Note: Descriptions are shown in the official language in which they were submitted.
CA 02275923 1999-06-21
WO 99/23727 PCT/US98/231Z6
t t=CTRIC~L CONNECTOR HAVING AN IMPROVED CONNECTOR
SHIELD AND A MULTI-PURPOSE STRAIN RELIEF
FIELD OF THE INVENTION
The present invention relates generally to improvements in electrical data
connectors. More particularly, the present invention relates to a compact data
connector with an improved connector ground shield and a multi-purpose strain
relief.
BACKGROUND OF THE INVENTION
in the field of datalcommunications technology, information in the form of
electrical signals is being transmitted at ever increasing speeds. Along with
the
desire to transmit information at faster data rates, the industry has also
seen the
need to reduce the size of hardware employed so as to increase portability and
ease of use. In order to keep pace with these improvements, the
interconnection
technology, which includes electrical cables and electrical connectors
designed
to connect such hardware, has also undergone significant changes. Electrical
connectors and cables are now available with are much smaller in size and
capable of transmitting data at higher rates.
Continued improvement in connection technology is not without problems.
When decreasing the size of electrical connectors while requiring the
connectors
to transmit data at higher rates, cross-talk befinreen adjacent conductive
components of the connector becomes a factor which must be addressed.
Additionally, as these components are normally used in close proximity to
other
CA 02275923 2006-O1-23
electronic components, the individual connector components must be shielded
from electro-magnetic interferences and radio-frequency interferences. These
interferences can adversely affect the performance levels of the connectors
especially at higher data rates.
Commonly owned U.S. Patent Nos. 5,538,440 and 5,564,940 to Rodrigues,
et al. disclose compact electrical connectors which provide for the
termination of
discrete insulated conductors of a multi-conductor cable. The connectors
include
an insulative connector housing supporting a plurality of electrical contacts
having
insulation displacing contact portions. The connector also features an
internal
contact shield to shield individual contact pairs from adjacent contact pairs.
The
shield is a die cast metallic member having horizontal and vertical walls
which
intersect perpendicularly in "cross" configurations to provide horizontal and
vertical
shielding of the contacts. The contact shield disclosed in these patents also
includes an extended ground element for electrical engagement with the multi-
conductor cable to maintain electrical ground continuity between the cable and
the
contact shield. The cable receiving end of the connector also includes a two
component strain relief device which helps secure the cable in the connector.
The
strain relief device engages the folded back portion of the cable braid to
fractionally
hold the cable to the connector. A separate metallic ground clip is positioned
between the strain relief device and the cable ground braid which electrically
engages the extended ground element of the contact shield to establish
electrical
continuity between the cable braid and the contact shield.
One of the disadvantages of the above-disclosed connector is that the
vertical and horizontal walls of the connector shield extend only as far as
the
insulation displacing contact portions of the electrical contacts. Thus, a
portion of
the individual conductors of the multi-conductor cable between the end of the
cable braid and the insulation displacing contacts is left unshielded.
2
CA 02275923 1999-06-21
WO 99/23727 PCTNS98/23126
Furthermore, strain relief devices of conventional connectors typically only
provide the function of securing the cable to the connector. Grounding of the
cable is normally accomplished by the use of one or more separate components,
such as a separate ground clip as an interface between the cable ground braid
and the contact shield. This adds to the complexity and cost of the connector.
Therefore, it would be desirable to provide an electrical connector which
provides overall and individual shielding of the electrical contacts as well
as the
termination ends of the conductors engaging therewith. It would also be
desirable to eliminate the requirement for separate components within the
connector to ensure electrical continuity between the cable ground braid and
the
connector contact shield.
SU AARY OF THE INVENTION
It is an object of the present invention to provide an electrical connector
for terminating discrete conductors of a multi-conductor cable.
It is a further object of the present invention to provide an electrical
connector having a contact shield for shielding the electrical contacts of the
connector as well as the discrete conductors of the multi-conductor cable
engaging therewith.
It is still a further object of the present invention to provide a strain
relief
device for an electrical connector which in addition to securing the multi-
conductor cable to the connector also provides for electrical grounding of the
cable to the connector thereby eliminating the need for separate components.
In accordance with one form of the present invention, the improved
electrical connector generally includes an electrically insulative contact
support
member having a rearward cable termination end, a plurality of electrical
3
CA 02275923 1999-06-21
WO 99123727 PCTIUS98/23126
contacts supported thereon and an electrically conductive contact shield
housing
substantially surrounding the support member. Preferably, the connector also
includes an electrically insulative housing which may be in the form of iwo
halves
which snap-ftt together to substantially enclose the contacts and the shield.
The
contacts include conventional conductor termination end portions which are
electrically connected to individual conductors of the multi-conductor cable.
~ressing blocks may also be provided which snap-fit to the contact support
member over the contact end portions to secure the conductors in place. The
contacts are positioned upon the contact support member so that the
termination end portions are spaced forward of the termination end of the
support member to allow for a length of fhe separated individual conductors of
the multi-conductor cable to be supported on a conductor support portion of
the
contact support member. The contact shield housing includes an outer wall
which substantially surrounds the contacts and one or more inner walls are
positioned so as to physically separate one or more contacts from the others.
The contact support member includes one or more longitudinal slots between the
contacts for receiving the one or more inner walls of the contact shield
housing.
Unlike prior art connectors, the outer and inner walls of the contact shield
housing extend rearward beyond the contact conductor termination end portions
and terminate adjacent the termination end of the contact support member.
Thus, the extended contact shield not only electrically isolates the contacts
but
also shields a length of individual conductors supported on the conductor
support portion of the contact support member positioned within the shield
housing. The result is a dramatic improvement in "cross-talk" perfiormance of
the
connector.
The present invention also includes a novel strain relief device positioned
adjacent the termination end of the shield housing for securing the multi-
conductor cable to the connector. The strain relief device is made from an
electrically conductive material, preferably formed from a metallic material.
The
strain relief device is comprised of mirrored strain relief members which,
when
4
CA 02275923 1999-06-21
WO 99/23727 PCT/US98I23126
engaged, define a substantially circular bounded opening adjacent the
termination end of the housing. The circular bounded opening is reduced in
size
as the strain relief members are moved toward each other to frictionally
secure
and electrically engage a ground braid of the multi-conductor cable. The
strain
relief members are preferably received in opposing slots which extend through
an outer wall of the contact shield housing adjacent the termination end
thereof
and are in electrical communication with the shield housing. The strain relief
members may also include one or more raised protrusions to enhance electrical
contact between the strain relief member and the shield housing. Thus, unlike
prior art strain relief devices, the electrically conductive strain relief
members of
the present invention provide ground continuity between the cable ground braid
and the connector shield housing. The strength of the metallic members also
allows for the use of a thinner strain relief device thereby reducing the
overall
size of the connector.
A preferred embodiment of an electrical data connector with an improved
connector shield and a multi-purpose strain relief, as well as other objects,
features and advantages of this invention, will be apparent from the following
detailed description which is to be read in conjunction with the accompanying
drawings.
ERIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an exploded rear perspective view of the electrical connector
formed in accordance with the present invention.
Figure 2 is an exploded front perspective view of the electrical connector
of Figure 1.
Figure 3 is a perspective view of a cross-section of the electrical
connector of Figures 1 and 2 as assembled.
5
CA 02275923 1999-06-21
WO 99/Z3727 PCT/US98/23126
Figure 4 is a perspective view of the contact support member with
contacts.
Figure 5 is a perspective view of the contact support member with the
contacts electrically connected to a mufti-conductor cable.
Figures 6a and fib are cross-sectional views of the termination sub-
assembly of Figure 3 taken along line 6-6 with the rear end of contact support
member and the strain relief device removed and showing alternate
embodiments of the contact shield.
Figure 7 is a perspective view of the preferred embodiment of a strain
relief member.
Figure 8 is a perspective view of an alternate embodiment of a strain relief
member.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to Figures 1-3, a shielded electrical data connector 10 is shown
in an exploded view. Connector 10 may be employed to terminate electrical
cable 12 having an insulative outer jacket 14, an inner ground conductor or
cable
braid 16 and a plurality of individually insulated electrical conductors 18
extending therethrough. In order to prepare cable 12 for termination in
connector 10, jacket 14 is cut-away exposing a portion of cable braid 16 and a
length of conductors 18 suitable for termination. While it may be appreciated
that the invention may be employed with cables having any number of
conductors, in the present illustrated embodiment, cable 12 is an eight
conductor
cable comprising four pairs of individual conductors.
6
CA 02275923 1999-06-21
WO 99/23727 PCT/US98/2312fi
Connector 10 includes outer connector housing halves 20a and 20b which
when assembled may take the foml of a plug as shown in Figures 1-3 or a jack
(not shown). The assembled housing for the jack is designed to receive and to
connect with the housing of the plug. Connector housing halves 20a and 20b
include a plurality of locking arms 22 which cooperatively engage recesses 24
to provide for a snap-fit engagement of the halves. Housing halves 20a and 20b
may be formed of any suitably electrically insuiative plastic material such as
polyester: Connector housing halves 20a and 20b each have a cable
termination end 26 which when assembled define a rearwardiy opening circular
passage which permits entry of cable 12 into connector 10.
Connector housing halves 20a and 20b support therein a termination
subassembly 30 which is identical for both the jack and the plug
configurations
of the connector. Termination subassembly 30 includes a contact support
member 32, a plurality of electrical contacts 34, a plurality of dressing
blocks 35,
a contact shield 58 and a strain relief device 72.
Referring now to Figures 4 and 5, contact support member 32 supports
the plurality of electrical contacts 34 thereon. Each of contacts 34 are
elongate
electrically conductive metallic members formed of beryllium-copper having a
connection end 36 and a termination end 38. Connection end 36 includes a
cantilevered element 40 for making mating resilient electrical engagement with
similar contacts in the mating jack or plug connector. Termination end 38
includes blade type insulation displacing contact (IDC) portions which are
constructed for insulation displacing termination with conductors 18 of cable
12.
In the present illustrative embodiment, contacts 34 are positioned in upper
and
lower longitudinally aligned transversely spaced rows. Termination ends 38 of
the lower row extend in the opposite direction than the termination ends of
the
upper row.
7
CA 02275923 1999-06-21
WO 99123727 PCT/US98/23126
Contact support member 32 is formed of a suitable insulative plastic, such
as polyester, and includes a forward interconnection end 42 and a rear
termination end 44. Contact support member 32 includes contact grooves 45 in
upper and lower platforms 46 and 47 which support contacts 34 in individual
electrical isolation. Contact support member 32 includes a conductor support
portion 48 which extends rearwardly beyond the IDC termination ends 38 of
contacts 34 to the to rear termination end 44 to support the conductors of the
cable thereon. Conductor support portion 45 includes raised longitudinal
projections 49 which define therebetween conductor receiving spaces 50 and
dressing block receiving spaces 51.
Support member 32 also includes a vertical slot 52 disposed between
lateral pairs of contacts 34 and a horizontal slot 53 disposed between the
upper
and lower rows of contacts. Slots 52 and 53 extend longitudinally from the
forward interconnection end 42 of support member 32 through the conductor
support portion 48 and terminate at a point 54 just intermediate rear end 44
of
support member 32. As illustrated, contact support member 32 is designed to
accommodate four pairs of contacts, however, it may be appreciated that the
contact support member may be designed to accommodate additional pairs of
contacts by increasing the width of the support member and providing
additions!
vertical slots between each lateral pair of contacts.
Referring specifically to Figure 5, the conductors 18 of cable 12 are
electrically connected to the contacts 34 on support member 32 prior to
assembly of the connector 10. Extending pairs of conductors 18 of cable 12 are
separated and positioned for insulation displacing connection with termination
ends 38 of contacts 34. Ends of the conductors 18 are placed within receiving
openings in the dressing blocks 35 and are electrically connected to contacts
34
in a conventional insulation displacing method. The insulative dressing blocks
secure the conductors in place and are provided with one or more raised
bosses 55 extending below a bottom portion thereof to be snap-fit into the
8
CA 02275923 1999-06-21
WO 99123727 PCT/US98/23126 '
dressing block receiving spaces 51 of the conductor support portion 48 of
support member 32.
As contacts 34 are maintained in close proximity in contact support
member 32, it becomes necessary to shield individual contact pairs from
adjacent contact pairs to minimize the effects of cross-talk. Returning to
Figures
1-3, an internal contact shield 58 is provided which encloses the pre-
assembled
contact support member 32. Shield housing 58 is a die cast conductive, e.g.,
metallic, member which is slidably insertable into and around contact support
member 32 from the forward interconnection end 42 thereof. Contact shield
IO housing 58 serves to shield the contacts 34 as a group and also to shield
pairs
of contacts 34 from one another both laterally and vertically. Contact shield
58
is an elongate housing roughly the same length as contact support member 32
and has an interconnection end 60 and a termination end 62. Contact shield 58
includes upper and lower U-shaped shield platforms 63a and 63b, each having
a central wall 64 at the interconnection end 60 thereof. The upper and lower
shield platforms 63a and 63b provide effective vertical and horizontal
shielding
as between the connection ends 36 of contacts 34. When connecting with a
mating connector, the interconnection ends are rotated 180 degrees with
respect
to each other. Thus, the U-shaped platforms of mating connectors will totally
enclose, and thereby shield, the connection ends 36 of the contacts 34.
Contact shield 58 includes an enclosed chamber 65 defined by an outer
wall 66 at the termination end 62 of the shield. The outer wall 66 provides
overall shielding to the termination ends 38 of contacts 34. Referring
additionally
to Figures 6a and 6b, contact shield 58 further includes a vertical and a
horizontal internal wall 68 and 70 extending along the length of the chamber
65
and terminating intermediate termination end 62 of shield 58. Vertical
internal
wall 68 separates and shields lateral pairs of contacts 34 and horizontal wall
70
separates and shields the upper and lower rows of contacts 34. Unlike prior
art
connectors, the outer and inner walls of the contact shield 58 extend further
9
CA 02275923 1999-06-21
WO 99/23727 PCT/US98I23126
rearward past the termination ends 38 of contacts 34 to the conductor
supporting
portion 48 of the contact support member 32 thereby also providing effective
overall and individual shielding of the exposed pairs of conductors 18
positioned
within the connector housing. Again, it may be appreciated that contact shield
58 may be designed to shield additional pairs of contacts 34 and conductors 18
by increasing its width and providing additional horizontal andlor vertical
walls.
Termination sub-assembly 30 is provided with a strain relief device 72 for
securing the cable 12 to the connector 10. Strain relief device 72 is
comprised
of a pair of matching strain relief components which are formed from an
electrically conductive metallic material. The preferred embodiment of the
strain
relief component 74 is shown in Figures 1-3 and 7. Alternate embodiments of
the strain relief components are discussed further in detail below. Generally,
a
pair of strain relief components are inserted in oppositely disposed receiving
slots 75 located at the termination end 62 of the contact shield housing 58.
Preferably, the receiving slots 75 are sized so that the strain relief
components
are in close electrical contact with the slots when inserted therein. The
strain
relief components when inserted in receiving slots 75 define a circular
opening
which is generally concentric with the chamber 65 of contact shield 58. When
the strain relief components are inserted in receiving slots 75 and brought
together, the circular opening defined therebetween will be reduced in size in
order to frictionally secure and electrically engage the outer cable braid 1fi
of the
cable 12 therebetween and secure the cable thereat.
Strain relief device 72 also provides continuity of ground between the
cable 12 and the contact shield housing 58. Prior to installation of the cable
12,
a portion of the cable jacket 14 is removed to reveal the cable ground braid
16.
It is this portion of the cable 12 that the strain relief components
frictionally
engage. Thus, the strain relief components are in electrical contact with the
cable braid 16. Since the strain relief components are made of an electrically
conductive metallic material, and since they are in electrical communication
with
CA 02275923 1999-06-21
WO 99l?,3727 PCT/US98123126 '_
the receiving slots 75 of the electrically conductive contact shield housing
58, the
ground of the cable 12 may be carried from the cable braid 16 through the
strain
relief component to the contact shield housing 58. To enhance electrical
contact befinreen the strain relief components and the receiving slot 75, the
strain
relief component may be provided with one or more raised contact protrusions.
When the strain relief components are inserted into receiving slots 75 of the
contact shield 58, the raised contact protrusion "skives" or cuts into a wall
of the
slot 75 and is mechanically forced thereagainst thereby providing secure
electrical contact between the strain relief component and the contact shield
58.
Alternatively, the raised contact protrusion provides for an interference fit
making
good electrical continuity between the shield housing 58 and the strain relief
component.
Figure 7 illustrates the preferred embodiment of the strain relief
component 74. Strain relief component 74 generally includes a top wall 76 and
a pair of J-shaped side arms 78 extending downwardly from the top wail. The
"hooks" 80 of the J-shaped arms 78 are directed inwardly and engage
cooperating outwardly directed ratchet teeth 82 formed on the outer wall 66 of
the shield housing 58 at the termination end 62 thereof, as shown in Figures
1,
2 and 6a. Side arms 78 are deflectable which, along with the positioning of
ratchet teeth 82, allow for one-way downward movement of the strain relief
components 74 within receiving slots 75 of shield 58. The internal surface of
top
wall 76 of strain relief component 74 is generally curved and is provided with
a
rib 84 to assist in frictional securement of the cable braid 16. Strain relief
component 74 also includes an arrangement of upper and lower raised contact
protrusions 86 and 88 which provide two-position enhanced electrical contact
between strain relief component 74 and contact shield 58. Upper protrusions 86
are oppositely disposed on the major surfaces of strain relief component 74
and
are laterally offset from similarly disposed lower protrusions 88.
11
CA 02275923 1999-06-21
_ WO 99/23727 PCT/US98/23126 -
Strain relief components 74 operate in the following manner. Strain relief
components 74 are inserted into the opposing slots 75 of the contact shield 58
with the side arms 88 positioned along the sides of contact shield 58. Strain
relief components 74 are then manually pushed toward each other to provide for
ratchet engagement of the J-hooks 80 and respective teeth 82 of contact shield
58. When the strain relief components 74 are inserted within receiving slots
75
and make electrical contact with the cable braid 16 in a pre-load stage, the
lower
protrusions 88 are in forced electrical contact with the receiving slot 75. As
the
strain relief components 94 are pressed downwardly to frictionally secure the
cable braid 16 under load, the upper protrusions 106 are mechanically forced
against the receiving slot 75. Thus, electrical ground continuity is
maintained in
both a pre-load and a loaded position. Strain relief components 74 are pushed
toward each other until the outer cable braid 16 of cable 12 is secured within
the
circular opening which is continually decreasing in size by the movement of
the
components 74 with respect to each other. As the strain relief components 74
press together, the side arms 78 move downwardly along the ratchet teeth 82
thereby preventing the strain relief components 74 from backing away from each
other. Thus, strain relief components 74 independently engage and lock to the
shield housing ratchet teeth 82. Because the locking zone is totally separate
from the strain relieving zone and grounding zone, the strain relief of the
present
invention provides more stability since the locking zone is not subjected to
strains that could be caused during cable pull out.
Figure 8 illustrates an alternate embodiment of a strain relief component
90. Strain relief component 90 is generally U-shaped having a top wall 92 and
downwardly extending side walls or legs 94 and 96. Legs 94 and 96 are
deflectable and include ratchet teeth 98. Ratchet teeth on leg 94 are directed
- outwardly while ratchet teeth on leg 96 are directed inwardly. The strain
relief
components 90 are oriented within the receiving slots 75 of the contact shield
58b so that legs 94 of each component engage legs 96 of the other. The
positioning of ratchet teeth 98 permit the moveable one-way ratchet engagement
12
CA 02275923 1999-06-21
WO 99/23727 PCTIUS9S/23126 __
of the components 90 with respect to the other. The deflectability of legs 94
and
96 permits such ratchet movement of components 90. The internal surface of
legs 94 as well as the internal surface of top wall 92 are generally curved so
as
to form a circular opening which is generally concentric with the chamber 65
of
contact shield 58b. In order to assist in frictional securement of the cable
braid
16, a rib 100 is provided on the internal surface of the top wall 92. These
ribs
provide increased localized friction against the cable braid 16.
Strain relief component 90 also includes one or more raised contact
protrusions 102, for providing enhanced electrical contact between the shield
58
and the strain relief component 90 as described above, and a locking arm 104
which extends downwardly from top wall 92. As shown in Figure 6b, locking arm
104 fits into a cooperating locking hole 106 of an alternate embodiment of the
contact shield 58b when strain relief component 90 is inserted in receiving
slot
75. Locking holes 106 also initially serve to properly orientate strain relief
components 90 within the opposing receiving slots 75 of the shield 58b.
Locking
arm 104 includes a tapered end 108 and one or more locking protrusions 110.
Locking protrusions 110 engage cooperating ribs 112 formed in locking hole 106
as shown in Figure 6b.
Strain relief components 90 operate in the following manner. Strain relief
components 90 are inserted into the opposing slots 75 of the contact shield
58b
with the locking arms 104 being inserted into the adjacent locking hole 106.
Strain relief components 90 are then manually pushed toward each other to
provide for ratchet engagement of the respective teeth of legs 94 and 96.
Strain
relief components 90 are pushed toward each other until the outer cable braid
16 of cable 12 is secured within the circular opening which is continually
decreasing in size by the movement of the components 90 with respect to each
other. As the strain relief components 90 press together, the locking arm 104
moves downwardiy in locking hole 106 until the locking protrusions 110 engage
and pass the locking ribs 112 of the hole 106. The tapered end 108 of locking
13
CA 02275923 1999-06-21
WO 99/23727 PCT/US98I23126
arm 104 allows for inward movement of the locking arm, but the arrangement of
locking protrusions 110 and cooperating ribs 112 prevent outward movement.
Thus, in addition to the ratchet teeth 98 of the strain relief component 90,
the
locking arm with locking protrusions 110 prevent strain relief components 90
from backing away from each other.
Once the strain relief device 72 is engaged, housing halves 20a and 20b
may be snap-fitted together to complete the assembly. Housing halves 20a and
20b shown in Figures 1-3 are formed in a plug configuration, but may
alternatively be formed in a jack configuration. The plug and jack are mating
connectors which may be mechanically and electrically connected by rotating
the
interconnection end of the plug 180 degrees and inserting it into the
interconnection end of the jack. A deflectable latch 114 may be provided on
either the plug or jack to provide for secure repeated connections and
disconnections between the connectors.
The present invention thus provides an electrical connector having an
improved connector shield and dual use strain relief component. Unlike prior
connectors, the present invention features a contact shield which extends
further
back into the cable dressing area. By extending the shield further back, the
cross-talk performance of the connector is dramatically improved. Also, the
metallic strain relief components provide an improved ground path from the
cable braid to the contact shield while eliminating the need for extra
grounding
components, such as spring clips, within the connector. Furthermore, the high
strength of the metallic strain relief component allows for the use of a
thinner
strain relief device than conventional connectors.
25- Although the illustrative embodiments of the present invention have been
described herein with reference to the accompanying drawings, it is to be
understood that the invention is not limited to those precise embodiments, and
14
CA 02275923 1999-06-21
WO 99123727 PCT/US98/23126
that various other changes and modifications may be effected therein by one
skilled in the art without departing from the scope or spirit of the
invention.
