Connector assembly for insulated cable

A cable connector assembly for sealably connecting the conductive sheath of an insulated cable. The connector assembly comprises a conductive member having insulation piercing contacts. The conductive member includes a spring element which is formed to provide a predetermined force by the contact on the cable. The assembly further includes a sealing enclosure for accommodating the conductive member and sealing the connection.

FIELD OF THE INVENTION 
This invention relates generally to an electrical connector for insulated, 
metallic shielded cable and more particularly relates to an insulation 
displacing connector for establishing ground continuity between connected 
cables. 
BACKGROUND OF THE INVENTION 
In connecting transmission cables of the type buried underground, and 
referred to as direct burial cables, an installer is usually faced with 
the problem of trying to connect cable of various construction. Typically, 
these cables contain a plurality of insulated conductors surrounded by an 
insulated thermoplastic sheet and a metallic conductive sheath which may 
or may not be itself insulated. An outer insulative jacket usually 
surrounds the entire cable structure. In various applications, these 
cables may vary as to the size and number of conductors, composition and 
construction of the metallic sheath and thickness of the outer jacket. 
Furthermore, most cables of this type often include a material core which 
fills the void between the conductors inside the conductive sheath. This 
core may range from a core constructed of a solid insulative material to 
one of relatively viscous petroleum gel which is injected between 
conductors. It is apparent that due to these construction variations, each 
type of cable will be subject to different degrees of deformation both 
upon interconnection and long term creep. It is not uncommon for many of 
the cable structures to deform from a normally circular cross-section to 
one that is more elliptical or flattened. 
The actual interconnection of the signal carrying conductors of two or more 
cables is accomplished in one of a number of well-known methods. However, 
in addition to connecting these signal-carrying conductors, the conductive 
ground sheaths must also be connected to insure ground continuity between 
the cables. 
The art has seen a number of interconnection techniques for connecting the 
ground sheath of two direct burial transmission cables. One such method 
employs a split bolt or nut to clamp the conductive sheath of two stripped 
cables. Another, described in a paper by David Lane and Bob Young 
entitled, "Sheath Bonding Terminal for Buried Service Wire, International 
Wire & Cable Symposium Proceeding" (1982), employs a clip "type" spring 
contact for engaging the stripped cable sheaths. In each of the prior 
methods, the cable would have to be previously stripped or "skinned" 
before the connector could be employed. Stripping a cable is both 
time-consuming and difficult as, in addition to stripping away the outer 
insulative jacket, the conductive sheat often contains a further 
insulative coating which is exceedingly difficult to remove. Failure to 
sufficiently remove the coating will result in an ineffective ground 
connection. 
There are still other connectors known in the art employing insulation 
piercing techniques for piercing the insulation of a cable and contacting 
the conductive member. Such an insulation piercing connector is shown and 
described in U.S. Pat. No. 4,293,176 issued Oct. 6, 1981 to Lindlof. 
However, connectors of this type could not be employed with transmission 
cable for contacting the conductive sheath, as depth of penetration cannot 
be precisely regulated. Overpenetration could cause a piercing of the 
conductive sheath and contact with a signal-carrying conductor thereby 
causing a short. Conversely, underpenetration would provide ineffective 
ground connection. Further, as the cable may exhibit some degree of 
"creep" due to stresses applied to the plastic elements by the connector, 
the insulation displacing contacts which were initially suitably connected 
may become dislodged from the sheath and fail to provide a continuous and 
reliable ground connection. 
It is therefore desirable to provide an insulation piercing cable connector 
which is capable of receiving a wide variety of cable constructions and 
where the piercing force can be precisely regulated to prevent over or 
under insertion. Further, the connector should be able to compensate for 
cable creep throughout its life. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an improved cable 
connector for connecting an insulated cable. 
It is a more particular objectof the present invention to provide an 
insulation piercing contact, the extent of penetration of which can be 
precisely regulated. 
In the efficient attainment of these and other objects, the present 
invention looks toward providing an electrical connector for insulated 
cable. The cable is supported in the connector. A movably secured 
conductive member includes a contact portion for engagement with the 
cable. The contact portion includes insulation piercing teeth thereon 
which engage the conductive sheath of the cable. Clamping means urge the 
conductive member into contact with the cable. The conductive member is 
formed into a spring, the selection of which regulates the force at which 
the insulation piercing teeth contact the conductive sheath. The force 
applied by the teeth to the cable is selected to be sufficient to pierce 
the insulation and provide a stable contact with the conductive sheath yet 
not penetrate through the insulative sheet which surrounds the conductors.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
As shown in FIGS. 4 and 5, the connector 10 of the present invention 
comprises primarily a pair of identical, interlocking hermaphroditic 
contact members 12 and 12' for engaging transmission cables 11 and 11'. 
For simplification of description, as contact members 12 and 12' are 
identical in the preferred embodiment of the present invention, contact 
member 12 primarily will be described in detail herein. It is noted that 
elements bearing similar reference numerals (e.g., 12 and 12') of contact 
member 12' will be identical to elements of contact member 12. 
Referring to FIGS. 1-3, contact member 12 is a conductive element which is 
preferably constructed of steel or similar metal. Steel is chosen as a 
preferable material as it exhibits both sufficient conductive 
characteristics and also is sufficiently resilient when employed as a 
cantilever-type spring, as will be described hereinafter. 
Contact member 12 includes an upper body extent 14 having an elongate flat 
central region 16. Central region 16 includes therethrough a centrally 
located mounting aperture 17 which receives a bolt or other fastening 
device for securing contact member 12 to contact member 12'. Flanking 
either side of central region 16 are a pair of limbs 18 and 20 which 
extend in a cantilevered fashion from opposite longitudinal sides of 
central region 16. Limbs 18 and 20 each include an upper shoulder 22 and 
24 respectively, which extend downwardly and outwardly from central region 
16. The distal extents of shoulders 22 and 24 from arcuate portions 26 and 
28 which curve below shoulders 22 and 24 as shown in FIG. 1. A pair of 
arms 30 and 32 extend inwardly and downwardly from arcuate portions 26 and 
28 respectively. These arms 30 and 32 underlie the outwardly extending 
shoulders 22 and 24. The distal extents of arms 30 and 32 (opposite 
arcuate portions 26 and 28) form flat contact portions 30a and 32a, which, 
upon interconnection, engage the cables 11 and 11' (not shown), as will be 
described in detail hereinafter. 
Contact portions 30a and 32a each include thereon a patterned array of 
insulation piercing teeth 34 and 36 which are lanced out of the flat 
surface thereof. Teeth 34 and 36 extend downwardly from contact portions 
30a and 32a respectively, and as is shown in FIGS. 1 and 3 are 
substantially perpendicular thereto. In preferred form, teeth 34 and 36 
are lanced out in triangular shape from the contact portions 30a and 32a, 
and are bent downwardly therefrom. However, any suitable insulation 
piercing configuration such as trapezoidal or rectangular shapes may be 
employed. Teeth 34 of contact portion 30a and teeth 36 of contact portion 
32a are respectively positioned to form a unique pattern thereon. As 
shown, for example, in FIG. 2, laterally adjacent teeth are formed in a 
mating pattern where teeth 34 number two in the first row (uppermost row), 
one in the second, two in the third and so on. Teeth 36 are arranged in an 
opposite fashion having one tooth in the first row, two in the second and 
so on. As will be described hereinafter, an identical contact member 12' 
will be connected to contact member 12, in an opposite overlying position, 
so that teeth 34 of contact member 12 will overlie teeth 36' of contact 
member 12'. Thus, in each row a single tooth row will be aligned with a 
double tooth row, so that the teeth will be staggered, having a tooth of 
one contact portion between two teeth of the other contact portion. This 
arrangement will insure proper contact with the ground sheath of the 
cables, and diminish the possibility of crushing the signal conductors by 
point-to-point contact. 
As shown in FIGS. 1 and 2, contact member 12 further includes visual 
indication fingers 40 and 42 which extend upwardly from opposite distal 
edges of contact portions 30a and 32a. Fingers 40 and 42 extend outwardly 
of the side margin of shoulders 22 and 24, as seen in FIG. 2, so that upon 
compression of arm 30 toward shoulder 22, as will be described 
hereinafter, fingers 40 and 42 will be in non-interfering position 
therewith. The specific position of visual indication fingers 40 and 42 is 
shown only by way of example. It is contemplated that the fingers may be 
placed on other portions of contact member 12, as, for example, depending 
downwardly from shoulders 22 and 24 adjacent central region 16. 
Contact member 12 further includes a pair of legs 44 and 46 extending 
downwardly from opposite transverse sides of central region 16. Legs 44 
and 46 support contact member 12 for mating connection with identically 
formed contact member 12'. Each of legs 44 and 46 comprises a pair of 
side-by-side leg portions. As best shown in FIGS. 1-3, legs 44, which is 
identical to leg 46, has a first leg portion 44a which is immediately 
adjacent central portion 16. Second leg portion 44b is spaced further 
outwardly from central portion 16 and provides a clearance 45 
therebetween. This clearance 45 permits accommodation of a first leg 
portion 46a' of identically formed contact member 12'. It can be 
appreciated that two identical contact members 12 and 12' such as shown in 
FIGS. 4 and 5 can be interlocked by arranging the contact members such 
that leg 44 of contact member 12 will engage leg 46' of contact member 
12'. Thus, leg portion 46a' will be accommodated in clearance 45 and leg 
portion 44a of contact member 12 will be accommodated in clearance 45' of 
contact member 12'. The same is true of the opposite interlocking legs 44' 
and 46. As leg portions 44a and 44b are supported only at one end (as are 
leg portions 46a and 46b), they have a tendency to deflect upon connection 
with contact member 12' to facilitate ready interconnection. Interlocking 
the contact members 12 and 12' in this manner will provide the proper 
orientation of the teeth as above desribed. Legs 44 and 46 each further 
include a substantially horizontally projecting ledge 47 which extends 
inwardly, as shown in FIG. 2, from first leg portion 44a and 46a. Ledge 47 
extends below and adjacent the distal edge of contact portions 30 and 32 
and forms a seating surface to support the contact portions in the 
non-crimped position. 
The connector 10 further includes a clamping assembly 49 which secures 
contact member 12 to contact member 12'. In the preferred form and as 
shown in FIGS. 4 and 5, clamping assembly 49 comprises a nut 50 and bolt 
52. Bolt 52 is accommodated in aperture 17 of contact member 12, for 
example. In this position the threaded end of bolt 52 will extend through 
aperture 17' of second contact member 12' connected thereto. Nut 50 is 
threadably secured to the end of bolt 52 and secures contact member 12 to 
contact member 12'. 
Having described the structure of the connector 10 of the present 
invention, its operation is best shown with reference to FIGS. 4 and 5. 
Contact member 12 is slideably inserted into contact member 12' with legs 
44 and 46 of contact member 12 being interlocked with the legs 44' and 46' 
of contact member 12' as above described. Bolt 52 is inserted through 
apertures 17 and 17' of the respective contact members, and is threadably 
secured to nut 50. 
In this position, oppositely facing contact portions 30a, 32a and 30a', 
32a' from a pair of cable receiving channels 56 and 58. Channels 56 and 58 
are bounded both by the interlocked legs of the connector 10 and by the 
oppositely facing insulation piercing teeth. As previously mentioned, 
cable 11 (which is similar to cable 11' in the presently described 
embodiment) is a direct bural transmission cable having a plurality of 
insulated conductors 11a which are usually wrapped in a thermoplastic or 
extruded sheet (not shown) which is surrounded by a metallic sheath 11b. 
Sheath 11b is a conductive, metallic member usually formed of aluminum, 
copper or similar metal, and may also include an outer insulative 
thermoplastic coating thereover. The cable further contains a petroleum 
gel core 11c between the individual conductors 11a to prevent moisture 
propagation therethrough. The entire cable structure is enclosed by an 
outer insulative jacket 11d, usually of extruded polypropylene. 
Cables 11 and 11' are inserted into the interlocked cable connector 10, 
having a longitudinal portion thereof seated in channels 56 and 58 between 
the overlying sets of insulation displacing teeth 34-36' and 36-34', 
respectively. The cables may be inserted laterally until they abut against 
the interlocked legs 44-46' and 46-44' of the connector 10. The legs 
provide an alignment guide, insuring proper insertion and alignment with 
the teeth. 
With the cables 11 and 11' properly positioned in the connector 10, the 
ground connection between sheaths 11b' and 11b may now be accomplished. As 
assembled connector 10 of the present invention is symmetrical about both 
the major horizontal and major vertical axes. Where convenient, 
description will only be made to one of the two contact members 12, 12' 
and/or its connection to one cable 11. It is apparent that both contact 
members 12 and 12' will make identical simultaneous connection to both 
cables 11 and 11'. 
The nut 50 is tightened on bolt 52. The screw tightening of bolt 50 will 
urge the contact members 12 and 12' progressively toward one another, thus 
forcing teeth 34, for example, into cable jacket 11d. Teeth 34 will easily 
penetrate the soft plastic jacket with little physical resistance 
thereagainst. In the description provided hereinafter, the term resistance 
will refer to the physical or mechanical resistance which the cable or 
sheath presents, rather than its electrically resistive properties. Thus, 
the corresponding cantilevered spring formed by limb 18 of contact member 
12 will only flex slightly, if at all, during teeth penetration of jacket 
11d. In addition, cable resistance against limb 18 will also be minimized 
as the cable will have a tendency to creep or flatten out upon compression 
due to its soft inner core 11c. Once the teeth 34 have fully penetrated 
the jacket 11d, further tightening of bolt 50 will cause the teeth 34 to 
contact metallic conductive sheath 11c. Upon contact with sheath 11c, 
further penetration of the teeth 34 will be resisted by the harder surface 
of the metallic sheath 11 c. This resistance will cause more severe 
deflection of the cantilevered limb 18 due to compression against the 
harder cable sheath 11c. This deflection of limb 18 will take two forms. 
The shoulder 22 will deflect upwardly (away from cable 11), while 
additionally, arm 30 will be compressed toward shoulder 22. Thus, arm 30 
will move in relation both to the cable 11 and to the shoulder 22. Once 
the teeth 34 have engaged the cable sheath, further compression will cause 
further dual deflection of the limb 18 and, as the cantilevered spring 
limbs are formed in accordance with the present invention. The rate at 
which the teeth further penetrate into cable 11 will be decreased. There 
will be, however, at least a slight scoring of the surface of conductive 
sheath 11c by teeth 34 which will insure adequate electrical connection. 
The present invention contemplates forming contact member 12 to have 
cantilevered spring limbs 18 and 20 which will deflect upon application of 
a controlled force which is less than the force necessary for teeth 34 to 
fully penetrate cable sheath 11c. In forming such a spring, the spring 
constant of the material and the shape and dimension of contact member 12 
are selected to provide a spring member which will apply a force (by the 
teeth 34), on the cable within a predetermined range, to assure a proper 
electrical connection between the ground sheaths, yet will not penetrate 
into the signal conductor. 
As shown in FIGS. 4 and 5, the contact members 12 and 12' are compressed 
together by the screw tightening of nut 50 and bolt 52. As above 
described, such compression will cause the teeth 34-36 to contact the 
conductive sheath 11c and 11c' of the cable. As practiced, once the teeth 
have engaged the sheaths, further screw tightening will result in further 
compression of the cantilevered springs rather than deeper penetration of 
the teeth due to the increased resistance of the metallic sheet. This 
allows the installer a wider range in which the contact members 12 and 12' 
can be compressed. The nut 50 and bolt 52 can be further screw tightened, 
within an acceptable range, without the teeth exceedingly penetrating the 
cable sheath; thus providing a wide range of screw-tightening in which 
adequate connection can be assured. In practice, the present invention 
provides a visual indication of the range in which reliable contact with 
the sheath 11c can be assured. As above described, the unsecured extents 
of arms 30 and 32 include a pair of visual indication fingers 40 and 42 
which extend upwardly (toward shoulders 20 and 22). As the arms 30 and 32 
are progressively compressed toward shoulders 20 and 22, due to teeth 34 
and 36 contacting sheaths 11c and 11c', the tips of the fingers 40 and 42 
will clear the horizontal level of shoulders 20 and 22, as shown in FIG. 
5. Once clear of this level, a proper electrical contact with sheaths 11c 
and 11c' will be indicated. 
Additionally, spring movement of cantilevered limbs 18 and 20 and thereby 
proper connection to sheaths 11c and 11c' can be gauged by observing the 
relative movement between contact portion 30a and 32a and the respective 
ledge 47. Movement of contact portions 30a and 32a relative to ledge 47 
will assure contact with sheath 11c and 11c'. 
It is appreciated that the simplest and preferred method of gauging proper 
insertion is to observe the movement of shoulders 22 and 24. Upon 
insertion, the shoulders will move from a relatively bowed position, 
convex configuration shown in FIG. 4, to a flat or slightly concave 
position shown in FIG. 5, indicating that proper force and teeth insertion 
has been attained. 
As limbs 18 and 20 depend from opposite sides of central portion 16, each 
limb acts as an independent cantilevered spring. More resistance against 
penetration on one side of the contact member will cause more deflection 
of the limb on that side. Thus, it can be appreciated that connector 10 
can connect cables of varying size and construction. 
Providing an illustrative example of a contact member formed in accordance 
with the present invention, the material chosen can be for example, 1050 
spring steel. When formed to have a cantilevered portion of about 0.750" 
in length, and a spring rate of about 3.42 lbs. per tenthousandths of an 
inch. 
In typical applications, cables 11 and 11' are connected by aligning them 
in parallel fashion, having the exposed ends thereof adjacently disposed. 
The extending signal carrying conductors 11a and 11a' are interconnected 
in a manner known in the art, and shown schematically at 83 in FIG. 8. The 
ground sheaths 11c and 11c' are then interconnected using the above 
described connector 10. As the connected cables are to be placed 
underground in a direct burial application, the connection is to be 
environmentally sealed. The present invention further contemplates 
providing a sealed enclosure which will accommodate the signal conductor 
connections, as well as the insulation piercing ground connector described 
above. 
Referring now to FIGS. 6 and 7, a sealable enclosure 60 is shown. Enclosure 
60 is generally a clamtype hollow member integrally formed of a suitable 
plastic material such as polypropylene. Enclosure 60 comprises two main 
members, a base shell 62 and an upper shell 64 hingedly attached thereto 
and engageable with the lower shell to form a substantially enclosed 
container. 
Base shell 62 includes a substantially flat bottom 66 and is bounded by 
upwardly extending side walls 68 and 69 and back wall 70, side walls 68 
and 69 extending substantially further upwardly than back wall 70. 
Additionally, a front wall 70a extends up from bottom 66. Base shell 62 
further includes an open tapered front portion 72 which accepts the 
side-by-side connected cable assembly. The tapered front portion is 
divided into two cable receiving channels 74 and 76 by two pairs of 
upstanding partitions 77a-77b and 78a-78b. The outside partitions 77a and 
78b are spaced inwardly from the side wwalls 68 and 66 respectively, have 
flat rib portions 71a and 71c thereof extending toward the rear of the 
base 62. Further, with side walls 68 and 69 they form therebetween a pair 
of side vents 80 and 82 which will be described in detail hereinafter. The 
inner partitions 77b and 78b have a rearwardly extending rib portion 71b 
which includes a centrally located cavity 79 which accommodates bolt 52 of 
the connector assembly 10. The rear portion of base shell 62 forms a 
connection receiving region 84 for accommodating the signal conductor 
connections 83. 
Upper shell 64 is attached to base shell 62 by a web of material 
therebetween which forms a hinge 75. Hinge 75 allows upper shell 64 to 
serve as a cover for enclosing base shell 62. A snap 85 or another 
conventional locking arrangement secures upper shell 64 in a closed 
position over base shell 62. As with base shell 62, upper shell 64 is 
bounded by side wealls 86 and 87, back wall 89 and front wall 89a. The 
dimensions of upper shell 64 are slightly greater than the corresponding 
dimension of base shell 62, to permit upper shell 64 to enclose base shell 
62 as shown in FIG. 8. Upper shell 64 further includes three longitudinal 
ribs 88a, 88b and 88c, which correspond with the extending rib portions 
71a-c of portions 77a-77b and 78a-78b of base shell 62 to further define 
the cable receiving channels 74 and 76. Central rib 88b also includes a 
centrally located cavity 85 which accommodates nut 50 of the connector 
assembly 10. 
As enclosure 60 provides a moisture-proof seal around the cable connection, 
the upper and lower shells 62 and 64 are filled with a petroleum based gel 
90 which is similar to gel 11d of cable 11. Gel 11d may be contained in 
either one or both of base shell 62 and upper shell 64. 
As shown in FIG. 8, the connected cables 11 and 11', having conventional 
signal connectors 83 and ground shield connector 10 connected thereto, are 
inserted into the base shell 62 of the opened enclosure 60. Each of cables 
11 and 11' lies in the respective cable receiving channel 74 and 76. The 
connector screw is inserted into cavity 79 for proper connector 
positioning. The signal-conductor connections 83 lie in region 84. Upon 
closure of upper shell 64 connector 10 is seated in the central portion of 
base shell 62 with nut 50 and bolt 52 being accommodated in cavities 79 
and 85, respectively. As the cables 11 and 11' and connector assembly 10 
have displaced some of the petroleum gel 90, this excess gel will be 
expelled through vent openings 80 and 82 at the front portion 72. Thus, 
the connection will be fully enclosed and encased in gel 90 thereby 
insuring a moisture-proof seal. The integrally formed enclosure 60 of the 
present invention allows all electrical connections to be done externally 
thereof. The connected assembly may then be securely seated in the 
enclosure, which is conveniently seated in a shell-type manner. 
Various other modifications to the foregoing disclosed embodiment will be 
evident to those skilled in the art. Thus, the particularly described 
preferred embodiment is intended to be illustrative and not limited 
thereto. The true scope of the invention is set forth in the following 
claims.