U.S. patent application number 11/438964 was filed with the patent office on 2007-11-29 for system and method for consolidating dry fabric around a mandrel.
This patent application is currently assigned to GKN Westland Aerospace, Inc.. Invention is credited to Robert Eric Baker, Stan Eckert, James R. Lander, Suzanne Looper, Tracey Kenneth Peters, Peter Shpik.
Application Number | 20070272346 11/438964 |
Document ID | / |
Family ID | 38441621 |
Filed Date | 2007-11-29 |
United States Patent
Application |
20070272346 |
Kind Code |
A1 |
Shpik; Peter ; et
al. |
November 29, 2007 |
System and method for consolidating dry fabric around a mandrel
Abstract
A system and method for wrapping fabric around a mandrel
including providing a drum of fabric and a mandrel, removing a
portion of the fabric from the drum and securing the fabric to the
mandrel, rotating the mandrel such that the fabric wraps around the
mandrel, and applying pressure to the fabric as the fabric is being
wrapped around the mandrel to consolidate the fabric about the
mandrel.
Inventors: |
Shpik; Peter; (Auburn,
AL) ; Eckert; Stan; (Pleasant Shade, TN) ;
Lander; James R.; (Mongomery, AL) ; Peters; Tracey
Kenneth; (Tallassee, AL) ; Looper; Suzanne;
(Montgomery, AL) ; Baker; Robert Eric; (Tallassee,
AL) |
Correspondence
Address: |
MCANDREWS HELD & MALLOY, LTD
500 WEST MADISON STREET, SUITE 3400
CHICAGO
IL
60661
US
|
Assignee: |
GKN Westland Aerospace,
Inc.
Tallassee
AL
|
Family ID: |
38441621 |
Appl. No.: |
11/438964 |
Filed: |
May 23, 2006 |
Current U.S.
Class: |
156/171 ;
156/184; 156/446 |
Current CPC
Class: |
B29C 53/566 20130101;
B29C 70/32 20130101; B65H 18/10 20130101; B65H 2301/414324
20130101; B65H 2301/414322 20130101; B29C 70/085 20130101; B29C
53/62 20130101; B65H 2701/177 20130101; B29C 53/8083 20130101 |
Class at
Publication: |
156/171 ;
156/184; 156/446 |
International
Class: |
B65H 81/00 20060101
B65H081/00 |
Claims
1. A system for wrapping fabric around a mandrel, comprising: a
sheet of fabric; a mandrel configured to receive said fabric; and
at least one tow line, wherein said sheet of said fabric is secured
to said mandrel and said tow line is secured to one of said fabric
and mandrel, said mandrel rotating such that said fabric and said
tow line are wrapped around said mandrel, said tow line being
configured to apply pressure to said fabric as said fabric is
wrapped around said mandrel.
2. The system of claim 1, further including a tensioning mechanism
that engages said tow line and applies tension to said tow line
such that said tow line applies pressure to said fabric.
3. The system of claim 1, wherein said tow line is carried on a
spool and as said tow line is wrapped around said mandrel, said tow
line is pulled from said spool.
4. The system of claim 1, wherein said sheet of fabric is carried
on a drum and said fabric is pulled from said drum as said fabric
is wrapped around said mandrel.
5. The system of claim 1, wherein said tow line is secured to said
fabric by a resin.
6. The system of claim 1, wherein said tow line is one of a fiber
strand and a fabric sheet.
7. The system of claim 1, further including a plurality of tow
lines.
8. The system of claim 1, wherein a resin is added to said fabric
to secure layers of said fabric theretogether as said fabric is
wrapped around said mandrel.
9. A system for wrapping fabric around a mandrel, comprising: a
sheet of fabric; a mandrel configured to receive said fabric,
wherein said sheet of said fabric is secured to said mandrel and
said mandrel rotates such that said fabric is wrapped around said
mandrel; and a roller head, said roller head including at least one
spring-loaded roller attached thereto, wherein said roller head is
configured to be positioned about said mandrel such that said
roller rotatably engages said fabric on said mandrel and applies
pressure to said fabric as said fabric is wrapped around said
mandrel.
10. The system of claim 9, wherein said roller is connected to a
spring.
11. The system of claim 9, wherein said roller head includes a
plurality of rollers.
12. The system of claim 9, further including a plurality of said
roller heads positioned about said mandrel to engage said fabric
and apply pressure to said fabric.
13. The system of claim 9, wherein said roller head is mounted to a
spring-loaded device.
14. A system for wrapping fabric around a mandrel, comprising: a
sheet of fabric; a mandrel configured to receive said fabric,
wherein said sheet of said fabric is secured to said mandrel and
said mandrel rotates such that said fabric is wrapped around said
mandrel; and a roller assembly, said roller assembly defining a gap
configured to receive said mandrel and including at least one
roller support along said gap, said roller support carrying at
least one spring-loaded roller attached thereto, wherein said
roller assembly is configured to be positioned about said mandrel
such that said mandrel is received in said gap and such that said
roller rotatably engages said fabric on said mandrel and applies
pressure to said fabric as said fabric is wrapped around said
mandrel.
15. The system of claim 14, wherein said roller support is a rail
carrying a plurality of rollers.
16. The system of claim 14, wherein said roller assembly includes a
plurality of roller supports carrying rollers positioned along a
perimeter of said gap such that said rollers engage said fabric as
said fabric is wrapped around said mandrel.
17. The system of claim 14, wherein said roller is connected to
said roller support by a spring.
18. A method for wrapping fabric around a mandrel, comprising:
providing a drum of fabric; providing a mandrel; removing a portion
of the fabric from the drum and securing the fabric to the mandrel;
rotating the mandrel such that the fabric wraps around the mandrel;
and applying pressure to the fabric as the fabric is being wrapped
around the mandrel to consolidate the fabric about the mandrel.
19. The method of claim 18, wherein said applying pressure step
comprises: securing a tow line to one of the fabric and mandrel;
wrapping the tow line about the mandrel with the fabric; and
applying tension to the tow line such that the tow line applies
pressure to the fabric as the fabric is being wrapped around the
mandrel.
20. The method of claim 18, wherein said applying pressure step
comprises: providing at least one spring-loaded roller; and
positioned the roller about the mandrel such that the roller
rotatably engages the fabric on the mandrel and applies pressure to
the fabric as the fabric is wrapped around the mandrel.
Description
BACKGROUND OF THE INVENTION
[0001] Embodiments of the present invention generally relate to a
system and method for making fiber preforms by consolidating dry
fiber fabric around a mandrel tool and, more particularly, to a
system and method for applying an external force to dry fabric as
it is consolidated in layers around a mandrel tool in order to
prevent the fabric from sagging, distorting, and moving during the
consolidation process.
[0002] In the composite industry, cylindrical fiber preforms made
of consolidated dry fiber fabric are used in numerous applications
requiring a sturdy, hollow, generally cylindrical structure, such
as a plane fuselage, a nacelle, the tail cone of a helicopter,
and/or a case. The fiber preforms are made by tightly wrapping a
sheet of dry fiber fabric, with the option of applying or
pre-applying a light adhesive/resin, around a generally cylindrical
mandrel in a series of layers--not unlike a long sheet of paper
towels being wrapped around a tube--until the wrapped fabric forms
a generally cylindrical structure having the desired thickness,
dimensions, and outer diameter for the intended application of the
fiber preform. Resin is then added to the bundle of fabric and the
structure is heat treated to consolidate and strengthen the fabric
into a structure. The fabric may be made of any number of fiber
materials such as carbon, glass, or other man-made or other natural
fibers, for example.
[0003] The fabric is typically tightly wrapped about the mandrel so
as to avoid any wrinkles or folds, which may compromise the overall
strength of the final fiber-preform structure. This fabric may
contain a small amount of resin applied thereto before or during
the wrapping process. However, as the fabric is wrapped around the
mandrel, and is overlapped around itself, the fabric can become
loose and move, bulky in areas, and in general, not tightly wrapped
around the mandrel. Therefore, periodically during the wrapping
process, the wrapped fabric has to undergo a consolidation process,
or a vacuum debulk process, where a solid sheet is placed over the
wrapped fabric. A vacuum is then created within the solid sheet
such that the fabric is pulled tight and consolidated. A heat
treatment process may be applied to assist in the consolidation
effort to bind and hold the structure intact. After the heat
treatment process, the solid sheet is then removed and the wrapping
process begins again. The vacuum debulk process is repeated several
times throughout the wrapping process, typically once after about
every five to seven layers are wrapped around the mandrel.
Therefore, for a fiber preform requiring 42 layers of fabric
wrapped around the mandrel, the process of wrapping the fabric will
have to be interrupted six to seven times so that the wrapped
fabric can undergo vacuum debulking and the consolidation
process.
[0004] The conventional method and system of consolidating dry
fabric around a mandrel to make a fiber preform suffers from
several drawbacks. The process of vacuum debulking the fabric is
very time consuming and costly, especially when the process is
performed numerous times while making a single fiber preform.
Another drawback is the application of heat treatment option, which
requires time to heat and cool the fabric before the solid film may
be removed. For example, due to the time required to prepare for,
and perform, the process of vacuum debulking plus the option of
applying heat, 30 plus days may be required to finish a preform
application having 42 layers of fabric. The additional cost of the
tools, labor, and energy for performing the vacuum debulking
process is also considerable.
[0005] Thus, a need exists for an efficient system and method for
effectively consolidating dry fabric, holding the fabric in place,
preventing fabric movement and fabric distortion, and eliminating
the need for the heat treatment process of the fabric wrapped
around a mandrel.
BRIEF SUMMARY OF THE INVENTION
[0006] Certain embodiments of the present invention include a
system for wrapping fabric around a mandrel. The system may include
a sheet of fabric, a mandrel configured to receive the fabric, and
at least one fiber and/or fabric tow line. The sheet of fabric is
secured to the mandrel and the tow line is secured to one of the
fabric and mandrel, and the mandrel rotates such that the fabric
and the tow line are wrapped around the mandrel. The tow line is
configured under specified tension to apply pressure to the fabric
as the fabric is wrapped around the mandrel.
[0007] Certain embodiments of the present invention provide a
system that may include a sheet of fabric and a mandrel configured
to receive the fabric, wherein the sheet of the fabric is secured
to the mandrel and the mandrel rotates such that the fabric is
wrapped around the mandrel. The system may further include a roller
head that has at least one spring-loaded roller attached thereto,
wherein the roller head is configured to be placed into position
about the mandrel such that the roller rotatably engages the fabric
on the mandrel and applies pressure to the fabric as the fabric is
wrapped around the mandrel.
[0008] Certain embodiments of the present invention provide a
system that may include a roller assembly defining a gap configured
to receive the mandrel. At least one roller support carrying at
least one spring-loaded roller attached thereto is configured to be
positioned about the mandrel such that the mandrel is received in
the gap and such that the roller rotatably engages the fabric on
the mandrel and applies pressure to the fabric as the fabric is
wrapped around the mandrel.
[0009] Certain embodiments of the present invention provide a
method for wrapping fabric around a mandrel. The method includes
providing a drum of fabric, providing a mandrel, removing a portion
of the fabric from the drum and securing the fabric to the mandrel,
rotating the mandrel such that the fabric wraps around the mandrel,
and applying pressure to the fabric as the fabric is being wrapped
around the mandrel to consolidate the fabric about the mandrel.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0010] FIG. 1 illustrates an isometric front view of a system for
consolidating fabric to form a fiber preform according to an
embodiment of the present invention.
[0011] FIG. 2 illustrates an isometric front view of a system for
consolidating fabric to form a fiber preform according to an
embodiment of the present invention.
[0012] FIG. 3 illustrates an isometric front view of a system for
consolidating fabric to form a fiber preform according to an
embodiment of the present invention.
[0013] FIG. 4 illustrates an isometric front view of a system for
consolidating fabric to form a fiber preform according to an
embodiment of the present invention.
[0014] FIG. 5 illustrates a bottom view of the roller head of FIG.
4 according to an embodiment of the present invention.
[0015] FIG. 6 illustrates an isometric front view of a system for
consolidating fabric to form a fiber preform according to an
embodiment of the present invention.
[0016] FIG. 7 illustrates an isometric front view of a flange
according to an embodiment of the present invention.
[0017] The foregoing summary, as well as the following detailed
description of certain embodiments of the present invention, will
be better understood when read in conjunction with the appended
drawings. For the purpose of illustrating the invention, there is
shown in the drawings, certain embodiments. It should be
understood, however, that the present invention is not limited to
the arrangements and instrumentalities shown in the attached
drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0018] FIG. 1 illustrates an isometric front view of a system 10
for consolidating dry fiber fabric to form a fiber preform
according to an embodiment of the present invention. The system 10
includes a roll 14 of dry fabric 18 wrapped around a drum or spool
22. The drum 22 is mounted to a base 24 and is configured to
rotate. The fabric 18 may be pulled off of the drum 22 as a
continuous sheet 26 as the drum 22 rotates in the direction of
arrow A. The fabric 18 may be made of any number of materials and
the sheet 26 may have any width or length. By way of example only,
the fabric 18 may be made from carbon glass, or other man made or
other natural fibers and/or may be a woven, braided,
unidirectional, crimped or non-crimped, or wool-stitched fabric.
The drum 22 may come in a variety of sizes and shapes and the
fabric 18 may be fabricated with any number of orientations or
constructions that provide the mechanical properties required for a
particular application.
[0019] The system 10 further includes a mandrel 30 having a
cylindrical body 34 formed with conical profiles 36 and rims 38.
The mandrel 30 may have any number of sizes, shapes, and
configurations. By way of example only, the mandrel 30 may be
significantly longer and have a greater diameter and circumference
than the drum 22 and may be significantly longer than the width of
the sheet 26 of fabric 18. The mandrel 30 may be generally
cylindrical, or may be barrel shaped, or have any number of other
shapes that correspond to the desired shape of the end-product
fiber preform. Optionally, the mandrel 30 may not have rims 38 such
that the body 34 may taper off at its ends. The mandrel 30 may be
made of any number of materials, for example, composite, plastic,
or metal. The mandrel 30 is mounted to a base 42 such that the
mandrel 30 is proximate the roll 14 of fabric 18 and is configured
to rotate in the direction of arrow B.
[0020] The system 10 also includes spools 46 mounted to a base 47
and positioned generally above the roll 14. Each spool 46 carries
wrapped thereon a tow line 50 or strand of material. The spools 46
are configured to rotate in the direction of arrow C as the tow
lines 50 are pulled off of the spools 46 in the direction of arrow
D. Each spool 46 may be any number of sizes in length and diameter.
The tow lines 50 may be wrapped around the spools 46 in a spiral
orientation like fishing line is wrapped about a fishing reel. By
way of example only, the tow lines 50 may be made of fiber or
fabric and may be a strand or a sheet. The tow lines 50 may be made
from plastic, glass, carbon, or any other man made or other natural
fibers and may have any number of different thicknesses or widths.
Each spool 46 is mounted to a platform 54 having a circular tow
guide 58 through which the tow line 50 extends from the spool 46.
The tow guide 58 guides the tow line 50 extending from the spool 46
such that, as the tow line 50 is pulled from the spool 46, the tow
line 50 extends from the tow guide 58 at a fixed angle with respect
to the spool 46. The tow lines 50 extend from the tow guides 58
through a tensioning bar 62 that is positioned between the spools
46 and the mandrel 30. The tensioning bar 62 can be adjusted to
control the amount of tension in each individual tow line 50
extending from a spool 46 to the mandrel 30 and fabric 18.
[0021] In operation, before the fabric 18 is first wrapped around
the mandrel 30, a resin is added to the exposed body 34 and/or
conical profile 36 of the mandrel 30. The fabric 18 is then pulled
from the drum 22 and an end of the sheet 26 is placed on at least
one of the body 34 and a conical profile 36 of the mandrel 30 over
the adhesive. The tow lines 50 are then pulled from the spools 46
and ends of the tow lines 50 are placed on top of the fabric 18 on
the mandrel 30 at the end of the fabric 18. The tow lines 50 are
then secured to the fabric 18 or the mandrel 30 by adhesive and/or
tacks. Alternatively, the tow lines 50 can be tied to the fabric 18
or mandrel 30. The tow lines 50 are positioned over the surface of
the fabric 18 in such a way as to evenly distribute pressure across
the fabric 18 as the fabric 18 and tow lines 50 are wrapped around
the mandrel 30. The mandrel 30 is then rotated in the direction of
arrow B such that the sheet 26 of fabric 18 is pulled from the drum
22 and wrapped around the body 34 and/or the conical profile 36 of
the mandrel 30. Similarly, as the mandrel 30 rotates in the
direction of arrow B, the tow lines 50 are pulled from the spools
46 in the direction of arrow D and wrap around the fabric 18 as the
fabric 18 is wrapped around the mandrel 30. The tow lines 50 are
therefore positioned between each overlapped layer of fabric 18 as
the fabric 18 wraps around the mandrel 30. The spools 22 may be
configured to move laterally as the tow lines 50 are wrapped around
the fabric 18 and the mandrel 30 such that the tow lines 50
crisscross each other on the fabric 18 or are otherwise positioned
along the fabric 18 in a manner that is not parallel to the edges
of the sheet 26 of fabric 18.
[0022] As the fabric 18 and tow lines 50 are wrapped around the
mandrel 30 together, the tow lines 50 are tightly pulled against
the fabric 18 during the wrapping process to hold the layers of
fabric 18 tightly against the mandrel 30 and each other, thereby
preventing the fabric 18 from moving or forming folds. Fabrics made
of different materials and having different weaves may require
different amounts of pressure from the tow lines 50 to be kept in
place on the mandrel 30. Moreover, different fabrics 18 may require
different amounts of consolidation. Therefore, as the tow lines 50
are pulled from the spools 46 and wrapped around the fabric 18 on
the mandrel 30, the tensioning bar 62 can be adjusted to increase
or decrease the tension on the individual tow lines 50. The tension
on the tow lines 50 may be adjusted through the tensioning bar 62
such that the tow lines 50 apply the appropriate amount of pressure
on the fabric 18 to keep the fabric 18 tightly in position about
the mandrel 30 as it is wrapped thereabout. Alternatively, pressure
may be applied to the tow lines 50 by any number of other ways,
such as by mounting the spool 46 or the mandrel 30 to a tension
device such that either one can be pulled away from the other to
increase tension in the tow line 50 as needed. By way of example
only, a pressure of anywhere from 10 to 100 pounds may be applied
by the tensioning bar 62 to the tow lines 50, and thus to the
fabric 18 on the mandrel 30. The mandrel 30 is structured to
withstand the pressure applied onto the fabric 18 wrapping
thereabout.
[0023] During the wrapping process, resin or some other tacky
substance may be added to the fabric 18 as the fabric 18 is wrapped
around the mandrel 30. The fabric 18 and the resin may be heated
during the wrapping process such that the overlapping layers of
fabric 18 better adhere to each other and are better consolidated
by the pressure applied by the tow lines 50.
[0024] After the fabric 18 has been tightly wrapped into a bundle
around the mandrel 30 in enough layers so that the fiber preform
has the proper thickness for the given application, the fabric 18
and tow line 50 are cut and tied to the bundle. Resin is then
applied to the fiber preform bundle by any number of different
methods, such as injection or infusion. The fiber preform is then
further treated and pressurized in an oven or autoclave until it is
appropriately consolidated and hardened. The mandrel 30 is then
removed from the preform and an end-user can use the finished fiber
preform for the appropriate application.
[0025] The spools 46 and tow lines 50 of FIG. 1 can have any number
of different orientations to distribute the tow lines 50 across the
fabric. By way of example only, the spools 46 may all be positioned
along the same plane, or may be positioned with respect to each
other such that the tow lines overlap and criss-cross each other on
the fabric 18 and thus are more evenly and uniformly distributed
across the fabric. Alternatively, instead of being stationary, the
spools 46 may oscillate such that the tow lines 50 crisscross each
other on the fabric 18. Alternatively, the system 10 may include
any number of different spools 46 distributing tow lines 50 across
the fabric 18. By way of example only, the system 10 may include
anywhere from 1 to 10 spools 46 that distribute tow lines 50 that
either criss-cross, or are parallel to, each other. The number and
arrangement of the spools 46 may be chosen to best apply and
distribute the appropriate amount of pressure on a particular kind
of fabric for a particular kind of application.
[0026] FIG. 2 illustrates a front isometric view of a system 70 for
consolidating dry fabric to form a fiber preform according to an
embodiment of the present invention. The system 70 includes fabric
18 being fed from a drum 22 to a mandrel 30. The fabric 18 may have
a weave and pattern such that the surface of the sheet 26 of fabric
18 is uneven and not generally smooth. Overlapped layers of such a
pattern may be more likely to form folds or wrinkles therebetween.
The system 70 includes a single spool 74 positioned above the drum
22 that includes numerous strands or tow lines 58 extending
therefrom to the fabric 18 around the mandrel 30. The tow lines 58
operate in the same fashion as the tow lines 50 of the system 10
shown in FIG. 1. As the fabric 18 is wrapped around the mandrel 30,
the tow lines 50 apply pressure to the fabric 18 as needed to
consolidate the fabric 18 about the mandrel 30. Because the tow
lines 50 all extend from the same spool 74, the pressure applied by
the tow lines 50 is centralized and distributed along the fabric 18
to tightly hold uneven fabric layers down on each other and prevent
folds. Alternatively, the tow lines 50 may extend from more than
one spool or each tow line 50 may extend from its own spool.
[0027] FIG. 3 illustrates a front isometric view of a system 80 for
consolidating dry fabric to form a fiber preform according to an
embodiment of the present invention. The system 70 includes fabric
18 being fed from a drum 22 to a mandrel 30 like the embodiments of
FIGS. 1 and 2. Again, the fabric 18 may have a weave and pattern
such that the surface of the sheet 26 of fabric 18 is uneven and
not generally smooth. The system 80 includes a single spool 84
positioned above the drum 22 that includes a single wide sheet or
tow line 58 extending therefrom to the fabric 18 around the mandrel
30. The tow line 58 may be as wide as the fabric 18 and operates in
the same fashion as the tow lines 50 of the systems 10 and 70 shown
in FIGS. 1 and 2, respectively. By way of example only, the tow
line 58 may be any type of fabric. The pressure applied by the tow
line 50 as the tow line 50 and fabric 18 are wrapped around the
mandrel 30 is distributed across the fabric 18 to tightly hold the
uneven fabric layers down on each other and prevent folds.
Alternatively, the tow line 58 may be a single netting or mesh and
not a sheet of material. Alternatively, the system 80 may include
multiple tow lines 50 that are thinner than the tow line 50 shown
in FIG. 3 that each extend from a separate spool and are
distributed across the fabric 18.
[0028] Alternatively, each embodiment shown in FIGS. 1-3 may
include tow lines 50 of varying thickness. By way of example only,
a tow line 50 may have a width ranging from 1/8 of an inch to 1
foot depending on factors such as the fabric and the application
for the fiber preform. By way of example only, a tow line 50 may
have a thickness ranging from 0.001 of an inch to 0.125 depending
on factors such as the fabric, application for the fiber perform
and/or the force needed to consolidate the fiber perform.
[0029] FIG. 4 illustrates an isometric front view of a system 100
for consolidating dry fabric to form a fiber preform according to
an embodiment of the present invention. The system 100 includes a
roll 14 of fabric 18 and a mandrel 30 with the fabric 18 partially
wrapped around the mandrel 30. The system 100 also includes a
roller head 104 that is mounted on a piston 108 such that the
roller head 104 is positioned above the mandrel 30. Alternatively,
the roller head 104 may be mounted to any number of other
spring-loaded, or actuated structures. The roller head 104 includes
a base 116 having a top surface 120 which is connected to the
piston 108 and a bottom surface 124 from which extends roller
assemblies 128. Each roller assembly 128 includes a cylindrical
roller 140 rotatably mounted to a roller frame 136 that is
connected to the base 116 by a spring 132. The roller assemblies
128 extend generally perpendicularly from the bottom surface 124 of
the roller head 104. Two end roller assemblies 130 extend from the
bottom surface 124 of the roller head 104 at a non-perpendicular
angle. Alternatively, each roller assembly 128 and 130 may extend
from the bottom surface 124 of the roller head 104 at any number of
different angles as needed for a particular application.
[0030] FIG. 5 illustrates a bottom view of the roller head 104 of
FIG. 4. The roller assemblies 128 and 130 are aligned along the
bottom surface 124 of the roller head 104 in two parallel rows 144
with each roller assembly 128 in a row overlapping a gap 148
between adjacent roller assemblies 128 in the other row.
Alternatively, any number of roller assemblies 128 and 130 may be
aligned along the bottom surface 124 of the roller head 104 in any
number of different alignments, arrays, rows, or orientations as
needed for a particular application. Alternatively, the size of
rollers 140 may vary. By way of example only, the roller head 104
may include at least one roller 140 that extends across the length
of the bottom surface 124 from side wall 152 to side wall 152. By
way of example only, the roller head 104 may include at least two
rollers 140 of different sizes.
[0031] Returning to FIG. 4, in operation, the fabric 18 is attached
to the mandrel 30 by a resin and then the roller head 104 is
lowered in the direction of arrow E on top of the fabric 18 on the
mandrel 30 such that the rollers 140 on the roller assemblies 140
engage the fabric 18 at a generally perpendicular angle and press
the fabric 18 against the mandrel 30. The mandrel 30 is then
rotated in the direction of arrow B such that the fabric 18 begins
to wrap around the mandrel 30. As the fabric 18 passes between the
mandrel 30 and the roller head 104, the rollers 140 are pushed
against the fabric 18 by the springs 132 and/or the piston 108 such
that the rollers 140 apply pressure to the fabric 18. The rollers
140 of the end roller assemblies 130 apply angular pressure to the
fabric 18. The rollers 140 also rotate in the direction of arrow F
as the fabric 18 passes under the rollers 140. Therefore, the
spring-loaded rollers 140 apply a compressive force on the fabric
18 as it is wrapped around the mandrel 30 without resisting the
progress of the fabric 18 in such a manner as to damage the fabric
18. The pressure applied by the rollers 140 consolidates the fabric
to prevent folds or wrinkles from forming in the fabric 18 and to
keep the fabric 18 tightly wrapped around the mandrel 30.
[0032] When the fabric 18 is wrapped around the mandrel 30 to the
desired thickness, the fabric 18 is cut and the loose end of the
fabric 18 is secured to the bundle of wrapped fabric 18 by resin
and is pressurized by the rollers 140. The roller head 104 is then
pulled away from the bundle of fabric 18 in the direction of arrow
G. The bundle of fabric 18 may be treated with resin and heat
treated to complete the fiber preform product.
[0033] The rollers 140 can be used to apply pressure to the fabric
18 regardless of the contours or textures of the fabric 18. By way
of example only, the fabric 18 of FIG. 4 may have an uneven texture
due to a criss-cross weave. The rollers 140 can be sized and
orientated to roll along the contours of a particular fabric and
apply pressure along both the "peaks" and "valleys" along the
surface of the fabric. For each kind of fabric having a specific
contour, a different assembly of rollers 140 having different sizes
and orientations may be used to apply the appropriate amount of
pressure along the surface of the particular fabric to properly
consolidate the fabric. Furthermore, the pressure applied by the
rollers 140 through the springs 132 and/or the piston 108 may be
adjusted depending on how tight and consolidated a fabric has to be
for a particular application.
[0034] Again, during the wrapping process, resin or some other
tacky substance may be added to the fabric 18 as the fabric 18 is
wrapped around the mandrel 30. The pressure applied by the rollers
140 helps the adhesive hold adjacent layers of fabric 18 tightly
together. Additionally, the fabric 18 and the resin may be heated
during the wrapping process such that overlapping layers of fabric
18 better adhere to each other and are better consolidated by the
pressure applied by the rollers 140. By way of example only, the
roller head 104 may include a heating unit that applies heat to the
fabric 18 as the fabric 18 passes under the rollers 140.
[0035] Additionally, the system 100 of FIG. 4 may include more than
one roller head 104 positioned around the mandrel 30 to apply
pressure to the wrapped fabric 18 at different points along the
mandrel 30. By using multiple roller heads 104, more pressure is
applied to the fabric 18 for a longer period of time as the fabric
18 is wrapped around the mandrel 30 to further consolidate the
fabric 18.
[0036] FIG. 6 illustrates an isometric front view of a system 200
for consolidating dry fabric to form a fiber preform according to
an embodiment of the present invention. The system 200 includes a
roll 14 of fabric 18 and a mandrel 30, with the fabric 18 partially
wrapped around the mandrel 30. The system 200 also includes a
roller assembly 204. The roller assembly 204 includes a main roller
housing 208 having a semi-circular gap 212 defining a perimeter or
inner contour 214 along curved side walls 216. The gap 212 is
generally sized to receive a portion of the mandrel 30 within the
main roller housing 208. The main roller housing 208 is mounted on
rails 220 proximate the mandrel 30 such that the main roller
housing 208 may be slid, or otherwise moved in relation to the
mandrel 30, such that the mandrel 30 may be positioned within the
gap 212. Alternatively, the main roller housing 208 may be mounted
on any number of other mechanisms that can be used to move the main
roller housing 208 in position about the mandrel 30.
[0037] The main roller housing 208 of the roller assembly 204
includes a series of roller supports or roller rails 222 mounted
therein along the inner contour 214 of the side walls 216. Each
roller rail 222 includes row of cylindrical rollers 224 rotatably
mounted to roller frames 228 that are connected to the roller rail
222 by springs 232. The rollers 224 are positioned within the main
roller housing 208 generally along the inner contour 214 of the
side walls 216 and may extend past the side wall 216 and into the
gap 212. The main roller housing 208 may include any number of
roller rails 224 along the inner contour 214 of the gap 212 from a
top end 236 of the main roller housing 208 to a bottom end 240. The
roller rails 222 may have any number of rollers 224 of different
sizes and shapes extending therefrom and positioned along the inner
contour 214 of the side walls 216. The rollers 224 extend generally
perpendicularly from the roller rails 222. Alternatively, each
roller 224 may extend from a roller rail 222 at any number of
different angles as needed for a particular application.
Alternatively, any number of rollers 224 may be aligned along a
roller rail 222 in any number of different alignments, arrays,
rows, or orientations as needed for a particular application.
Alternatively, the size of the rollers 224 may vary. By way of
example only, a roller rail 222 may include at least one roller 224
that extends across the length of the roller rail 222. By way of
example only, a roller rail 222 may include at least two rollers
224 of different sizes.
[0038] In operation, the fabric 18 is attached to the mandrel 30 by
an adhesive and then the roller assembly 204 is slid along the
rails 220 in the direction of Arrow H until the mandrel 30 is
received within the gap 212 and the rollers 224 engage the mandrel
30 and the fabric 18 at a generally perpendicular angle. The
mandrel 30 is then rotated in the direction of arrow B such that
the fabric 18 begins to wrap around the mandrel 30 in layers. As
the fabric 18 passes between the mandrel 30 and the rollers 224 on
the series of roller rails 222, the rollers 224 are pushed against
the fabric 18 by the springs 232 such that the rollers 224 apply
pressure to the fabric 18. The rollers 224 also rotate in the
direction of arrow F as the fabric 18 passes under the rollers 224.
Therefore, the spring-loaded rollers 224 apply a compressive force
on the fabric 18 as it is wrapped around the mandrel 30 without
resisting the progress of the fabric 18 in such a manner as to
damage the fabric 18. By using multiple rails 222 of rollers 224
along the gap 212 from the top end 236 to the bottom end 240 of the
main roller housing 208, the fabric 18 is repeatedly pressurized as
it passes on the mandrel 30 through the roller assembly 204. Such
repeated pressurization consolidates the fabric tightly around the
mandrel 30.
[0039] The force applied by the rollers 224 to the fabric 18 may be
adjusted by moving the main roller housing 208 closer to, or
further from, the mandrel 30 along the rails 220. Alternatively,
the main roller housing 208 may be adjusted in other ways so as to
adjust the pressure applied by the rollers 224 to the fabric 18.
Alternatively, different springs 232 may be used to apply different
amounts of force on the fabric 18 through the rollers 224 depending
on the consolidation required for a particular fabric 18.
[0040] The pressure applied by the rollers 224 consolidates the
fabric 18 to prevent folds or wrinkles from forming in the fabric
18 and to keep the fabric 18 tightly wrapped around the mandrel 30.
When the fabric 18 is wrapped around the mandrel 30 to the desired
thickness, the fabric 18 is cut and the loose end of the fabric 18
is secured to the bundle of wrapped fabric 18 by adhesive and is
pressurized by the rollers 224. The roller assembly 204 is then
slid away from the bundle of fabric 18 on the rails 220. The bundle
of fabric 18 is then treated with resin and treated in the oven to
complete the fiber preform product.
[0041] In an alternative embodiment, the roller assembly 204 may be
configured to receive most of the mandrel 30 within a gap lined
with the roller rails 222. By way of example only, the roller
assembly 204 may be configured to receive generally about
three-fourths of the mandrel 30 (such as by engaging generally 270
degrees of the cylindrical mandrel) at any given time. The more of
the mandrel 30 that is received in the gap, the more rollers 224
that can engage the fabric 18 and consolidate the fabric 18 as it
is wrapped around the mandrel 30.
[0042] FIG. 7 illustrates an isometric front view of a flange 250
according to an embodiment of the present invention. Referring to
FIG. 1, in some applications, creases or contours may be added to
the fabric 18 such that the fabric 18 is pre-shaped for wrapping
around a particular mandrel 30. For example, where the mandrel 30
has rims 38 extending out from the body 34 and the fabric 18 is
wider than the body 34, the fabric 18 may be shaped to wrap around
the body 34 and along the sides of the inner rims 38 of the mandrel
30. Returning to FIG. 7, the flange 250 has a generally flat base
254 formed with side walls 258 extending therefrom. Each side walls
258 extends upward from the base 254 at an angle. In operation, the
flange 250 may be used with any of the systems 10, 100, or 200 of
FIGS. 1-6 to form the fabric 18 prior to the fabric 18 being fed
onto the mandrel 30. That is, the flange 250 is positioned between
the mandrel 30 and the roll 14 such that, as fabric 18 is fed from
the drum 22 to the mandrel 30, the fabric 18 is pulled over the
flange 250. The side walls 258 engage the fabric 18 to form creases
along the fabric 18 such that the fabric 18 is formed to fit along
the body 34 and rims 38 of a mandrel 30 as the fabric 18 is wrapped
around the mandrel 30.
[0043] The embodiments of the present invention provide many
benefits over conventional methods and systems for wrapping dry
fabric around a mandrel to make a fiber preform. The embodiments
apply pressure to, and consolidate, the fabric as the fabric is
wrapped around the mandrel without a need to stop the wrapping
process to vacuum debulk the bundle of fabric. Thus, the
embodiments save considerable amounts of time, money, materials,
energy, and labor in preparing cylindrical fiber preforms. For
example, using the embodiments of the present invention, a fiber
preform that would ordinarily take up to 30 days to prepare using
the vacuum debulk method may only take roughly 2-3 days to
prepare.
[0044] While the invention has been described with reference to
certain embodiments, it will be understood by those skilled in the
art that various changes may be made and equivalents may be
substituted without departing from the scope of the invention. In
addition, many modifications may be made to adapt a particular
situation or material to the teachings of the invention without
departing from its scope. Therefore, it is intended that the
invention not be limited to the particular embodiments disclosed,
but that the invention will include all embodiments falling within
the scope of the appended claims.
* * * * *