An elongated fixture handle member is connected to a fixture body member with both members having interconnecting longitudinal central axial bores for the passage of an optical cable therethrough. The axial bore of the fixture body member, however, terminates in a shoulder stop for the outer end of a jacket of the optical cable covering both an optical fiber and a coating therefor, with an axial bore of reduced diameter continuing from the shoulder stop forward for a predetermined desired length to the outer end of the fixture body member. A subsequent insertion of the fixture body member including the above optical fiber elements into a chemical stripping solution results in a softening of the exposed external coating thereat which permits easy removal thereof from the optical fiber while leaving a desired length coated fiber intact within the fixture body member

Coleman, Alexander M.

Kolasinski, John R.

NASA Technical Reports Server

I11111 1ll1ll111 IIIII 11111 11111 11111 11111 11111 111ll1ll111111 
US00545 1294A 
United States Patent [191 [113 Patent Number: 5,45 1,294 
Kolasinski et al. [45] Date of Patent: Sep. 19, 1995 
OPTICAL FIBER CABLE CHEMICAL 
STRIPPING FIXTURE 
Inventors: 
Assignee: 
Appl. No.: 
Filed: 
John R. Kolasinski, Greenbelt; 
Alexander M. Coleman, Brandywine, 
both of Md. 
The United States of America as 
represented by the Administrator of 
the National Aeronautics and Space 
Administration, Washington, D.C. 
254,360 
May 31,1994 
Int. C l . 6  ......................... B44C 1/22; B296 37/00 
216/83 
Field of Search ............... 156/630, 655, 663, 668, 
156/345; 134/2; 216/7, 24 
US. c1. .......................................... 216/7; 216/24; 
References Cited 
U.S. PATENT DOCUMENTS 
3,332,757 7/1967 Hawkins ......................... 156/655 X 
3,885,071 5/1975 Blad et al. ....................... 156/630 X 
5,100,507 3/1992 Cholewa et al. ............... 156/663 X 
Primary Examiner-William Powell 
Attorney, Agent, or Firm-Robert D. Marchant 
1571 ABSTRACT 
An elongated fixture handle member is connected to a 
fixture body member with both members having inter- 
connecting longitudinal central axial bores for the pas- 
sage of an optical cable therethrough. The axial bore of 
the fixture body member, however, terminates in a 
shoulder stop for the outer end of a jacket of the optical 
cable covering both an optical fiber and a coating there- 
for, with an axial bore of reduced diameter continuing 
from the shoulder stop forward for a predetermined 
desired length to the outer end of the fixture body mem- 
ber. A subsequent insertion of the fixture body member 
including the above optical fiber elements into a chemi- 
cal stripping solution results in a softening of the ex- 
posed external coating thereat which permits easy re- 
moval thereof from the optical fiber while leaving a 
desired length coated fiber intact within the fixture 
body member. 
5 Claims, 1 Drawing Sheet 
https://ntrs.nasa.gov/search.jsp?R=20080004756 2019-08-30T02:38:42+00:00Z
US. Patent Sep. 19, 1995 5,45 1,294 
FIG. 1 
14 
FIG. 3 
\12 FIG. 4 
5,45 1,294 
1 2 
optical fiber while leaving a desired length of coated 
fiber within the fixture body member intact. 
BRIEF DESCRIPTION OF THE DRAWINGS 
The following detailed description of the invention 
OPTICAL FIBER CABLE CHEMICAL STRIPPING 
FIXTURE 
ORIGIN OF THE INVENTION 5 
will be more readily understood when considered in 
conjunction with the accompanying drawings, wherein: 
FIG. is a side elevational view of an end section of 
an optical fiber cable ready for chemical stripping of the 
FIG. 2 is an exploded elevational view of three varia- 
The invention described herein was made by employ- 
ees of the United States Government, and may be manu- 
and wed by Or for the Government for 
ernmental PUToses without the payment Of any 10 fiber coating from the end of an optical fiber; 
ties thereon or therefor. 
FIELD OF THE INVENTION tions of the prefeked embodiment of the subject inven- 
tion; 
This invention relates generally to a method and FIG. 3 is a central longitudinal cross sectional view 
apparatus for stripping an optical fiber cable and, more 15 of one fixture body shown in FIG. 2 attached to a fix- 
particularly, to a method and apparatus for chemically 
removing the coating surrounding glass fibers in optical 
fiber cables. 
ture handle member; and 
cable shown in FIG. 1 with a portion of the fiber coat- 
ing stripped. from the optical fiber. 
Heretofore, when the coating needed to be removed DETAILED DESCRIPTION OF THE 
from the optical fiber of an optical fiber cable so that it INVENTION 
can be terminated with a connector assembly or termi- Referring now to the drawings and more particularly 
nals, it typically involved using electrical wire stripping to FIG. 1, shown thereat is an end portion of an optical 
techniques or the fiber was simply dipped and with- 25 fiber cable 10 which is comprised of an outer jacket 12 
drawn from a chemical stripping solution by hand. within which there is an intermediate cloth-like member 
Mechanical fiber coating removal techniques, how- 14 and an inner jacket 16 which in turn covers a coating 
ever, can nick, scratch, score or otherwise damage ex- 18, covering an optical conductive fiber 20, typically 
tremely small and fragile optical fibers. Such damage is consisting of glass. The coating 18 is typically corn- 
difficult to detect and can result in a latent defect in the 30 Pised of a well known material such as acrylate. 
cable which is unacceptable in high reliability applica- 
tions. Hand held chemical removal techniques also do 
not provide the control necessary to strip the fiber coat- 
ing to precise lengths, and generally do not produce 
sharp, well defined edges or interfaces between the 35 upon the type Of termination 
FIG. 4 is a side elevational view of the optical fiber 
BACKGROUND OF THE INVENTION 2o 
Before the optical fiber cable 10 can be terminated 
with a connector assembly or terminals, however, a 
certain Portion of the coating l8 must be removed Or 
stripped from the glass fiber 20- Moreover, depending 
an exposed 
optical fiber and the fiber coating. 
SUMMARY 
length L of fiber coating 18 must remain intact, such 
that it projects from the outer end 22 of the inner jacket 
16, with the exposed glass fiber 20 then being severed at 
It is an object of the present invention, therefore, to an appropriate length* leaving a structure shown provide an improvement in the removal of coatings 40 in FIG. 4. 
from optical fiber. To accomplish this result and where the length L is variable and yet controlled so as to have a very precise 
dimension, a chemical fixture, shown in FIG. 
45 material, such as tetrafluoroethylene (TFE), a fixture 
handle member 24 and a fixture body member 26, are 
to be stripped inserted therein as shown in FIG. 3. 
The handle member 24 is shown connectable to one of 
It is a further object of the invention to improve the 
chemical removal Of 'Oatkg which surround glass 2, comprised of two elements fabricated frorn an inert bers used in optical fiber cables. 
It is another object of the invention to provide in- 
fiber coatings so that substantially flawless optical fiber 
surfaces are provided. 
creasing Of the chemical removal Of Optical coupled together with the end of the optical fiber cable 
It is still a further object of the invention to provide 50 three different fixture body members 26-1,26-2 and 26-3 
by being screwed together by mating threads 28 and 30, fiber coating removal Of an Optical fiber to precise 
dimensions so that the cable can be more efficiently respectively. 
terminated with a connector assembly. As further shown in FIG. 2, the fixture handle mem- 
The foregoing and other objects of the invention are ber 24 comprises an elongated member which is gener- 
provided by an elongated fixture handle member con- 55 ally cylindrical in cross section and which is typically 
netted to a fixture body member, both members having three inches long and 0.5 inches in diameter. The handle 
interconnecting longitudinal central axial bores for the member 24 includes an external flat portion 32 for grip- 
passage of an optical cable therethrough, the axial bore ping and marking and a longitudinal central axial bore 
of the fixture body member, however, terminates in a 34 which includes a fluted outer end 36. The inner end 
shoulder stop for the outer end of the inner jacket of the 60 of the axial bore 34 terminates in a threaded inner end 
optical cable covering both an optical fiber and a coat- portion 38 of relatively larger diameter and which in- 
ing therefor, with an axial bore of reduced diameter cludes female type threads 28. 
continuing from the shoulder stop forward for a prede- Each of the fixture body member 26-1,26-2 and 26-3 
termined desired length to the outer end of the fixture are substantially identical in construction with the ex- 
body member, whereby a subsequent insertion of the 65 ception that three different bore lengths L1, L2 and L3 
fixture body member into a chemical stripping solution are implemented by respective central longitudinal axial 
results in a softening of the exposed external coating bores 40 having a relatively smaller diameter to accom- 
thereat which permits easy removal thereof from the modate a glass fiber 20 and its associated fiber coating 
4 
5,45 1,294 
3 
18 (FIG. 1). At the inner end of the bores 40, there is materials so that the fixture assembly is not damaged or 
located a relatively larger shoulder portion 42 which is affected by contact with most chemical stripping solu- 
dimensioned to receive the forward end 22 of the inner tions used to remove optical fiber coatings. 
jacket 16, also shown in FIG. 1. The rear ends of the Having thus shown and described what is at present 
fixture body members 26-1 . . .26-3 include a set of male 5 considered to be the preferred embodiment of the in- 
type threads 30 and a relatively larger longitudinal axial vention, it should be noted that the same has been made 
bore 44 whose diameter substantially matches that of by way of illustration and not limitations. Accordingly, 
the bore 34 in the handle member 24. The fixture body all modifications, alterations and changes coming 
members 26-1 . . . 26-3 each include an intermediate within the spirit and scope of the invention as set forth 
body portion 48 and have a flat gripping and marking 10 in the appended claims are herein meant to be included. 
surface 50 at the front thereof. A reduced diameter tip we claim: 
portion 52 extends from the intermediate body portion 1. A method of chemically stripping a portion of a 
48. The tip portion 52 includes a peripheral notch 54 a coating covering an optical fiber of an optical fiber 
acts as an immersion line for the operation now to be 15 steps of: 
explained. exposing a first length of optical fiber including a 
coating from an end of said at least one outer When an optical fiber cable 10 is ready for removal of 
jacket; the fiber coating 18, the cable is first inserted into a 
disassembled stripping fixture, as shown in FIG. 2, corn- 
prised of the handle member 24 and one of the fixture 20 fiber including said coating into a fixture including 
a chemically inert fixture body member having a body members 26-1, 26-2, 26-3, where it is seated into 
longitudinal axial bore therein, said bore having a the fixture body member 26-1, for example, such that 
second length and terminating inwardly at a shoul- the end surface 22 (FIG. 1) of the inner jacket 16 abuts the shoulder 42. Once the cable 10 is seated properly, der stop of said body member for receiving said the coated optical fiber 20 and the fiber coating 18 to be 25 end of said outer jacket, said bore further terminat- stripped therefrom protrudes from the tip portion 52. ing outwardly at an outer surface of said fixture The fixture handle member 24 is screwed onto the fix- body member, said first length being greater than ture body 26-1 and the cable assembly is picked up via 
said second length so that a portion of said optical the fixture handle member 24. The protruding fiber 20 
outer surface of said fixture body member; chemical stripping solution up to the notch 54' encir- 
cling the tip portion 52. ne immersed fiber elements immersing said portion of said optical fiber including 
are held in the stripping solution until the fiber coating said coating via the fixture body member into a 
18 softens, which is typically about 90 seconds. At this coating stripping solution for a time until said coat- 
point, the fiber coating 18 is removed UP to the front 35 ing extending beyond said outer surface softens, 
end face 56 of the tip portion 52, by sliding the fixture removing said Portions Of said coated optical fiber 
body member 26-1 off the cable 10 or by wiping the from said stripping solution; and 
softened coating 18 off using a cloth, leaving a length L stripping the softened coating from the optical fiber 
of fiber coating 18 within the fixture body member extending beyond said outer surface, 
which when removed therefrom provides a structure 40 whereby a length of exposed coating remains intact 
such as shown in FIG. 4. adjacent a stripped length of optical fiber. 
The fixture body members 26-1, 26-2 and 26-3 ensure 2. A method according to claim 1 and additionally 
that optical fibers are stripped to a precisely controlled including the step of connecting a handle member to 
lengths L1, Lz and L3, respectively, typically within said fixture body member prior to said immersing step, 
0.010 inches and that the remaining fiber coating 18 has 45 said handle member including a longitudinal axial bore 
a sharp well defined interface 58 as shown in FIG. 4. therethrough and having a diameter for passing the 
The stripping fixture according to the subject inven- outer jacket of said optical fiber cable. 
tion, when used with chemical stripping solutions, elim- 3. A method according to claim 1 wherein said coat- 
inates the possibility of nicking, scratching or otherwise ing is comprised of acrylate. 
damaging the extremely fragile optical fibers during 50 4. A method according to claim 1 wherein said opti- 
fiber coating stripping operations. The fixture body cal fiber includes another outer jacket externally of said 
member together with the chemical stripping agent at least one outer jacket. 
reduces the possibility of latent defects in the cable in 5. A method according to claim 3 wherein said jack- 
high reliability applications. Both the handle member ets are separated by a strengthening member. 
predetermined distance back from the end face 56 and cable, including at least one outer jacket, comprising the 
inserting the exposed said first length of said optical 
and its fiber coating 18 is immersed into an appropriate 30 fiber said coating extends beyond said 
and the fixture body member are fabricated from inert 55 * * * * *  
60 
65 


Optical fiber cable chemical stripping fixture

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