U.S. patent application number 11/717999 was filed with the patent office on 2007-12-06 for precision feed end-effector composite fabric tape-laying apparatus and method.
Invention is credited to David Groppe.
Application Number | 20070277924 11/717999 |
Document ID | / |
Family ID | 32107865 |
Filed Date | 2007-12-06 |
United States Patent
Application |
20070277924 |
Kind Code |
A1 |
Groppe; David |
December 6, 2007 |
Precision feed end-effector composite fabric tape-laying apparatus
and method
Abstract
A fabric and tape laying machine operable with: (a) a robot
including programmable control means, (b) a supply roll containing
a continuous strip of composite tape or fabric, and (c) a mold,
plug or mandrel of predetermined surface shape relative to x, y and
z coordinates, including: a. a chassis for laying the tape or
fabric onto the mold along a programmed path that is straight with
respect to the x and y coordinates and follows contours of the
predetermined surface shape with respect to the z coordinate, b. a
tape supply roll, c. a contact roller module adapted to receive the
tape from the supply roll, and moved along the programmed path, d.
a tape cutting unit, e. feed rollers for driving the tape from the
supply roll and maintaining the tape taut while it passes through
the tape cutting unit, and driving the tape to the contact roller
module, f. the contact roller module including at least one set of
pressure contact rollers adapted to have the tape received from the
tape-cutting unit laid-up onto the mold, and g. a suspension system
for dynamically energizing the contact roller module to have its
rollers apply a predetermined level of force downward on the tape
during the lay-up process regardless of any varying contours on the
mold surface.
Inventors: |
Groppe; David; (Arnold,
CA) |
Correspondence
Address: |
ABELMAN, FRAYNE & SCHWAB
666 THIRD AVENUE, 10TH FLOOR
NEW YORK
NY
10017
US
|
Family ID: |
32107865 |
Appl. No.: |
11/717999 |
Filed: |
March 13, 2007 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10661383 |
Sep 12, 2003 |
7206665 |
|
|
11717999 |
Mar 13, 2007 |
|
|
|
60410066 |
Sep 12, 2002 |
|
|
|
Current U.S.
Class: |
156/235 ;
156/527 |
Current CPC
Class: |
B63H 9/067 20200201;
D04H 3/04 20130101; B65H 35/0013 20130101; B29C 70/32 20130101;
B29C 70/388 20130101; B63H 9/0678 20200201; B29C 70/545 20130101;
Y10T 156/1788 20150115; Y10T 156/1365 20150115 |
Class at
Publication: |
156/235 ;
156/527 |
International
Class: |
B32B 38/10 20060101
B32B038/10 |
Claims
1. (canceled)
2. (canceled)
3. (canceled)
4. (canceled)
5. (canceled)
6. (canceled)
7. (canceled)
8. (canceled)
9. (canceled)
10. (canceled)
11. (canceled)
12. (canceled)
13. (canceled)
14. (canceled)
15. (canceled)
16. (canceled)
17. (canceled)
18. (canceled)
19. (canceled)
20. (canceled)
21. (canceled)
22. (canceled)
23. (canceled)
24. A composite tape laying machine operable with: (a) a mold, plug
or mandrel of predetermined surface shape relative to x, y and z
coordinates, (b) a supply roll containing a continuous strip of
composite tape, and (c) a robot including programmable control
means comprising: a. a chassis mountable to said robot and movable
by said robot for laying said tape onto said mold along a
programmed path that is straight with respect to said x and y
coordinates and follows contours of said predetermined surface
shape with respect to said z coordinate, b. means on said chassis
for supporting said supply roll, c. a contact roller module mounted
on said chassis and spaced apart and downstream from said supply
roll and adapted to receive said tape from said supply roll, said
contact roller module being carried by said chassis as said chassis
is moved along said programmed path, d. said contact roller module
comprising at least one modular frame, a set of three pressure
contact rollers carried by said at least one said frame, namely a
center roller and two side rollers in end-to-end relationships,
said at least one set of pressure contact rollers adapted to have
said tape received from said tape-cutting unit pass around said
pressure contact rollers and be laid onto said mold, and where each
of said side rollers has its central axis angularly displaceable
relative to the central axis of said central roller, and e. a
suspension system mounted on said chassis for dynamically
energizing said contact roller module to have its rollers apply a
predetermined level of force downward on said tape during the
lay-up process regardless of any varying contours on said mold
surface.
25. A composite tape laying machine operable with: (a) a mold, plug
or mandrel of predetermined surface shape relative to x, y and z
coordinates, (b) a supply roll containing a continuous strip of
composite tape, and (c) a robot including programmable control
means comprising: a. a chassis mountable to said robot and movable
by said robot for laying said tape onto said mold along a
programmed path that is straight with respect to said x and y
coordinates and follows contours of said predetermined surface
shape with respect to said z coordinate, b. means on said chassis
for supporting said supply roll, c. a contact roller module mounted
on said chassis and spaced apart and downstream from said supply
roll and adapted to receive said tape from said supply roll, said
contact roller module being carried by said chassis as said chassis
is moved along said programmed path, d. a tape cutting unit carried
by said chassis and situated between said supply roll and said
contact roller module, e. a first set of feed rollers downstream of
said supply roll and upstream of said tape cutting unit, and a
second set of feed rollers downstream of said tape cutting unit and
upstream of said contact roller module for driving said tape from
said supply roll and maintaining said tape taut while it passes
through said tape cutting unit, and driving said tape to said
contact roller module, said tape extending from said supply roll to
said tape-cutting unit having opposite generally parallel side
edges, f. said tape-cutting unit comprising at least one cutter to
cut a predetermined profile along one of said opposite sides of
said tape as said tape is moving through said tape-cutting unit and
to cut said tape transversely to have a predetermined length when
it covers a predetermined surface area of said mold, and g. a
suspension system for dynamically energizing said contact roller
module to have its rollers apply a predetermined level of force
downward on said tape during the lay-up process regardless of any
varying contours on said mold surface.
26. A tape-laying machine according to claim 24 wherein said
contact roller module moves along said programmed path in a forward
direction as said tape is laid behind it, and wherein for each
contact roller module said pressure contact rollers in end-to-end
relationship define between each two adjacent ends of said rollers
a gap, said contact roller module further comprises at least one
follower element situated adjacent and generally parallel to and
behind said pressure contact rollers for contacting and pressing
portions of laid-up tape which are adjacent said gap and are not
contacted by said pressure contact rollers.
27. A tape-laying machine according to claim 26 wherein said gap
between adjacent ends of said at least one set of pressure contact
rollers has a length L, and said at least one follower element is a
roller having axial length substantially the same as L.
28. A tape-laying machine according to claim 24 wherein said tape
on said supply roll includes an adjacent strip of protective film,
and said chassis further comprises a take-up roll, said protective
film being separated from said tape and fed onto said take-up
roll.
29. A tape-laying machine according to claim 24 wherein said center
roller is mounted at a fixed orientation and location on said frame
of said contact roller module.
30. A tape-laying machine according to claim 24 wherein each of
said modular frames comprises a base, and wherein said center
roller has opposite ends and each of said side rollers has an inner
end adjacent one of said opposite ends of said center roller and
has an outer end, and wherein said modular frame further comprises
(a) a pair of spaced-apart fixed arms which extend from said base
and rotatably support said opposite ends of said center roller and
pivotably and rotatably support said inner ends of said side
rollers, and (b) a pair of length-extendable arms, each having one
end pivotably connected to said outer end of each of said side
rollers and an opposite end pivotably connected to said base, said
side rollers being angularly displaceable relative to said center
roller when said length extendible arms are varied in length.
31. A tape-laying machine according to claim 24 comprising a
plurality of said contact roller modules, each having a frame with
said three contact pressure rollers in end-to-end configuration
with the adjacent frame, and with the outer end of one side roller
pivotally coupled to the outer end of the adjacent side roller of
the adjacent modular frame, with said end-to-end aligned modular
frames forming a first tier of the tape-dispensing head
structure.
32. A tape-laying machine according to claim 31 wherein each of
said frames with its three rollers is a modular sub-assembly with
respect to an adjacent frame, with the adjacent side rollers of
each two adjacent frames remaining pivotally coupled together such
that all the rollers of all the frames always define a continuous
line in a single plane.
33. A tape-laying machine according to claim 32 wherein each of
said length-extendable arms comprises a telescoping piston and
cylinder, the piston being axially energized by said control means
to configure the aligned rollers to be compliant with said mold
surface.
34. A tape-laying machine according to claim 30 wherein said
tape-dispensing head comprises a base and a plurality of said
modular frames fixed to said base and situated such that the
central axis of the two outer and center rollers of each modular
frame lie in a plane, and said planes of said plurality of modular
frames are co-planar, and each of said modular frames is adjacent
to at least one other modular frame with the outer ends of one side
roller of each of said adjacent modular frames being adjacent and
pivotally coupled together, and with said rollers of said plurality
of modular frames being configurable so that their respective
central axes define a continuous line that may be concave, convex,
wavy, sinusoidal or other shape.
35. A tape-laying machine according to claim 24 wherein said
predetermined path is defined by successive points, each being at a
specified elevation relative to a reference plane, and said
predetermined path further defines at each of said points a surface
contour defined by a line perpendicular to said path, whereby at
each of said points said chassis frame is controlled to position
the center roller on said line and at said specified elevation, and
to position said side rollers on both sides adjacent said center
roller at an angle and elevational as defined by said path.
36. A tape-laying machine according to claim 25 wherein said
chassis frame of said tape dispensing head has top and bottom parts
with said tape moving in the direction from top to bottom in a
generally flat plane, and said tape-cutting unit comprising a beam
having a cutter support surface generally parallel to said plane of
said tape and generally perpendicular to said top-to-bottom
direction, said pair of cutters being movable on said support
surface transversely of said tape movement direction.
37. A tape-laying machine according to claim 25 further comprising
a heater for heating a surface of said tape to its melting
temperature after it passes said tape-cutting unit and before it
reaches said contact roller module.
38. A tape-laying machine according to claim 25 further comprising
a cooler for maintaining the temperature below the melting point of
said tape on said supply roll and said tape extending from said
supply roll to said cutting unit.
39. A tape-laying machine according to claim 25 wherein said tape
defines a plane as it extends from said cutting unit to said
contact roller module, and wherein said pressure contact rollers of
said contact roller module lie in a plane generally perpendicular
to said plane of said tape, said center roller positioned with its
central axis of rotation a fixed perpendicular distance from said
frame and perpendicular to the direction of said tape movement,
said side rollers having their respective central axis pivotable
relative to said central axis of said center roller, said contact
roller module further comprising at least one follower element
situated adjacent and generally parallel to and behind said contact
pressure rollers with respect to said path traversed by said
contact roller module, said at least one follower element pressing
said laid tape against said mold.
40. Apparatus according to claim 25, wherein said at least one
contact roller module is movable by said robot in the x,y plane in
a direction designated upstream along said predetermined path, with
said tape being laid and extending behind and downstream of said
contact roller module, said contact roller module further
comprising an idler roller mounted on said contact roller module
and positioned upstream of said contact pressure rollers of said
contact roller module, whereby said tape fed from said tape cutting
unit is directed to go forward in said upstream direction and
around said idler roller, thus making a generally 90 degree turn,
and thence to go beneath said pressure contact rollers as it is
laid onto said mold.
41. A method of performing composite fabric or tape lay-up onto a
mold surface with a tape laying machine that uses a supply roll of
composite tape and includes a tape cutting unit and a contact
roller module having a set of pressure contact rollers in
end-to-end relationship and around which said tape from said supply
roll is directed to be laid-up onto said mold, comprising the
steps: a. defining the topography of said mold surface, b.
directing a contact roller module to traverse a plurality of
successive passes, each pass generally parallel to and laterally
displaced from the prior pass, where each pass follows a path which
defines a portion of said topography, and c. providing a dynamic
suspension system which urges said pressure contact rollers of said
contact roller module to push against said mold surface with
substantially the same force at all times regardless of the changes
in topography of the mold as the contact roller module passes are
made.
42. A method according to claim 41 comprising the further steps for
each strip dispensed with each pass of said tape dispensing head,
of a. determining the profiles of the opposite side edges and the
length of that each strip should have, before said contact roller
module makes the lay-up pass with that strip, and b. directing said
tape cutting unit to cut said edge profiles as said tape is moving
through said cutting unit toward said mold, and to make a
transverse cut across said tape to establish the predetermined
strip length.
Description
[0001] This application claims priority of the Sep. 12, 2002 file
date of applicant's provisional application, Ser. No.
60/410,066.
FIELD OF THE INVENTION
[0002] The present invention relates to apparatus and methods for
composite fabric tape lay-up, including tape edge profiling and
tape placement onto molds, plugs and mandrels and use of robots in
combination with such apparatus.
BACKGROUND OF THE INVENTION
[0003] Composite fabrics, dry or pre-preg (pre-impregnated resin
systems), including fiberglass, carbon fiber, graphite, ceramics,
Kevlar, Aramid and other hybrids of uni-directional or
bi-directional makeup have been used in the construction of a
variety of products, including aircraft components, marine
applications, automotive and various industrial and appliance
applications to reduce weight while improving structural properties
and aesthetic flexibility. These products lend themselves to
products in size and shape typically not less than one square foot
in surface area and that may be flat, faceted, concave, convex or a
combination thereof.
[0004] Typically in applications where these products are used, the
lay-up process is performed by hand. Exceptions include chopper gun
technology, tape-laying and fiber placement machines. To achieve
the desired structural properties with the use of chopper gun
technology the application of more product in a given area is the
most common method; however, disadvantages of this method include
increased weight of the final product and limited ability of the
result to be an engineered product. Further, robots have been
employed to expedite and provide for a more-uniform and repeatable
application. In either method of application this process tends to
be very messy.
[0005] Tape laying machines have proven to be very accurate and
reliable; however, because of the size and extreme costs associated
with them, only a limited number of companies can provide product
via this method. Plugs, molds and mandrels employed within the
`work cell` or envelope of the system must be very precisely built
and placed. Set-up can be very costly and time consuming due, in
part, to the method by which the systems are programmed.
[0006] These systems are also limited, in that the plug, mold or
mandrel must typically be placed `in position` or that the tape is
always placed with gravity assist. Exceptions to this may be where
the `tack and drape` of the product being used lends itself
otherwise.
[0007] A limiting factor with these machines is that the tape
dispensing rolls have been limited in size, allowing for only
1.00'' to 12.00'' of material to be laid in a single pass, and
subject to the amount of engineered overlap per seam. Because of
this limitation, additional weight is added to the product being
constructed. This, in turn adds to the time required for the lay-up
itself and becomes an issue with respects to the out time allotted
for a given resin system.
[0008] These machines do not lend themselves to the lay-up of dry
fabrics such as those used in the construction of boat or ship
hulls and deck components. Autoclaves large enough to house such
products are impractical and therefore limit the amount of pre-preg
material that can be used, even by hand, unless mobile IR
(infrared) modules are placed about the product for curing
purposes. These products are generally large and multi-faceted
and/or concave, convex or combination surfaced and do not lend
themselves to the work envelopes of commercially available
tape-laying machines of today. As a result, the majority of such
lay-up work is performed by hand and vacuum bagging is performed
locally.
[0009] In many instances lay-up schedules established by design and
engineering requirements for large parts are performed by hand with
the mechanics working in concert with overhead lasers to position
fabric edges in a given direction. To facilitate this process,
fabric profiling and cutting machines have flourished in concert
with the lay-up regime. These X-Y gantry systems have come of age
providing various cutting systems including slitting, flying
knives, waterjet, laser and ultrasonic tools to perform the
required cuts and profiles for a given lay-up.
[0010] Again, the issue of out time for a given matrix and resin
system requires diligence by the mechanic whose individual reach
may limit his or her ability to place the fabric in the correct
position without getting up and onto the plug or mold. Scaffolding,
mobile platforms or man-lifts would then be utilized to facilitate
the lay-up regime.
[0011] Typically, once the fabric for a specific lay-up has been
cut or profiled, it must be returned to cold storage, typically 40
degrees Fahrenheit or cooler, until it can be laid up. This is due,
in part, to the amount of time that has been used to roll out, cut
or profile and label by schedule, and the additional issue that the
plug or mold may be in use and not available to perform the lay-up.
Even with automated versions of the cutting and profiling machines,
the rate at which the human roll is performed limits the `thru-put`
of the entire process. This process is further complicated when
different types of fabrics are selected by design for a given
lay-up schedule.
[0012] As a result of this current lay-up process, regardless of
the component being constructed, thru-put is greatly reduced
because of multiple handling of the material, especially where ISO
standards are practiced. These limitations therefore tend to drive
up the part costs per square foot of lay-up exponentially due to
component size.
[0013] With fiber placement machines specific fiber matrices and
resin systems are typically placed in many applications employing
mandrels, whether vertically or horizontally positioned.
Cylindrical and conical shaped products lend themselves well to
this method. Fiber placement machines have also been employed in
the process of making up flexible products, such as sails used in
marine applications that are typically complex in shape and surface
geometry. In these applications mobile IR panels perform the cure
process upon completion of the fiber placement. Again, such
machines are limited in the amount of material that can be laid up
in a given pass or path, coupled with the typically slow placement
speeds.
[0014] These machines require a great deal of attention and
monitoring as there are issues relating to broken fibers, resin
viscosity and impregnation, not to mention the programming
flexibility limitations imposed by currently used motion control
software systems.
[0015] Upon examination of the aforementioned composite
application, lay-up and/or placement systems currently being
utilized by the various industries discussed, four areas of concern
continue to plague the practical implementation and use of advanced
composite construction systems, namely, human labor, out-time
limitations of the material itself, flexibility of the process or
system for lay-up and the enormous costs associated with the
equipment currently available.
SUMMARY OF THE INVENTION
[0016] The new invention abbreviated herein as `Precision Feed
End-Effector` or `PFE`, has been designed to overcome many of the
issues defined above. It has been designed with both modularity and
flexibility in mind. The PFE device combines various proven
technologies into one simple configuration. This simple approach
allows for simplicity in its components and service
requirements.
[0017] The PFE device was designed specifically to be used by
commercially available robots that can manipulate working loads 50
KGs or greater. With the advent of quick release couplings and
active and passive force sensing technology units, the provision
for the flexible placement of both dry and pre-preg composites can
be realized.
[0018] The PFE device is constructed from basic assembly modules
allowing for the expansion of the basic module unit, capable of
laying six inches of material to be chained together in six inch
increments up to but not limited to sixty inch rolls of
commercially available fabrics. The basic module unit provides the
tool the ability to conform to a given plug, mold or mandrel
surface in real-time as the robot performs a given path and program
offset. This invention can be used with smaller units such as
shorter rollers or a single roller.
[0019] The PFE's basic module unit performs this surface shape
change via use of a realtime gas, pneumatic or mechanical spring
pressure regulated force feedback system that operates in the 40-80
psi range, depending upon the density of the fabric make-up and
resin system. The functionality of the basic module unit is similar
to that of the application of paint on a flat surface using a paint
roller.
[0020] In one preferred embodiment there are three two inch long,
5/8 inch diameter rollers per basic module unit. The rollers are
made up of two parts, the core being a dense solid composite
material and the exterior consumable sleeve being soft in density
to provide for the absorbing of plug, mold or mandrel surface
deviation that the flexibility of the basic module unit does not
provide for. The basic module unit is comprised of one set of three
rollers, with an adjacent `guide` panel that provides for the
fabric to be channeled down between the set of rollers and the
guide panel to lay-up onto the mold. These non-powered rollers are
linked via a flexible shaft that is supported at both ends of each
roller by hinging roller link arms that pivot in the cross-axis top
and bottom. From a top view the rolls maintain a straight-line
regardless of how many basic module units are linked together.
However, from the front view each roller can pivot in its
relationship to the one next to it by as much as twelve degrees up
or down. A minimum radius of twelve inches can be achieved in
either concave or complex surface geometry. Additionally, a spline
curve may be achieved by having the out-board rollers pivot in
opposite directions with the twelve inch radius being maintained in
both directions. Also shown and described herein is a second
embodiment of the basic module comprising two adjacent sets of
three rollers as identical halves. The tape is then dispensed
around one set onto the mold.
[0021] In one configuration, the pivoting is performed via the
pneumatic system incorporating two double-acting cylinders at
opposing ends of the basic module unit. These cylinders are
connected to a shared pivot point located at the top center
position of the basic module unit. These cylinders independently
apply or bleed air, based upon the mold surface the unit passes
over and a programmed positive and negative pressure value limit.
As the mold surface below changes in relation to a given programmed
path and offset the robot performs, air pressure is added or bled
off to compensate. The basic module unit is attached to a
structural chassis that provides for several process functions to
be performed in concert with the actual lay-up regime.
[0022] The current design incorporates two tiers of suspension
regardless of how many individual six inch (nominal) modules are
incorporated into a specific overall tool width (i.e. 6, 12, 18
inch, etc). Each module includes a set of gas springs that are
sized based upon the process the PFE will be asked to perform,
which is to lay up the tape at the appropriate pressure. In the
first tier of individual modules the distance that the outboard
rollers will travel in either the concave, convex or opposite
directions respectively, will be constrained via the gas springs'
stroke (to be determined) and force desired (to be determined).
When assembled, the module will maintain a level line via
mechanical constraints that limit the swing travel for each roller
to the center of the maximum and minimum radius that the module
will have to see during the lay-up regime.
[0023] When combined, multiple modules are attached to the second
tier suspension system that accommodates the travel (in the same
fashion as the first tier), only it is constrained in a vertical
slide movement of which each joint at each lower module connection
provides the pivot point. Each suspension slide mechanism is
comprised of a sliding stanchion that moves vertically in
relationship to the combined movement required, as the robot moves
the tool (PFE) over a given path geometry at a fixed offset
dimension that is based upon the maximum and minimum radius' that
the tool (PFE) will see during the lay-up.
[0024] Other designs will accomplish this without the use of
gas-springs where the radius' seen by the tool will be shallow.
Otherwise, the gas spring design will be employed to accommodate
the large radius movements that may be seen by the tool. Still
other designs will use a sponge type of spring in place of the gas
or pneumatic spring to reduce overall size, or will use mechanical
or pneumatic spring systems.
[0025] When connecting multiple basic module units together for
increased fabric area placement, a second tier pneumatic force
compensating link system is added to a second level uniform
structural chassis and operates in the same manner as the
individual basic module unit.
[0026] The structural chassis provides the method of connection and
communication with the robot and is attached via commercially
available quick change systems that incorporate both perpendicular
and radial active force sensing capabilities that actively instruct
the robot to make changes in its position about a three-dimensional
point in space based upon the forces seen by the system as it moves
over the surface of the mold along a given path.
[0027] This chassis also contains an `in-line` fabric profiling
system that cuts and profiles the fabric as it is dispensed from
the supply roll mounted on the chassis upstream of the profiling
system. An internal set of powered drive rolls of similar
construction to those in contact with the surface of the mold,
drive and supply tension both upstream and downstream of the fabric
cutting area so that the fabric is always taut, either in a
vertical or horizontal plane.
[0028] The cutting system employs an encoder that measures the
amount of material required for a given lay-up pass. The steps
taken by the system to locate the end of the material and establish
the offset dimension are simple. Once the material is loaded into
the PFE and the leader is placed below the cutting line (the line
established by the path the cutting wheel makes) and the system is
closed for use, a cross cut is made establishing the new offset
dimension. At that point the distance from the encoder to the `cut
line` is known and is now added to the final dimension of the first
part laid up. After that, the system now knows how much material is
ahead of the encoder position.
[0029] When slitting (cutting vertically with the direction of
material feed) the cutting head assumes the vertical position and
is positioned accordingly, based upon the centerline of the
material width being used. The centerline is the same line used by
the robot for path planning and the same line applied to the model
of the mold when assigned off-line by the system. The cutting
system creates the `Y` axis (cross axis) to the `X` axis (material
feed direction). An alternate design may incorporate an ultrasonic
cutting head that will provide cuts in any angle. This will also
lend itself to the cutting of free forms, including circles.
[0030] Because the supply roll will change in weight and size as
material is drawn from it, a supply roll surface friction drive of
the same diameter as those used throughout the system, applies a
programmed pressure against the supply roll, and is linked to the
drive rolls used within the cutting area. This simplifies the
control requirements and standardizes the system components
employed. The cutting system performs cutting against the direction
of fabric flow and can perform cuts in either linear or spline
configuration in the 0 degrees (horizontal left to right) to the 90
degrees (vertical) counter clockwise quadrant.
[0031] To address issues of out time for a given fabric and resin
system, the roll is encapsulated within its own refrigeration
module integrated into the chassis that supports and drives the
fabric. In-line IR panels can be incorporated to rapidly bring the
resin system to the desired temperature just prior to its
profiling/cutting and lay-up.
[0032] The PFE device can perform a wet lay-up process using
supplied dry fabric material. Individual heated pumped resin vat
systems are attached to the chassis both above and below the last
set of lay-up rollers at the surface of the mold, and identically
functioning roller/squeegee tools, with functionality and
positioning the same as the base module unit, perform the resin
impregnation process typically performed by hand. Excess resin is
vacuumed and recycled at the surface as the volume of resin
increases during the squeegee process.
[0033] To provide the most flexible production process, individual
PFE devices may be stored in a docking station about the robot cell
work envelope allowing for change in size or type of fabric being
placed in a given lay-up. PFE devices can be loaded with the
desired fabric and/or resin system at the docking stations and
therefore provide the lay-up system with uninterrupted
operation.
[0034] The PFE devices are controlled via their own onboard PLC
controller. When the robot arm engages the device, communication
and programming parameters are then transferred to the unit. If a
supply roll runs out before a given path has been completed, the
robot will be given instructions to return to that location upon
exchange or refill of the supply roll. The resin system will
function in a similar manner.
[0035] Options to the device may include vision and camera systems
to document the lay-up and real time, NDT (non-destructive
testing), three dimensional stitching and UV (ultraviolet) curing
and documentation to expedite the inspection process prior to the
placement of the parts within an autoclave or performing vacuum
bagging.
[0036] Because the PFE device has been designed for use by
commercial robots, expansion of the work envelope in all three axes
is made simple. By integrating floor track systems, wall mount
monorail systems and gantries, the robot may be shuttled,
wall-mounted or inverted via an external transport system.
Commercial robot controllers are capable of communicating to as
many as twenty-four axes or more in either coordinated or
simultaneous motion control. This, therefore, addresses the last
issue, that of the cost of implementation. Turnkey system costs can
typically be paid for in as little as 18-24 months, depending upon
the configuration selected, including the robot and all required
`off the-shelf` software, while providing greatly enhanced thru-put
with unmatched repeatability.
[0037] Programming of the system or cell may be performed either at
the cell via a hand held teach pendant or off-line using software
models of the part to laid up and the calibrated kinematic model of
the robot and any peripheral positioning devices.
[0038] This composite fabric tape lay-up invention includes a new
complete Precision Feed End-Effector (PFE) alone and in combination
with a robot, and also the component subassemblies of the
suspension and tape-dispensing system, the in-line fabric profiling
or tape cutting system, and the refrigeration and heating systems.
This invention includes various combinations of these subassemblies
and various embodiments of same.
[0039] This invention incorporates or cooperates with certain known
parts or subassemblies such as a commercially available robot, a
supply roll of composite tape having pre-selected composition,
characteristics and dimensions, and a mold, plug or mandrel onto
which the tape is laid-up. For convenience hereinafter the term
"mold" will be used to represent mold, plug or mandrel.
[0040] In the tape lay-up process the PFE delivers the tape along a
path that is a straight line across the surface of the mold. The X,
Y, Z spatial location of the path and the direction and speed along
the path are predetermined in the controller. Thereafter the PFE
conforms to the Z-component contours to the left and right of the
path (line) by the contact and feedback of the suspension system,
while maintaining relative perpendicularity to the mold
surface.
[0041] More particularly, force-sensing feedback is achieved at the
faceplate of the robot along the sixth axis, where it will average
the combined forces from the lower suspension system. The
dispensing rollers will now be totally compliant with the mold
surface at every point of travel. The force feedback located at the
sixth axis of the faceplate of the robot combined with force
feedback information in the lower suspension system will provide
the desired force for each given lay-up. Force sensing is done
electrically or pneumatically or by a combination of both.
[0042] Thus, the PFE tape dispensing device comprises one or more
PFE basic module units, each having a set of three articulated
lay-up rollers, each module thus is capable of laying six inches of
tape width. When "daisy-chained" together such basic module units
can lay tape of up to a sixty-inch width or greater. The length,
diameter and number of these rollers can be varied as required.
[0043] In the basic PFE module the center roller is set at a fixed
distance relative to the robot arm, and the two side rollers are
either coaxial with the center roller or articulated or angulated
to define with the center roller a line of contact that is convex,
concave curve, sinusoidal or some combination of these forms. In
this module the three rollers are in an end-to-end configuration
with the center roller rotatably mounted at a fixed elevation
relative to the robot arm and the side rollers pivotal relative to
the central roller so that all three rollers remain in the same
plane which is generally parallel to the plane of the tape
descending onto these rollers. For convenience of description
herein, we will assume the PFE is below the robot arm and the mold
is below the PFE; however, PFE orientation may also be horizontal,
upward or angled.
[0044] The invention herein has been described above with respect
to various of its components and operations. A more global or
generalized description now follows.
[0045] This invention is a totally new apparatus and method for
composite fabric and tape lay-up that will be summarized below,
first as to general concepts, and thereafter as to components and
details. For convenience herein, the term tape is intended to mean
tape or composite fabric, and tape lay-up means tape or composite
fabric lay-up.
[0046] The invention begins with the object to form with layers of
tape a predetermined shape such as an airplane wing or fuselage or
a boat hull, windmill blade, or other configuration. The topography
of the desired shape is initially defined by a physical mold,
mandrel or plug or by a computer generated simulation of the
desired shape which is subsequently formed into a physical mold. A
plan is established to lay-up strips of tape of predetermined width
onto the mold, with successive passes the tape strips being laid up
either with overlapping edges or adjacent buttjoints. The
centerline of each strip will be laid along a predetermined path
which is established from points defined by x, y, z coordinates and
further defined by pitch, yaw and roll values. Thus, a program is
established to traverse the mold surface by successive parallel
passes of a contact roller module which lays a strip of tape in
each pass. As described below, there may be one, two or more
aligned contact roller modules for each pass. Also, the contact
roller module(s) may be fixed in position with the mold being
rotated to achieve the pass. The passes achieve lay-up of strips of
tape in parallel paths onto the mold regardless of the changing
contours of the mold surface. Each strip of tape is laid-up to lie
with its center line aligned with a line of said program of
parallel lines on said surface.
[0047] The contact roller module may have a single contact roller
or a set of two or three rollers, or two or more modules may be
aligned and linked together. For understanding this invention, this
first example will assume a single module with a center contact
roller and two adjacent side or outboard rollers. These rollers are
axially linked, all are freely rotatable, and the outboard rollers
may be articulated or angled with respect to the center roller.
[0048] The center roller is positioned by the robot to be
contacting the mold with the center line of the roller aligned with
the programmed line to be traversed on the mold, and it is
positioned to contact the mold and thus to be at a predetermined
offset distance from the robot. This center roller is maintained in
contact with the mold by a suspension system that applies a
predetermined force to press the tape down against the mold during
the tape lay-up process. The robot is programmed to direct the
module and its center roller to traverse the straight line (each
straight line pass) and at all times to remain in said
predetermined pressure contact, regardless of elevational changes
of the surface or changes in incline of the surface. At all times
the robot orients the module to be perpendicular to the mold
surface being contacted.
[0049] Thus, at each moment there is a specific first area of mold
surface being contacted by the central roller. Adjacent said first
area are side areas which may be contoured downward, for example,
relative to the first area. It is necessary for the outboard
rollers to contact with pressure these side areas during the tape
lay-up. The robot's computer program does not need to "know" the
topography of these side areas, because the suspension system will
constantly urge the outboard rollers downward into contact with
said side areas. The tape being laid up has width essentially the
same as the total width of the three rollers. A feedback aspect of
the suspension system will register the force applied and adjust
the downward force to the designated amount. The suspension and
feedback system may average or at least evaluate the forces at the
center and outboard rollers so that all three rollers apply force
on the tape being laid-up at approximately the same desired
force.
[0050] The suspension system may utilize gas, pneumatic, mechanical
spring or other elements. This system allows the side rollers to be
compliant with contours that extend upward (closer to the robot) or
extend downward (farther from the robot) while still applying a
downward force within a predetermined range.
[0051] As noted above, a series of contact roller modules may be
linked together to have total width of five to 200 feet or more,
and thus to lay-up tape of equivalent width. With multiple modules,
the suspension system requires additional linkages and feedback
elements; however, the overall system still uses the central roller
to follow a designated path that is programmed into the control
means and effectuated by the robot, and the suspension system that
causes the outboard rollers and linked additional contact roller
modules to be compliant with the mold surface and to apply the
designated force during lay-up.
[0052] Additional aspects of this system include profiling or
cutting one or both side edges of the tape to deliver each strip
with the designed shape as dictated by the control means, and
cutting each strip to have a desired length before it leaves the
dispensing head.
[0053] During each lay-up phase a strip is driven by feed rollers
from the feed roll to the profiling and cutting unit, and thence by
lower feed rollers to the contact roller module(s). During the
delivery of the cut strip to the contact rollers, it is desired to
form the tape into a forward directed or bullnose curve just before
it contacts the mold surface and starts under the contact roller.
The lower part of the tape strip is thus formed to bulge in a curve
or wave form directed forward in the direction of movement of the
contact rollers. The result is most significant, in that the tape
begins its descent in a vertical plane generally perpendicular to
the mold surface being contacted, then the tape bulges forward,
then curves downward and finally rearward and goes under the
contact roller. The tape in being laid-up thus goes through a
transition from vertically downward to horizontally rearward, which
is a 90.degree. turn, but it does so by first traversing a
relatively large radius forward curve, so that it never takes a
sharp turn and it is neither stretched nor crumpled as it makes the
turn and becomes laid up under the contact roller(s).
[0054] This forward bullnose curve is established and maintained by
an idler support roller situated within the bullnose for
establishing, supporting and maintaining the bullnose shape. This
support roller is itself supported by linkages of suspension and
feedback means which direct the support roller as regards the shape
of the bullnose curve and the force applied depending on many
factors, including but not limited to the speed of lay-up, the
weight, size and characteristics of the tape, and the mold contours
encountered.
DESCRIPTION OF THE DRAWINGS
[0055] FIG. 1 is a top and front perspective view of the new PFE
attached to a robot,
[0056] FIG. 1A is a front perspective view of the PFE of FIG. 1
shown in horizontal extension,
[0057] FIG. 1B is a front perspective view of the PFE of FIG. 1
shown in downward extension,
[0058] FIG. 1C is a right rear perspective view of the PFE of FIG.
1B,
[0059] FIG. 1D is a left rear perspective view of the PFE of FIG.
1B,
[0060] FIG. 1E is a rear perspective view of the PFE of FIG. 1B
shown with the chassis in open condition,
[0061] FIG. 1F is a left front perspective view,
[0062] FIG. 2 is a left side elevation of FIG. 1,
[0063] FIG. 3 is a schematic view showing the path of the tape
through the PFE with added illustrations to the bullnose formation
of the tape fabric,
[0064] FIG. 4 is a left side elevation view partially in section of
the PFE,
[0065] FIG. 4A is a simplified version of FIG. 4,
[0066] FIG. 5 is a top and front perspective view of the PFE within
its housing,
[0067] FIG. 6 is a front elevation view of the PFE of FIG. 4
including four PFE modules,
[0068] FIG. 6A is the same as FIG. 6, without the supply and
take-up rolls,
[0069] FIG. 7 is top and front perspective view of the PFE of FIGS.
4 and 6,
[0070] FIG. 7A is the same as FIG. 7, with the supply roll and
take-up rolls shown and with the cutting system,
[0071] FIG. 7B is the same as FIG. 7 without the supply and take-up
rolls and without the cutting system and cutting plane,
[0072] FIG. 7C is the same as FIG. 7B without hot air ducts,
[0073] FIG. 7D is a top and front perspective view as a simplified
version of FIG. 7B,
[0074] FIG. 7E is a front elevation view of FIG. 7D,
[0075] FIG. 8 is a front elevation view of FIG. 7B,
[0076] FIG. 8A is the same as FIG. 8 without the cutting plane and
hot air ducts,
[0077] FIG. 9 is a top and front perspective view of FIG. 7C,
[0078] FIG. 10 is a front elevation view of FIG. 9,
[0079] FIG. 11 is a top and front perspective view of the placement
suspension system seen in FIG. 9 with separation panels removed and
deflection panels showing,
[0080] FIG. 11A is a front elevation view of FIG. 11 with
separation panels removed and deflection panels showing,
[0081] FIG. 12 is the same as FIG. 11 with the deflection panels
removed,
[0082] FIG. 12A is the same as FIG. 12 with the deflection panels
removed,
[0083] FIG. 13 is a top and front perspective view of the lower
placement suspension system as seen in FIG. 11
[0084] FIG. 14 is a front elevation view of FIG. 13,
[0085] FIG. 15 is a top and front perspective view of a left link
subassembly of the lower placement suspension system as seen in
FIGS. 13 and 14,
[0086] FIG. 16 is a top and front perspective view of the center
link subassembly of the lower placement suspension system as seen
in FIGS. 13 and 14,
[0087] FIG. 17 is a top and front perspective view of the module
link subassembly left/right links of the lower placement suspension
system as seen in FIGS. 13 and 14,
[0088] FIG. 18 is a fragmentary front elevation view showing one
example of a profiled tape in the tape cutting unit,
[0089] FIG. 19 is a top plan view of a second embodiment of a
PFE,
[0090] FIG. 20 is a front elevation view of the PFE of FIG. 19,
[0091] FIG. 21 is a right side elevation view of the PFE of FIG.
19,
[0092] FIG. 22 is a top and front perspective view of the PFE of
FIGS. 19-21,
[0093] FIG. 23A, 23B and 23C are fragmentary front elevation views
of the lay-up roller configurations of the PFE of FIGS. 19-22,
[0094] FIG. 24 is a top and front perspective view showing the
lay-up roller configurations of FIG. 23,
[0095] FIG. 25 is a fragmentary perspective view of a support link
pair between the side rollers of two first tier modules and a
follower roller,
[0096] FIG. 26 is a fragmentary perspective view of a support link
between a center roller and a side roller of a basic module and a
follower roller,
[0097] FIG. 27 is similar to FIG. 25 but shows an end link,
[0098] FIGS. 28, 29 and 30 are similar to FIGS. 25, 26 and 27 but
show a follower blade instead of a follower roller
[0099] FIGS. 31A, 31B and 31C are fragmentary schematic views
showing a three-module tape-laying head in straight-line,
sinusoidal and wave shapes respectively.
[0100] FIG. 32 is a photo showing front perspective view of four
PFE module units partially assembled,
[0101] FIG. 33 is a photo showing top perspective view of FIG.
25,
[0102] FIG. 34 is a photo similar to FIG. 33 showing the PFE in
further assembled state,
[0103] FIG. 35 is a photo showing an enlarged front perspective
view of FIG. 32,
[0104] FIG. 36 is a photo showing an enlarged front elevation view
of FIG. 35,
[0105] FIG. 37 is a photo showing an enlarged right side
perspective view of FIG. 35,
[0106] FIG. 38 is a photo showing an enlarged top perspective view
of the upper link subassembly of FIG. 32,
[0107] FIG. 39 is a fragmentary and front perspective view of four
basic modules linked together and showing a first embodiment of
spring cylinders, with lines drawn to indicate an alternate
placement of these cylinders coupled to a bottom part of the
stanchions and a lower part of the module plates, and
[0108] FIG. 40 is a fragmentary schematic view showing the new PFE
on a gantry and carried on a mobile robot.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0109] This invention is illustrated herein in the form of a first
embodiment, shown primarily in FIGS. 1-18, where the PFE
tape-laying head has four basic modules or module units, each
having three rollers, and a second embodiment where the PFE has
three basic modules. While both of these embodiments are shown with
two side-by-side sets of basic modules where the tape is fed
between them, the preferred embodiments of this invention comprise
a variation of said first and second embodiments where one of said
two side-by-side sets of basic modules is replaced by a guide plate
as seen in FIG. 30. Thus, it should be understood that the
descriptions of the first and second embodiments are intended to
include this third embodiment variation. For convenience, some of
the components in the second embodiment which are essentially the
same as components in the first embodiment will be given the same
reference number. As will be explained later, in both the first and
second embodiments the rollers are configured as two sets of
rollers situated side-by-side, thus defining two planes generally
parallel to each other.
[0110] FIG. 1 shows the Precision Feed End-Effector, PFE, as a
complete system 10 which includes robot 12 and the PFE assembly 18.
The robot in these embodiments is available under the name Motoman
Robot Controller coupled with an off-line programming Software
package and providing up to twenty-four axes of control within the
work envelope.
[0111] In FIG. 1 the PFE unit 18 is shown generally within a
housing 20 with the suspension subsystem 22 shown at the bottom
portion of the PFE and a supply roller 24 providing the continuous
strip of composite fabric which may be dry or pre-impregnated for
use with this system. Obviously different supply rolls of different
composite tapes can be used as needed.
[0112] The PFE is connected to the robot arm 14 by a robot
attachment plate 16, since the PFE can be replaced by other PFE's.
A basic offset distance is established from said robot attachment
plate to the surface of the lay-up rolls at the lower portion of
the PFE subassembly, so that the placement of the tape by the
lay-up rolls is precisely located.
[0113] FIG. 1A shows the PFE device in horizontal orientation
extending from the robot arm.
[0114] FIG. 1B shows the apparatus with the PFE in downward
directed vertical orientation.
[0115] FIGS. 1C and 1D illustrate further views of the PFE
apparatus in downward extending orientation, and FIGS. 1E and 1F
show the same device in downward orientation with a side panel of
the housing pivoted up and away into a generally horizontal
orientation to expose the tape within and to expose the workings of
the PFE for adjustment or correction or change.
[0116] FIG. 2 shows the same apparatus as in FIG. 1 but in a side
elevation view.
[0117] FIG. 3 is a simplified schematic view and FIGS. 4 and 4A in
side elevation views show the path of the composite tape from the
supply roll 24 to the upper feed rolls 28 and then down past the
tape profiling or tape-cutting unit 32 as pulled by lower feed
rolls 30 and then to the suspension and placement subsystem 22
where the tape is delivered by lay-up rollers 36 onto a mold 37. As
further seen in this figure, the tape 25 as it passes over the
first set of feed rollers 28 is separated from its back-up or
support tape 25, the latter tape then travels to the take-up roll
26. The cutting unit or profiling unit which cuts the two side
edges of the tape 25 is indicated by reference number 32, and this
will be described in detail later.
[0118] [FIG. 3A shows one preferred variation of the apparatus of
FIG. 3 whereby] FIG. 3 further shows the tape is formed into a
bullnose curve 36A which bulges forward in the "X" direction of the
path of the contact roller module with its contact roller 36 and
follower roller 38. Within and supporting the bullnose curve is an
idler roller 36B carried by swing arm 36C that establishes the
position of roller 36B and the force it applies against the inside
surface of the bullnose portion of the tape. Swing arm 36C is part
of the dynamic suspension system which establishes and maintains
the bullnose wave form during lay-up. Such bullnose formation
allows the tape to traverse a wide radius curve before lay-up and
thus to avoid a right angle turn. It also supports the tape from
stretching or crumpling up due to mold surface contours being
encountered during lay-up.
[0119] The follower roller 38 is positioned primarily to track and
follow the zone or space between the adjacent ends of any two
contact rollers. Thus, for a single contact roller module having a
center pressure roller and two outboard rollers, there will be a
small space between the adjacent ends of the center roller and each
outboard roller. The tape in this "space" will not have been
contacted and pressed by any of the center and outboard rollers;
however, it will be contacted and pressed by the follower roller
which thus assures full compliance of the tape with mold surface
being covered. Follower rollers are carried by the suspension
system and positioned to track and cover all spaces missed by the
pressure rollers of the contact roller modules.
[0120] FIG. 4 in a more detailed view shows how the system begins
with supply roll 24, then upper drive rolls 28, then the cutting
unit 32 and then lower feed rolls 30. The tape between upper and
lower feed rolls is maintained taut during the cutting process;
however, the tape extending from the lower feed rolls 30 down to
the lay-up rolls is moved through the system solely because it is
pulled as the PFE is moved forward while the tape is laid-up onto
the mold.
[0121] This FIG. 4 further shows lower horizontal cutting head
drive elements 44 and 46 and upper cutting head drive 45. FIG. 4A
is similar to FIG. 4 showing the supply roll 24, take-up roll 26
and the cutting unit 32. At the lower portion of this assembly is a
hot air manifold 42 for heating pre-preg tape just before it
reaches the lay-up rolls 36. Also shown is a trailer, follower or
pressing roller 38 which presses the tape down against the mold in
the areas between the adjacent lay-up rollers.
[0122] FIG. 5 illustrates the upper portion of the PFE with a
housing or shroud 20 which encloses the upper mechanism including
the supply and take-up rolls and a refrigeration housing when
needed for pre-preg tape.
[0123] FIG. 6 begins to show more detail of the PFE, particularly
the cutting subassembly 32 which has two horizontal drives driven
by motors 44 and 46 and a vertical cutter drive 47 and 45. Also
seen in this view are the lower feed rollers 30 and the lay-up
rollers 36. The cutters are carried by slide members 33A and 33B
and are programed to provide the selected profile along the
opposite side edges of the tape as it passes through the cutter
unit.
[0124] FIG. 6A is similar to FIG. 6 but with the supply roll
removed for clearer showing of the upper-drive rolls 28.
[0125] FIG. 7 shows cutter members 33A and 33B driven by cutter
drives 44 and 46 respectively, the tape then passing downward to
lay-up rolls 36 which are also shown adjacent to the hot-air
manifolds 42. FIG. 7A is similar to FIG. 7 with the additional
viewing of the supply roll 24 and the take-up roll 26. FIG. 7B is
similar to prior FIGS. 7 and 7A and shows more clearly the upper
drive rolls 28 and lower drive rolls 30.
[0126] FIG. 7C is similar to 7B, but with a more clear illustration
of the chassis 27 which is formed of tubular beams joined together
into the rectangular framework for supporting the upper and lower
feed rolls, the cutting unit and the suspension placement subsystem
22.
[0127] FIG. 7D is further clarification of 7C, and FIG. 7E
illustrates more clearly details of the suspension subassembly 22
which has in this embodiment four modules represented by plates
50A, 50B, 50C, and 50D. Each module has three lay-up rollers 36,
and each module has the rollers of that module adjustable
positionally and each module is adjustable relative to the adjacent
modules. The adjustment of one module relative to another is
demonstrated in FIG. 23 which utilizes three instead of four
modules. In FIG. 23 the modules can be articulated so that all the
rollers line up in one continuous straight-line as seen in FIG. 23A
or they can define a convex curvature as seen in 23B or a concave
curvature as seen in 23C.
[0128] FIG. 8 shows parts of the PFE 22 including the cut plane 35
of the tape profiling unit 32 and how air ducts 42. FIG. 8A is
similar to FIG. 8 except that it omits the showing of the cutting
plane above the lower drive rollers in FIG. 8 and omits the hot air
ducts.
[0129] FIGS. 9-17 illustrate details of the structure of the
suspension and tape dispensing subsystem 22. As seen in FIG. 9
there are four modules represented by mounting plates 50A through
50D. Also seen in this figure is a second row of modules behind the
first row. As noted earlier, in a preferred embodiment the second
row of modules is eliminated, with the tape then descending around
the single set of rollers. In the embodiment shown in FIG. 9 the
tape would descend between the two sets of rollers and then be
laid-up around only one.
[0130] FIG. 12 illustrates more clearly the construction of the
suspension and placement subassembly.
[0131] Next will be described the PFE basic module, then an
assembly of basic modules into the four-module embodiment of FIGS.
1-18 and the three-module embodiment of FIGS. 19-24, and then the
pneumatic regulated force feedback system gas spring suspension
system applied to all the individual modules and to the groups or
subassemblies of modules. FIGS. 23A-23C provide overviews of the
simpler three-module embodiment.
[0132] As seen in these three figures, there are three modules
115A, 115B and 115C, having mounting plates 116A, 116B and 116C
respectively. FIG. 23A shows the rollers of each module in a
straight-line configuration and the rollers of the three modules in
a continuous straight-line configuration. FIG. 23B shows the center
rollers 130A, 130B and 130C of each module in its fixed straight
orientation on its respective mounting plate, and the adjacent side
rollers of each module are inclined to produce one comprehensive
convex curvature. Typically, the side or outboard rollers 131 and
132 in module 115 in FIG. 23A are inclined relative to the center
roller 130A. FIG. 23C merely shows the modules and their rollers
respectively reversed to produce a concave curvature.
[0133] As indicated generally in FIG. 23A, pivoting of the typical
side roller 131 is possible because of its suspension between inner
end coupling 118 at the end of arm 117 and outer end coupling 119
connected to further link 120, pivot 121, piston/cylinder 122 and
upper pivot 123.
[0134] The typical cylinder of gas spring 122 is a gas spring which
is set to position the link 120 such that the outer roller 131 is
nominally oriented in a straight-line with center roller 131. At
this nominal position the piston 122A exerts a predetermined force
through link 120 so that the roller applies a predetermined
pressure on the tape as it is laid. This predetermined pressure is
to be maintained regardless of whether roller 131 is inclined
upward, downward or stays straight. The robot arm carries the PFE
such that the center roller will be at a predetermined offset
distance from the robot mounting plate, and the various gas spring
cylinders are arranged to apply final predetermined forces to all
the modules, so that all the rollers apply the same force to the
tape being laid on a mold.
[0135] When any roller reaches a point on the path for which the
program dictates a change in elevation and/or orientation, the
control means directs the contact roller module to automatically
follow the designated course, and appropriate gas springs of the
whole suspension system adjust in length while maintaining
appropriate force so that the reoriented roller continues to exert
its predetermined force.
[0136] As seen in FIGS. 20-22, for example, each PFE has a main
chassis 40, a lower or first tier of basic modules and a second
tier mid-chassis 42 supporting the center module and connected side
modules. Between the first and second tier chassis are additional
gas spring cylinders 74A and 74B, and between the mid-chassis 72
and the main chassis 70 are vertical gas springs as required. All
are calibrated so that the lower tier rollers all exert the same
force regardless of their elevational positions or angular
orientations. Typically a second tier spring exerts a force
slightly greater than double that of a first tier spring since
there is one second tier spring associated with each two first tier
springs. For special situations force exerted by specific rollers
could be varied from others. FIGS. 21 and 22 illustrate in a
three-module system the first tier gas springs 122, 125 and the
second tier gas springs 74A, 74B.
[0137] FIGS. 9, 12, 12A, 13 and 14 show the gas spring suspension
system in a four-module system. FIG. 14 shows the bare and
simplified system of gas springs 60. FIG. 13 shows the system of
FIG. 13 with two adjacent sets of first tier rollers, with omission
of the mounting plates for each module. FIGS. 12 and 12A show this
suspension system with posts 52A, 52B and 52C added links 66 and 67
and pivot connection 68. FIGS. 11 and 11A add deflection panel
80.
[0138] FIG. 9 adds module mounting plates 50A, 50B, 50C and 50D and
chassis beam FIGS. 8 and 8A add chassis 27 and upper and lower feed
rollers 28, 30. FIGS. 7B-7D show more clearly the PFE chassis and
FIGS. 7 and 7A add the supply and take-up rolls 24, 26, and the
tape edge profiling unit 32 and heating ducts 42.
[0139] FIGS. 32-38 illustrate by photographs the components of the
PFE modular system having four linked modules. These photos show
the PFE suspension system in various degrees of assembly. These
photos show the mounting plates with support arms on each for the
center lay-up roller and lower drive cylinders, two on each
mounting plate to maintain the proper force in each of the side
rollers regardless of articulation. At the top of each mounting
plate is a system of further linkages for moving each module
relative to the adjacent module for creating the total articulation
of the system.
[0140] FIG. 39 shows the earlier embodiment of a four-module
tape-laying head where each module's generally triangular mounting
plate is connected at its top end to gas springs. The top end of
each of these gas springs is coupled to a vertical stanchion which
is coupled to a second tier gas spring (not shown). This photo also
shows a variation in structure whereby the first tier gas springs
are relocated. Now the first tier gas springs are each coupled
between the lower end of a stanchion and a lower part of a module
mounting plate, as compared to the prior arrangement of coupling
between upper parts of the stanchions and upper ends of the
mounting plates. This new arrangement reduces space requirements
and also positions each first tier gas spring in a more vertical
orientation which results in mechanically preferable force
application by the gas spring pistons. Each mounting plate is
vertically slidable between a rear guide plate seen behind the
mounting plate and a front guide plate that has been removed in
this photograph.
[0141] As stated earlier, the lay-up rollers are mounted in sets of
three on each module, namely a center roller between two side
rollers all in end-to-end relationship. Each set of rollers is
mounted on a first tier chassis which also has a first tier
pneumatic system for articulating the two side rollers so that
three rollers (on their respective central axis) can define either
a straight-line, or a concave or convex curved line or other
curvature. Thus, each side roller has an inner end pivotably
coupled to one end of the center roller and an outer end. Each
outer end is coupled to a gas spring secured between said outer end
and said first tier chassis.
[0142] Next, the four modules are coupled together such that their
combined twelve lay-up rollers can be articulated to define a
straight-line, or convex, concave or other curvature. For each
module the center roller has a fixed relationship to its first tier
chassis while the adjacent modules are movable by a similar
extendible-link (pneumatic or other). Here the center of said first
tier comprises two center modules and two outer modules. The second
tier comprises one center and two outer posts of said second tier
chassis. In this embodiment the stanchion or center post 52B as
seen in FIG. 12A, for example, joins two adjacent rollers which
establish the elevational reference point for the nominal position
of the whole suspension system. Angulations by these rollers, as
caused by their contact with curvature of the mold surface
initiates feedback from their respective first tier gas springs. A
change in elevation of these rollers while they remain coaxial, for
example, initiates feedback from their respective second tier gas
springs at the upper part of support 52B.
[0143] The tape edge profiling unit is seen in FIGS. 6, 6A, 7 and
7A and also in FIGS. 4 and 4A. As described earlier, the tape
passes between upper and lower feed rolls 28 and 33 which maintain
the tape taut during the cutting phase. FIG. 4 shows a separate
supply tape roll servomotor 24A. FIG. 6 tape cutter slides 33A and
33B which are directed by the controller to cut the two side edges
of the tape on-the-fly to produce the predetermined edge profiles
for each pass of the tape-dispensing head. Appropriate programming
with knowledge of the distance offset of the cutter from the tape
laying rollers, and the PFE speed of travel and the desired profile
will result in the correct cut. FIG. 18 shows a segment of tape
with a simple profiling on both side edges. Positioning of the
cutters is controlled by cutting unit servomotors drive system
including components 44, 45, 46 and 47. As described earlier,
cutting systems may use slitting, flying knife, water-jet or other
devices. Cutter slides 33A, 33B carry the selected type of cutting
device and are positioned within the PFE chassis 27.
[0144] A still further feature of the PFE tape-laying head is the
follower roller or other pressing element 38 seen in FIGS. 3, 4, 7,
11 and in FIGS. 24-29. As stated earlier, the preferred embodiment
of the PFE has a single set of rollers at the bottom of the tape
dispensing head. Due to the roller mounting arrangement which
allows each side roller adjacent a center roller to angulate in
addition to roll freely, a space exists between the adjacent ends
of each two adjacent rollers. Thus, as the tape is dispensed and
pressed by two adjacent rollers, a path of unpressed area will
result on the laid tape in the space between the adjacent ends of
each two adjacent rollers. To press this path a follower roller or
presser blade is positioned in that space behind each two adjacent
rollers and at the same elevation as their outer contact surface.
The follower roller thus has length substantially the same as the
width of said unpressed area or gap between adjacent ends of each
two adjacent rollers. This can be seen as roller 90 in FIGS. 25-27
and blade 91 in FIGS. 28 and 29, and roller 38 in FIGS. 3, 4, 7 and
11. Blade 91 is a very smooth low friction element and suitably
flexible to properly complement the pressure applied by the
principal rollers. In one embodiment the blade is made of plastic
such as polypropylene having flexibility of 60-70 Durometer rubber.
The follower element in FIG. 25, for example, is supported by the
bracket that supports the basic dispensing rollers and thus applies
the same force from pneumatic pressure regulated force feedback
system.
[0145] FIGS. 31A-30C show schematically how the rollers of FIG. 23A
can conform, for example, to flat, sinusoidal and/or undulating
surfaces on a mold.
[0146] The invention as shown in FIGS. 1 and 2, for example,
include a robot which is floor mounted and whose arm that supports
the PFE is moved according to the programmed articulation. FIG. 40
illustrates schematically how this invention can be utilized with a
very long mold to produce a pipe, boat or submarine hull, airplane
fuselage or satellite structure, or propellor, turbine blade or
windmill blade or a multitude of other structures. Here, the mold
100 represented for ease of illustration as a simple pipe, is
mounted to be rotatable. A series of PFEs 101 are attached to
robots 102 along a gantry 103. During a single revolution of the
mold the multiple PFEs can lay-up a sheet of fabric on the entire
length of the mold. In a very short time, multiple layers can be
laid up. In a generally similar manner one can achieve lay-up of
the interior surfaces of a rotated mold. With PFE systems like this
new composite fabric structures can be made that were never before
possible. As discussed earlier, substantially all types of
composite fabric may be utilized, both dry and pre-preg and those
requiring refrigeration and/or heating.
[0147] It should be understood that the foregoing description of
the invention is intended merely to be illustrative thereof and
that other modifications and embodiments may be apparent to those
skilled in the while still being within the spirit and scope of the
appended claims.
* * * * *