Adhesive bonding and miscellaneous chemical manufacture – Surface bonding means and/or assembly means therefor – Indefinite or running length flexible strand – rod – tube – or...
Reexamination Certificate
2002-06-10
2004-06-01
Aftergut, Jeff H. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Surface bonding means and/or assembly means therefor
Indefinite or running length flexible strand, rod, tube, or...
C156S441000, C156S502000, C057S022000, C057S023000, C057S350000
Reexamination Certificate
active
06742560
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a flat fiber bundle and to a method and an apparatus for manufacturing the same.
2. Description of the Related Art
In the case where non-twisted multifilament (long staple fiber) yarns (fiber bundle) are used as reinforcement fibers for producing a fiber reinforced composite structure, there is a method such as a filament winding method wherein a fiber bundle is impregnated with a solution of resin and wound on a mandrel, and the resin is then cured. There is also a method wherein a three-dimensional woven fabric (three-dimensional fibrous structure) is formed of fiber bundles, impregnated with a solution of resin, and the resin is then cured.
When the non-twisted fiber bundle is wound, for example, on the mandrel, the fiber bundle is wound in a flat condition due to a winding force. Similarly, when the three-dimensional fibrous structure is manufactured, a fibrous layer constituting the three-dimensional fibrous structure is compressed for the purpose of increasing the content of reinforcement fibers per unit volume, whereby the fiber bundle becomes flat in shape.
In the case where the fiber reinforced composite structure is manufactured by the filament winding method, or when the three-dimensional fibrous structure is used as a reinforcement material of the fiber reinforced composite structure, it is preferable to arrange the fiber bundles in an opened state from the beginning to ensure physical properties of the resultant composite structure. In this regard, the opened state refers to a state wherein filaments constituting the fiber bundle are spread in the widthwise direction to flatten the fiber bundle.
In the filament winding method or the method for the production of three-dimensional fibrous structure, since the fiber bundle is unwound from the bobbin, it is necessary to join the fiber bundle on the bobbin to a fiber bundle on the next bobbin before the former has been completely exhausted. If the fiber bundles are joined by forming a knot as in the piecing of ordinary yarns, knots remain in the resultant product in a non-opened state and the physical property of the product is deteriorated. Therefore, a method has been proposed wherein ends of fiber bundles are joined together, by the entanglement of filaments, without using knotting.
For example, Japanese Unexamined Patent Publication (Kokai) No. 51-147569 discloses a method for joining strands of a plurality of continuous fibers by overlapping ends of the strands with each other and applying an air stream to the overlapped portion to cause the filaments therein to be entangled with each other. The joining apparatus used for this purpose is shown in
FIG. 16A
in the attached drawings, and comprises a tubular casing
81
having a substantially vertical air inlet port
82
positioned in the casing at the center thereof, a pair or more of air exit ports
83
on the opposite ends of the casing, and a pair of gripper sections
85
for gripping strands
94
so that the center of the overlapped portion of the strands is at the center of the casing.
Also, Japanese Unexamined Patent Publication (Kokai) No. 6-100246 discloses an apparatus for joining fiber bundles wherein ends of two fiber bundles are overlapped with each other and air is injected to the overlapped portion to cause filaments forming the fiber bundles to be entangled, as shown in
FIG. 17
of the attached drawings. This apparatus comprises an apparatus body
86
having a supporting section
89
, and a cover plate
88
coupled to the apparatus body
86
by a hinge
87
. A plurality of elongated flow control plates
90
are arranged on the supporting section
89
in parallel to each other at a predetermined interval so that the short sides thereof extend vertically. The outermost flow control plate
90
is slightly higher than the others.
The cover plate
88
is provided with a rectangularly annular fiber holding member
92
having an air blowing window
91
. The fiber holding member
92
is provided with a plurality of pressing thin rods
94
fixed at opposite ends thereof to a pair of support rods
93
arranged parallel to the flow control plates
90
, and an air injection nozzle
95
. The air injection nozzle
95
is movable in the direction perpendicular to the flow control plates
90
. Two fiber bundles (not shown) are placed on the support section
89
with the ends thereof in an overlapped state and after the cover plate
88
is placed on the apparatus body
86
, the fiber bundles are joined together by injecting air from the air ejection nozzle
95
which is moved in the direction perpendicular to the flow control plates
90
.
In the joining method disclosed in Japanese Unexamined Patent Publication No. 51-147569, portions of the joined strands in the vicinity of the gripped portions are narrowed, as shown in
FIG. 16B
, since the joining operation is carried out by rotating the portion of the strands in the tubular casing
81
as a whole by the turbulent air stream impinging on the central region of the strands. Filaments in the narrowed portions are difficult to open, and if such a joined region is inserted and mixed in the resultant composite structure, a matrix-rich portion is generated to deteriorate the physical property of the manufactured product. If the narrowed portions are in a state to be readily opened, the connecting strength is lowered.
On the contrary, in the method disclosed in Japanese Unexamined Patent Publication No. 6-100246, the fiber bundles to be joined are acted on by air while the ends of fiber bundles are in a free condition and portions of the fiber bundles adjacent to the overlapped portion are held. The fibers are prevented from moving in the lateral direction (perpendicular to the lengthwise direction of the filaments), by the action of the flow control plates
90
, and the filaments are entangled with each other without dispersing in the lateral direction, resulting in the improvement of the withdrawing strength. However, since the fiber bundles are subjected to the air action while the ends of the fiber bundles are in a free state, the orientation of the filaments in the joined region is largely disturbed, and the physical property of the resultant composite, structure is deteriorated.
Also, in the prior art, there is a three-dimensional fibrous structure for reinforcing a composite structure formed by a plurality of cloth sheets superposed on each other with a fastening thread. The cloth sheet is convenient for handling and is easily laid on a curved surface. However, since at least one of warp yarns and weft yarns forming the cloth sheet are arranged in a meandering manner, the physical property of the resultant composite structure is deteriorated in comparison with that using a reinforcement material in which filaments forming each of layers are linearly arranged. Accordingly, if there was a one-directional material convenient in handling such as the cloth sheet and having filaments linearly arranged in one plane, a three-dimensional structure excellent in physical property would be easily obtainable.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above-mentioned problems in the prior art, and the first object of the present invention is to provide a fiber bundle which can be easily handled and which is formed by joining a plurality of flat fiber bundles of non-twisted filaments, wherein filaments in the joined region of the fiber bundles are movable in the direction perpendicular to the filament-extending direction to have a large degree of freedom in shape but not too loose.
The second object of the present invention is to provide a method for joining fiber bundles.
The third object of the present invention is to provide a method for joining two flat fiber bundles of non-twisted filaments so that a degree of freedom in the shape is large even in the joined region and the ease of handling is not lowered.
The fourth object of the present invention is to provide an apparatus for joining fiber bundles in a
Miyashita Yasuki
Takeuchi Junji
Yasui Yoshiharu
Aftergut Jeff H.
Kabushiki Kaisha Toyoda Jidoshokki Seisakusho
Kilkenny Todd J
Morgan & Finnegan , LLP
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