positioned on opposite sides of the rear portion
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: - . -.. - . . ~ :: . . . .................................. -.
. ~
of a connector -to be cooperably inter~engageable with respect to
mounting on the connector. For this purpose, each of the strain
relief adapters is provided with a releasable l~ocking means 82
which, as can be best seen from FIGS. 4 and 7, comprises at one
end o~ the adapter a resilient yieldable arm 84 which projects
laterally from the adapter proper and which terminates in a se- :
cond projection 86 extending perpendicular thereto to form a hook.
The distal end of the projection 86 lncludes a cam sur~ace 88
which functions in cooperation with another slement to flex the
arm 84 during engagement o~ the two adapters.
The releasable locking means 82 ~urther comprises, at
the other end o~ the adapter, a cam sur~ace 90 which leads to a
flat surface 92 which together ~orm a barrier that terminates at
a shoulder 94. Beyond the shoulder 94 is a recess 96, and a sur-
face 92 also constitutes the rear surface of another recess form-
ed by a pair o~ surfaces 98 and 100.
As the $wo adapters are moved into engagement about op-
posite sides o~ the rear partion 14 of a connector, the cam sur~
~ace 88 slidably engages the cam surface 90 fle~ing the arm 84
20 un$il the projection 86 slides along the surface 92. The projec- .-. . -
tion 86 con$inues to slide along the sur.face 92 until it passes - ...
the shoulder 94 whereupon the energy stored in the flexed arm 84
is released causing the projection 86 to snap into the recess 96
and the arm 84 to snap into the recess formed between the surfaces :
92, 98 and 100.
The adapter 44 is also provided with means for posi- :
tioning, aligning, and guiding the adapter with respect to the ;..... ... :
connec-tor and with respect to the other cooperable adapter. Refer .:
ring tc FIGS. 1 and 3, each adapter 44 is provided with a pair o~
shoulders 102 and 104 respective cam guide sur~aces 106 and 108 .
to be received in the recesses 30 and 32. In addition, and as
can best be seen in FIG. 7, the resilient yieldable arm 84 has .:
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A~ t
upper and lower papered guide edges 110 and 112, respectively, for
iniSially guiding the arm in-to the area between the suriaces 98
and 100.
Referring to FIG. 8, a pair of adapters 44 and 44' are
illustrated in sectlon as they appear when mounted on a connector
10. In FIG. 8 a bundle of conductors, which may be in the ~orm
of a cable 114, has a plurality o~ conductors which are electri-
cally connected to respective insulation-piercing co~tacts of` an
electrical connector. For simplicity, only two of such conductors
have been illustrated. These two conductors include an incoming
or lead in portion 116 and 118, respectively, an electrically con-
tacted or intermediate portion 120 and 122, respectively, and a
lead out or outgoing portion 124 and 126, respectively. In FIG. 8
the digging in o~ the projection or spur 62 is apparent, as is
the additional strain relief provided by the shallow recess 48 and
the wire clamping means 74. Also in FIG. 8 it will be appreciated
that the force diverter 66 functions to prevent dislocation of
conductors from the piercing notches of the contact portions when
a pulling force is applied in the direction of the arrows.
The strain relief adapter connector is provided ~ith
additional strain relief and is protected by a hood assembly in
the form of a hollow housing 130 having a pair of complementary
hollow shells 132 and 134, which are more specifically described
below with reference to FIGS. 9-13. In FIG. 9, an adapted con-
nector is illustrated as being mounted in the hollow housing
shell 132. The housing shell 132 includes a top wall 136, a pair
of spaced bottom portions 138 and 140, which define a recess
through which the front portion 12 of the connector extends, a
pair of portions 14~ and 144 spaced from the bottom portions 138
and 140 to form slots for receiving the mounting ~langes 18 and
16 of the connector 10, and a pair of end walls 146 and 148.
The end wall 148 is provided with a semi-circular recess
~ 9 _
P~ `3
150 and the top wall 13~7 is provided with a shallow reces~ d~
ned by a raised edge 152. The recesses 141, 150 and 152 are co- -
operable and complementary to ~orm openings in the hollow hood
assembly 130. As mentioned above, the ~ront portion 12 of the
connector 10 extends through the opening formed by the recess
141 and its complementary recess. The recess 150 and its comple-
mentary recess form an opening ~or receiving a bundle of conduc-
tors which may be in the ~orm o~ a cabl~, while the recess de~ined
by the edge 152 and its complementary recess forms an elongate
narrow slot for distrihuting the individual conductors.
Each of the housing shells is provided with a longitu-
dinally extending rail 154 which projects into the hollow interior
of the housing at a point i~mediately above and adJacent the wire
clamping means 74 o~ the strain relief adapter 44. As can be
seen more clearly in FIG. 8, the rail 154 engages and presses the
conductors toward the rear of the strain relie~ slots 80 to pro-
vide additional strâin relief to the outgoing portions of the con-
ductors.
Each o~ the shells is also provided with a boss 157
which has an adjustment screw 156 threaded therethrough to engage
and position the connector longitudinally with respect to the
housing.
The housin~ shells 132 and 134 are provided with a re-
leasable latching means which performs several functions. First
0~ all7 as the shells are latched together, they clamp incoming
and outgoing conductors so that additional strain relief is pro-
vided for the entire hooded assembly. Secondly, the shells are
releasably held together by the releasàble latching means. Al-
thbugh four such structures have been indicated on the drawings,
only one is illustrated in detail for discussion, the others bPing
of the same structure. The housing shell 132, ~or example, inclu-
des a recess 159 in which there is a shoulder 15~ which develops
-- 10 --
into a ramp 160 that terminates at the parting line o~` the shells.
The complementary shell 134 includes a pair of resilient yieldable
arms 162 and 164 having a cross member 166 at the distal ends
thereof which rides up the ramp 160 until passing the shoulder
158 whereupon the arms 162 and 164, and the cross member 166 snap
into the recess 159.
A completely assembled hooded and strain relief adapted
electrical connector 10 i5 illustrated in FIG. 13 as receiving a
cable 114 and distributing a plurality oI individual conductors
114a. The hollow shells of the hood assembly 130 may be addi-
tionally and mvre securely held together by the utilization of
suitable additional fastening means, such as machine screws 168
and 170.
The hood assembly and conductor receipt and distribution
illustrated in FIG. 13 provides for an L-shaped conductor distri-
bution. Different forms o~ T-shaped conductor distribution are
illustrated in FIGS. 11 and 12.
The hollow shells in FIGS. 11 and 12 have substantially
the same structure as that previously discussed. Therefore, only
distinguishing features will be dealt with in connection with the
T-shaped conductor distribution arrangements.
In FIGURE 11, for e~ample, the housing 132' receives a
plurality of incoming conductors in the form of a bundle or a
cable 214 which are electrically tapped at the connector 12 and
become outgoing conductors in the form of a bundle or cable 214.
The housing shell 132', and its complementary shell, are provided
wi-th end wall openings 150' and 150'i for passing the conductors
therethrough and clamping the pluralities of conductors when the
hood assembly is latched together~
A combination of distributions between the structures
of FIGS. 9 and 11 is illustrated in FIG. 12 wherein the adapted
connector 10 receives a plurality of conductors in the bundle o~r
- 11 -
cable 314 at one end o~ the hood assembly, passes through a num-
ber of those connectors in the form of a bundle or cable 314~ at
the opposite end of the assembly, and distributes the remaining
number of individual conductors, as indicated at 314". This
conductor arran~ement also takes into consideration that some o~
the conductors may be tapped and extended in a first direction,
other conductors tapped and extended in a second direction, and
even that further conductors may be extended through the hood
assembly for ease in wire distribution without heing tapped or
terminated. Also, dead end terminations may be accomplished with
the conductor tap and strain relief features disclosed herein
without extension of the outgoing leads much beyond the strain
relief provided by the wire clampi~g means 74, and possibly the
ridge 154.
Although the present invention has been described by
reference to particular illustrative embodiments thereof, many
changes and modifications of the invention may become apparent to
those skilled in the art without departing from the spirit and
~- scope of the invention. It is therefore intended that the patent
warranted hereon include all such changes and modifications as
may reasonably and properly be included within the scope of this
contribution to the art.
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