FOLDING TOWER
A multi-section folding tower for supporting wind turbines, windmills, power generation, communication, lighting, and measurement machines comprises an upper tower section and a lower tower section pivotally connected at an upper hinge, a lever, and a lower hinge attaching the lower tower section to an anchor foundation not requiring concrete wherein equipment mounted to the top of the tower is accessible by lowering a portion of the tower. The two tower sections and lever are assembled on the ground by connecting the upper and lower sections with a hinge, and the lower tower section is hinged to the tower foundation. The hinged tower sections are raised by first pulling the lower tower section to a vertical position, and a removable installation wheel attached to the tower top enables the lower section to be raised to a vertical position. The upper section is raised to a vertical position by pulling the lever.
This application claims the benefit of U.S. Provisional Application No. 61/396,083 filed on May 21, 2010, titled “FOLDING TOWER,” which is hereby expressly incorporated by reference in its entirety.
BACKGROUND1. Field
The invention relates to tower support structures and methods for erecting them.
2. Description of the Related Art
Wind power is typically harvested by positioning and holding a wind turbine into the wind at some elevation from the ground, in various types of terrain. To accomplish this, a tower structure standing vertically is used to mount a power producing rotor and nacelle. A wind turbine is typically installed in an area with an uncluttered horizontal view at the hub level, to allow the wind to flow into the blades of the wind turbine with the least air turbulence generated by the surrounding.
Tower structures for wind turbines are constructed to accommodate and withstand the weight of the wind turbine assembly, the wind forces acting on the wind turbine blades and on the tower, the precession forces created by change of direction of the spinning wind turbine blades, the vibrations caused by aerodynamic forces on the blades, and by the wind turbine turning mechanisms. In addition, tower structures for horizontal axis wind turbines are constructed to adapt to methods available for erecting the assemblies. Key tower installation considerations include factors such as safety, damage avoidance to the wind turbine, and limiting installation cost such as that of using a crane and concrete.
Various types of towers have been used in the past to support small wind turbines generating electrical power. Supporting towers for horizontal axis wind turbines may be grouped under three common types, guyed towers, tilt-up towers, and self supporting towers. Tower structures are typically constructed with lattice, truss or tubular assemblies. The tower is typically assembled on the ground prior to starting the erection process.
Guyed towers are typically used for small wind turbines. The guyed tower may be installed with a crane that lifts the assembled tower to a standing position prior to tensing and securing the guy wires. Guyed towers can also be erected one section at a time without the use of a crane, A temporary boom extending beyond the top of the tower is used to lift the next tower sections and finally, the small wind turbine or other top mounted equipment. Guyed towers require wide space access around the base of the tower for anchoring the guy wires.
Tilt-up towers are towers hinged at the ground level and can be lowered to perform maintenance on the equipment installed on top of the tower. Typically, the wind turbine and tower are assembled while the tower lies on the ground at the installation site. The tower is raised using a winch or a heavy vehicle located some distance away from the base of the tower to pull on cables attached to the top of the tower, with a pivoting gin pole transferring the initial horizontal force into a vertical lifting component. Guy cables are often required during the erection process to limit lateral movements of the tower structure.
Self-supporting towers are free-standing structures often pre-assembled on the ground and lifted to the upright position using a crane. The wind turbine may be installed and lifted with the tower, or may be lifted separately and then positioned on top of the tower, Once erected, the tower is typically not lowered again. A built-in ladder provides access to the equipment on top of the tower. Free-standing towers are typically heavier and more expensive.
Though some of the proposed concepts in the above referenced patents and prior art address the need to facilitate construction and erection of the tower and the installation of the wind turbine on top of a tower structure at the installation site, other factors such as tower structure complexity, reliability and need for a large crane need careful review. Raising and lowering of a tower in a harsh environment in typically remotely accessible areas involving snow, ice or dirt build-up on telescoping, sliding and rail type structural elements are technically challenging. Using special external structures or large lifting devices or vehicles add burden and cost to installation operations. In general, tower structures and their erection method for wind turbine applications have evolved by adding complexity to the construction of the tower and lifting system.
Though non-telescopic tilt-up towers facilitate the access to the equipment located at the upper end of the tower structure and do not need a crane for their erection to a standing position, common tilt-up towers involve the pivoting of a lengthy structure with equipment load at its upper end which implies a single lifting maneuver which puts at risk the entire wind turbine and tower assemblies. The use of tilt-up towers is therefore generally limited to small wind turbines.
There have been many attempts to lower the cost of wind turbine towers, but to date none have been commercially successful because it is very difficult to reduce the cost of tilt up guyed single pole or lattice towers, which use a gin pole for tower raising and anchors to secure the guy wires. These towers do not require concrete for the foundation, and typically use a steel plate for the tower base. However, as the size of the turbine grows and the tower height increases, loads increase to a point where raising the tower with a gin pole becomes impractical, and a crane is used to install the tower, and concrete is used for the foundation.
Generally, the best way to reduce the cost of energy, or COE of a wind turbine for towers under 150 feet is to raise the height of the tower. Oversimplified, COE is the ratio of turbine cost to how much energy it produces annually. Higher towers benefit from increased wind speeds, and importantly, smoother wind, which not only allows the turbine to operate more efficiently but also increases its life. Power in the wind increases with the cube of the wind speed increase, and thus increasing tower height from 50 feet to 100 feet will typically result in a power increase of over 50%, but only an approximate 11% increase in the installed cost of the wind turbine. Almost all of this 11% increase is due to a more expensive tower, tower foundation, and tower erection. A key factor in helping wind turbines to become more economically viable in the future will be to raise tower height.
Another trend in the wind turbine industry is a move to larger wind turbines. Larger wind turbines, for both small wind turbines (1 kW-100 kW) and utility class wind turbines (1 MW+) reduces COE. Typically, embodiments disclosed herein will maximize a reduction in COE for small wind turbines from about 5 kW to 100 kW. Below about 5 kW, tower foundations can be designed without concrete, and the towers can be tilted up using a gin pole. Above about 100 kW, the tower top thrust loads produced by large rotors, and their great mass, require the use of concrete for the foundation and a crane during tower installation.
SUMMARYThe systems and methods illustrated and described herein have several features, no single one of which is solely responsible for its desirable attributes. Without limiting the scope as expressed by the description that follows, its more prominent features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description of the Preferred Embodiments” one will understand how the features of the system and methods provide several advantages over traditional systems and methods.
Embodiments disclosed herein incorporate a novel tower design, novel foundation, and installation method. An objective of the embodiments disclosed herein is to lower the installed cost of the tower as well as the cost to access equipment secured to the top of the tower to perform maintenance and repairs, and to be able to lower the equipment to the ground during extreme storms, such as hurricanes and tornados. These embodiments lower the cost of the tower at least three ways: 1. eliminating the need for a crane, 2. eliminating the need for concrete, and 3. reducing the time it takes to raise the tower. In one embodiment a tower is designed to be a tower for wind turbines, which benefit from high towers and require periodic access to the turbine for maintenance.
In one aspect, a folding tower, includes two tower sections, an upper section and a lower section, the upper section being shorter than the lower section. The two tower sections are connected by an upper hinge, which allows the upper section to pivot approximately 180 degrees. A lower hinge connects the lower section to the foundation, which uses anchors in place of concrete to secure the tower to the earth. In some embodiments the anchors are helical anchors, and are screwed into the ground. In some embodiments the folding tower is guyed, and anchors also secure the guy wires. In other embodiments the folding tower does not require guy wires and is self supporting.
The folding tower further incorporates a lever, which in some embodiments is offset from the upper hinge, for raising and lowering the upper section. Offsetting the lever from the hinge increases its mechanical advantage. The folding tower further incorporates a component for securing the upper section to the lower section, which in some embodiments is a latch.
In another aspect, a foundation system for a folding tower having at least three legs includes a plurality of anchors, a centroid absorber, a plurality of force distribution members, a first hinge, and a first leg mount. The anchors include elongated members configured to penetrate into an underlying surface to secure the tower relative to the underlying surface, the plurality of force distribution members extend from the centroid absorber and are configured to distribute forces applied to the tower. The system includes at least one force distribution member for each tower leg and the force distribution members distribute a first portion of said forces to the anchors and a second portion of said forces to the centroid absorber, wherein a sum of the forces to the anchors plus a sum of the first and second portions equals a total force transferred by the tower to the anchors and the absorber. The first hinge is configured to be attached to at least one of the legs of the tower and the first leg mount is attached to one of the force distribution members and disposed between the first hinge and said force distribution member.
In one aspect, a folding tower includes a hinged base portion, an anchor, and a damping system. The hinged based portion is configured to rotate relative to the anchor and the damping system couples the base portion to the anchor. The damping system includes a lever bar, a first energy storing element, and a second energy storing element. The lever bar has a first end and an opposite second end and the base portion and the anchor are coupled to the lever bar near the first end. The first energy storing element is coupled to the lever bar near the second end. The second energy storing element is coupled to the lever bar near the second end and extends from the lever bar in a direction that is generally opposite to a direction that the first energy storing element extends from the lever bar.
In another aspect, a foundation system for a folding tower includes a plurality of damping systems with at least one of the systems comprising a hinged leg mount, a concrete base, and a force distribution system. Each of the damping systems is coupled to the force distribution system and to the concrete base.
In one aspect, a folding tower includes a first portion, a second portion, a pivot, a lever, a boom, and at least one connector. The first portion is configured to rotate relative to the second portion between at least a first position and a second position. The pivot is located between the first portion and the second portion and defines an axis of rotation for the first portion relative to the second portion. The lever includes an elongated structure that is substantially collinear with the first portion. The boom includes an elongated structure that is substantially perpendicular to the first portion. The connector includes a first end and a second end, the first end attached to the first portion and the second end attached to the boom.
In another aspect, a folding tower includes a first portion, a second portion, a pivot, a lever, and a pulley lever. The first portion is configured to rotate relative to the second portion between at least a first position and a second position and the second portion is attached at a first end to an immovable surface. The pivot is located between the first portion and the second portion and defines an axis of rotation for the first portion relative to the second portion. The lever includes an elongated structure that is substantially collinear with the first portion. The pulley lever is attached at a first end to a first end of the lever and the pulley lever can rotate relative to the lever.
In one aspect, a folding tower includes a first pivot, a lower section, a second pivot, and an upper section. The first pivot comprises a first pin defining an axis of rotation of the first pivot. The first pivot also includes a first lower connection and a first upper connection. The first lower and upper connections are rotatable about the axis of rotation and the first pivot is located at least halfway up the folding tower when it is erected. The lower section includes an elongated structure with a first lower end and a second lower end, the first lower end is connected to the first lower connection of the first pivot. The second pivot is connected to the second lower end of the lower section and defines an axis of rotation for the lower section. The second pivot is operably attached to an immovable surface. The upper section includes an elongated structure with a first upper end and a second upper end. The first upper end is connected to the first upper connection of the first pivot and the second upper end defines the top of the folding tower when it is erected. The lower section is enabled to rotate about the axis of rotation of the first pivot and the second pivot. The axis of the second pivot is immovable, the axis of the first pivot is movable, and the during erection of the tower the upper and lower sections are initially in substantially horizontal positions and the first pivot forms an angle relative to the upper and lower sections that is between 129 and 179 degrees.
In another aspect, a method for installing a hinged tower includes providing a tower with a lower section and an upper section rotatably coupled to the lower section, rotating the upper section relative to the lower section such that the upper section extends away from the lower section and such that the upper section and lower sections are substantially collinear, and forming a latch connection between the upper and lower sections by applying tension to a cable to engage a latch mechanism.
In one aspect, a folding tower includes a first pivot, a lower section, a second pivot, an upper section, a first link, a second link, a third link, a fourth link, a first hinge connecting the first link to the second link, a second hinge connecting the second link to the third link, a third hinge connecting the third link to the fourth link, a fourth hinge connecting the fourth link to the first link, a screw, and a nut. The first pivot includes a first pin defining an axis of rotation for the first pivot and also includes a first lower connection and a first upper connection. The first lower and upper connections are rotatable about the axis of rotation and the first pivot is located at least halfway up the folded tower when it is erected. The lower section includes an elongated structure with a first lower end and a second lower end. The first lower end is connected to the first lower connection of the first pivot. The second pivot is connected to the second lower end of the lower section and defines an axis of rotation for the lower section and is operably attached to an immovable surface. The upper section includes an elongated structure with a first upper end and a second upper end. The first upper end is connected to the first upper connection of the first pivot and the second upper end defines the top of the folding tower when it is erected. The first link is fixedly attached to the upper section and the fourth link is fixedly attached to the lower section. The screw is operably attached to the fourth hinge and the nut is operably attached to the second hinge and threaded over the screw. In this aspect, if the screw is fixed the nut can rotate and if the nut is fixed the screw can rotate. The lower section is enabled to rotate about the axis of rotation of the second pivot and the axis of the first pivot can rotate about the axis of rotation of the second pivot and the axis of the second pivot is fixed.
In another aspect, a method of installing a hinged tower includes providing a tower with a lower section that is hinged to an upper section, securing the lower section to a surface, rotating the upper section about the hinge relative to the lower section until the upper section extends away from the lower section and the upper and lower sections are substantially coaxial, and applying tension to a cable member coupled to a latch mechanism, wherein applying tension to the cable member forms a latch connection between the upper section and the lower section.
In one aspect, a folding tower includes a first pivot, a lower section, a second pivot, an upper section, a first link, a second link, a third link, a fourth link, a first hinge connecting the first link to the second link, a second hinge connecting the second link to the third link, a third hinge connecting the third link to the fourth link, a fourth hinge connecting the fourth link to the first link, a screw operably attached to the fourth hinge, and a nut operably attached to the second hinge and threaded over the screw. The first pivot includes a first pin defining an axis of rotation for the first pivot. The first pivot also includes a first lower connection and a first upper connection. The first lower and upper connections are rotatable about the axis of rotation and first pivot is located at least halfway up the folded tower when it is erected. The lower section includes an elongated structure with a first lower end and a second lower end. The first lower end is connected to the first lower connection of the first pivot. The second pivot is connected to the second lower end of the lower section and defines an axis of rotation for the lower section. The second pivot is operably attached to an immovable surface. The upper section includes an elongated structure with a first upper end and a second upper end. The first upper end is connected to the first upper connection of the first pivot and the second upper end defines the top of the folding tower when it is erected. The first link is fixedly attached to the upper section and the fourth link is fixedly attached to the lower section. In this aspect, if the one of the screw or nut is fixed relative to the other, the other can rotate relative to the one of the screw or nut. The lower section is rotatable about the axis of rotation of the second pivot and the axis of the first pivot can rotate about the axis of rotation of the second pivot, and the axis of the second pivot is fixed.
In another aspect, a tower includes an elongated structure including one or more substantially vertical members each having a first end and a second end. The first end of the members defines a base of the tower and the second end of the members is disposed substantially opposite from the first end. The tower also includes a force distribution system having a lever, a force distribution pivot operable attached to the lever, and a rigid structure fixed to a surface. The lever has a first end and a second end. The first end is operably attached to the first end of a member and the second end is operably attached to a force distribution component. The force distribution pivot is attached to the rigid structure and the elongated structure is configured to move relative to the rigid structure.
In one aspect, a tower includes an elongated structure including at least one substantially vertical member having a first end and a second end. The first end of the member comprises a base of the tower and the second end of the member is located substantially vertically about the first end. The tower also includes a force distribution system having at least one lever operably attached to the first end of a member, a force distribution component configured to absorb movement of the lever and operably attached to the lever, a force distribution pivot configured to allow rotation of the lever about the axis of the force distribution pivot and operably attached to the lever, and a rigid structure fixed to the earth and operably attached to the force distribution pivot.
In another aspect, a folding tower includes a first portion, a second portion, and at least one anchor. The anchor is operable to secure the folding tower to a surface and the second portion is hingedly coupled to the anchor such that the second portion is configured to be rotated relative to the surface. The first portion is hingedly coupled to the second portion such that the first portion is configured to be rotated relative to the surface.
In one aspect, a folding tower includes a first portion, a second portion, and a latch mechanism. The first portion is configured to rotate relative to the second portion between at least a first position and a second position and the latch mechanism is configured to inhibit motion of the first portion relative to the second portion when the first portion is in the second position. The latch mechanism includes a first latch plate coupled to the first portion, a second latch plate and comprising a receiving member configured to receive at least a portion of the first latch plate, and a flexible tension member coupled to the first latch plate. The flexible tension member is configured to move the first latch plate relative to the second latch plate.
There exists a need for a tower that is easily erected, without need for a crane or other expensive installation equipment. There also exists a need for a tower where the device mounted at the top of the tower can be accessed without a crane, and where maintenance can be performed without climbing the tower. There exists a need where the top of the tower can be lowered to the ground, and where heavy objects can be removed or mounted to the top of the tower without raising them to the tower top when it is erected. Finally, past solutions to address these problems have been expensive and not commercially successful. There exists a need for an economical solution that solves the aforementioned problems.
Embodiments will now be described with reference to the accompanying figures, wherein like numerals refer to like elements throughout. The terminology used in the description presented herein is not intended to be interpreted in any limited or restrictive manner simply because it is being utilized in conjunction with a detailed description of certain specific embodiments. Furthermore, embodiments disclosed herein may include several novel features, no single one of which is solely responsible for its desirable attributes or which is essential to practicing the embodiments herein described.
The towers described herein are of the folding type that use two hinges, a lower hinge connecting the tower to the foundation, and an upper hinge about halfway up the tower. The upper hinge divides the towers into an upper and lower section.
The folding towers also incorporate a lever to which a flexible tension member, such as a steel cable, is attached. The flexible tension member can be reeled in or out manually or by a machine such as a winch at ground level, to raise and lower the upper section of the tower. The folding towers further incorporate a latch or lock that secures the upper section of the tower to the lower section. The folding towers also incorporate a friction reducer attached to the tower top to minimize the forces required to raise the tower during erection. The folding towers described herein further incorporate a stand or jack to create an angle at the upper hinge that is less than 180 degrees to further minimize the forces. In some embodiments the folding towers use a foundation incorporating anchors.
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In some embodiments the lower latch coupler 344 is a rigid tube with an inside diameter slightly larger than the outside diameter of the tube used to construct the short leg 356. The short leg 356 is inserted into the lower latch coupler 344 and secured using a bolt or set screw screwed into the lower latch hole 440. In some embodiments the angle braces 346 are attached to the lower latch coupler 344 by bolting them to lower latch tabs 438 through lower latch tab holes 436.
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The first and second pulleys 736, 732 can be disposed adjacent to one another and can form a receiving space therebetween to receive a portion of flexible tension member (not shown), for example, a steel cable. The flexible tension member can pass between the pulleys 732, 736, through a slot 712 in the lower latch plate 702, and through aperture 718 in upper latch plate 716. The flexible tension member can be fastened, attached, or otherwise coupled to the upper latch plate 716 such that movement of the flexible tension member can manipulate the upper leg portion 728, and upper portion of the folding tower, about one or more hinges. As the upper leg portion 728 rotates relative to one or more hinges, the flexible tension member can apply pressure to the first or second pulleys 736, 732. In some embodiments, the flexible tension member applies pressure to the second pulley 732 when the upper latch plate 716 is biased away from the lower latch plate 702. In one embodiment, the flexible tension member applies pressure to the second pulley 732 when the upper latch plate is initially biased away from the lower latch plate 702 during reverse erection of the folding tower. In some embodiments, the flexible tension member applies pressure to the first pulley 736 when the upper latch plate 716 is biased towards the lower latch plate 732. In one embodiment, the flexible tension member applies pressure to the first pulley 736 when the upper latch plate 716 rotates past a point where it is vertically positioned above the lower latch plate 702. Thus, the pulley system 729 can be configured to guide a flexible tension member used to manipulate a portion of the folding tower during erection or reverse erection of the folding tower.
Upper latch plate 716 can include a second aperture 722 disposed adjacent to aperture 718. The second aperture 722 can be configured to receive a portion of a safety tension member (not shown), for example, a safety cable, in order to fasten, attach, or otherwise couple the safety tension member to the upper latch plate 716. The safety tension member can extend downward from the upper latch plate 716 through a slot (not shown) in the lower latch plate 702 and may be attached, fastened, or otherwise coupled to the bottom portion of the tower and/or to another structure in order to secure the upper latch plate in a fixed position relative to the lower latch plate. In one embodiment, the safety tension member comprises a steel cable with a ⅝″ diameter that is used to secure the upper latch plate 716 relative to the lower latch plate 702 after a latch connection has been established therebetween.
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In some embodiments, the lower plate 702 further includes a locking member 706 and a receiving member 720. The receiving member 720 extends from the lower plate 702 away from the lower portion of the tower and forms a receiving space between the receiving member and the lower plate 702. The receiving space is sized and configured to receive a portion of the upper plate 716 when the upper plate 716 is seated on the lower plate 702. Thus, the receiving member 720 limits the movement of the upper plate 716 relative to the lower plate 702 in the vertical direction. In one embodiment, the receiving member 720 includes a lip configured to receive a portion of the upper plate 716 between the lip and the lower plate 702. The locking member 706 can comprise a pin, for example, a spring-loaded pin that can be remotely actuated, and can extend into an aperture 726 formed in the upper plate 716. For illustration purposes, the locking member 706 in
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On an end of the lever bar 752 that is opposite from the end of the lever bar 752 that is coupled to the hinge 788, the lever bar 752 can be coupled to a first energy storing element 778 and a second energy storing element 768. In one embodiment, the first and second energy storing elements 768, 778 are springs that are coupled to the lever bar 752 by bolts 782, 770 and washers 772, 776. In one embodiment, the first energy storing element 778 can extend upwardly from the lever bar 752 and the second energy storing element 768 can extend in an opposite direction from the lever bar (e.g., in a downward direction). In one embodiment, the first energy storing element 778 can be disposed between the bracing member 784 and the lever bar 752 and the second energy storing element 768 can be disposed between the lever bar 752 and the surface of the ground that the folding tower rests upon. In this way, the first and second energy storing elements 768, 778 can engage the lever bar 752 therebetween such that movement of the lever bar 752 towards the ground causes the second energy storing element 768 to compress while the first energy storing element 778 goes into tension. Similarly, movement of the lever bar 752 away from the ground causes the first energy storing element 778 to compress while the second energy storing element 768 goes into tension. The opposing compressive and tension forces of the first and second energy storing elements 768, 778 applied to the lever bar 752 can act to absorb and/or dampen energy that is received from the environment and transferred through the folding tower toward the ground before the energy is transferred to the anchors 762. In some embodiments, the first and second energy storing elements 768, 778 are configured to absorber energy only in compression or only in tension. Furthermore, in some embodiments, the lever bar 752 is formed of a flexible energy absorbing material, for example, steel, spring tempered steel, titanium, and high modulus composites such as carbon fiber. The absorption or dampening of energy by the lever bar 752 can further act to dampen energy that is transferred through the folding tower toward the anchors 762. Accordingly, the damping system 750 can act to prevent the disengagement of the anchors 762 from the soil and save costs incurred in the construction and installation of folding towers.
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Force distribution system 802 is coupled to an anchor 820 on a first end and to damping system 850 at a second opposite end. The damping system 850 couples the three force distribution systems 802, 804, 806 to a central anchor 894. The first end of the first force absorbing member 808 is coupled or fixedly attached to a bracket 816 that couples the force absorbing member 808 with anchor 820. The bracket 816 includes an aperture 818 that receives a fastener, for example, a threaded fastener, bolt, pin, or screw, to secure the anchor 820 relative to the first force absorbing member 808. Disposed between the first and second ends of the force distribution system 802 is a tower leg mount 832. The tower leg mount 832 can comprise various structures including, for example, a plate or flange. The tower leg mount 832 is configured to engage the bottom of a folding tower leg (not shown) to couple a folding tower to the foundation system 800. As illustrated, each force distribution system 802, 804, 806 includes a leg mount 832 and the leg mounts 832 are aligned with one another such that tower legs (not shown) coupled to the foundation system 800 face a single direction. In some embodiments, one or more of the leg mounts 832 may comprise a hinged plate. For example, the leg mount 834 of force distribution system 806 includes a hinged plate 834 with a hinge tube 836. The hinged plate 834 and hinge tube 836 may coact to hingedly engage a tower leg (not shown) to allow the tower leg to rotate relative to the hinged plate 834 and force distribution system 806. In embodiments where two leg mounts 832 include hinged plates 834 and hinge tubes 836, both hinge plates 834 and hinge tubes 836 may be aligned such that the two hinge structures are coaxially aligned with one another to allow the rotation of the lower portion of the tower about the coaxially aligned hinge tubes 836.
A post or pipe stub 830 and first clamping plate 828 couple the leg mount 832 with the force absorbing members 808, 810, 812, 814. In some embodiments, the leg mount 832 can be clamped or otherwise secured relative to the force absorbing members 808, 810, 812, 814 by securing the first clamping plate 828 relative to a second clamping plate 822 by one or more bolts 826 and nuts 824. For example, in one embodiment, the first and second clamping plates 822, 828 form a clamp structure between the force absorbing members 808, 810, 812, 814 to secure the leg mount to the force distribution system 802.
As discussed above, the movement of a folding tower over time due to high loads can create space between soil and an installed anchor which can lead to anchor failure. Seating a folding tower on a foundation system with one or more force distribution systems can increase the lifetime of the anchor(s) without increasing the cost and/or weight of the anchor(s). In the illustrated embodiment, the force distribution systems 802, 804, 806 can dampen compressive or tensile forces received from tower leg members through the tower leg mounts 832. Additionally, these dampened forces can be transferred to the central damping system 850 to lessen the loads received by the anchors. This foundation system 800 allows for towers to be installed with smaller anchors and allows for the construction of towers with narrow faces (e.g., narrower distances between the bottoms of the legs) because loads from wind and other factors are reduced by the force distribution systems 802, 804, 806 and/or cancelled by the damping system 850.
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The damping system 850 can include an anchor 894 disposed beneath the force distribution systems 802, 804, 806 and configured to secure the damping system 850 to the ground. The anchor 894 can be coupled to a post 884 by a bracket 890. The bracket 890 can include an aperture or bore 888 that is configured to align with an aperture 892 on the anchor and receive a fastener, for example, a bolt, pin, or threaded fastener therethrough to couple the anchor 894 with the bracket 890. The post 884 can extend from the bracket 890 through bores or apertures in the top plate 856, bottom plate 880, and slotted brackets 862, 870, 874, and a nut 852 can be used to secured the anchor 894 relative to the top plate 856. In this way, the damping system 850 couples the force distribution systems 802, 804, 806 relative to one another to cancel the forces received from the force distribution systems 802, 804, 806 and the anchor 894 couples the damping system 850 with the ground.
In some embodiments, the foundation system 900 can include one or more braces 911 securing the force distribution systems 904a, 904b, 904c relative to one another. In one embodiment, the system 900 can include a first brace 911 coupled to the first force distribution system 904a and the second force distribution system 904b, a second brace 911 coupled to the second force distribution system 904b and the third force distribution system 904c, and a third brace 911 coupled to the third force distribution system 904c and the first force distribution system 904a. The one or more optional braces 911 can provide several advantages, including, for example, providing torsional support for the foundation system 900 when the folding tower is subjected to seismic waves (e.g., providing torsional support during earthquakes) and securing the force distribution systems 904a, 904b, 904c relative to one another to create a stronger foundation system 900. The additional torsional support and strength provided by one or more optional braces 911 disposed between force distribution systems 904a, 904b, 904c can also be advantageous during the tower raising when the anchors 917a, 917b, 917b are subject to substantial lateral forces that could cause the anchors 917a, 917b, 917b to move horizontally relative to the ground.
As discussed above with reference to
The lower section 943 of the folding tower 942 can be rotatably coupled to foundation system 900 by one or more hinges 912. A leverage boom 944 can extend from a lower portion of the lower section and a flexible tension member 947 can be guided over a distal end of the leverage boom 944 and coupled to a portion of the lower section 943. In this way, the flexible tension member 947 can be used to rotate the lower section 943 relative to the foundation system 900 (e.g., to raise the lower section 943).
A turbine offset system 950 extends from the lower section 943 of the tower 942. The turbine offset system 950 can offset the lower section 943 from the ground 946 such that the lower section 943 and the ground 946 form an acute angle therebetween. In this way, when the lower section 943 and upper section 941 of the tower 942 are lying on the ground, the lower section 941 and upper section 943 form an angle less than 180° therebetween. The angle between the lower section 941 and the upper section 943 caused by the offset system 950 can reduce the force required to rotate the lower section 941 relative to the upper section 943 because the lower section 941 is not horizontal with the ground surface 946. Additionally, when the lower section 941 is in an upright position and the upper section 943 has not been raised, the turbine offset system 950 prevents the upper section 943 from contacting the lower section 941. Similarly, when a turbine (not shown) or similar object is coupled to the distal end of the upper section 941, and the upper section 941 rests against the turbine offset system 950, the turbine will be offset from the lower section 943 (e.g., will not contact the lower section 943). Moreover, when the lower section 943 is raised and the upper section 941 is not raised, the turbine offset system 950 can be used to brace the upper section 941 relative to the lower section 943 in order to install or work on a turbine or another object coupled near the distal end of the upper section 941.
As shown in
Turning now to
The lower section 1210 can be coupled to an anchor 1306, for example a helical anchor. The helical anchor 1306 can include a plurality of helices 1308, 1310, 1312 configured to secure the anchor 1306 relative to the ground. The lower section 1210 can be rotatably coupled to the anchor 1306 by a base hinge 1302. In this way, the tower 1200 can be raised in more than one step. In one embodiment, the lower section 1210 can be rotated about the hinge 1302 relative to the ground to an upright or raised position and the upper section 1212 can be subsequently rotated about the upper hinge mechanism relative to the lower section 1210 to an upright or raised position such that the lower section 1210 and the upper section 1212 are substantially aligned. In some embodiments, one or more flexible tension members 1230, 1232, 1254 and a winch mechanism 1304 can be used to raise and/or lower the upper section 1212 and/or lower section 1210 of the tower 1200. In one embodiment, upper section 1212 can include a lever 1226, which in some embodiments is a steel tube, that can be used to manipulate the upper section 1212 and to rotate the upper section 1212 relative to the lower section 1210. In some embodiments a boom 1258, which can be a steel tube, can be attached at a first end substantially perpendicular to a first end of the lever 1226, and a flexible tension member 1230 can be attached at a first end to a boom bracket 1256 welded to a second end of the boom 1258, and at a second end can be attached to a second end 1228 of the lever 1226. A flexible tension member 1232 can be attached at a first end to the boom bracket 1256 using standard fasteners, and at a second end be attached to the upper section top 1234. The boom 1258 and flexible tension members 1230 and 1232 can provide support to the upper section 1212 during the raising and lowering of the upper section 1212.
As shown in
Certain of guy wires 1270a-d or 1280a-d may be in place during rotations of portions of the tower relative to one another to raise or lower said portions of the tower. For example, in particular embodiments, the lower guy wires 1280a-d may be installed in place after the lower section 1210 has been rotated about the hinge 302 relative to the ground to an upright or raised position, but before the upper section 1212 is subsequently rotated about the upper hinge mechanism 1282 relative to the lower section 1210 to place the upper section 1212 in an upright or raised position. Thus, the lower guy wires 1280a-d can provide stability to the structure during the subsequent raising of the upper section 1212 about the upper hinge mechanism 1282.
Because the lower guy wires 1280a-d may be in place during the subsequent raising of the upper section 1212, and the upper section 1212 will itself rotate through a plane of rotation during the raising of the upper section 1212, the plane of rotation of the upper section 1212 may be angularly offset from the vertical planes through which the lower guy wires 1280a-d extend. Still with respect to
In certain embodiments, the planes of rotation of both the upper and lower sections of the tower may be substantially aligned with one another. In other embodiments, a given pair of upper and lower guy wires may be secured to the ground at different locations, which may be radially or angularly offset from one another, and there may be greater or fewer numbers of upper or lower guy wires. In such an embodiment, the plane of rotation of a portion of the tower may be selected to be angularly offset from guy wire planes corresponding to those guy wires which may be installed at the time that the given portion tower is to be rotated.
The foregoing description details certain embodiments of the invention. It will be appreciated, however, that no matter how detailed the foregoing appears in text, the invention can be practiced in many ways. As is also stated above, it should be noted that the use of particular terminology when describing certain features or aspects of the invention should not be taken to imply that the terminology is being re-defined herein to be restricted to including any specific characteristics of the features or aspects of the invention with which that terminology is associated. The scope of the invention should therefore be construed in accordance with the appended claims and any equivalents thereof.
Claims
1. A foundation system for a folding tower having at least three legs, comprising:
- a plurality of anchors, the anchors comprising elongated members configured to penetrate into an underlying surface to secure the foundation system relative to the underlying surface;
- a centroid absorber;
- a plurality of force distribution members extending from the centroid absorber and configured to distribute forces applied to the tower, at least one force distribution member for each tower leg, the force distribution members distributing a first portion of said forces to the anchors, and a second portion of said forces to the centroid absorber, wherein a sum of the first and second portions equals a total force transferred by the tower to the anchors and the absorber; and
- a first hinge configured to be attached to at least one of the legs of the tower;
- a first leg mount attached to one of the force distribution members and disposed between the first hinge and said force distribution member.
2. The foundation system of claim 1, further comprising a second hinge configured to be attached to at least one of the legs of the tower.
3. The foundation system of claim 2, further comprising a second leg mount attached to one of the force distribution members and disposed between the second hinge and said force distribution member.
4. The foundation system of claim 2, wherein the first hinge comprises a first axis of rotation, wherein the second hinge comprises a second axis of rotation, and wherein the first axis of rotation and the second axis of rotation are coaxial.
5. The foundation system of claim 1, wherein the number of anchors is equal to or greater than the number of tower legs.
6. The foundation system of claim 1 wherein the centroid absorber is configured to offset tensile and compressive forces transferred by the folding tower to the plurality of force distribution members.
7. The foundation system of claim 6 wherein the centroid absorber dampens forces applied by the folding tower to the plurality of force distribution members.
8. The foundation system of claim 1 wherein the force distribution members dampen forces applied by the folding tower to the plurality of force distribution members.
9. A folding tower comprising:
- a hinged base portion;
- an anchor, wherein the hinged base portion is configured to rotate relative to the anchor; and
- a damping system, wherein the damping system couples the base portion to the anchor, the damping system comprising a lever bar having a first end and an opposite second end, wherein the base portion and anchor are coupled to the lever bar near the first end, a first energy storing element, wherein the first energy storing element is coupled to the lever bar near the second end, and a second energy storing element, wherein the second energy storing element is coupled to the lever bar near the second end, and wherein the second energy storing element extends from the lever bar in a direction that is generally opposite to a direction that the first energy storing element extends from the lever bar.
10. The folding tower of claim 9, wherein the anchor and the second energy storing element engage a common ground surface.
11. The folding tower of claim 9, wherein the base portion is hingedly coupled to the damping system.
12. The folding tower of claim 10, further comprising a bracing member, wherein the bracing member is generally aligned with the lever bar, and wherein the bracing member is coupled to the base portion and to the first energy storing element.
13. The folding tower of claim 9, wherein the first and second energy storing elements comprise springs.
14. A foundation system for a folding tower, the foundation system comprising:
- a plurality of damping systems, wherein at least one damping system comprises a hinged leg mount;
- a base rigidly attached to an underlying surface; and
- a force distribution system attached to the base and configured to reduce loads applied to the base,
- wherein each of said plurality of damping systems is coupled to the force distribution system and to the base.
15. The foundation system of claim 14, wherein each of said plurality of damping systems comprises a leg mount configured to support a leg of a folding tower.
16. The foundation system of claim 15, wherein each leg mount is disposed on at least one force absorbing member.
17. The foundation system of claim 16, wherein each damping system comprises a plurality of force absorbing members.
18. The foundation system of claim 14, wherein at least one of the plurality of damping systems comprises a leg mount that is not hinged.
19. The foundation system of claim 14, wherein two of the plurality of damping systems comprise hinged leg mounts, wherein each of the two hinged leg mounts include hinges, and wherein each of the two hinges is coaxially aligned with the other hinge.
20. A folding tower comprising:
- a first portion;
- a second portion, wherein the first portion is configured to rotate relative to the second portion between at least a first position and a second position;
- a pivot, the pivot located between the first portion and the second portion, the pivot defining an axis of rotation for the first portion relative to the second portion,
- a lever, the lever including an elongated structure that is substantially collinear with the first portion;
- a boom, the boom including an elongated structure that is substantially perpendicular to the first portion; and
- at least one connector, the connector including a first end and a second end, the first end attached to the first portion, and the second end attached to the boom.
21. The folding tower of claim 20, further comprising a second connector, the second connector including a first end a second end, the first end attached to the lever, and the second end attached to the boom.
22. The folding tower of claim 21, wherein the first and second connectors are flexible tension members.
23-83. (canceled)
Type: Application
Filed: May 19, 2011
Publication Date: Nov 24, 2011
Applicant: Catadon Systems, Inc. (Encinitas, CA)
Inventor: Donald C. Miller (Encinitas, CA)
Application Number: 13/111,809
International Classification: E04H 12/18 (20060101); E02D 27/42 (20060101); E04H 12/00 (20060101);