SYSTEMS AND METHODS FOR TRANSPORTING AND ASSEMBLING SEGMENTED WIND TURBINE BLADES
Systems and methods for transporting and assembling segmented wind turbine blades are disclosed. A system in accordance with a particular embodiment includes multiple transport devices that are each moveable as a unit from a blade fabrication site to a blade assembly site, and that have corresponding carriers positioned to carry corresponding spanwise segments of a wind turbine blade. The system can still further include a guide structure carried by at least one of the transport devices and coupled to a corresponding one of the carriers, with a motion path aligned with a corresponding blade axis. The guide structure can be positioned to guide the corresponding carrier along the motion path toward the other transport devices, e.g., to facilitate assembly of the blade segments.
The present application is a continuation of International Patent Application No. PCT/US2010/035957, filed May 24, 2010, entitled SYSTEMS AND METHODS FOR TRANSPORTING AND ASSEMBLING SEGMENTED WIND TURBINE BLADES, which claims priority to U.S. Provisional Application No. 61/180,812, and U.S. Provisional Application No. 61/180,816, both filed May 22, 2009 and both incorporated herein by reference.
TECHNICAL FIELDThe present disclosure is directed generally to systems and methods for transporting and assembling segmented wind turbine blades, including wind turbine blades having multiple segments aligned along a spanwise axis.
BACKGROUNDAs fossil fuels become scarcer and more expensive to extract and process, energy producers and users are becoming increasingly interested in other forms of energy. One such energy form that has recently seen a resurgence is wind energy. Wind energy is typically harvested by placing a multitude of wind turbines in geographical areas that tend to experience steady, moderate winds. Modern wind turbines typically include an electric generator connected to one or more wind-driven turbine blades, which rotate about a vertical axis or a horizontal axis.
In general, larger (e.g., longer) wind turbine blades produce energy more efficiently than do short blades. Accordingly, there is a desire in the wind turbine blade industry to make blades as long as possible. However, long blades create several challenges. Such blades are heavy and therefore have a significant amount of inertia, which can reduce the efficiency with which the blades produce energy, particularly at low wind conditions. In addition, long blades are difficult to manufacture and in many cases are also difficult to transport. Accordingly, there remains a need for large, efficient, lightweight wind turbine blades, and suitable methods for transporting and assembling such blades.
The present disclosure is directed generally to systems and methods for efficiently transporting and assembling wind turbine blade sections. Several details describing structures or processes that are well-known and often associated with such systems and methods, but that may unnecessarily obscure some significant aspects of the disclosure, are not set forth in the following description for purposes of brevity. Moreover, although the following disclosure sets forth several embodiments, several other embodiments can have different configurations or different components than those described herein. In particular, other embodiments may have additional elements or may lack one or more of the elements described below with reference to
In a particular aspect of an embodiment shown in
In any of the foregoing embodiments, individual segments 116 can include ribs 142, truss members 143, and portions of the spars 170 that extend for the length of the segment 116. The segments 116 can be joined to each other by joining adjacent spar portions, e.g., as discussed later with reference to
In a particular embodiment shown in
Referring now to
In an embodiment shown in
In a particular embodiment, once the carrier 780 has the desired position, the resistance provided by the threads of the studs 166 can prevent the carrier 780 from changing its elevation. Optionally, the studs 166 can be further secured, e.g., with locknuts. Similarly, the resistance provided by the windings and/or internal gearing of the axial motion actuator 162 and the lateral motion actuator 163 can prevent the carrier 780 from moving from the desired position in the axial and lateral directions, respectively. In other embodiments, separate locking devices can be used for this purpose.
In any of the foregoing embodiments, the motion device 160 can also be automated. For example, the motion device 160 can include a processor (e.g., a computer-based controller), and an input device. An operator can input a desired location and/or orientation for the carrier 780, and the motion device 160 can automatically drive the carrier 780 to the desired location and/or orientation using one or more sensors (e.g., position sensors) in a closed loop arrangement. In still further embodiments, the actuators 162, 163 can be removable, so that they can be moved from one portion of a support 123 to another, or from one support 123 to another, thereby reducing the number of actuators required to position the blade segments.
As shown in
As is also shown in
In a particular embodiment, the carrier 780 is detached from the second portion 127, the first portion 126 and the base 124 before the blade segment 116c is placed on the transport platform, as described above with reference to
In other embodiments, the alignment system can have other arrangements. For example, the alignment system 190 can include multiple emitters 192, and/or a single receiver 193. In still further embodiments, the alignment system can include components that do not rely on emitting or receiving radiation for suitable operation.
As described above, the platform alignment system 190 can be used to align each of the transport platforms 121 relative to the others in a generally horizontal or other desired plane. In addition, each of the transport platforms 121 can be aligned axially. For example, each of the transport platforms 121a-121c can include a corresponding axial guide path A1-A3 along which the corresponding blade segment 116 is moved. In a particular embodiment, each of the axial guide paths A1-A3 is aligned along a common axis. In other embodiments, however, the guide paths may be angularly offset from each other, depending upon the desired orientation of the plane at the interface between the neighboring blade segments. Also, as discussed above with reference to
The first portion 171a can include multiple, stacked, laminated first layers 172a, and the second portion 171b can include multiple, stacked, laminated second layers 172b. In another embodiment, the layers 172a, 172b can be made in one piece without gluing. In a particular embodiment, the layers 172a, 172b can be formed from a unidirectional fiber material (e.g., fiberglass or a carbon fiber) and a corresponding resin. Each of the layers 172a, 172b can be formed from a single ply or multiple plies (e.g., six plies). The layers 172a, 172b can be prepared layers, hand lay-ups, pultrusions, or can be formed using other techniques, e.g., vacuum-assisted transfer molding techniques. The first layers 172a terminate at first terminations 173a, and the second layers 172b terminate at second terminations 173b. Neighboring terminations 173a, 173b located at different positions along a thickness axis T can be staggered relative to each other along a span axis S to create the zig-zag bond line 176. This arrangement produces projections 174 and corresponding recesses 175 into which the projections 174 fit. In a particular aspect of this embodiment, each layer has a termination that is staggered relative to its neighbor, except where the bond line 176 changes direction. At such points, two adjacent layers can be terminated at the same location and bonded to each other, to prevent a single layer from being subjected to increased stress levels. The zig-zag bond line 176 can be symmetric, as shown in
During a representative manufacturing process, each of the first layers 172a are stacked, bonded and cured, as are each of the second layers 172b, while the two portions 171a, 171b are positioned apart from each other. The layers 172, 172b can be pre-cut before stacking so that when stacked, they form the recesses 175 and projections 174. After the two portions 171a, 171b have been cured, the recesses 175 and/or projections 174 can be coated and/or filled with an adhesive. The two portions 171a, 171b are then brought toward each other so that projections 174 of each portion are received in corresponding recesses 175 of the other. The joint region can then be bonded and cured.
To join the first blade segment 116a to the second blade segment 116b, a push/pull device 1210 (e.g., a manual or automatic spreader bar, come-along, hydraulic device, etc. that can pull objects together or push objects apart at a controlled rate and with sufficient force) is temporarily installed between the corresponding truss attachment portions 154a and 154b. More specifically, in the illustrated embodiment the push/pull device 1210 includes a first clevis 1212a on one end and a second clevis 1212b on the opposite end. The clevises 1212 are attached to the body of the push/pull device 1210 by threaded rods 1216 that can be drawn into the body of the push/pull device 1210 or extended out of the body of the push/pull device 1210 by appropriate operation of a manual actuator 1214 (e.g., a ratchet handle). Each of the clevises 1212 can be releasably attached to the corresponding truss attachment portion 154 by a temporary fastener 1218 (e.g., a bolt) that extends through the clevis 1212 and the corresponding aperture 1202. After the push/pull device 1210 has been coupled to the opposing truss attachment portions 154, the actuator 1214 can be moved up and down in the appropriate direction to ratchet the spar end portions 171c and 171d together and/or apart as desired.
To join the first blade segment 116a to the second blade segment 116b in accordance with one embodiment of the disclosure, a second push/pull device (not shown) is operably coupled between the third and fourth truss attachment members 150c, 150d on the first spar 170a, and a third push/pull device (also not shown) is operably coupled between the fifth and sixth truss attachment members 150e, 150f on the third spar 170c, as described above with reference to the second spar 170b. The spars 170 are then simultaneously pulled together by operation of the three push/pull devices 1210 to “dry fit” the end portions 171 and confirm that they are properly aligned. After this has been done, the push/pull devices 1210 are operated to separate the spar end portions 171 so that the end portions 171 can be suitably prepared for bonding as described in detail below.
Once the end portions 171 of the spars 170 have been fit checked as described above, the overlapping surfaces of the projections/recesses 174/175 (
In the illustrated embodiment, a clamping assembly 1330 can include a clamping tool 1320 that includes at least two opposing plate portions 1321a, 1321b that clamp inwardly on the joint between the engaged spar end portions 171c, 171d. The clamping tool 1320 applies adequate pressure to the joint during the adhesive curing process. The clamping tool 1320 can include manually operable clamping devices (e.g., such as C-clamps) and/or automatic clamping devices, such as hydraulic clamps. In addition, a vacuum blanket or bag 1322 can be wrapped around the joint and evacuated to remove any air pockets from the adhesive bond line. Moreover, in one particular aspect of this embodiment, a heating element 1324 (e.g., an electro-thermal heating element) can also be positioned locally around the joint to ensure proper curing of the adhesive at a suitable temperature for a suitable period of time (e.g., 24 hours). In the other embodiments, the heating element 1324, the vacuum bag 1322, and/or the clamping tool 1320 can be omitted, and the bonded joint can be positioned in an autoclave or other suitable apparatus for elevating the temperature and/or pressure of the joint to ensure suitable curing of the adhesive. Although only a single clamping assembly 1330 is illustrated in
In other embodiments the spar 170 can be joined using techniques other than those described above with reference to
The foregoing process can be used to connect the first and second blade segments, and then to connect the second and third blade segments. The order in which the process steps are completed can be changed in other embodiments. For example, the second and third segments can be attached to each other first, and then the first segment can be attached to the second segment. Once the spars 170 of adjacent blade segments are connected, a section of skin 115 (
In
Referring next to
In operation, an operator can adjust the axial position, lateral position, and yaw angle of the second blade segment 116b by rolling the second transport device 1480b appropriately. The operator can adjust the vertical position of the second blade segment 116b by adjusting each of the engagement members 1484 (e.g., by the same amount). The operator can adjust a rotation angle R1 (e.g., a roll angle) of the second blade segment 116b relative to a first axis A1 by adjusting the engagement members 1484 on one side of the first axis A1 by a different amount than the engagement members 1484 on the other side of the first axis A1. The operator can adjust a transverse rotation angle R2 (e.g., a pitch angle) of the second blade segment 116b relative to a second (transverse) axis A2 by adjusting fore and aft engagement members 1484 by different amounts. When the second blade segment 116b has the proper orientation relative to the first blade segment 116a, the operator can roll the second transport device 1421b toward the first blade segment 116a as indicated by arrow T1 to align the ends of the spars 170a-170c carried by each of the first and second blade segment 116a, 116b. The foregoing operations can be completed manually, or via powered drivers (e.g., motors) or other devices.
In
In
One feature of an embodiment described above with reference to
Another feature of several of the foregoing embodiments is that the blade segments can be easily transported from one or more manufacturing facilities to an installation site using conventional transport systems e.g., highway trucks, trains, or barges. Because the blade is segmented, it is easier to transport than it would be if it were completely assembled at the manufacturing site. In addition, the transport platforms can include guide structures that accurately align each of the blade segments relative to neighboring segments to facilitate accurate and repeatable assembly techniques. This in turn can produce more uniform blades, despite the fact that the blades are segmented. As a result, the blades can operate more efficiently when installed on corresponding wind turbines, and can reduce maintenance costs over the life-time of the blades.
From the foregoing, it will be appreciated that specific embodiments have been described herein for purposes of illustration, but that various modifications may be made without deviating from the present disclosure. For example, the guide structures described above may have arrangements other than nested portions that are each movable along a single axis. The guide structures may include features other than rollers to control the motion of the supports relative to each other. In another embodiment, the guide structure can be configured to facilitate restricted rotational motion, in addition to restricted linear motion. The supports can have other arrangements, including arrangements in which the supports extend above the blade and straddle the blade, with the blade supported (e.g., suspended) from above. In still further embodiments, not all the transport platforms 121 provide axial motion for the corresponding blade segment. For example, the second blade segment 116b can have a fixed axial position relative to the second transport platform 121b, and the first and third segments 116a, 116c can move toward opposing ends of the centrally located second segment 116b. While
Certain aspects of the disclosure described above in the context of particular embodiments may be combined or eliminated in other embodiments. For example, the motorized or otherwise powered actuators described in the context of providing lateral and axial motion may be applied to vertical motion in particular embodiments. The carriers and guide structures described in the context of the first transport devices 121, 1421a may be combined with the second transport device 1421b in particular embodiments. Further, while advantages associated with certain embodiments have been described in the context of those embodiments, other embodiments may also exhibit such advantages. Not all advantages need necessarily exhibits such advantages to follow within the scope of the present disclosure. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein.
Claims
1. A system for assembling spanwise segments of a wind turbine blade, comprising:
- a first transport device being movable as a unit from a blade fabrication site to a blade assembly site, the first transport device having a first carrier positioned to carry a first spanwise segment of a wind turbine blade with the first segment aligned along a first blade axis;
- a second transport device being movable as a unit from a blade fabrication site to the blade assembly site, the second transport device having a second carrier positioned to carry a second spanwise segment of a wind turbine blade with the second segment aligned along a second blade axis; and
- a guide structure carried by at least one of the first and second transport devices, the guide structure being coupled between the at least one transport device and a corresponding one of the carriers, the guide structure having a motion path aligned with a corresponding one of the first and second blade axes, the guide structure being positioned to guide the corresponding carrier along the motion path toward the other of the first and second transport devices.
2. The system of claim 1 wherein the guide structure is positioned to guide the corresponding carrier in a linear manner.
3. The system of claim 1 wherein the first and second transport devices are wheeled.
4. The system of claim 3 wherein the first and second transport devices include corresponding highway truck trailers.
5. The system of claim 1, further comprising a drive mechanism carried by at least one of the first and second transport devices, the drive mechanism being positioned to drive at least one of the first and second carriers relative to the other along the guide path.
6. The system of claim 1 wherein the guide structure includes a base portion carried by the first transport device, a first portion carried by the base portion and movable relative to the base portion along a restricted first motion path, and a second portion carried by the first portion and movable relative to the first portion along a restricted second motion path, transverse to the first motion path.
7. The system of claim 6 wherein the second portion includes a roller assembly that is movable relative to the first portion and that is releasably engaged with the first carrier.
8. The system of claim 6 wherein the first portion includes a first roller assembly that is engaged with the base and rollable relative to the base along the first motion path, and wherein the second portion includes a second roller assembly that is engaged with the first portion and rollable relative to the first portion along the second motion path.
9. The system of claim 6, further comprising:
- a first driver operatively coupled between the base and the first portion to move the first portion relative to the base; and
- a second driver operatively coupled between the first portion and the second portion to move the second portion relative to the first portion.
10. The system of claim 6 wherein the base includes an axial guide, and wherein the first portion includes a roller assembly, and wherein the roller assembly include a first, load-bearing roller positioned to rotate about a generally horizontal axis, and a second, guide roller positioned to rotate about a non-horizontal axis.
11. The system of claim 1 wherein the guide structure is a first guide structure positioned between the first transport device and the first carrier, the first carrier being movable along the first blade axis, and wherein the system further comprises a second guide structure positioned between the second transport device and the second carrier, the second carrier being movable along the second blade axis.
12. The system of claim 1, further comprising:
- a driver device operatively coupled to the guide structure to move the corresponding carrier along the motion path;
- a sensor positioned to sense a location of the carrier; and
- a controller operatively coupled to the driver device and the sensor, the controller being programmed with instructions that, when executed, automatically activate the driver to move the carrier in response to a signal received from the sensor.
13. A system for assembling spanwise segments of a wind turbine blade, comprising:
- a transport device;
- an all-terrain positioning unit depending from the transport device and activatable to move the transport device along a first axis;
- a carrier supported by the transport device, the carrier being positioned to support a spanwise-extending wind turbine blade segment; and
- multiple engagement members depending from the carrier, with individual engagement members releasably connectable to the blade segment, and movable relative to the carrier to adjust a vertical position of the blade segment, a first rotation angle of the blade segment relative to the first axis, and a second rotation angle of the blade relative to a second axis transverse to the first axis.
14. The system of claim 13 wherein the positioning unit includes four all-terrain tires.
15. The system of claim 13 wherein the multiple engagement members include four engagement members, and wherein individual engagement members include a flexible tension member.
16. The system of claim 13 wherein the carrier includes multiple upright support members, and wherein the multiple engagement members include four engagement members, and wherein each engagement member includes a flexible strap having an adjustable length portion between the carrier and the blade segment.
17. A method for assembling spanwise segments of a wind turbine blade, comprising:
- transporting a first assembled spanwise segment of a wind turbine blade as a unit from a blade fabrication site to a blade assembly site while the first blade segment is carried by a first transport device;
- transporting a second assembled spanwise segment of a wind turbine blade as a unit from a blade fabrication site to the blade assembly site while the second blade segment is carried by a second transport device;
- at the blade assembly site, moving at least one of the first and second blade segments relative to the other along a restricted guide path, while the first blade segment is carried by the first transport device and the second blade segment is carried by the second transport device;
- connecting the first and second blade segments to each other while the first blade segment is carried by the first transport device and the segment blade section is carried by the second transport device;
- separating the connected first and second blade segments from the first and second transport devices; and
- mounting the first and second blade segments as a unit to a wind turbine.
18. The method of claim 17 wherein separating the first and second blade segments from the first and second transport devices includes:
- disengaging the second blade segment from the second transport device while the connected first and second blade segments are carried by the first transport device;
- carrying the connected first and second blade segments from the assembly site to the wind turbine with the first transport device; and
- removing the connected first and second blade segments as a unit from the first transport device.
19. The method of claim 17 wherein transporting the first assembled spanwise segment of the wind turbine blade includes transporting the first segment via a first over-the-road truck-drawn trailer, and wherein transporting the second assembled spanwise segment of the wind turbine blade includes transporting the second segment via a second over-the-road truck-drawn trailer.
20. The method of claim 17, further comprising moving at least one of the first and second blade segments relative to the corresponding transport device and relative to the other blade segment at the assembly site prior to connecting the first and second blade segments.
21. The method of claim 20 wherein moving at least one of the first and second blade segments relative to the other includes moving the at least one blade segment along a linear axis while restricting or preventing motion of the at least one blade segment transverse to the linear axis.
22. The method of claim 20 wherein moving at least one of the first and second blade segments relative to the other includes moving the at least one blade segment along motion path that includes components in two orthogonal directions.
23. The method of claim 20 wherein moving at least one of the first and second blade segments relative to the other includes connecting a pulling device between the first and second blade segments and drawing the at least one blade segment toward the other with the pulling device.
24. The method of claim 17 wherein transporting the first assembled spanwise segment includes transporting the first assembled spanwise segment with a carrier while the carrier has a fixed position relative to the first transport device, and wherein the method further comprises removably positioning a guide structure between the carrier and the first transport device prior to moving the first blade segment, and wherein moving at least one of the first and second blade segments relative to the other along a restricted guide path includes moving the first blade segment along a restricted guide path established by the guide structure.
25. The method of claim 17 wherein carrying the first blade segment includes carrying multiple assembled blade segments with the first transport device.
26. The method of claim 17 wherein transporting a first assembled spanwise segment of a wind turbine blade includes transporting the first segment from a first fabrication site, and wherein transporting a second assembled spanwise segment of a wind turbine blade includes transporting the second segment from a second fabrication site.
27. A method for assembling spanwise segments of a wind turbine blade, comprising:
- transporting a first assembled spanwise segment of a wind turbine blade as a unit on a surface road from a blade fabrication site to a blade assembly site while the first blade segment is supported by a first carrier that is in turn supported by a first truck-drawn trailer;
- transporting a second assembled spanwise segment of a wind turbine blade as a unit on a surface road from a blade fabrication site to the blade assembly site while the second blade segment is supported by a second carrier that is in turn supported by a second truck-drawn trailer;
- transporting a third assembled spanwise segment of a wind turbine blade as a unit on a surface road from a blade fabrication site to the blade assembly site while the third blade segment is supported by a third carrier that is in turn supported by a third truck-drawn trailer;
- at the assembly site, aligning the first and second truck-drawn trailers relative to each other, while the first blade section is carried by the first truck-drawn trailer and the second blade section is carried by the second truck-drawn trailer;
- at the assembly site, aligning the first and second carriers relative to each other, while the first blade section is carried by the first truck-drawn trailer and the second blade section is carried by the second truck-drawn trailer;
- moving at least one of the first and second carriers relative to the other along a restricted motion path to position the first and second spanwise segments adjacent to each other;
- connecting the first and second blade segments to each other while the first blade segment is carried by the first truck-drawn trailer and the second blade segment is carried by the second truck-drawn trailer;
- moving at least one of the second and third carriers relative to the other along a restricted motion path to position the second and third spanwise segments adjacent to each other;
- connecting the second and third blade segments to each other while the second blade segment is carried by the second truck-drawn trailer and the third blade segment is carried by the third truck-drawn trailer;
- removing the first, second and third blade segments from the first, second and third truck-drawn trailers; and
- mounting the first, second and third blade segments as a unit to a wind turbine.
28. The method of claim 27 wherein connecting the first and second blade segments includes:
- aligning a first spar end portion of the first blade segment with a second spar end portion of the second blade segment;
- aligning a third spar end portion of the first blade segment with a fourth spar end portion of the second blade segment; and
- moving the first spar end portion toward the second spar end portion and the third spar end portion toward the fourth spar end portion to connect the first spar end portion to the second spar end portion and connect the third spar end portion to the fourth spar end portion.
29. The method of claim 28 wherein the first and second end spar portions include staggered layers of material that form a non-monotonically varying bond line when the two end spar portions are connected.
30. The method of claim 28, further comprising temporarily coupling a compressing device between the first spanwise segment and the second spanwise segment, wherein moving the first spar end portion toward the second spar end portion and the third spar end portion toward the fourth spar end portion includes acuating the compressing device to draw the first spanwise segment and the second spanwise segment together.
31. A method for assembling spanwise segments of a wind turbine blade, comprising:
- transporting a first assembled spanwise segment of a wind turbine blade as a unit to a blade assembly site;
- transporting a second assembled spanwise segment of a wind turbine blade as a unit to the blade assembly site;
- at the assembly site, connecting the first and second segments to each other;
- carrying the first and second segments with a transport device;
- transporting the connected first and second segments as a unit from the assembly site to a wind turbine, with the transport device;
- removing the connected first and second segments, as a unit, from the transport device; and
- installing the connected first and second segments, as a unit, to the wind turbine.
32. The method of claim 31 wherein transporting a first segment includes transporting the first segment while the first segment is carried by a first transport device, and wherein transporting a second segment includes transporting the second segment while the second segment is carried by a second transport device, and wherein connecting the first and second segments includes connecting the first and second segments while the first segment is carried by the first transport device and the second segment is carried by the second transport device, and wherein transporting the connected first and second segments includes transporting the connected first and second segments with the first transport device and not the second transport device.
33. The method of claim 31 wherein transporting a first segment includes transporting the first segment over a first distance and at a first average rate, and wherein transporting the second segment includes transporting the second segment over a second distance and at a second average rate, and wherein transporting the connected first and second segments includes transporting the connected first and second segments over a third distance less than each of the first and second distances, and at a third average rate less than each of the first and second average rates.
34. The method of claim 31 wherein the connected first and second segments have a connected segment length, and wherein transporting the connected first and second segments as a unit includes transporting the connected first and second segments with at least 50% of the connected segment length cantilevered relative to the first transport device.
35. A method for assembling spanwise segments of a wind turbine blade, comprising:
- transporting a first assembled spanwise segment of a wind turbine blade as a unit to a blade assembly site;
- transporting a second assembled spanwise segment of the wind turbine blade as a unit to the blade assembly site;
- carrying at least the second segment with a transport device at the assembly site;
- rolling the transport device over rough terrain at the assembly site to position the second segment adjacent to the first segment;
- connecting the first and second segments to each other at the assembly site;
- installing the connected first and second segments, as a unit, on a wind turbine.
36. The method of claim 35, further comprising transporting the connected first and second segments as a unit from the assembly site to the wind turbine.
37. The method of claim 35:
- wherein carrying the second segment includes supporting the second segment at four different locations with four independently adjustable engagement members;
- wherein rolling the transport device includes rolling the transport device over unpaved terrain to adjust an axial position, lateral position, and yaw angle of the second segment; and
- wherein the method further comprises: adjusting the engagement members to adjust a height of the second segment; adjusting the engagement members to adjust a pitch angle of the second segment relative to the ground; and adjusting the engagement members to adjust a roll angle of the second segment relative to the ground.
38. The method of claim 35 wherein carrying the second blade segment includes suspending the second blade segment from four independently adjustable engagement members.
Type: Application
Filed: Nov 21, 2011
Publication Date: May 24, 2012
Inventors: Cory P. Arendt (Huntington Beach, CA), Myles L. Baker (Long Beach, CA), Sheldon Vilhauer (Carson, CA), Michael Johnson (Huntington Beach, CA)
Application Number: 13/301,613
International Classification: B21D 53/78 (20060101);