Optical cable connector assembly including breakable link and process using same

A cable connector assembly capable of mating to an armored optical cable and providing a hermetically sealed electronics cavity is described. A connector assembly provides a means for placing electronics in an electronics cavity. The electronics are capable of converting electrical signals to optical signals or optical signals to electrical signals within the electronics cavity in the connector assembly so that optical to optical matching of optical fibers is unnecessary. The connector contains a means for anchoring the armoring wire of the armored optical cable and at least two-spaced apart means for sealing the electronics cavity from leakage of pressure around the optical fiber cable. Furthermore, the connector assembly contains a means for passing the optical fiber core through a breakable link before termination in the electronics cavity. W

FIELD OF THE INVENTION 
The invention relates to a cable connector assembly. More specifically, the 
invention relates to an optical cable connector assembly. 
BACKGROUND OF THE INVENTION 
Cable connector assemblies are used at the termination of a cable to enable 
the quick connection or disconnection of a device, such as a well logging 
sond or a hydrophone. The cable connector assembly permits the 
substitution of different sonds without the need for a separate cable for 
each sond. This procedure has been used with standard electrical cables. 
As the number and complexity of the downhole measurements increase, the 
data that must be transmitted up an electrical cable strains capacity to 
carry the information. This limits the number and complexity of the 
measurements that can be taken and/or requires preprocessing of the data 
downhole to limit the amount of information that is transferred along the 
cable. 
Optical well logging cables provide a solution to the limitations of 
standard electrical cables and offer increased data transmission rates and 
much larger data carrying capacity. Previously, the optical cable 
connector assembly terminated on the cable and had to mate to an optical 
receiver in the sond. However, this procedure required precise alignments 
between the optics or optical fibers in the sond and the cable connector 
assembly. It also required cleanliness seldom encountered in such harsh 
environments to avoid loss of signal transmission across the interface. 
U.S. application Ser. No. 285,146, filed July 20, 1981, now abandoned, 
completely incorporated herein by reference for all purposes, disclosed a 
cable connector assembly wherein the light signals to be transmitted up or 
down the optical cable are converted into electrical signals in the cable 
connector assembly. This permitted the mating of an optical cable with 
conventional electrical sonds without the need of a precise transmission 
of light through a make/break connector interface. However, the connector 
disclosed therein was limited in that the sond and cable could not be 
disengaged in an emergency if the sond became lodged in a well bore and it 
was necessary to extract the cable alone. Furthermore, the connector did 
not seal individual conductors in individual units. And finally, as the 
temperature increases it would be desirable to have a hermetic seal on the 
sond end of the cable connector assembly, i.e., the interface between the 
electrical pin conductor and the sond. Still an additional desirable 
feature is a separate sealing system to isolate the electronics cavity 
from the cable termination and a sealing system surrounding the 
termination of the conductor elements in the optical fiber which can be 
tested at pressure to determine the integrity of the system prior to the 
insertion into a high pressure environment such as a well bore. 
SUMMARY OF THE INVENTION 
I have invented a cable connector assembly which possesses all the 
desirable features described above as well as additional benefits, and 
which are apparent to any ordinary skilled artisan, amplified hereinafter. 
The cable connector will be described with respect to its interfacing to 
the optical well logging cables described in U.S. applications Ser. Nos. 
408,971 now U.S. Pat. No. 4,504,112; 408,972 now U.S. Pat. No. 4,522,464 
and 408,975 now U.S. Pat. No. 4,523,804 all of which were filed on Aug. 
17, 1982. These applications are to be completely incorporated herein by 
reference for all purposes. However, the connector assembly is not limited 
to interfacing with those specific cables. Obvious modifications to the 
termination of the armor wirings will render the cable connector assembly 
suitable for use with other optical cables. 
The cable connector assembly is connected to the end of an optical fiber 
cable which is to be inserted into a well bore. The cable is inserted into 
and terminated in an electronics cavity in the connector assembly which 
contains at least one means for converting optical to electrical signals 
and/or electrical to optical signals such that only electrical signals 
pass between the sond and the connector assembly. The connector includes a 
means for anchoring the armoring of the optical fiber cable. At least 
two-spaced apart means for sealing and defining an electronics cavity 
therebetween. The sealing means adjacement the means for anchoring seals 
the electronics cavity from leakage around the optical fibers and the 
conductor wires. The connector assembly also contains means for passing 
the optical fiber core through a breakable link before termination in the 
electronics cavity.

DETAILED DESCRIPTION OF THE INVENTION 
The invention will be more clearly illustrated by referring to the 
accompanying Figures. The cable connector will be described with respect 
to fitting an armored optical cable having an outer diameter of about 
0.469 inch as described in U.S. application Ser. Nos. 408,972, and 
408,975. However, it should be understood that the connector assembly can 
be sized to form a termination for any armored optical cable. 
More specifically, the cable connector is designated as 100 in FIG. 1. The 
preferred cable connector 100 attaches to an armored optical fiber well 
logging cable 200 through the armor wires 400. The connector 100 has an 
approximate length of about 34.25 inches with an outer diameter at the 
widest point of about 3.375 inches. The electronics cavity has a length of 
about 12 inches and an inner diameter at the widest point of about 2.25 
inches. From the widest point of the connector, it necks down to a 
diameter of about 2.25 inches wherein the electrical conductors 600 and 
the optical fibers 800 are sealed and terminated. The necking down of the 
connector assembly is designed so as to mate the armored wires 400 of the 
cable 200 at a standard armored cable terminator such as one designed by 
Preform Line Products Company of Cleveland, Ohio. The terminator secures 
the inner and outer armor wires 400 of the cable. Having generally 
described the preferred dimensions of the cable connector 100, the 
specific details thereof are more clearly illustrated by referring to FIG. 
1. 
The cable connector 100 includes a means for sealing the connector at the 
point at which it interfaces with the sond. The sealing means is 
illustrated as plug 1. The plug 1 further includes a screw 21 and lock 
seal washer 13b between the screw 21 and the plug 1. The plug 1 protects 
the portion of the engaging nut 3, which threadedly engages a sond, from 
dirt and grease when the connector assembly 100 is not in use. An O-ring 2 
seals the cap seal plug to the inner opening of the front shell 7. Any 
sond connected thereto should also have a provision for an O-ring seal 2. 
The engaging nut 3 also threadedly engages the front shell 7. The front 
shell 7 contains a pin insert 5 positioned therein by a spacer tube 6 on 
the end of front shell 7 which mates with the engaging nut 3. The sealing 
means, O-rings 22 and 22a, seal the pin insert 5 in the front shell 7 and 
define an end of the electronics cavity. The front shell 7 protects the 
electronics cavity from the outside environment. The number and size of 
the threads between the engaging nut 3 and the front shell 7 and sond are 
determined by the pressures and temperatures to which the apparatus will 
be subjected and the need to seal and mate the sond to the connector 
assembly 100. 
The pin insert 5 has a multilam contact 50 attached therein. A dowel pin 4 
serves as the locator point for mating up the multilam contact 50 to the 
appropriate female connector in the end of a sond. A view of the means for 
engaging and contacting the sond portion of the apparatus 100 is more 
clearly illustrated in FIG. 2. 
FIG. 2 is a cross-sectional view of the connector 100 along lines 2, 
illustrated in FIG. 1. The multilam contact 50 contains male contact pins 
50A for insertion into the female receptacle in the sond. Of course, the 
contact could be configured so that the male pins 50A are in the sond and 
the female receptacle would be in the multilam contact 50. In addition, 
pin insert 5 can also contain multilam female inserts interior to within 
male pins 50A or between the pins. The multilam contacts 50 provide a 
pressure tight seal for the transfer of electrical power or electrical 
signals between the sond and the electronics cavity. The pins 50A are 
properly mated up by the pin dowel 4 which forces the male and female 
contacts to engage in a predetermined pin to receptacle configuration. 
An electronics cavity is formed between the interior proportions of the pin 
insert 5 abutting the spacer tube 6 and the end opposite thereto 
contacting the tension rod shell 15. A typical electronics cavity has a 
length of about 12 inches and a diameter of about 2.25 inches. However, 
the size of the electronics cavity is limited only by the need of the 
optical to electrical conversion electronics and any other hardware that 
may be desired to be placed within the electronics cavity. Suitable 
additional electronics would be optical modulators, such as those 
described in the U.S. application Ser. No. 285,146. 
The tension rod shell 15 contacts front shell 7 and is threadedly fixed 
with a second engaging nut 8. The front shell 7 and the tension rod shall 
form a connector housing. Although it would be more difficult to 
disassemble, the housing could be formed from a unitary tubular member. 
The front shell 7 seals to the tension rod 15 on its inner surface through 
sealing means o-rings 22b and c. These o-rings provide a further seal 
between the insert feed-through insert 10 and the tension rod 15. The 
feed-through insert 10 also seals the cavity and is held in place by the 
retaining nut 9 threadedly engaged in the tension rod 15 and the spacer 
tube 12. The feed-through insert 10 and feed through boot 11 permit the 
cable conductors 600 and optical fibers 800 to pass therethrough to the 
electronics cavity while providing a back-up seal to the outside 
environment. The conductor wires 600 and optical fiber core 800 is 
individually sealed by the feed-through insert and boot 10 and 11, 
respectively. The feed-through 10 further includes additional sealing 
means, such as o-rings 23 and 23A. The feed-through boot seal 11 is 
fabricated from suitable sealing materials, such as natural rubber, 
Viton.RTM. and the like. Higher temperature use of the connector assembly 
100 favors the use of materials like Viton.RTM.. 
Between feed-through insert 10 incorporating feed-through boot 11 and 
feed-through 16 incorporating feed-through boot 11A is a cavity formed 
therebetween for pressure testing the individual seals surrounding the 
conductors 600 and the optical fiber 800 of the cable 200. The spacing for 
a pressure test cavity between feed-through insert 10 and feed-through 
insert 16 is provided for by spacer tube 12. Access to the pressure test 
cavity is through button screws 14 sealed in the tension rod shell 15 by 
sealing means O-rings 13 and 13a. The feed-through insert 16 is sealed 
within the tension rod shell 15 by sealing means O-rings 23b and 23c. 
The feed-through insert 16 contains an additional feed-through boot 11b on 
the end of the insert 16 opposite to the end containing the feed-through 
boot 11A. The feed-through insert 16 with O-rings 23b and 23c and 
feed-through boot 11b form the main seal to the electronics cavity when 
the connector is in a pressured environment. The feed-through insert 10 
with o-rings 23 and 23a and feed-through boot 11 form a second back-up 
seal for the electronics cavity when the connector is in a pressured well 
bore environment. The feed-through inserts 10 and 16 individually seal the 
conductor wire 600 and optical fiber core 800 to provide a pressure tight 
seal to the electronics cavity. Thus, an up-hole, i.e. ambient environment 
pressure, test cavity to test the seals is defined between feed-through 
inserts 10 and 16 while the actual sealing of the electronics cavity is on 
the sides of the feed-throughs containing the boots 11 and 116b. 
Since the feed-through boots 11, 11a and 11b provide additional sealing, 
the electronics cavity is sealed by two hard seals 10 and 16 and the soft 
boot seals 11, 11a and 11b. A unique feature of this connector assembly 
100 is the multi-step individual sealing around the conductor wires 600 
and optical fiber core 800. This provides additional protection to the 
electronics package for extended use at high temperatures and pressures. 
Preferably, the feed-through boots 11, 11a and 11b are maintained with an 
inward pressure in use so as the temperature rises, have a tendency to 
squeeze down on the conductors 600 and the core optical fibers 800 to 
maintain the seal for the electronics cavity. Further, additional sealing 
is provided for by adding silicone grease and the like around all inserts 
and boots. 
On the end of tension rod 15 opposite to the end in communication with the 
electronics cavity is a retaining collar 17 which positions the 
feed-through insert seal 16 in an appropriate position. The retaining 
collar 17 is held in place by an engaging nut 18 which threadedly engages 
the tension rod shell 15. The engaging nut 18 also contacts and abuts an 
armor termination adaptor 19. The armor termination adaptor 19 is a 
termination point for the armor wires 400. The adaptor 19 along with the 
armor termination assembly 20 secure the armored optical cable 200 to the 
connector 100. 
The cable connector 100 also contains a tension rod comprising the 
rectangular U-shaped dowel pins 24 and 26 and a hollow tension rod 25. The 
hollow tension rod 25 permits the passage of the conductors 600 through 
the outer portions thereof while the optical fiber 800 passes through the 
hollow center. The tension rod design creates a breakable link which 
permits the extraction of the cable 200 from the sond and cable connector 
100 if the cable connector 100 and sond become trapped or wedged in a well 
bore. This prevents damage to the optical fiber cable. The hollow tension 
rod 25 is configured so as to break at a tension which is about the 
maximum working strength of the cable. The working strength of the cable 
is a function of its design and the stretch limitations of the components 
such as optical fibers used therein. Generally, the hollow tension rod 25 
should be designed to break at a tension which is equal to or slightly 
less than the elastic in-elastic transition of the cable. For the cable 
connector 100 illustrated a suitable tension is about 7000 to 8000 pounds. 
The tension rod assembly, i.e., breakable link, is more clearly illustrated 
in FIGS. 3, 4 and 5. FIG. 3 illustrates a top plan view of the tension rod 
assembly containing the hollow tension rod 25 and the rectangular U-shaped 
dowel pins 24 and 25. The tension rod has means, i.e. passages 700 and 900 
therethrough, for passing the conductor elements 600 and optical fiber 
elements 800 therethrough. These passages are illustrated as dashed lines 
700 and 900, respectively. The ends of the passages are chamfered to avoid 
cutting the insulation, not illustrated, surrounding the conductor wires 
600. A cross-sectional view of the tension rod assembly along line 4. FIG. 
4 more clearly illustrates the configurations of the rectangular U-shaped 
dowel pins 24 and 26 and the hollow tension rod 25 including passages 700 
and 900. The eight conductor elements 600 are spaced around where the 
dowel pins 24 and 26 fit through the hollow tension rod 25. The 
configuration of the passages 700 for conductor elements 600 is more 
clearly illustrated by referring to the end view in FIG. 5 along line 5 of 
FIG. 3. FIG. 5 illustrates the configuration of the rectangular U-shaped 
dowel pins 24 and 26 through the hollow tension rod 25 containing passages 
700 and 900 through which the conductor elements and the optical fibers 
600 and 800, pass respectively. The central hollow passage through hollow 
tension rod 25 permits the optical fibers 800 to pass therethrough without 
bending or kinking around the breakable link assembly of elements 24, 25 
and 26. The U-shape of the dowel pins 24 and 26 surround the optical 
fiber. 
Returning to FIG. 1, the armoring of the cable is terminated in a standard 
armor cable termination assembly 20 such as one manufactured by Preform 
Line Products. The armor termination assembly 20 includes the armor 
termination adaptor 19 for mating the armor termination assembly 20 to the 
connector 100 at the engaging nut 18. When the armor termination assembly 
is fitted to the armor termination adaptor, a means is provided for 
preventing the armor termination assembly 20 from rotating and disengaging 
from the armor termination adaptor 19. A suitable means is a dowel pin 27 
which is inserted through a passageway provided in the engaging threads of 
the armor termination assembly 20 and the armor termination adaptor 19. 
During the assembly of the connector 100, the dowel pin 27 is inserted 
between the armor termination adaptor 19 and the armor termination 
assembly 20 prior to the insertion of the rectangular U-shaped dowel pins 
24 and 26 through the retaining collar 17 and the armor termination 
adaptor 20, respectively. Thereafter, the engaging nut 18 tightens the 
whole assembly. A unique feature of this arrangement is the complete 
connection of the armored optical cable 200 to the connector assembly 100 
is through the hollow tension rod 25 affixed only therebetween at the 
retaining collar 17 with dowel pin 24 and at the armor termination 
adaptor/assembly 19/20 with dowel pin 26. This permits a clean break 
between the connector assembly 100 and the armored optical cable 200 at 
the hollow tension rod 25 if the force on the cable-connector interface 
exceeds the breaking strength of the hollow tension rod 25. Another unique 
feature is the sealing means 2, 5, 10, 16, 22, 22a, 23, 23a, 23b and 23c 
enhance the likelihood that neither the sond nor the electronics cavity 
will be damaged if the cable and connector separate. 
Having described the invention with reference to a particularly preferred 
embodiment, it should be understood that modifications which would be 
obvious to the ordinary skilled artisan are intended to be within the 
scope of the invention. For example, the threaded engaging means can be 
effected with gluing or welding if disassembly is not needed. In addition, 
the size of the cable connector and its configuration can be varied to 
suit the desired sond connected thereto. Furthermore, the cable connector 
assembly is not limited to oil well logging operations but can be used in 
any environment wherein high pressures are encountered and optionally high 
temperatures, such as oceanographic uses and/or geothermal operations.