Package containing optical fibres made of glass and apparatus for packing glass optical fibres

Package containing a glass optical fiber and apparatus for packaging glass optical fibres. A package containing optical fibres, made of glass, consists of two plates between which the optical fiber is wound in a double helix pattern. Such a package is compact and enables unwinding of the optical fibers without stresses. In addition, the optical fiber can be tested for continuity in the package and during unwinding. The invention further relates to an apparatus for producing such a package.

BACKGROUND OF THE INVENTION 
The invention relates to a package of and apparatus for packing glass 
optical fibers. 
Packages of optical fibers may be used as an intermediate product during 
the production of conductive optical fiber cables. 
It is known from the German Patent Application No. 2701650 to unwind 
optical fibers, which were previously coated with a protective layer, from 
a reel, or to pull them from a holder before working of the glass fiber. 
Because of the relatively big core, only a limited quantity of optical 
fiber can be wound on a reel in proportion to the volume of the reel. 
Feeding the optical fiber into a holder and pulling it out again easily 
results in torsional stresses and kinks (sharp bends) in the optical 
fiber, which greatly reduce the optical properties of the optical fibers. 
SUMMARY OF THE INVENTION 
The invention provides an improved package of optical fibers, which is 
easily obtainable immediately after drawing and/or coating of the optical 
fiber before it is made into a cable. 
According to the invention, the package optical fibers comprises two plates 
between which the optical fibers are wound in accordance with a double 
helix pattern. 
In order to fix the optical fibers in the package at least to some extent, 
one or both of the two plates is preferably provided with a fibrous 
surface at the side facing the optical fiber. For an optimum utilization 
of space, the two plates are preferably circular. With the package 
according to the invention the helices are compressed so that the pitch is 
substantially equal to the thickness of the optical fiber. The diameter of 
at least one of the helices is preferably larger than half the diameter of 
the disk; in this embodiment the possibility that the optical fibers get 
tangled is then substantially reduced to zero. For the last-mentioned 
embodiment, in accordance with a preferred embodiment, the thickness of at 
least the plate on which the optical fibers are located decreases from the 
edges to the center to compensate for the thickness of the heap of glass 
fibers, which is thicker in the center. 
The invention also relates to an apparatus for packaging optical fibers by 
means of which package of the above-mentioned type can be obtained. This 
apparatus comprises a feeder for the optical fibers. This feeder is 
capable of revolving around a first axis. Possibly, first axis is mounted 
to be capable of revolving around a second axis. The apparatus also 
comprises a support for a plate. When the first axis does not revolve 
around the second axis, the plate is mounted in a rotary manner around a 
second axis. All axes are arranged vertically, the first axis not being 
coaxial relative to either second axis. The feeder may consist of a pair 
of rollers. 
The invention is based on the recognition of the fact that a package 
containing an optical fiber arranged in accordance with a regular pattern 
between two plates can be easily unwound, free from stress in the optical 
fiber, and can be obtained in a simple way. In addition, such a package 
requires little space. An additional advantage is that the optical fiber 
can be tested for continuity in its package and during unwinding. This is 
not possible when the optical fiber is packaged "randomly" in a holder, 
owing to the kinks then occuring.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIGS. 1a and 1b, reference numeral 12 denotes a mass of 
optical fibers which are wound in a double helix pattern. The optical 
fibers 12 are disposed between two plates 10 and 20. FIG. 1b shows a 
special embodiment wherein, for clarity, it is shown in a highly 
exaggerated manner that the thickness of the plates 10 and 20 decreases 
from their edges to their centers to compensate for the greater thickness, 
in the center of the mass of optical fibers 12. 
The apparatus shown in FIG. 2 is comprised of a frame 1 to which a first 
axle 2 is attached via an arm 6. A feeder 9 for the optical fiber is 
attached to axle 2 via an arm 5. In the embodiment shown, the feeder 9 
comprises a pair of rollers. References 5' and 9' show, by means of a 
broken line, the positions of 5 and 9 after 180.degree. rotation around a 
first axis defined by axle 2. 
Alternatively, it is possible to connect axle 2 to the frame via a second 
axle 3 and an arm 8 (shown in the drawing by means of broken lines). In 
that event arm 6 is omitted. 
An axle 4, bearing a support 7 for plate 10 is also attached to the frame. 
FIG. 3 shows, in elevational view, loading of the optical fiber 11 on 
plate 10. 
When the apparatus shown in FIG. 2 is used, feeder 9 is rotated around axle 
2 the first axis defined by optical fiber 11 being simultaneously fed 
forward. At the same time, axis 2 rotates around a second axis defined by 
axle 3 or plate 10 rotates around a second axis defined by axle 4. As soon 
as a sufficient length of optical fiber has been deposited on plate 10, 
plate 10 is removed from the support and a second plate 20, for example a 
foam rubber plate is placed on top of the heap of optical fibers 12. 
In order to fix the optical fibers on plate 10, the upper surface of plate 
10 has, preferably, a fibrous surface area. Plate 10 may consist of 
several types of material, such as wood, synthetic resin material and 
metal, a suitable material being foam rubber. 
If the optical fiber must be subjected to further operations, plate 20 is 
first removed from the package. Then the optical fiber is pulled from mass 
12. The optical fiber is then obtained stress-free and without kinks 
(sharp bends). 
It is possible to accommodate a length of 5 km of optical fibers (100.mu.m 
thick) in a layer thickness of only 1 mm on plate 10 when a circular plate 
10 having a diameter of 1 m is used. With fluctuations in the ambient 
temperature, the optical fiber continues to lie flat.