U.S. patent application number 09/733352 was filed with the patent office on 2002-06-13 for method and apparatus for tensile testing and rethreading optical fiber during fiber draw.
Invention is credited to Bumgarner, Kirk P., Roberts, Kenneth W., Tucker, David A..
Application Number | 20020069675 09/733352 |
Document ID | / |
Family ID | 22631841 |
Filed Date | 2002-06-13 |
United States Patent
Application |
20020069675 |
Kind Code |
A1 |
Bumgarner, Kirk P. ; et
al. |
June 13, 2002 |
Method and apparatus for tensile testing and rethreading optical
fiber during fiber draw
Abstract
A method and apparatus for automatic threading and winding of
optical fiber onto various components in a fiber draw system, as
well as methods and apparatus for conducting online tensile
screening of optical fiber at high speeds. In a preferred
embodiment, the fiber is tensile tested during fiber draw and wound
directly onto a shipping spool to be shipped to a customer. The
tensile stress can be imparted to the fiber during the draw process
by feeding the fiber through a screener capstan, which works in
conjunction with another capstan to impart the desired tensile
stress to the fiber during the draw process. Another aspect is a
method and apparatus for threading or rethreading of a moving
length of fiber through a fiber draw or fiber testing process, in
which fiber is wound onto a spool, comprising activating an
aspirator to obtain the fiber at a first location and moving said
aspirator in at least two dimensions to thereby move the fiber to a
second location and thread the fiber through or onto at least one
component in the fiber draw or testing process.
Inventors: |
Bumgarner, Kirk P.;
(Wilmington, NC) ; Roberts, Kenneth W.;
(Wilmington, NC) ; Tucker, David A.; (Wilmington,
NC) |
Correspondence
Address: |
CORNING INCORPORATED
SP-TI-3-1
CORNING
NY
14831
|
Family ID: |
22631841 |
Appl. No.: |
09/733352 |
Filed: |
December 8, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60173401 |
Dec 28, 1999 |
|
|
|
Current U.S.
Class: |
65/378 |
Current CPC
Class: |
C03B 37/032 20130101;
G01N 3/08 20130101; B65H 57/003 20130101; C03B 2205/40 20130101;
G01N 2203/028 20130101; B65H 67/048 20130101; B65H 2701/32
20130101; B65H 54/88 20130101; G01N 2203/0278 20130101; G01M 11/088
20130101 |
Class at
Publication: |
65/378 |
International
Class: |
G01N 023/00 |
Claims
What is claimed is:
1. A method of screening an optical fiber during a fiber draw
process, comprising pulling a length of optical fiber from an
optical fiber preform at a fiber draw speed greater than 20 m/s,
imparting a desired tensile stress to said fiber to thereby test
the strength of said fiber and subsequent to said imparting a
tensile stress, winding said fiber onto a spool.
2. The method of claim 1, wherein said desired tensile stress is
greater than about 80 psi.
3. The method of claim 1, wherein said desired tensile stress is
greater than about 95 psi.
4. The method of claim 1, wherein said spool is a shipping spool to
be shipped to a customer, and said fiber is wound onto said
shipping spool.
5. The method of claim 4, further comprising, shipping said
shipping spool with said fiber thereon to a customer.
6. The method of claim 2, wherein said fiber is wound onto a spool
which enables access to both ends of said fiber on said spool.
7. The method of claim 2, wherein said fiber is wound onto said
shipping spool in a manner which enables both ends of said fiber to
be accessed while said fiber is stored on said spool.
8. The method of claim 4, wherein said fiber is wound onto said
shipping spool in a manner which enables both ends of said fiber to
be accessed while said fiber is stored on said spool.
9. The method of claim 5, wherein said method further comprising,
prior to said shipping, conducting tests on said fiber while said
fiber is on said spool.
10. The method of claim 9, wherein said tests include at least one
test selected from the group consisting of optical time domain
reflectometry, dispersion geometry and polarization mode
dispersion.
11. The method of claim 2, further comprising conducting at least
one optical property test on said fiber while said fiber is on said
shipping spool by a testing method which involves connecting one
end of said fiber on said spool to a light source, and evaluating
the light at the other end of the fiber.
12. The method of claim 9, further comprising conducting at least
one optical property test on said fiber while said fiber is on said
shipping spool by a testing method which involves connecting one
end of said fiber on said spool to a light source, and evaluating
the light at the other end of the fiber.
13. The method of claim 1, wherein said imparting a tensile stress
comprises feeding said fiber through a screener capstan which works
in conjunction with another capstan which is in contact with said
fiber to impart said desired tensile stress to said fiber during
said draw process, and said screener capstan is rotated at a higher
circumferential speed than said other capstan to thereby impart
said desired tensile stress.
14. The method of claim 13, further comprising monitoring the
tension in the fiber in said draw process and adjusting the speed
of said screener capstan in response to said monitored tension, to
thereby maintain said tensile stress.
15. The method of claim 14, wherein said monitoring step comprises
monitoring said tension via a load cell operatively connected to
said fiber.
16. The method of claim 15, wherein said load cell is connected to
a pulley which in turn contacts said fiber, said fiber contact
causing said pulley to rotate
17. The method of claim 15, wherein a computer monitors said
tension in said fiber via said load cell.
18. The method of claim 4, wherein less than 150 km of fiber is
wound onto said spool.
19. The method of claim 4, wherein a length of fiber is wound onto
said spool which is sufficiently short to enable the attenuation of
said fiber to be measured while said fiber is on said spool.
20. A method of screening an optical fiber during a fiber draw
process, comprising pulling a length of optical fiber from an
optical fiber preform, imparting a desired tensile stress to said
fiber to thereby test the strength of said fiber and subsequent to
said imparting a desired tensile stress, winding said fiber onto a
spool which is to be shipped to a customer or optical fiber cabling
operation with said fiber thereon.
21. The method of claim 20, wherein said desired tensile stress is
greater than about 80 psi.
22. The method of claim 20, wherein said desired tensile stress is
greater than about 95 psi.
23. The method of claim 20, further comprising shipping said spool
with said fiber thereon to a customer.
24. The method of claim 20, wherein said fiber is wound onto said
spool in a manner which enables access to both ends of said fiber
while said fiber is stored on said spool.
25. The method of claim 23, wherein said fiber is wound onto said
shipping spool in a manner which enables both ends of said fiber to
be accessed while said fiber is stored on said spool.
26. The method of claim 20, wherein said fiber is wound onto said
shipping spool in a manner which enables both ends of said fiber to
be accessed while said fiber is stored on said spool.
27. The method of claim 26, wherein said method further comprising,
prior to said shipping, conducting tests on said fiber while said
fiber is on said spool.
28. The method of claim 26, wherein said method further comprising,
prior to said shipping, conducting tests on said fiber while said
fiber is on said spool.
29. The method of claim 28, wherein said tests include at least one
test selected form the group consisting of optical time domain
reflectometry, dispersion geometry and polarization mode
dispersion.
30. The method of claim 28, further comprising conducting at least
one optical property test on said fiber while said fiber is on said
shipping spool by a testing method which involves connecting one
end of said fiber on said spool to a light source, launching light
from said light source through said fiber, and evaluating said
launched light at the other end of said fiber.
31. The method of claim 20, wherein said imparting a tensile stress
comprises feeding said fiber through a screener capstan which works
in conjunction with another capstan which is in contact with said
fiber to impart said desired tensile stress to said fiber during
said draw process, and said screener capstan is rotated at a higher
circumferential speed than said other capstan to thereby impart
said desired tensile stress.
32. The method of claim 31, further comprising monitoring the
tension in the fiber in said draw process and adjusting the speed
of said screener capstan in response to said monitored tension, to
thereby maintain said tensile stress.
33. The method of claim 32, wherein said monitoring step comprises
monitoring said tension via a load cell operatively connected to
said fiber.
34. The method of claim 33, wherein said load cell is connected to
a pulley which in turn contacts said fiber, said fiber contact
causing said pulley to rotate
35. The method of claim 34, wherein a computer monitors said
tension in said fiber via said load cell.
36. The method of claim 20, wherein no more than 100 km of fiber is
wound onto said spool.
37. The method of claim 20, wherein a length of fiber is wound onto
said spool which is sufficiently short to enable the attenuation of
said fiber to be measured while said fiber is on said spool.
38. A method of threading a moving length of fiber through a
component in a fiber draw, fiber winding or fiber testing process,
comprising: activating an aspirator to obtain said fiber at a first
location and moving said aspirator in at least two dimensions to
move said fiber to a second location to thread said fiber through a
component in said fiber draw process.
39. The method of claim 38, wherein said moving length of fiber is
a moving length of fiber in a fiber draw process, and said method
further comprises orienting at least a first, second, and third
pulley so that, when said aspirator moves said fiber to said second
location, said pulleys are disposed along the length of said fiber
and on alternating sides of said desired fiber, and said method
further comprises moving said second pulley across the path of said
fiber to retain said fiber in contact with said first, second, and
third pulleys, thereby causing said fiber to move in a serpentine
path.
40. The method of claim 38, wherein said aspirator is moved to
guide said fiber onto at least one guide pulley by said aspirator
guiding said fiber between or against a pair of surfaces which are
disposed on each side of said guide pulley, said surfaces sloping
toward said guide pulley to thereby guide said fiber onto said
guide pulley.
41. The method of claim 39, wherein said aspirator is moved to
guide said fiber onto at least one guide pulley by said aspirator
guiding said fiber between or against a pair of surfaces which are
disposed on each side of said guide pulley, said surfaces sloping
toward said guide pulley to thereby guide said fiber onto said
guide pulley.
42. The method of claim 38, wherein said second location is
proximate to a fiber winding spool.
43. The method of claim 42, further comprising engaging said fiber
at a point along said fiber which is between the aspirator and the
source of fiber, and winding said engaged fiber onto said
spool.
44. The method of claim 43, wherein said engaging said fiber
comprises engaging said fiber by a snagger tooth which is located
on said spool
45. The method of claim 38, further comprising engaging said fiber
at a point along the length of said fiber which is between the
source of said fiber and said aspirator, and moving said engaged
fiber to facilitate threading of said fiber through said at least
one component of said fiber draw process.
46. The method of claim 45, wherein said engaging a fiber step
comprises engaging a moving length of fiber, moving said engaged
length of moving fiber into contact with a capstan to thereby
thread said fiber around said capstan.
47. The method of claim 46, wherein simultaneous with said
threading of said capstan, said aspirator is moving to said second
location, and said second location is proximate to a winding
spool.
48. The method of claim 47, wherein said moving length of fiber is
a moving length of fiber in a fiber draw process, and said method
further comprises orienting at least a first, second, and third
pulley so that, when said aspirator moves said fiber to said second
location, said pulleys are disposed along the length of said fiber
and on alternating sides of said desired fiber, and said method
further comprises moving said second pulley across the path of said
fiber to retain said fiber in contact with said first, second, and
third pulleys, thereby causing said fiber to move in a serpentine
path.
49. The method of claim 48, further comprising moving said
aspirator to guide said fiber onto at least one guide pulley by
said aspirator guiding said fiber between or against a pair of
surfaces which are disposed on each side of said guide pulley, said
surfaces sloping toward said guide pulley to thereby guide said
fiber onto said guide pulley.
50. An apparatus for drawing and winding fiber onto a spool, and
prooftesting the fiber after drawing of the fiber but prior to the
fiber being wound onto the spool, comprising: a furnace for
softening an optical fiber preform sufficiently that a fiber can be
drawn therefrom; a tractor device capable of drawing fiber from
said preform at a rate exceeding 20 m/s; a prooftesting device
comprising a first tractor assembly downstream of said furnace
including at least one wheel and a motor for driving said wheel at
a first circumferential speed a second tractor assembly including
at least one wheel and a servo motor for driving said wheel at a
second circumferential speed the difference between said first and
second circumferential speeds creating a desired proof testing
tensile stress; a load cell operatively connected to the fiber for
monitoring tension in said fiber; and a computer control for
receiving input from the load cell and adjusting the speed of the
first or second tractor assemblies to aid in maintaining uniform
tensile stress.
51. Apparatus of claim 50, wherein said second circumferential
speed is faster than the first circumferential speed.
52. A method of changing optical fiber storage spools in an optical
fiber winding process, comprising: cutting the fiber being fed from
a fiber supply source after a first fiber storage spool has
received a desired amount of optical fiber; capturing the fiber
being supplied from said fiber supply source in an aspirator; and
moving said aspirator and a second fiber storage spool with respect
to one another to rethread the fiber onto said second fiber storage
spool.
53. The method of claim 52, wherein said fiber supply source is a
moving length of fiber in a fiber draw operation.
54. The method of claim 52, wherein a snagger tooth on said second
storage spool snags said fiber onto said second storage spool.
55. The method of claim 52, wherein said aspirator is moved in at
least two dimensions to wind said fiber onto said second storage
spool.
56. A method of exposing optical fiber to a tensile screening test
comprising: feeding said fiber through a tensile screening tester
which is located in the path of a moving length of optical fiber,
said length of optical fiber being drawn from an optical fiber
preform, said tensile screening tester located between said preform
and a storage spool for collecting said length of fiber, wherein
the tension in said fiber being drawn from said preform is
monitored and the tension being applied to said fiber via said
fiber tensile tester is adjusted in response to fluctuations in
said incoming fiber tension.
57. In a process for winding a length of fiber being drawn in an
optical fiber preform in a fiber draw process onto at least one
storage spool, the improvement comprising, after the length of
fiber has begun to be stored on said at least one storage spool,
identifying fiber which is out of specification and removing said
out of specification fiber from the source of fiber before the
fiber is wound onto said at least one storage spool.
58. The method of claim 57, wherein said method comprises winding
said length of fiber onto a first storage spool, and said method
further comprises cutting and removing a portion of said length of
fiber, and rewinding at least a portion of the remainder of said
length of said fiber onto a second storage spool.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is application claims the benefit of U.S. Provisional
Patent Application Serial No. 60/173,401 filed on Dec. 28, 1999,
the content of which is relied upon and incorporated herein by
reference in its entirety, and the benefit of priority under 35
U.S.C. .sctn. 120 is hereby claimed.
FIELD OF THE INVENTION
[0002] The present invention relates to a method and apparatus for
automatic threading and winding of optical fiber onto various
components in a fiber draw system. The invention further relates to
methods and apparatus for conducting online tensile screening of
optical fiber at high speeds and winding of the screened optical
fiber directly onto optical fiber shipping spools.
BACKGROUND OF INTRODUCTION
[0003] Optical waveguide fibers (optical fibers) are a well-known
transmission medium used in optical communication systems. Fiber
draw manufacturing techniques are known wherein the optical fiber
is drawn from an optical fiber preform and wound onto a spool. In
the past, the drawing of optical fiber has typically involved
winding of the fiber onto bulk spools that may hold up to 400 km of
fiber. The bulk spool is then typically manually transported to an
off-line rewinding machine that is threaded manually by an
operator. The off-line machine rewinds fiber from the bulk spool to
a plurality of smaller shipping spools. Prior to or during the
transfer of the fiber from the bulk spool to the smaller shipping
spools, various tests are conducted on the fiber. For example, the
same machine used to wind the fiber from the bulk spool to the
shipping spool is also commonly employed to apply a predetermined
minimum level of stress (typically 100 kpsi) to the fiber to make
sure the fiber meets the minimum strength requirements. This
application of stress is commonly called screening or proof
testing. The machine stops winding to the shipping spool when
screening breaks occur, and the operator must then manually
rethread the machine again and begin winding the fiber onto a new
spool.
[0004] It would be desirable to conduct tensile strength proof
testing on the fiber during the fiber draw process, before it is
wound onto a storage spool, which preferably is a shipping spool.
However, with the high draw speeds (e.g. greater than 20-25 m/s)
employed in some of today's fiber manufacturing operations, such
online proof testing has not been achievable. For one thing, online
screening would increase the number of fiber breaks in the fiber at
the draw, due to the added tensile stress applied to the fiber to
proof test it. In addition, because the fiber draw process cannot
be stopped, there would be a great deal of lost fiber while the
operator rethreaded the online tensile screening equipment. Of
course at the higher draw speeds (e.g. greater than 20 m/s)
employed in many of today's fiber draw processes, the fiber being
threaded would somehow also have to keep up with the length of
fiber being fed by the fiber draw process. Also, because of the
time involved with threading conventional tensile testing
apparatus, using conventional techniques a great deal of fiber
would be lost during the rethreading operation. As a result,
manufacturers have thus far instead had to resort to manufacturing
processes wherein they draw the fiber at lower draw tensions onto
relatively large (e.g. can store 400 km or more) bulk spools. These
fiber on these bulk spools is then proof tested off-line, during or
prior to its being wound onto smaller shipping spools.
SUMMARY OF THE INVENTION
[0005] One aspect of the present invention relates to a method of
tensile proof testing an optical fiber during a fiber draw process,
comprising pulling a length of optical fiber from an optical fiber
preform at a fiber draw speed greater than 20 m/s, imparting a
desired tensile stress to said fiber to thereby test the strength
of said fiber and subsequent to said imparting a tensile stress,
winding said fiber onto a spool. The tensile stress applied to the
fiber preferably is equal to a desired proof testing force.
Preferably the desired tensile stress is greater than about 80 psi,
and more preferably the desired tensile stress is greater than
about 95 psi.
[0006] In a preferred embodiment, the fiber is wound directly onto
a shipping spool to be shipped to a customer. Preferably the
shipping spool is not capable of holding more than 150 km, more
preferably not more than 100 km, and most preferably not more than
about 75 km of optical fiber. Such shipping spools can then be
shipped directly to a customer without having to be rewound onto
smaller spools. Preferably, the shipping spool is one which enables
access to both ends of said fiber on said spool, and the fiber is
wound onto said shipping spool in a manner which enables both ends
of said fiber to be accessed while said fiber is stored on said
spool. In this way, optical properties testing and other forms of
testing can be conducted on the fiber while stored on the spool,
without having to remove the fiber from the spool. For example, the
fiber can be tested by a testing method which involves connecting
one end of said fiber on the spool to a light source, launching
light from the light source through the fiber, and evaluating the
properties of the light at the other end of the fiber. Examples of
such tests include optical time domain reflectometry (OTDR), which
is used to measure the amount of dispersion per unit length in the
fiber, as well as dispersion geometry and polarization mode
dispersion.
[0007] The tensile stress can be imparted to the fiber during the
draw process by feeding the fiber through a screener capstan, which
works in conjunction with another capstan to impart the desired
tensile stress to the fiber during the draw process. For example,
the screener capstan may be located downstream of another capstan
and rotated at a higher circumferential speed than the other
capstan to thereby pull the fiber and impart a desired tensile
stress. Preferably, the fiber tension between the two capstans is
monitored during the draw process and the speed of the screener
capstan adjusted in response to the monitored tension, to thereby
constantly maintain a desired tensile screening force or range of
forces. For example, the tension in the fiber can be monitored via
a load cell (for example, which may be located between the two
capstans) operatively connected to a pulley, which in turn contacts
the fiber. A computer can be used to monitor the tension in said
fiber via the load cell and adjust the speed of the screener
capstan accordingly. Alternatively, other methods could be employed
to impart the desired amount of tensile stress to the fiber during
the draw process. For example, such stress could be applied using a
weight which is applied onto a pulley around which the fiber
travels during the draw process. Alternatively, the fiber could be
wound around two capstans which are mechanically linked so that one
of the capstan travels at a higher circumferential speed than the
other capstan. A still further alternative would be to have the
fiber travel around a pulley having two different adjacent fiber
track channels, each fiber track channel having different
circumferences, the difference in circumferences being selected to
provide a desired tensile force onto the fiber as it passes through
the two track channels of the pulley.
[0008] Another aspect of the invention relates to a method and
apparatus for threading or rethreading of a moving length of fiber
through a fiber draw or fiber testing process, in which fiber is
wound onto a spool, comprising activating an aspirator to obtain
the fiber at a first location and moving said aspirator in at least
two dimensions to thereby move the fiber to a second location and
thread the fiber through or onto at least one component in the
fiber draw or testing process. The moving length of fiber can be,
for example, a moving length of fiber in a fiber draw process or an
off-line fiber screening process. In a preferred embodiment, the
aspirator is moved to guide the fiber onto at least one guide
pulley, after which the fiber is moved proximate to the winding
spool, where it is engaged and the fiber is wound upon the spool.
For example, the fiber length may be engaged by a snagger tooth or
other device capable of grabbing the fiber on the storage spool.
Immediately after the fiber is engaged by the rotating spool, the
fiber is cut to separate the fiber from the aspirator. The guide
pulley in this case and the fiber storage spool then traverses with
respect to one another to wind the fiber onto the spool.
[0009] In another embodiment, the method further comprises
orienting at least a first, second, and third pulley so that, when
the aspirator moves said fiber to said second location, the pulleys
are disposed along the length of said fiber and on alternating
sides of said desired fiber. The second pulley is then moved across
the path of the fiber to thereby retain the fiber in contact with
the first, second, and third pulleys, thereby causing the fiber to
move in a serpentine path.
[0010] In still another embodiment, the aspirator is used together
with another, separate fiber guiding device, to guide the fiber
through at least one component in a fiber winding system. For
example, a mechanical guide finger assembly can be used to engage a
portion of the fiber, between the source of the fiber and the
aspirator. The guide finger can then bend and move the path of the
moving optical fiber and thereby guide the fiber onto or through
the component to be threaded. Preferably, the guide finger is a
cylindrical member over which the fiber may travel freely and
continue to be collected by the aspirator. Such a guide member
could be in the form of a hook or J-shaped member, or more
preferably is a cylindrical tube or rod, which may or may not be
rotatable around its axis to facilitate free travel of the fiber
over the guide finger.
[0011] Another aspect of the invention relates to an apparatus for
drawing and winding fiber onto a spool, and prooftesting the fiber
after drawing of the fiber but prior to the fiber being wound onto
the spool. The apparatus includes a furnace for softening an
optical fiber preform sufficiently that a fiber can be drawn
therefrom; a first capstan of other fiber drawing device designed
to draw fiber from the preform at a rate exceeding 20 m/s, and
preferably exceeding 25 m/s, and a prooftesting device. The
prooftesting device preferably includes the first capstan device
(also known as the tractor capstan assembly) located downstream of
the furnace including at least one wheel and a motor for driving
the wheel at a first circumferential speed, and a second capstan
assembly including at least one wheel and a servo motor for driving
the wheel at a second circumferential speed so that the difference
between the first and second circumferential speeds creates a
desired proof testing tensile stress which is applied to the fiber.
A load cell is preferably operatively connected to the fiber (e.g.,
between the two capstans) for monitoring tension in the fiber. A
computer control is provided for receiving input from the load cell
and adjusting the speed of the first or second capstan assemblies
to aid in maintaining a uniform tensile stress or within a desired
range of tensile stress.
[0012] The automatic rewinding methods and apparatus described
herein enable a number of advantages over the prior art. For one
thing, by using the aspirator and guide finger in the manner and
method disclosed herein to rethread the optical fiber through
various components of the fiber winding system, fiber can
continuously be removed and discarded from the manufacturing
process as it is simultaneously being threaded through the system.
Consequently, the supply of fiber does not have to be stopped in
order to rewind or rethread the system. Using the techniques
disclosed herein, an entire on-line winding system, including an
on-line prooftesting section, can be rewound in less than 10
seconds. In fact, using the methods and apparatus disclosed herein,
rewinding of the entire fiber winding system, including an on-line
fiber tensile strength screening device, has been achieved on line
during a experimental fiber draw operation in less than 7 seconds.
This includes providing a fresh shipping spool, guiding the fiber
into winding engagement with the new spool, and beginning winding
of the fiber to the new spool. Because the present invention
enables rethreading of the fiber winding system in such a short
period of time, on-line proof testing can be achieved, even at draw
speed of 25-30 m/sec. or more, without having to worry about losing
a significant amount of fiber.
[0013] On-line screening of the fiber in turn enables the fiber to
be wound directly onto shipping spools, rather than large bulk
storage spools, thus greatly reducing or even totally eliminating
the costs associated with the previous method of drawing the fiber
onto a bulk spool, conducting off-line proof-testing, and then
winding the fiber onto shipping spools.
[0014] By winding the fiber onto a spool capable of providing
access to both ends of the fiber, and by selecting the length of
fiber wound on the spool to be short enough (e.g. less than 150 km,
more preferably less than 100 km, and most preferably less than 75
km), any optical measurements that are to be conducted on the fiber
can be done while the fiber is stored on the spool. Consequently,
the fiber can be drawn from an optical fiber preform at high speed
(e.g., greater than 20, more preferably greater than 25, and most
preferably greater than 30 m/s), tensile tested during the fiber
draw process, and then wound onto a fiber storage spool. The fiber
could then be tested offline while stored on the fiber storage
spool for any additional (e.g. other optical) desired measurements,
and then shipped directly to a customer (e.g. a fiber optic cable
company who then cables various strands of optical fiber into an
optical fiber cable) without ever having to rewind the fiber onto a
different spool.
[0015] Also, because the automatic rewinding methods and apparatus
disclosed herein greatly facilitate and speed up the fiber
rewinding process, fiber can now be selectively removed during the
fiber draw operation if desired without the loss of significant
amounts of fiber. For example, if fiber is detected that has a
diameter (e.g. fiber or coating diameter) that is out of
specification, the defective fiber can be cut, and the bad fiber
allowed to be collected and discarded into the aspirator, until
good (i.e., in specification) fiber is again detected, after which
time the fiber is wound onto the ondraw sceener and onto a fiber
storage spool.
[0016] Additional features and advantages of the invention will be
set forth in the detailed description which follows, and in part
will be readily apparent to those skilled in the art from that
description or recognized by practicing the invention as described
herein, including the detailed description which follows, the
claims, as well as the appended drawings.
[0017] It is to be understood that both the foregoing general
description and the following detailed description are merely
exemplary of the invention, and are intended to provide an overview
or framework for understanding the nature and character of the
invention as it is claimed. The accompanying drawings are included
to provide a further understanding of the invention, and are
incorporated in and constitute a part of this specification. The
drawings illustrate various embodiments of the invention, and
together with the description serve to explain the principles and
operation of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a perspective view of a preferred embodiment of a
winding apparatus according to the present invention.
[0019] FIG. 2 is an enlarged perspective view of the screener
section of the winding apparatus of FIG. 1.
[0020] FIG. 3 is an enlarged perspective view of the spool winding
section of the winding apparatus of FIG. 1.
[0021] FIGS. 4A-4E are top plan views of the winding apparatus of
FIG. 1, illustrating the optical fiber being threaded onto the
screener capstan.
[0022] FIGS. 5A-5C are top plan views of the winding apparatus of
FIG. 1, illustrating threading of the optical fiber through the
winder section.
[0023] FIG. 6 illustrates a preferred fiber storage spool for use
in accordance with the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0024] FIGS. 1, 2, and 3 illustrate a preferred optical fiber
winding system 10 in accordance with the present invention, wherein
optical fiber 8 is drawn directly from an optical fiber preform or
draw blank in an optical fiber draw process. As illustrated in FIG.
1, the major components of the system include a screening section
12, where the fiber is proof tested, and a winding section 14,
where the fiber is wound onto a fiber storage spool 15.
[0025] The fiber is mechanically stressed a desired amount (i.e.,
proof tested) while traveling through screener section 12 which is
illustrated in FIGS. 1 and 2. The fiber is then wrapped directly
onto spool 15 in fiber winder section 14, illustrated in FIGS. 1
and 3. Spool 15 preferably is a shipping spool which is either to
be shipped directly to a customer, which may be a purchaser of
optical fiber and/or a cable manufacturing plant to be cabled
directly without having to be respooled onto another fiber storage
spool. In this way, from the time the fiber is first drawn into an
optical fiber until the fiber is cabled into an optical fiber
cable, the fiber may be stored on a single storage spool, without
having to endure transfer to successive storage spools, between the
time at which the fiber is manufactured and the time the fiber is
shipped to a customer, to enable various testing procedures.
[0026] A preferred optical fiber storage spool which may be used in
accordance with the invention is illustrated in FIGS. 6A and 6B,
which show, respectively, side and bottom views of preferred
shipping spool 15. As shown in FIG. 6, the spool 15 includes a
primary barrel portion 60, and lead meter barrel portion 62, and an
angled slot 64 through which fiber can be fed during the winding
process from the lead meter portion 64 to the primary barrel
portion 62, or vice versa depending on desired winding techniques.
Such spools are described further, for example, in U.S. patent Ser.
No. 09/438,112, filed Nov. 10, 1999, titled System and Method for
Providing Under-Wrap Access to Optical Fiber Wound Onto Spools,
which claims the benefit of U.S. Provisional Application No.
60/114,516, filed Dec. 30, 1998, and No. 60/115,540, filed Jan. 12,
1999, the specification of which is hereby incorporated by
reference. In a preferred embodiment of the invention, the fiber is
fed onto spool 15 beginning at lead meter barrel portion 62. When a
desired amount of fiber has been stored on the lead meter portion
62, the fiber is then fed through the slot and onto primary barrel
portion 60, and a desired amount of fiber is then wound onto
primary barrel portion 60. Once the spool is full and/or a desired
amount of fiber is contained within the primary barrel portion 60,
the fiber is cut, e.g. between the fiber winding system and the
fiber screening system and rotating turret 40 indexes 180 degrees
to provide another empty storage spool 15 onto which fiber can
again be wound. The previously filled spool is then removed, and an
empty spool loaded in its place, and so forth, so that when the
newly provided empty spool is filled, the next spool will ready,
and so forth. One reason shipping spool 15 is preferred is that
fiber may be stored on spool 15 in a manner which enables access to
both ends of the fiber. Because the spool enables access to both
ends of the fiber, optical and other testing can be conducted on
the fiber which is stored on spool 15 after the fiber draw and
winding process, without having to remove the entire length of
fiber from the spool or rethread the fiber onto a different
spool.
[0027] The system also includes aspirator 16, illustrated in FIGS.
1 and 2, which is used to remove scrap fiber from the process as
well as to facilitate automated threading of the fiber onto the
various components of the system at the beginning of the draw
operation or after a fiber break, of after the fiber is
intentionally cut, as will be further described below. As can be
seen in FIGS. 1 and 2, aspirator 16 consists basically of a
cylindrical tube such as a vacuum hose, and is movably attached to
vertical support member 17 along which the aspirator can be moved
in an upward or downward path. Such aspirators can, for example,
use compressed air to provide the sucking force needed to suck
fiber into aspirator 16. Preferably the compressed air has a
velocity which is high enough to provide sufficient tension to
capture and control movement of the fiber throughout the winding
system as it is being rethreaded, as well as to convey away any
scrap fiber. Vertical support member 17 is in turn movably mounted
on transverse support member 18, which in turn is movably mounted
on main aspirator support frame 19. In this way the aspirator can
be moved in 3 dimensions, e.g., the aspirator can be moved closer
to or further away from screener section 12 by the sliding of
transverse support member 18 along the main support frame 19. The
aspirator 16 can also be moved transverse to the main support frame
(toward or away from the back of the machine system, i.e., parallel
to the axis of the indexing spool winding 40) by sliding of the
vertical suport member 17 along transverse support member 18.
[0028] Operation of the fiber winding system in accordance with the
present invention is preferably controlled via a computer control
system, which may be programmed to respond to various inputs, which
may be either automatically sent from the winding system or
manually inputted by a machine operator.
[0029] During the fiber draw operation, an optical fiber draw blank
(also known as an optical fiber preform) is mounted in a draw
furnace (not shown), and the temperature in the furnace is raised
to a temperature suitable for drawing optical fiber from the
preform. As can be seen in FIG. 2, screener section 12 includes a
pair of capstan assemblies 20 and 24, each of which consist of a
large capstan wheel and a belt which is in engagement with a
portion of the circumference of the large capstan wheel. The belt
is also supported by three smaller wheels, which are positioned so
that the belt is held firmly against the larger capstan wheels. As
used generally herein, capstan refers to such capstan assemblies as
are illustrated in FIG. 2, although alternative capstan assemblies
could also be employed without detracting from the spirit of the
invention. Optical fiber 8 is pulled from the drawblank during the
fiber draw operation by belted capstan 20, also known as and
referred to herein as the tractor capstan, illustrated in FIG. 2.
The speed of belted capstan 20 can be controlled by suitable
control means to achieve a desired speed for drawing the fiber.
[0030] As shown in FIG. 2, in the embodiment illustrated, the fiber
exits tractor capstan 20 and wraps 180 degrees around turnaround
pulley 22. Turnaround pulley 22 has a recessed groove around its
periphery within which the fiber 8 is retained. Turnaround pulley
22 is connected to a load cell which monitors the amount of tension
applied onto the turnaround pulley by the passing fiber, and thus
monitors the amount of tension being imparted to the fiber. From
turnaround pulley 22, the fiber enters belted screener capstan 24.
In the embodiment illustrated the screener capstan 24 is
electronically "slaved" to tractor capstan 20 so that at all times
it rotates slightly faster than tractor capstan 20. The speed
differential between screener capstan 24 and tractor capstan 20 is
maintained at a magnitude, which causes a desired amount of strain
within the fiber. The strain imparted to the fiber is directly
proportional to the tensile stress in the fiber. Any tension
present in the fiber prior to entering the tractor capstan 20 is
added to the tension caused by the differential speed of the two
capstans 20 and 24. Depending on the speed at which the fiber is
being drawn, the incoming tension during a normal blank run can
vary by as much as 30 kpsi. Consequently, in a preferred
embodiment, feedback from the load cell of the turnaround pulley 22
is used to adjust the differential speed of the screening capstan
24 so that a sufficient screening tension is maintained
consistently throughout drawing of the entire optical fiber blank
into optical fiber.
[0031] During the fiber draw process, fiber exits screener capstan
24 in screening section 12 and proceeds to winding section 14,
which is illustrated in FIG. 3. In the embodiment illustrated, the
fiber leaves screening capstan 24 in FIG. 2 at an angle which is
approximately 30 degrees to the manufacturing plant floor, and
proceeds to the winding section 14 illustrated in FIG. 3. At
winding section 14, the fiber 8 is wound through four process
pulleys 30a-30d before being wound onto fiber storage spool 15. In
the embodiment illustrated, the first three process pulleys 30a-30c
are disposed substantially within the same plane as the incoming
fiber, in this case 30 degrees relative to the plant floor. The
fiber wraps 90 degrees around the first pulley 30a and then 180
degrees around second pulley 30b, which is a dancer pulley. Dancer
pulley 30b is attached to a pivot arm 32. Such dancer pulley
mechanisms are described further, for example, in U.S. patent
application Ser. No. 09/390,866, filed September 7, titled Passive
Tension Regulator, the specification of which is hereby
incorporated by reference.
[0032] From dancer pulley 30b, the fiber wraps 90 degrees around
third pulley 30c and then around fourth pulley 30d, whose axis of
rotation is perpendicular to that of the first three pulleys
30a-30c. The fiber wraps approximately 45 degrees around the fourth
pulley 30d and then continues to the take up spool 15. Pulley 30d
is oriented to redirect and guide fiber 8 onto take up spool 15.
The third and fourth pulleys 30c and 30d are both mounted on
traversing carriage 34 which traverse back and forth parallel to
the axis of the take up spool 15 during the fiber winding operation
to result in uniform winding of the fiber onto spool 15. Carriage
34 moves back and forth along a support bar (not shown),
reciprocating parallel to the axis of spool 15. The movement of
carriage 34 is preferably controlled via computer.
[0033] During the winding of the fiber onto spool 15, a constant
torque is applied to the dancer pivot arm 32 in a direction which
is opposite, or away from, first pulley 30a. Such a torque may be
provide, for example, via a hydraulic air cylinder attached to
dancer pivot arm 32. The torque applied to dancer pivot arm 32 and
the speed with which the spool is rotated are controlled so as to
wind the fiber onto the spool with a uniform winding tension
applied to the fiber.
[0034] The angular position of dancer arm 32 is monitored and
employed in conjunction with a control computer to control the
rotating take up speed of the spool 15. A sensor senses the angular
position of the second pulley 30b. In a preferred embodiment, the
sensor is an RVDT. The position of the second or dancer pulley 30b
is used to determine the difference between the speed at which the
optical fiber is being supplied from screener section 12 and the
speed at which the optical fiber is being wound on a spool. The
speed at which the spool 15 is rotating can then be adjusted
according to the speed of the optical fiber being supplied from
screener section 12, so that the fiber is wound under the spool 15
with a uniform amount of tension. The vertical position of the
second pulley 30b is also used to detect a break in the optical
fiber, as the load cell attached to the second pulley 30b will
register zero load when the optical fiber breaks.
[0035] As illustrated in FIG. 1, winder section 14 includes two
independent spindles which each retain a take up spool 15. The
spindles are mounted 180 degrees apart on an indexing turret 40.
Winding of fiber only occurs to the spindle that is in the upper
position. The lower position is used to hold an empty spool that is
ready in the event of a fiber break.
[0036] The breaks that occur during a fiber draw operation can be
broken down into two basic categories, pre-screener breaks, which
are breaks that occur in the fiber before the fiber has reached the
screener capstan 24, and post-screener breaks, which are breaks
that occur in the fiber after the fiber has passed the screener
capstan 24. By monitoring the load cells attached to turnaround
pulley 20 and the position of dancer arm 32, the control computer
can control operation of the winding system and react to breaks
which occur at various points in the winding operation. For
example, when a pre-screener break occurs, the load cell on
turnaround pulley 22 will almost immediately register zero load.
Consequently, when the computer senses that the load at turnaround
pulley is zero, the computer initiates a control sequence for
rethreading of the fiber through the screener capstan as well as
the remainder of the winding system.
[0037] In a preferred embodiment of the invention, several
simultaneous fiber threading actions occur at the screening section
and at the winding section of the machine when a pre-screener break
is detected. The actions at the screener section will be described
first, followed by the winder section description.
[0038] Threading of the Screener Section:
[0039] In normal operational mode, while fiber is being drawn and
wound onto spool 15, the nozzle of aspirator 16 is positioned
adjacent the fiber path as it exits tractor capstan 20 traveling
toward winder section 14. When a fiber break occurs between the
tractor and screener capstan, the fiber down stream of the break is
pulled through the four remaining process pulleys downstream and
onto the take up spool. The computer immediately detects the fiber
break via the turnaround pulley load cell, registering zero load.
With nothing to guide it, fiber exiting the tractor capstan is
pushed out from the capstan in a straight line. Aspirator 16 may be
positioned such that the fiber streaming from the tractor capstan
will be sucked into the nozzle of the aspirator 16, as illustrated
in FIG. 4A. Alternatively, aspirator 16 can be positioned at a
location which is remote from the path of the fiber, and after a
fiber break occurs, the aspirator can be moved into a position in
which it collects the fiber.
[0040] High pressure air is supplied to the aspirator 16 from an
electronically controlled proportional air valve, and the pressure
to aspirator 16 creates a vacuum at the aspirator nozzle, and the
vacuum pulls the fiber into the aspirator 16. The fiber exits the
aspirator into a fiber collection can. The amount of time between a
prescreener break and acquisition of the fiber by the aspirator is
only a fraction of a second due to the fact that the aspirator is
positioned nearly in line with the path of the fiber during normal
winding operation. Of course, the aspirator could be positioned
further away from the path of the incoming fiber and the aspirator
vacuum increased until such time as the fiber is captured by the
aspirator.
[0041] Consequently, almost immediately after a prescreener break
occurs, the fiber is being sucked into aspirator 16. The aspirator
is then moved in accordance with the invention to facilitate
rethreading of the fiber through the screener capstan. As
illustrated in FIG. 1, the aspirator is movable along three
motorized linear axes 17, 18 and 19 (and thereby is movable in
three dimensions) to facilitate threading of the entire
machine.
[0042] The screener capstan rethreading sequence is illustrated
with reference to FIGS. 1 and 4A-4E. It should be noted that FIGS.
4A-4E are only schematic, and actual relative dimensions have been
altered to facilitate illustrations of the invention. Once fiber 8
is acquired by aspirator 16, a rethreading sequence is initiated to
rethread the turnaround pulley 22 and the screener capstan 24. To
accomplish this, the aspirator may be positioned or moved to be
positioned essentially in line with fiber exiting the tractor
capstan, as illustrated in FIG. 4A, so that the aspirator begins to
collect the fiber exiting the capstan 24. The aspirator is then
moved along transverse support member 18 to guide the fiber onto
the groove of turnaround pulley 22 and wrap the fiber around 90
degrees of turnaround pulley 22, as illustrated in FIG. 4B.
Threading of the final 90 degrees of turnaround pulley 22 and the
screener capstan is preferably done using a guide finger system 44,
as shown in FIG. 2. Guide finger system 44 consists of at least
one, and preferably a pair of guide fingers 45a and 45b. These
finger-like guide fingers do not grasp the fiber, but rather enable
the fiber to slide around their outer periphery and into the
aspirator, where it is continuously discarded. This process
facilitates rethreading of the fiber while the fiber continues to
be drawn during the fiber draw operation. The guide fingers may be
for example, a pair of cylindrical metal tubes which may or may not
be rotatable around their axis to facility transport of the fiber
over the surface of the guide fingers. The guide fingers are moved
up and down via Z-axis support bars 46 and back and forward (left
and right) along X-axis support member 47, by pneumatic slides. The
second guide finger 45b also has a pneumatic slide 48 that allows
motion in and out (Y axis). The guide fingers 45a and 45b are in
the Z-up, X-forward (toward the winder section), and Y-in position,
as illustrated in FIG. 2, prior to the initiation of the
rethreading sequence. Once the aspirator has threaded 90 degrees of
turnaround pulley 22, the guide fingers are moved to the Z down
position so that both guide fingers are behind the line of fiber
going into the aspirator from the turnaround pulley, as illustrated
in FIG. 4B.
[0043] The guide fingers 45a and 45b are then moved toward the
X-back (away from the winder section) position so that threading of
the screener capstan can take place. As the guide fingers 45a and
45b are moved in this manner, guide finger 45a engages fiber 8 and
moves it toward screener capstan 24. At the same time, guide
fingers 45a and 45b are moving to rethread the screener capstan 24,
aspirator 16 begins moving toward the winder section 14 to begin
rethreading of winder section 14, as illustrated in FIG. 4C. This
action allows for faster rethreading of the entire system as two
portions of the machine, the screener section 12 and the winder
section 14, are being threaded simultaneously. Guide fingers 45a
and 45b continue until first guide finger 45a is adjacent screener
capstan 24, at which point the fiber path is almost 180 degrees
around turnaround pulley 22, 180 degrees around first guide finger
45a, and into the aspirator which is still moving to a position
behind the fiber take up spool 15 as illustrated in FIG. 4D. At
this point, the second guide finger 45b moves to the Y-out position
i.e., toward screener capstan 24, as illustrated in FIG. 4E. Guide
finger 45b urges the fiber into the area of the screener capstan
where the belt and the capstan meet. The screener capstan may also
be provided with one or more nubs or snagger hooks that are
positioned on the outer diameter of the capstan. As the capstan
rotates, the nubs can help urge the fiber into the area where the
belt and capstan meet. Once the fiber is captured between the belt
and capstan, the fiber is carried around the capstan, below and out
of engagement with the first guide finger 45a as it is carried
around the screener capstan. At this point guide finger 45b
retracts, and the threading of screener section 12 is complete,
with the fiber traveling around turnaround pulley 22 and screener
capstan 24. The result is that the turnaround pulley 22 and
screener capstan 24 are threaded without breaking the line of
fiber, which is traveling into the aspirator. Guide fingers 45a and
45b are then returned to the Y-in, Z-up, and X-forward
positions.
[0044] Threading of the Winder Section
[0045] Threading of the winder section 14 preferably takes place
simultaneous with the threading of the screener section 12. Thus,
referring to FIG. 3, when a pre-screener break is detected by the
turnaround pulley 22 load cell, the first actions of winder section
14 occur simultaneously to facilitate threading of the winding
section by the aspirator. In FIG. 3, a pair of rotatable fiber
storage spools 15 are mounted 180 degrees apart on turret 40. In
the embodiment illustrated, only one of the spools 15 is visible,
and is collecting fiber being supplied via the fiber draw process.
The other fiber storage spool 15 is positioned 180 degrees, or
directly underneath the spool 15 which is visible. The other spool
15 is empty and ready to be moved into position to receive fiber
from the fiber draw process. Also visible in FIG. 3 is dancer
platform 56, upon which dancer pulley 32 is mounted. Dancer
platform 56 is movable along a transverse slide (not shown), from
the closed position illustrated, in which dancer pulley 32 is
engaging fiber 8 and forcing fiber 8 to take a serpentine path, to
an open position, in which dancer pulley 32 is moved and positioned
on the other side of the path of fiber 8. In FIG. 3, dancer pulley
32 is shown in the closed position. Likewise, pulley 30c is mounted
on a traverse (not shown), which is capable of moving pulley 30c
into and out of engaging position with the path of fiber 8. As
mentioned above, while the guide fingers 45a and 45b are moving the
fiber 8 toward screener capstan 24 to thread the screener 24,
aspirator 16 and thus fiber 8 are simultaneously moved toward the
winding section 14. At the same time, three things preferably occur
simultaneously:
[0046] (1) the winder turret 40 indexes 180 degrees so that a new
empty fiber storage spool 15 is in place for winding;
[0047] (2) the new spool 15 begins rotating slightly faster than
the linear speed of the incoming fiber; and
[0048] (3) the pulley 30a, dancer pulley 30b and pulley 30c are
moved on their respective traverse slides into an open position (as
shown in FIG. 5a) to enable threading of the fiber 8 through winder
section 14. For this to occur pulley 30c is moved along its own
pneumatic slide toward a position outboard of the fiber path.
[0049] The dancer stops 33 come together to hold the dancer arm 32
in a fixed position, and the dancer slide (not shown) moves the
dancer platform 34 toward the inboard position of the path to be
taken by the fiber. Pulley 30a is moved along pneumatic slide 57 to
a position outboard of the path to be taken by the fiber.
[0050] As can be seen in FIG. 3, the winder section was designed so
that the aspirator 16 can pass freely above all of the winder
components while fiber is being pulled into the aspirator nozzle.
The aspirator 16 moves to a position that is above and behind the
take up spool 15. Aspirator 15 then moves downward, guiding the
fiber 8 onto the fourth process pulley 30d. The aspirator continues
moving down until the line of fiber coming from pulley #4 is
tangent to the barrel of the take up spool. At this point the
winding section is as illustrated in FIG. 5a.
[0051] When the aspirator has threaded fiber 8 onto the pulley 30d
and the fiber is tangent to the barrel of the spool 15, pulleys
30a, 30b, and 30c are moved to their normal run position. Thus, as
illustrated in FIG. 5b, pulleys 30a and 30b move into contact with
the fiber. The dancer slide then moves the dancer pulley 30b toward
a position which is outboard of the path of the fiber. This action
brings the fiber path to its normal running position illustrated in
FIG. 5b, namely, approximately 90 degrees around pulley 30a, 180
degrees around pulley 30b, 90 degrees around pulley 30c and
approximately 15 degrees around pulley 30d. The dancer stops are
moved to their run position and the dancer is forced to the
outboard stop.
[0052] Spool 15 is then traversed to bring the fiber into contact
with a snagger tooth 58, which is present on the flange of spool
15. The fiber is wedged into the snagger and cut, separating the
fiber from the aspirator and beginning the winding of the fiber
onto spool 15. The dancer is initially pulled toward the inboard
position of the winder due to the over spinning of the take up
spool. The speed of the rotation of the take up spool 15 may be
controlled by the dancer position and the speed adjusted so that
the dancer arm is pulled to a nominal running position. The
aspirator then moves back to the staged position, which is
proximate to in line with the fiber exiting the tractor
capstan.
[0053] The spool that was taking up fiber before the break is
automatically unloaded from the bottom of the winder turret 40, and
a new empty spool is loaded into the spindle. The machine is then
ready for the next fiber break event.
[0054] Cases also exist where the fiber is broken somewhere between
the screener capstan and the take up spool. The first case may be
when the take up spool is full. A second case occurs when the fiber
is detected that is out of specification (e.g. the diameter is too
large or too small). In either of these two cases, an automatic
fiber cutter 36 intentionally cuts the fiber. Such a mechanical
cutting device may be positioned, for example, just before the
fiber enters the first process pulley 30a. A third case of a post
screener break occur when something unexpected causes the fiber-to
break (stray fiber, nicked process pulley, etc. . . . ) after the
screener capstan 24.
[0055] The only difference in the threading sequence between a post
screener break and a pre-screener break is that the screener
section does not need to be rethreaded. In the case of a post
screener break, the fiber is carried out of the screener capstan in
a straight line. The aspirator is moved to a position adjacent the
screener capstan so that the fiber can be captured by its vacuum.
Once captured, the machine goes through the winder section
threading sequences described above, as if it were a screener
break, except that no actions need be performed to thread the
screener capstan since it is still threaded.
[0056] A control system for controlling the winding apparatus 10 to
perform the abovementioned threading and winding operations is
preferably also provided. The control system preferably includes a
programmable logic controller to control the operation of the
various sequence of events, monitor all of the sensors (e.g., the
load cell on turnaround pulley 20 and the load applied by the fiber
to dancer 34). The logic controller may also be used to control air
cylinders which are used to move various components (e.g. pulleys
30a-30c) into position, as well as to communicate with a motion
control computer. The motion control computer preferably controls
and monitors the moving mechanisms such as aspirator 16, guide
fingers 45A and 45b.
[0057] It will be apparent to those skilled in the art that various
modifications and variations can be made to the present invention
without departing from the spirit and scope of the invention. Thus,
it is intended that the present invention cover the modifications
and variations of this invention provided they come within the
scope of the appended claims and their equivalents.
* * * * *