Tubular cable grounding mechanism

An electrical connector assembly simply, and securely, grounds a shielding layer of a telephone cable to a conductive, grounded electrical box housing a protector module. During assembly, an insulation layer is removed from an end of the telephone cable to expose a portion of the shielding layer. The exposed portion of the shielding layer is folded back onto an adjacent, remaining portion of the insulation layer. A first sleeve is inserted into the end of the telephone cable and resides beneath a portion of the shielding layer. A second sleeve, formed of an electrically conductive material, is physically and electrically attached to the electrical box. The end of the telephone cable, having the first sleeve inserted therein, is inserted into the second sleeve. At least one crimp is formed in the second sleeve, which causes an inner conductive surface of the second sleeve to contact the folded back, shielding layer of the telephone cable to thereby establish an electrical connection between the electrical box and the shielding layer.

FIELD OF THE INVENTION 
This invention relates to electrical connectors. More particularly, the 
present invention relates to a coupling mechanism for coupling a shielding 
layer of a multi-phone line cable to a conductive, grounded chassis of a 
protector module. The coupling mechanism simultaneously, physically 
attaches the multi-phone line cable to the protector module, grounds the 
shielding layer of the multi-phone line cable to the grounded chassis of 
the protector module, and provides strain relief to the coupling. 
BACKGROUND OF THE INVENTION 
A protector module is typically provided shortly after an incoming 
multi-line phone cable enters into an office or apartment building, having 
multiple independent phone lines. The incoming multi-line phone cable 
includes many independent pairs of telephone wires, such as fifty pairs. 
The purpose of the protector module is to protect each of the independent 
pairs of phone lines from a power surge, such as a surge induced by a 
nearby lightening strike. 
To accomplish this purpose, the incoming multi-line phone cable is cut, or 
terminated, at the protector module. Each pair of phone lines is 
electrically connected to one of a plurality of electrical surge 
protectors of the protector module. The building's internal phone lines 
are collectively presented to the protector module as an outgoing 
multi-line phone cable. The outgoing multi-line phone cable is also 
terminated at the protector module and has its pairs of phone lines 
connected to the plurality of electrical surge protectors of the protector 
module. 
In operation, the surge protectors of the protector module respond to any 
power surge on one or more of the incoming phone lines by diverting the 
surge to the grounded chassis of the protector module. By diverting surges 
to ground, the surge protectors prevent the surges from passing into the 
phone lines of the outgoing multi-line phone cable and possibly damaging 
telephone equipment located within the office or apartment building. 
All of the pairs of telephone wires of the incoming multi-line phone cable 
are surrounded by a shielding layer, which in turn is surrounded by an 
insulation layer. It is important to ground the shielding layer of the 
incoming multi-line phone cable to the grounded chassis of the protector 
module. Likewise, all of the pairs of telephone wires of the outgoing 
multi-line phone cable are surrounded by a shielding layer, which in turn 
is surrounded by an insulation layer, and it is important to ground this 
shielding layer to the grounded chassis of the protector module. By so 
doing, a conductive path is formed for induced currents within the 
shielding layers, a uniform ground is established, and electrical noise 
within the phone lines is reduced. 
FIG. 1 is an overhead view of a protector module 1, according to the 
background art. An incoming multi-line phone cable 2 enters the protector 
module 1 through an opening provided in a sidewall 3. The incoming 
multi-line phone cable 2 includes numerous individual phone lines 100 
(illustrated in FIG. 8) which are wire wrapped to selected individual 
terminals beneath a bread board 4. Each of the individual terminals 
beneath the bread board 4 is electrically connected to a respective 
electrical socket 5 provided on an upper surface of the bread board 4. 
As also illustrated in FIG. 1, an outgoing multi-line phone cable 6 enters 
the protector module 1 through an opening provided in an opposite sidewall 
7. The outgoing multi-line phone cable 6 also includes numerous individual 
phone lines (illustrated in FIG. 8), which are wire wrapped to different 
individual terminals beneath the bread board 4. 
A plurality of removable and replaceable, electrical surge protectors 8 
have plug terminals, which are inserted into the sockets 5 on the upper 
surface of the bread board 4. The electrical surge protectors 8 
electrically connect the individual phone lines of the incoming multi-line 
phone cable 2 to the individual phone lines of the outgoing multi-line 
phone cable 6. The electrical surge protectors 8 include components, such 
as gas filled vials, which can divert a power surge from the phone lines 
of the incoming multi-line phone cable 2 to ground. By this arrangement, 
the protector module 1 can protect phone equipment, located within the 
office or apartment building, attached to the individual phone lines of 
the outgoing multi-line phone cable 6. 
FIG. 2 illustrates the physical connection between the incoming multi-line 
phone cable 2 and the protector module 1. The physical connection between 
the outgoing multi-line phone cable 6 and the protector module 1 is 
identical to the physical connection between the incoming multi-line phone 
cable 2 and the protector module 1. Therefore, the later physical 
connection will not be described in detail. 
As shown in FIG. 2, a bracket 9 is installed to a bottom of the protector 
module 1 adjacent the sidewall 3. The bottom of the protector module 1 
includes threaded studs 10, which are passed through holes 11 formed in 
the bracket 9. The bracket 9 is tightly secured to the bottom of the 
protector module 1 by engaging washers 12 and nuts 13 to the threaded 
studs 10. 
An upper portion of the bracket 9 includes a plurality of ribs 14. The 
incoming multi-line phone cable 2 is placed upon the ribs 14, and secured 
to the bracket 9 by a standard hose clamp 15. The hose clamp 15 presses an 
insulation layer 16 of the incoming multi-line phone cable 2 tightly 
against the ribs 14 of the bracket 9. By this arrangement, the hose clamp 
15 provides strain relief to the connection by preventing any tension on 
the wire wrap connections between the individual phone lines and the wire 
wrap terminals of the bread board 4. 
Inside the insulation layer 16 is a shielding layer 17. The shielding layer 
17 prevents electromagnetic fields adjacent to the incoming multi-line 
phone cable 2 from inducing currents with the individual phone lines, and 
thereby prevents undesirable electrical noise. It is important that the 
shielding layer 17 be electrically connected to a ground potential. In 
order to accomplish this grounding, a clamping device 18 is provided. 
The clamping device 18 includes an electrically conductive, stationary jaw 
19. The stationary jaw 19 has a threaded stud 20 integrally formed 
therewith. A short slit is cut through the insulation layer 16 and the 
shielding layer 17, wide enough to accommodate the threaded stud 20. Then, 
the stationary jaw 19 is inserted into an end of the incoming multi-line 
phone cable 2 so that the stationary jaw 19 contacts the shielding layer 
17, while the threaded stud 20 passes along in the slit formed in the 
insulation layer 16 and the shielding layer 17. 
A clamping jaw 21 has a through hole 22 formed therein. The threaded stud 
20 is passed through the through hole 22, and then the clamping jaw 21 is 
placed adjacent to the insulation layer 16. A washer 27 and nut 23 are 
installed on the threaded stud 20 and the nut 23 is tightened. By this 
arrangement, the stationary jaw 19 can be securely, electrically connected 
to the shielding layer 17. 
A ground strap 24 connects the stationary jaw 19 to a first grounding post 
25 provided on a conductive, grounded chassis of the protector module 1, 
adjacent the bread board 4. The outgoing multi-line phone cable 6 has its 
shielding sleeve connected to a second grounding post 26 provided on the 
grounded chassis of the protector module 1, in a manner identical to that 
described above in conjunction with the incoming multi-line phone cable 2. 
Because the grounded chassis is conductive, the first grounding post 25 is 
electrically connected to the second grounding post 26, and thereby the 
shielding sleeves of the incoming and outgoing multi-line phone cables are 
electrically connected. 
The above described method of grounding the shielding layers of the 
incoming and outgoing multi-line phone cables suffers several drawbacks. 
The pressure exerted by the hose clamp 15, against the insulation layer 
16, translates into internal stresses on the phone lines within the 
incoming multi-line phone cable 2. The stresses can break a conductor 
within a particular phone line, resulting in a loss of phone service. The 
stresses can deform the conductor within a particular phone line, creating 
a resistance in the conductor, resulting in noise in the phone service. 
Also, the stresses can press the phone lines closer together, resulting in 
cross-talk between phone lines. Further disadvantages are that a service 
technician must remember, and spend time installing, the clamping device 
18. The clamping device 18 takes up space within the protector module 1, 
and the ground strap 24 presents an obstacle within the protector module 
1. 
SUMMARY OF THE INVENTION 
The electrical coupling mechanism of the present invention overcomes one or 
more of the disadvantages associated with the clamping device 18 of the 
background art. The electrical coupling mechanism of the present invention 
simultaneously, physically attaches a shielded electrical cable, such as a 
multi-line phone cable, to an electrical box, such as a protector module, 
grounds the shielding layer of the multi-line phone cable to the 
conductive chassis of the protector module, and provides strain relief to 
the coupling. 
Other objects and further scope of applicability of the present invention 
will become apparent from the detailed description given hereinafter. 
However, it should be understood that the detailed description and 
specific examples, while indicating preferred embodiments of the 
invention, are given by way of illustration only, since various changes 
and modifications within the spirit and scope of the invention will become 
apparent to those skilled in the art from this detailed description.

DETAILED DESCRIPTION 
FIG. 3 is a cross sectional view of a first sleeve 30 for use in the first 
and second embodiments of the electric coupling mechanism of the present 
invention. The first sleeve 30 is shaped as a cylinder having two open 
ends. The first sleeve 30 is approximately three and half inches long, and 
is formed of a rigid material. The first sleeve 30 is inserted into the 
cut end of the incoming multi-line phone cable 2, and an outer surface of 
the first sleeve 30 resides against an inner surface of the shielding 
layer 17. A plurality of phone lines 100 (see FIG. 8), such as fifty to 
one hundred phone lines, would pass through the cross section of the first 
sleeve 30 and extend up to the wire wrap terminals under the bread board 
4. 
FIG. 4 illustrates a second sleeve 31 for use in the first embodiment of 
the electric coupling mechanism of the present invention. The second 
sleeve 31 is shaped as a cylinder having two open ends, and is formed of a 
conductive alloy or conductive metal, such as aluminum, gold, or copper. 
One end of the second sleeve 31 includes a threaded portion 32 on its 
outer surface. The other end of the second sleeve 31 has a smooth outer 
surface 33. 
Now, the construction of the first embodiment of the electric coupling 
mechanism will be described with reference to FIGS. 5 and 6. The 
insulation layer 16 is removed from an end of the incoming multi-line 
phone cable 2, thereby exposing the shielding layer 17. The exposed 
shielding layer 17 is folded back onto an adjacent, remaining portion of 
the insulation layer 16. The first sleeve 30 is inserted into the end of 
the incoming multi-line phone cable 2, so as to reside beneath the folded 
back portion of the shielding layer 17. 
Next, the end of the incoming multi-line phone cable 2 is inserted into the 
second sleeve 31. A first crimp 34 is formed in the smooth outer surface 
33 of the second sleeve 31. The first crimp 34 is located, so that it 
overlies the folded back portion of the shielding layer 17. The first 
crimp 34 causes an inner surface of the second sleeve 31 to contact the 
shielding layer 17, and to form good electrical contact therewith. The 
rigidity of the first sleeve 30 provides protection to the plurality of 
phone lines of the incoming multi-line phone cable 2. Therefore, the first 
crimp 34 will not translate into breakage, deformation, or displacement of 
the phone lines of the incoming multi-line phone cable 2. 
A second crimp 35 may also be formed in the smooth outer surface 23 of the 
second sleeve 31. The second crimp 35 would be located, so that it 
overlies the insulation layer 16 of the incoming multi-line phone cable 2. 
The second crimp 35 would provide strain relief to the electrical 
connection formed by the first crimp 34. 
The first and second crimps 34, 35 would be made by a special crimping 
tool, which encircles the second sleeve 31 and provides a uniform pressure 
to cause the second sleeve 31 to controllably collapse toward the incoming 
multi-line phone cable 2. Although FIG. 5 illustrates continuous first and 
second crimps 34, 35, it is envisioned that non-continuous crimps could be 
formed in the second sleeve 31, such as segmented crimps. Also, it is 
envisioned that the first crimp 34 could be supplemented by an additional 
crimp or crimps, to better ensure that good electrical contact is made 
between the inner surface of the second sleeve 31 and the folded back 
portion of the shielding layer 17. 
In order to attach the second sleeve 31 to the protector module 1, a first 
nut 36 is threaded onto the threaded portion 32 of the second sleeve 31. 
Then, the second sleeve 31 is inserted into the opening provided in the 
sidewall 3 of the protector module 1. Next, a second nut 37 is threaded 
onto the threaded portion 32 of the second sleeve 31. The first and second 
nuts 36, 37 capture the sidewall 3 of the protector module 1 to thereby 
physically attach the second sleeve 31 to the protector module 1. 
The sidewall 3 is constructed of an electrically conductive material, such 
as sheet steel. Since the second sleeve 31 is constructed of an 
electrically conductive material, the physical connection between the 
second sleeve 31 and the sidewall 3 results in an electrical connection 
between the shielding layer 17 of the incoming multi-line phone cable 2 
and the sidewall 3 of the protector module 1. If the opening in the 
sidewall 3 is overly large, washers may be included adjacent to the first 
and second nuts 36, 37 to enable the physical and electrical connection of 
the second sleeve 31 to the protector module 1. 
FIG. 7 illustrates a third sleeve 40 for use in the second embodiment of 
the electric coupling mechanism of the present invention. The third sleeve 
40 is shaped as a cylinder having two open ends, and is formed of a 
conductive alloy or conductive metal such as aluminum, gold, or copper. A 
bracket 41 is attached to one end of the third sleeve 40. The bracket 41 
includes a vertical portion 42 and a horizontal portion 43. The bracket 41 
is connected to the third sleeve 40 by welding, soldering, a threaded 
engagement, or any other suitable form of fixing. The bracket 41 is also 
formed of an electrically conductive material. 
Now, the construction of the second embodiment of the electric coupling 
mechanism will be described with reference to FIGS. 8, 9, and 10. As in 
the first embodiment, the insulation layer 16 is removed from the end of 
the incoming multi-line phone cable 2, thereby exposing the shielding 
layer 17. The exposed shielding layer 17 is folded back onto the adjacent, 
remaining portion of the insulation layer 16. The first sleeve 30 is 
inserted into the end of the incoming multi-line phone cable 2, so as to 
reside beneath the folded back portion of the shielding layer 17. 
Next, the end of the incoming multi-line phone cable 2 is inserted into the 
third sleeve 40. A third crimp 44 is formed in the outer surface of the 
third sleeve 40. The third crimp 44 is located, so that it overlies the 
folded back portion of the shielding layer 17. The third crimp 44 causes 
an inner surface of the third sleeve 40 to contact the shielding layer 17, 
and to form good electrical contact therewith. Again, the rigidity of the 
first sleeve 30 provides protection to the plurality of phone lines of the 
incoming multi-line phone cable 2. Therefore, the third crimp 44 will not 
translate into breakage, deformation, or displacement of the phone lines 
of the incoming multi-line phone cable 2. 
A fourth crimp 45 may also be formed in the outer surface of the third 
sleeve 40. The fourth crimp 45 would be located, so that it overlies the 
insulation layer 16 of the incoming multi-line phone cable 2. The fourth 
crimp 45 would provide strain relief to the electrical connection formed 
by the third crimp 44. 
As in the first embodiment, the third and fourth crimps 44, 45 would be 
made by a special crimping tool, which encircles the third sleeve 40 and 
provides a uniform pressure to cause the third sleeve 40 to controllably 
collapse toward the incoming multi-line phone cable 2. As illustrated in 
the FIGS. 8 and 9, the third and fourth crimps 44, 45 are segmented 
crimps. Of course, the third and fourth crimps 44, 45 could be continuous 
crimps, as illustrated in FIG. 5, with regard to the first embodiment. 
Also, it is envisioned that the third crimp 44 could be supplemented by an 
additional crimp or crimps, to better ensure that good electrical contact 
is made between the inner surface of the third sleeve 40 and the folded 
back portion of the shielding layer 17. 
In order to attach the third sleeve 40 to the protector module 1, a 
threaded stud 46 is provided on a bottom of the protector module 1. A 
through hole is provided in the horizontal portion 43 of the bracket 41. 
The threaded stud 46 is passed through the through hole of the horizontal 
portion 43, and the bracket 41 is secured to the protector module 1 by a 
washer 47 and nut 48. 
The bottom of the protector module 1 is constructed of an electrically 
conductive material, such as sheet steel. Since the third sleeve 40 and 
bracket 41 are constructed of an electrically conductive material, the 
physical connection between the bracket 41 and the bottom of the protector 
module 1 results in an electrical connection between the shielding layer 
17 of the incoming multi-line phone cable 2 and the protector module 1. 
The outgoing multi-line phone cable 6 enters the sidewall 7 and is 
connected to the protector module 1, in a manner identical to the 
connection between the incoming multi-line phone cable 2 and the protector 
module 1. Because the chassis of the protector module 1 is formed of an 
electrically conductive material, such as sheet steel, the shielding 
layers of the incoming and outgoing multi-line phone cables are in 
electrical contact. 
It can be seen from the present invention, that the ground strap 24 and two 
piece clamp assembly 18, of the background art, are no longer required. 
Further, it can be seen that the rigidity of the first sleeve 30 will 
protect the phone lines, within the incoming multi-line phone cable 2, 
from damage during the crimping of the second or third sleeves 31, 40. 
Therefore, the problems associated with the grounding assembly of the 
background art can be avoided. 
Although the present invention has been illustrated in conjunction with 
grounding a shielding layer of a multi-line phone cable to a chassis of a 
protector module, it should be readily apparent that the invention would 
be suitable for different types of shielded electrical cables. For 
example, the connection device would be suitable for connecting a chassis 
to a shielding layer of a power line, speaker wires, 75 ohm video cable, 
computer cable, etc. Further, although a threaded stud 46 and nut 48 are 
illustrated as securing the bracket 41 to the protector module 1, it 
should be appreciated that other securing assemblies would be possible. 
For example, the bracket could be welded or riveted to the bottom or 
sidewall 3 of the protector module 1. 
The invention being thus described, it will be obvious that the same may be 
varied in many ways. Such variations are not to be regarded as a departure 
is from the spirit and scope of the invention, and all such modifications 
as would be obvious to one skilled in the art are intended to be included 
within the scope of the following claims.