Telescopic support tower

Abstract

A support tower for heavy loads or large structures such as a wind turbine generators, constructed of a plurality of telescopic tower sections with the outer lower tower section having a lower end supported from a foundation and at least one or more inner upper tower sections telescoped in an initial vertical nested relation within the outer lower tower section. The heavy load is mounted on an upper end of the inner upper tower section while in the initial vertical nested relation. The inner upper tower section or sections are then lifted upwardly to an extended tower height by lift mechanisms and the tower sections are secured in vertically extended position by inter-engaging wedge joint structure with bolt fasteners extending through mating wedge surfaces to retain the telescopic tower sections vertically extended and position the heavy load in a vertically elevated position.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to tall support towers for large structures, such as wind turbine generators, microwave antennas or the like, and, more specifically, to tall support towers which are constructed of multiple telescopic sections that telescopically extend vertically to the tower's full height and/or to tall support towers which are telescopically and vertically nested at the site of installation in a generally vertical position, and then extended upwardly to a final extended position to form a support tower.

2. Description of the Prior Art

Wind-powered windmills and turbines have been in use for many years for producing power for many purposes. Wind power to drive wind turbine generators to generate electrical energy have been used as an alternative energy source for many years, and the development of such uses of wind power is ongoing as exemplified by the following U.S. Pat. Nos.:

11,181	133,017	446,744
2,213,870	2,267,705	2,384,279
2,675,211	2,795,303	3,248,831
3,495,370	3,500,429	3,638,806
3,715,852	4,079,559	4,151,534
4,176,360	4,231,200	4,323,331
4,568,808	4,590,718	4,598,509
4,785,309	4,903,442	4,932,175
5,058,336	5,330,032	5,537,125
6,408,575	DE3136176A	CH677516A

Initial development of wind turbine generators to produce electrical energy involved relatively small turbines and generators having a capacity of approximately 50 to 65 kilowatts, which were supported by small towers of approximately 50 to 75 feet in height. Towers of this height were typically fabricated from steel truss members of rectangular plan configuration and of lightweight construction. The lightweight construction enabled the towers to be initially positioned generally horizontally with the lower end pivotally connected to a foundation and the wind turbine and generator mounted at the upper end. The tower was then tilted upwardly to a vertical position by a cable and winch assembly or other power source to pivot the tower to a vertical position on the foundation from the generally horizontal position. This tilting of the tower provided a relatively inexpensive installation that could be quickly and efficiently completed in a short time and required the use of only small and highly mobile erection equipment. A problem existed, however, in that as the tower was tilted into vertical position, the feet of the tower conflicted with anchor bolts that protruded from the foundation which would prevent the tower from setting flat on the foundation. This was resolved by bolting multiple steel adapter structures to the anchor bolts with the flat upper surface of each adapter receiving one of the feet on the tower. The tower feet were then bolted to the top of the adapters through matching bolt holes in the feet and top surface of the adapter.

More recent wind power generation included the development of larger and more efficient and cost-effective turbines capable of driving larger generators, having capacities up to approximately 750 kilowatts. The larger turbines and higher capacity generators required that taller support towers be provided in order to maximize the use of winds existing at higher elevations which have higher average speeds and smoother air flow characteristics than winds closer to the ground. In order to erect the larger towers to support the wind turbine generators at the higher elevations needed to maximize power production, heavy lift cranes with a lift capacity of up to 230 tons are used. The taller towers, either steel truss or tubular cross-sectional configuration are erected in sections by the crane and assembled in the vertical position. Each section of the tower is rigidly affixed to the adjacent tower sections by means of bolted connections. In the case of tubular cross-section towers the bolted connections are created through use of matching inwardly oriented flanges at each joint which contained matching bolt holes to receive the bolts. The wind turbine generators are then mounted on top of the vertically oriented tower. This procedure is effective for towers up to approximately 180 feet in height with turbine and generator assemblies weighing up to approximately 60,000 pounds.

However, as the tower height increased along with the generating capacity and the weight of the wind turbine generator, the costs of installation increased materially. The transportation costs to move a heavy lift crane to a site of installation and then remove it from the site of installation, as well as the rental cost for a heavy lift crane, can be extremely high. A typical heavy lift crane with a lifting capacity of approximately 230 tons is barely capable of installing a 750 kilowatt wind turbine generator on a tower that is about 200 feet tall. Extra-heavy lift cranes with even higher costs are required for taller towers or heavier generators. Use of the extra-heavy lift cranes increases costs dramatically due to the very high rental and transportation costs of these larger units. Additional costs include the requirement for multiple large trucks and trailers for moving the extra-heavy lift crane to and from the job site, increased risk of serious accidents while traveling during movement of the crane to and from the job site, as well as at the job site, and increased wear and tear on public highways and plant site roads.

The massive size of extra-heavy lift cranes and their limited mobility require that work sites be well prepared to assure stability during the erection process. An extra-heavy lift crane work site requires extensive preparation of road bases with minimal tolerance for allowable slope of the road or for side to side pitch and crane working pads which require the use of heavy temporary matting beneath the cranes. Also, once on a job site, the cranes need to be moved frequently from one wind turbine foundation to another which further adds to high maintenance costs on the cranes and roads and expensive time-consuming moving procedures. This is especially problematic at preferred and available job sites which are usually near the top of hills, ridges or mountains which require erection equipment to be highly mobile in order to minimize erection time and cost. Use of the extra-heavy lift cranes means that many of the best sites cannot be used due to the excessive cost of road and pad construction needed for the larger cranes.

Heavy lift cranes are typically near their maximum safe working ranges when erecting wind turbine generators of 600-750 kilowatt capacity on towers as high as 200 feet. This condition makes it necessary to suspend erection work during winds in excess of 20 to 25 miles-per-hour in order to avoid excessive wind loads on the long crane booms and on the structure being lifted that exceed the safe working loads of the crane. In job sites where such towers are erected, it is not unusual for erection work to be delayed for several days during a windy season and work is frequently delayed due to inclement weather such as rain, ice accumulation or snow. Other constraints associated with heavy and extra-heavy lift crane use include requirements for good visibility so that the operator can see hand signals given by a load master, limited availability of extra-heavy lift cranes during periods of high construction activity, limited availability of extra-heavy lift cranes capable of erecting wind turbine generators having a capacity greater than 750 kilowatts and the time and large number of equipment components necessary to move larger capacity lift cranes to and from the site of tower erection.

The cost and availability of extra-heavy lift cranes has become a serious limiting factor to further economic development of wind energy especially in view of the ongoing development of wind turbine generators having a capacity of up to approximately 2,500 kilowatts. Such generators will require towers as tall as 350 feet in height with turbine generator combinations weighing in excess of 150,000 pounds. Accordingly, the use of increasingly heavier wind turbine generators mounted on even taller towers has reached a point where the cost of construction has become a significant constraint to further development. Likewise, the limited availability of extra-heavy lift cranes capable of erecting such taller towers and installing heavier wind turbine generators at the upper end thereof have introduced additional serious constraints on the development of wind-powered electrical energy generation.

While the above-identified patents and prior developments in the construction of supporting towers for wind-powered energy include towers which are pivotally supported for tilt-up erection, sectional tower constructions and telescopic tower constructions, the prior art does not disclose a tower assembly incorporating features which can be constructed to a height and weight capacity necessary to support the larger wind turbine generators without the use of extra-heavy lift cranes.

SUMMARY OF THE INVENTION

In order to overcome the constraints described above in connection with tall towers for large and heavy wind turbine generators, the present invention provides a tall tower capable of supporting a heavy wind turbine generator that starts out as multiple independent tubular tower sections which are telescopically nested inside each other while in a generally vertical position at the job site. The number of tower sections is dependent on the desired tower height and configuration and may require two, three or four, or even more, tower sections. The telescopically nested vertical sections are appropriately interconnected so as to be internally spaced one from another while oriented in a generally vertical nested position at the job site prior to vertical extension. The outermost vertical tower section has a lower end rigidly connected to a tower supporting foundation by the use of appropriate anchor bolts. One or more inner tower sections are then lifted and placed vertically in nested relation inside the outermost tower section. The wind turbine generator is then mounted on the top end of the innermost tower section.

The inner tower section or sections and the wind turbine generator are then telescopically extended vertically to a final elevated position to a final elevated position or the maximum vertical height of the tower. As the tower sections are extended to full height, segmental wedge sections mounted around the outside wall of the lower end of an inner upper section matingly engage circular wedge surfaces on the inside wall at the upper end of the lower outer tower section. The tower sections are then fastened together by securing the mated wedge components using radial bolts to form a rigid wedge joint structure. By using a telescoping tower assembly, the necessity for having extra-heavy lift cranes at the job site can be eliminated. Additionally, the towers can be telescopically lowered for maintenance access purposes, eliminating the need for extra-heavy lift cranes during maintenance activities.

In order to telescopically extend the tower sections nested in their starting vertical position with the outermost section rigidly bolted to the foundation, lifting mechanisms in the tower are activated to extend the nested tower sections. Upper and lower sway roller assemblies are provided on the tower sections to guide the tower sections during relative vertical movement. The upper sway roller assemblies are removed after the tower sections have been vertically extended and bolted. In one embodiment, the lifting mechanism between the outermost tower section and the adjacent or second tower section nested inside the outermost section is a jacking mechanism, and the lifting mechanism between the second tower section and additional tower sections, such as a third and perhaps fourth tower section, is a cable and pulley mechanism. The cable and pulley mechanism interconnects each of the innermost upper tower sections preferably in a manner such that all of the innermost upper nested tower sections automatically extend when the jacking mechanism extends the second tower section from its nested relationship within the outer lowermost tower section.

Alternatively, additional jacking mechanisms in lieu of the cable and pulley mechanisms may be positioned internally of the second tower section to engage and lift the lower end of the third tower section, and similarly for additional tower sections, if used. The multiple jacking mechanisms can be operated simultaneously or independently through the use of manual controls or a computerized control system, giving full control of the telescoping operation.

The lifting mechanisms further include a guide system to guide the tower sections as they telescope vertically with respect to each other. The guide system includes upper and lower sway rollers interacting between adjacent tower sections in a manner to engage the rollers with internal and external surfaces of the tower sections as the sections are being extended. This engagement of the rollers prevents relative lateral movement between tower sections so that adjacent tower sections are kept vertical and in-line and resisting the force of side winds while telescoping upward. The guide system also prevents the tower sections from coming into contact with each other, which could cause damage to hardware installed on the inner surfaces of each tower section, as well as guiding the tower sections during assembly and retraction.

The jacking mechanism is positioned internally of the outermost lower tower section and can include crawler jacks positioned on vertical, parallel jackrods extending between the upper and lower ends of the outermost lower tower section. The crawler jacks are positioned below the second tower section and engage the lower end of the second tower section to lift it upward, or lower it downward. Preferably, conventional hydraulic jacks are used.

It is therefore an object of the present invention to provide a support tower for a wind turbine generator in which the tower includes a plurality of telescopically associated tower sections that are initially assembled in vertically nested relationship while being supported on a tower foundation with the outer lowermost tower section rigidly connected to the supporting foundation. A wind turbine generator is mounted on the upper end of the innermost upper tower section. The nested tower sections are then telescopically extended vertically to elevate the inner tower sections and the wind turbine generator to a fully extended position.

Another object of the present invention is to provide a support tower including a plurality of nested telescoped tower sections of decreasing cross-sectional area from a lower tower section to an upper tower section. The tower sections are initially nested in a vertical position with the outermost section securely anchored to the foundation and the one or more inner tower sections supported on the top of its next outermost tower section. The tower load, such as a wind turbine generator or the like, is mounted on the upper end of the uppermost tower section after which the tower sections are extended to their full vertical height to position the tower load in an elevated position.

Still another object of the present invention is to provide a telescoping support tower in which adjacent tower sections in the fully extended position have a rigid and fixed wedge joint between the lower end of the inner upper section and the upper end of the lower outer section which extends around the circumference of the joined sections.

A further object of the present invention is to provide a support tower in accordance with the preceding objects in which the erection process can be safely and quickly performed by a small crew of personnel while maintaining complete stability of the tower sections during erection, with the elevating process being reversible in the event it is necessary to lower the load supported at the upper end of the tower for maintenance or replacement purposes.

Yet another object of the present invention is to provide a telescoping support tower for heavy wind turbines in which the telescoping tower sections are provided with guiding mechanisms to maintain the sections in alignment during lifting and lowering and to prevent sway that may be caused by high winds acting on the nacelle and turbine blades.

Still a further object of the present invention is to provide a support tower for supporting heavy structures at a high elevation in accordance with the preceding objects in which the cost of erection is minimized by utilizing equipment that can be easily transported to and from the site of erection, requiring the use of a minimum number of personnel during the erection procedure, enabling the erection process to be completed in a safe and efficient manner in adverse weather and lighting conditions and enabling heavy structures to be mounted on the tower when the tower sections are in vertical nested position and then extending the nested telescopic tower sections along with the heavy load to the full vertical height of the tower.

Yet another object of this invention to be specifically enumerated herein is to provide a telescopic tower for wind turbines and other structures in accordance with the preceding objects and which will conform to conventional forms of manufacture, be of simple construction and easy to use so as to provide a support tower that will be economically feasible, long lasting and relatively trouble free in operation.

These together with other objects and advantages that will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1F are schematic side elevational views illustrating the steps in assembling three tower sections in vertically nested relation, mounting a turbine generator on the upper end of an uppermost tower section and extending the tower sections and turbine generator to final tower height.

FIGS. 2A and 2B are sectional views of the wedge joint between upper and lower tower sections with FIG. 2A illustrating the upper tower section moving upwardly and FIG. 2B illustrating the wedge joint between the tower sections being mated and bolted.

FIGS. 3A and 3B are enlarged sectional views illustrating the wedge joint between upper and lower tower sections with FIG. 3A illustrating the wedge joint prior to mating and FIG. 3B illustrating the wedge joint mated and bolted securely.

FIGS. 4A and 4B are sectional views illustrating the guide structure utilized when the tower sections are being telescopically moved, with FIG. 4A illustrating the upper section traveling downwardly for nesting in a lower section and FIG. 4B illustrating the movement of the upper section telescoping upwardly toward a position for mating the wedge joint between tower sections.

FIGS. 5A-5E are detailed sectional views illustrating details of the upper and lower sway roller assemblies which guide an upper tower section while it is raised with respect to a lower tower section.

FIG. 6 is a schematic side elevational view illustrating a support block on an upper tower section and an alignment block on an upper tower section associated with an alignment receptacle block arrangement on a lower tower section along with a guide bar supported internally of the upper tower section.

FIGS. 7A-7F are detailed views illustrating additional details of the guide rollers, the guide bar and the guide rollers engaging the guide bar to prevent relative rotation of upper and lower tower sections when moved into initial telescoping relation.

FIGS. 8A-8E are schematic side elevational views illustrating a three section tower arrangement from an initial nested starting position in FIG. 8A to a final extended position in FIG. 8D with FIG. 8E illustrating an alternative mechanism for simultaneously extending the tower sections from a nested vertical position to an extended telescoped position.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Although a preferred embodiment and alternative lift mechanisms for vertically extending the tower are disclosed and explained in detail, it is to be understood that the embodiment and alternatives are given by way of illustration only. It is not intended that the invention be limited in its scope to the details or sequence of construction and arrangement of components set forth in the following description or illustrated in the drawings. Also, in describing the preferred embodiment specific terminology will be utilized for the sake of clarity. It is to be understood that each specific term includes all technical equivalents that operate in a similar manner to accomplish a similar purpose.

Referring to FIGS. 1A-1F of the drawings, an extended sectional telescopic tower and turbine generator assembly is illustrated in FIG. 1F and generally designated by reference numeral 10. FIGS. 1A-1F illustrate schematically the steps in assembling three tower sections 12, 14, and 16 and a turbine generator 18 mounted at the upper end of the uppermost and innermost tower section 16. Each of the tower sections 12, 14 and 16 include an elongated, cylindrical tubular member constructed of a plurality of metal segments, each preferably about ten feet in length and rigidly welded end to end to provide sufficient strength characteristics to support the turbine generator 18 at an elevated position as illustrated in FIG. 1F. The tower sections 12,14 and 16 are preferably about 80 feet to 90 feet in length. FIGS. 1A-1F also include vertical height dimensional characteristics of the tower during various stages of assembly.

The steps in assembling and extending the tower 10 include first the mounting of the lowermost and outermost tower section 12 onto a foundation 20. After the tower section 12 has been lifted by a suitable crane and positioned on the foundation 20, flange 22 on the lower end of tower section 12 is secured with anchor bolts 24 to fixedly and rigidly support the tower section 12 on the foundation 20. The second tower section 14 is then lifted to a position above and in alignment with the foundation-secured tower section 12 and lowered vertically into the lowermost tower section 12 for a major portion of its length, as illustrated in FIGS. 1B and 1C. The tower section 16 is then lifted by a suitable crane into a position above and in alignment with the upper end of the second tower section 14 and is lowered vertically into the second tower section 14, thus forming a vertically nested three tower section assembly having a relatively short vertical height as compared to the extended tower 10. The tower sections 14 and 16 are supported on the top edge of the next lower tower sections 12 and 14 by block assemblies to be described hereinafter.

After the three tower sections have been nested, the turbine generator 18 is lifted by a crane and supported on the upper end of the uppermost and third tower section 16 as illustrated in FIG. 1E. The tower sections 12, 14 and 16 are in vertically telescoped and nested relation and the turbine generator 18 has been mounted on the upper end of the uppermost and innermost tower section 16. The nested telescoped tower sections 14 and 16 are then vertically extended to the total tower height with the turbine generator 18 being elevated at the same time to a final desired height.

It is noted that while three tower sections 12, 14, and 16 have been illustrated, the number of tower sections may be varied from as few as two to as many as five or more. The total number of tower sections used is determined by the total height of the tower. As illustrated in FIG. 1E, the turbine generator 18, which is the heaviest component of the tower, is mounted on the nested tower sections; hence, the total height to which the turbine generator 18 must be lifted by a crane is slightly less than 100 feet. FIG. 1F illustrates that the turbine generator 18 would have to be lifted over 200 feet if three tower sections are assembled and extended before lifting the turbine generator 18 to the upper end of the extended tower. A crane would have to lift the tubular generator 18 up to as much as 400 feet if five tower sections are assembled and extended to form the tower. This method of assembling and extending the tower sections after mounting the turbine generator 18 on the nested upper tower section reduces the necessity of utilizing a crane capable of lifting heavier loads to high elevations.

The weight of the tower sections vary with the largest, outer tower section 12 weighing up to approximately 80,000 pounds and the combined nacelle, generator 18 hub and blade assembly forming the turbine generator weighing up to approximately 140,000 pounds. The weight characteristics of the tower sections and the turbine generator varies considerably but the necessity of lifting the tower sections for sequential vertical telescopic nesting as illustrated in FIGS. 1A-1E and lifting the turbine generator a relatively short height as illustrated in FIG. 1E enables the use of a much smaller crane to lift the turbine generator 18 to the position of FIG. 1E as compared to the position in FIG. 1F. Therefore, the nesting of the sections vertically and mounting the turbine generator 18 on the innermost upper tower section 16 before extending the tower sections reduces the size of crane necessary to erect a tower as compared to using previous techniques in which the tower sections are secured vertically lengthwise to each other and the turbine generator lifted to and attached to the upper end of the full height of the preassembled tower.

As illustrated in FIGS. 2A and 2B, tower section 12 is provided with a generally conic transition section 26 at the upper end thereof which terminates at its upper end with a cylindrical upper end section 28. The tower section 14 and any other tower section except for the uppermost tower section also include a similar cylindrical upper end section. The inside surface of the cylindrical upper end section 28 includes upper and lower annular wedge surfaces 32 and 34 which incline upwardly and inwardly, as illustrated in FIGS. 3A and 3B. The annular wedge surfaces are spaced apart vertically and the central inner surface 36 is recessed and generally cylindrical.

The annular wedge surfaces 32 and 34 coact and engage with vertically spaced arcuate segmented wedge members 38 and 40 which are mounted around the exterior surface of a lower end portion of an upper tower section 14. The wedge members 38 and 40 include upwardly and inwardly inclined wedge surfaces 42 and 43, respectively, which mate with and rigidly engage the wedge surfaces 32 and 34 on the inside wall of the cylindrical upper end section 28 of the tower section 12. As illustrated in FIGS. 3A and 3B, the wedge members 38 and 40 are received in a shallow peripheral recess 50 around the periphery of the lower end of tower section 14 to rigidly mount the wedge members 38 and 40 in position on tower section 40 and to resist vertical movement of the wedge members 38 and 40 when the wedge surfaces 42 and 43 are mated with the wedge surfaces 32 and 34 on the upper cylindrical end section 28 of the tower section 12.

The wedge members 38 and 40 include bolt holes 44 which are aligned with bolt holes 48 in the lower end of the tower section 14. The upper cylindrical end section 28 has corresponding holes 46. When the wedge members 38 and 40 are mated with wedge surfaces 32 and 34 during the vertical extension of the tower section 14 in relation to the tower section 12, bolt holes 46 and 44, 48 become aligned. Radial bolts 52 can then be extended therethrough, preferably from the interior of the tower section 14 and retaining nuts 54 threaded onto the outer end of the bolts 52 thereby to rigidly and fixedly form a wedge joint, generally designated by reference numeral 41, between the lower end of upper tower section 14 and the upper end of lower tower section 12. Wedge joint 41 retains the tower section 14 in its extended and elevated relation to the outermost and lowest tower section 12.

The above-described wedge joint anchoring connection between the tower sections as they are extended from their initial vertically nested relationship to their extended telescopic relationship provides a rigid connection between a lower end of an upper tower section and an upper end of a lower tower section. At the same time, this anchoring connection can be undone to enable upper tower sections to be lowered down into the lower tower sections if it becomes necessary to lower the turbine generator for repair or replacement. The lift mechanism that is used for elevating the upper tower sections is also used to lower the upper tower sections back to the initial nested position illustrated in FIG. 1E.

In order to maintain alignment of the bolt holes in the mated wedge surfaces 32, 34, 42 and 43, the horizontal radial bolt joint requires alignment of the sections when extending the sections from their nested position to their extended position. This alignment is necessary in order to assure that the bolt holes 46 at the top of a lower outer tower section align with the bolt holes 44 and 48 near the bottom of the next upper tower section. The alignment structure is illustrated in FIG. 6 and FIGS. 7A-7F and includes an alignment block 60 which projects a short distance outwardly from the external surface of an upper tower section 14 adjacent the upper end thereof and below the transition section 26. The alignment block 60 engages and coacts with a pair of tapered alignment blocks 62 that are mounted on the top edge of the cylindrical upper end section 28 of lower tower section 12 as illustrated in FIG. 6. When positioned within alignment blocks 62, the bottom surface 61 of alignment blocks 60 rests on the top edge 129 of cylindrical upper end section 28. This structure provides an initial alignment of the tower sections 12 and 14.

Support blocks 64 are welded to the exterior of the tower section 14 in peripherally spaced and aligned relation to the alignment block 60. Each support block 64 includes a horizontal bottom surface 66 that is parallel to the bottom surface 61 of the alignment block 60. Thus, when lowered into position, the bottom surfaces 61 and 66 support the section 14 when nested in tower section 12 by engaging the upper end or top edge 129 of cylindrical upper end section 28 of the tower section 12.

In addition, in order to prevent relative rotation of the tower sections 12 and 14 during vertical movement of the upper tower section 14, a vertically extending guide bar 68 is welded to the inside of the lower tower section 12; the guide bar 68 extends substantially throughout the length of the tower section 12. A roller bracket 70 is mounted on the exterior of the upper tower section 14 and supports a pair of rollers 72 that engage opposed surfaces of the guide bar 68 as illustrated in FIGS. 7A-7F. The rollers 72 engage opposite surfaces of the guide bar 68 in order to guide the tower sections 12 and 14 as the upper section 14 moves vertically in relation to the lower section 12. This guiding mechanism maintains alignment of the sections and prevents the upper tower section from rotating, while being telescoped, which might otherwise result from side wind loads against the radial blades and nacelle of the turbine generator 18.

The guide bar 68 is accurately positioned relative to the joint bolt holes 46 and 44, 48 in the mating wedge structures 38 and 40 so as to control the rotational position of the upper tower section 14 when being telescoped upwardly in tower section 12 and maintain alignment of the bolt hole 46 with the bolt holes 44 and 48. As illustrated in FIG. 7E, the guide bar 68 preferably has a thicker portion 74 near the upper end thereof to reduce the clearance between the guide bar 68 and the rollers 72. This reduced clearance ensures the accuracy of the rotational position of section 14 which is being telescoped and the alignment of the bolt holes for receiving the bolts 52. As illustrated in FIGS. 7A-7F, the guide bar 68 preferably includes inclined end edges 75 and the bracket 70 is attached to skirt rings 76 at the inner and outer edges of a skirt flange 78 with bracket 70 being a continuation of the skirt flange 78 on tower section 14.

Vertical movement of the telescopic tower sections, such as tower section 14, is also guided by upper sets of sway roller assemblies, generally designated by reference numeral 80, mounted in spaced relation around the upper end section 28 of the tower section 12 (and tower section 14 in the case of a three section tower). Preferably, twelve sets of sway roller assemblies 80 are removably mounted on the upper end of lower tower section 12. The roller assemblies 80 act against the outside surface of the tower section 14 while section 14 is being nested downwardly into tower section 12 and then subsequently telescoped upwardly. In addition, lower sway control roller assemblies, generally designated by reference numeral 82, are mounted at the bottom of tower section 14 (and tower section 16 in a three tower section arrangement) which act against the inside of the shell of the lower tower section 12 to provide guidance and sway prevention control while tower section 14 is being telescoped. As illustrated in FIGS. 4A, 4B and FIGS. 5A-5D, the lower sway control roller assemblies 82 include a clevis frame 84 that is mounted on a second skirt ring 86 which is clamped by clamps 88 to the skirt 89 at the bottom of the upper tower sections, such as tower section 14. The clevis frame 84 which supports roller assembly 82 is bolted to a mounting bracket 85 with three high strength bolts 94.

The roller assembly 82 is initially installed on the mounting bracket 85 with only one bolt 94 while the tower section 14 is still on the ground and easily accessible. The clevis frame 84 thus hangs vertically on the one bolt 94 while the section 14 is being nested to avoid interference with the inside diameter of the wedge surfaces 32 and 34 on the cylindrical upper end section 28 at the top of the lower section 12. After nesting of the tower sections and before telescoping the nested tower sections upwardly, the clevis frame 84 is rotated on the single mounting bolt 94 to a generally horizontal position with the assistance of lever arm 96, and the other two bolts 94 are inserted and tightened. After completion of the upward telescopic movement of tower section 14 and the wedge members 38 and 40 are bolted in place with bolts 52 after mating of the wedge surfaces 32,34 and 42,43, the lower sway control roller assemblies 82 mounted on the second skirt ring 86 on tower section 14 are lowered by retracting the hydraulic jacks 100 to the bottom of tower section 12 for removal.

The upper sway control roller assemblies 80 are mounted at the top of tower section 12, and tower section 14 if a third tower section 16 is used, while the tower sections are still on the ground and easily accessible. Each upper sway control roller assembly 80 includes a roller assembly 81 and a roller assembly bracket 106, preferably in the form of a rectangular tube. The bracket 106 extends vertically approximately three feet above the top of the cylindrical upper end 28 of the lower tower section 12 and down to a pad 107 that contacts the outer surface of the conic transition member 26. The roller assembly 81 at the top of the tubular bracket 106 is positioned with clearance to the outside of the tower section 14 that is being telescoped down into tower section 12. The roller assembly 81 is pivotally mounted on bracket 106 by a shaft 83 to allow the roller assembly to swivel which permits the roller assembly 81 to swivel 30° outwardly when the sections 12 and 14 are being vertically nested. The multiple roller assemblies 80 thus form a tapered lead-in when swiveled 30° as shown in FIG. 4A. When in the vertical position the rollers in roller assemblies 80 function to guide the tower section 14 traveling downward in conjunction with the lower sway rollers 92. When the section 14 is being telescoped upwardly, the upper sway control rollers 80 act on the outside of upper tower sections 14 and lower rollers 92 act on the inside surface of tower section 12, as illustrated in FIG. 4B, to prevent sway that may be caused by high winds.

FIGS. 5A-5E illustrate how the upper sway roller assembly bracket 106 is mounted releasably on the upper end of the lower tower section 12. Attaching blocks 101 are welded to the upper edge 29 of the cylindrical upper end 28 of tower section 12. A heavy plate 102 with two openings 104 is welded to the outside of the roller support bracket 106 and the openings 104 receive and surround the blocks 101. The support bracket 106 is additionally held by a pivotal latch mechanism 108 engaging a horizontal peripheral bar 110 welded to the outside of the cylindrical upper end 28 of tower section 12. Compression spring 112 maintains each of the latches 108 in the locked position as illustrated in FIG. 5B. A hoop 114 is attached to the latch 108 and extends above the roller bracket 106 in proximity to another hoop 116 that is welded to the top of the bracket 106. The two hoops 114 and 116 are connected by a wire rope sling 118 for connection with a crane hook (not shown). When the crane pulls lower hoop 114 upwardly, the latch 108 rotates around pivot 109 against the force of spring 112 to release latch 108 from bar 110. The upper hoop 116 can then lift roller assembly 80 including bracket 106 upwardly. A plurality of the roller assemblies 80 can be attached to a curved spreader beam (not shown) for simultaneously releasing and removing several of the roller assemblies 80 from the top of the lower tower section 12.

As illustrated in FIGS. 4A and 4B, the transition conic section 26 of the lower tower section 12 provides the reduction in diameter from that of the lower tower section 12 to the diameter of the upper tower section 14. The transition conic section 26 is rigidified preferably by triangular gussets 27 which have lower ends fixed to an internal circular flange 29. The circular flange 29 and gussets 27 not only support the wedge joint 41, but also withstand out-of-plane bending loads that may be imposed by strong winds exerted on the blades and nacelle of the turbine generator 18. The transition conic section 26 and wedge joint 41 between tower sections may be used regardless of the height and number of tower sections with it only being necessary to alter the dimensional characteristics in accordance with the different diameters of the tower sections.

The wedge joint 41 described previously functions to provide a very strong joint when an upper section 14 is telescoped upwardly within a lower section 12 and the internal wedge surfaces 32 and 34 on the lower section 12 mate with and lockingly engage the external wedge segments 38 and 40 on the upper tower section 14. The joint is completed when the bolts 52 and nuts 54 rigidly secure the cylindrical wedge mating surfaces to one another. The mating engagement of the internal and external wedge surfaces forms a very strong joint when the surfaces are engaged by upward movement of an upper tower section to a position to enable securing bolts 52 to be inserted through the wedge structures to form the wedge joint and rigidly secure the tower sections in their extended position.

When lowering an upper tower section into a lower tower section, it is necessary that wedge members 38 and 40 be removed from the upper tower section in order for the upper tower section to move downwardly through the cylindrical upper end section 28 of the lower tower section. After the upper tower section has been lowered into the lower tower section, the wedges 38 and 40 are applied to the recesses 50 in the lower exterior surface of the upper tower section, such as tower section 14. This assembly is preferably obtained by having the wedge members 38 and 40 made of an arcuate sectional or segmented construction which can be bolted to or otherwise detachably secured in recesses 50 on the external surface of the lower end portion of the upper tower section. When the upper tower section is lowered into the lower tower section, the external diameter of the lower end of the upper tower section, without the wedge members 38 and 40 thereon can be moved downwardly into the lower tower section. After the upper tower section is moved downwardly into the lower tower section, the segmental wedge members 38 and 40 are attached to the exterior surface of the lower end of the upper tower section by bolts or the like with access to the lower end of the upper tower section being provided by a large access opening 13 at the lower end of the lower tower section 12. If it becomes necessary to move an upper tower section completely out of a lower tower section, such as when disassembling the tower, access may be had to the lower end of the upper tower section through the access opening 13 when the upper tower section is lowered thereby enabling removal of the segmental wedge members 38 and 40 so that the upper tower section can be lifted vertically upwardly out of the lower tower section.

After the segmental wedge members 38 and 40 have been applied to the lower end of an upper tower section, the upper tower section can be moved upwardly to engage the wedge members 38 and 40 with the wedge surfaces 32 and 34. The dimensional configuration of the inclined wedging surfaces is such that the bolt holes in the upper tower section in wedges 38 and 40 and the bolt holes in the cylindrical upper end portion 28 of the lower tower section will be at the same elevation. The guide 68 and rollers 72 prevent relative rotation of the tower sections thereby aligning the bolt holes to enable bolts 52 to be inserted through the inclined mating surfaces to rigidly secure the wedge joint.

To provide access to the interior of the upper tower section after it has been elevated to its final position, an internal ladder structure (not shown) is provided in the tower sections in the same manner as disclosed in the cross-referenced co-pending application Ser. No. 09/729,250 (hereinafter the “referenced '250 application”). The guide bar 68 and associated rollers 72 maintain alignment of the bolt holes in the lower and upper tower sections, in the wedge members 38 and 40, and in the cylindrical upper end section 28 of the lower tower section.

The tower sections 14 and 16 can be extended and retracted by conventional hydraulic jacks 100 on jackrods 103. The jackrods 103 have their upper ends extending through flange 29 at the lower end of the transition area 26 adjacent gussets 27 for attachment on the flange 29. Conventional hydraulic jacks useful for the present invention are available from Scanada Lifting Systems, Inc. of Bow, N.H. Depending on the size and weight of the tower section, four to eight such hydraulic jacks should be used to lift and lower each section, and preferably five or six. Alternatively, crawler jacks may be used, or a cable rigging assembly may be used to lift upper section 16, in a three or more section tower, all in the manner disclosed in the referenced '250 application. However, the cable rigging arrangement for the instant invention utilizes rope constructed of composite fibers in lieu of steel cables or wire rope. The composite fiber rope is lighter in weight for the rated strength and diameter and has greater flexibility and durability as compared to a steel wire rope. Composite fiber rope useful in the present invention is available from Puget Sound Rope Co. of Anacorta, Wash., or the Cortland Rope Co. of Cortland, N.Y.

As illustrated in FIGS. 8A-8E multiple rope assemblies 120 are provided having a terminal connection 122 in the form of a bracket at the bottom of the upper tower sections and connected with screw jacks 126 at the lower end of the lower tower section. A load cell 128 is provided at each screw jack for connection with the composite rope cable assemblies 120. Pulleys 130 are provided at the upper end of the first upper tower section 14 in order to simultaneously elevate both towers 14 and 16 by actuating the hydraulic jack and jackrod arrangement for elevating tower section 14 and simultaneously elevating tower section 16 so that the wedge joint between tower section 12 and tower section 14 and between tower section 14 and tower section 16 will be simultaneously engaged to enable insertion of the retaining bolts 52 in each of the wedge joints.

The access opening 13 also provides access to the hydraulic jacks 100 and the jackrods 103. The jacks and jackrods enable the lower sway roller assemblies 82, once separated from the lower end of the upper tower section to be lowered by the jacks after the wedge joint has been completed for removal of the lower sway rollers. Thus, by removal of the upper roller assemblies 80 and the lower roller assemblies 82, the interior and exterior of the tower sections are substantially devoid of external and internal projections.

When it becomes necessary to perform maintenance or replacement of components that can not be accomplished by accessing the interior of the extended tower through the internal ladder (not shown), the tower can be lowered by reversing the extension procedure. By sequential attachment of the lower roller assemblies 82 and the upper roller assemblies 80 to each tower section as the tower sections are lowered enables stable retraction of the tower sections. With the tower sections extended, the lower sway rollers 82 may be attached to the bottom of the upper tower section 14 and the upper roller assemblies 80 may be attached to the exterior of the upper end portion of the lower tower section 12. The upper tower section 14 then may be lowered after the bolts 52 holding the wedge joint connection are removed. Thus, the tower can be returned to the position illustrated in FIG. 1E which enables the turbine generator to be repaired or replaced at a lower elevation thereby providing the same advantages derived from initially installing the turbine generator at the lower elevation.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and, accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

Claims

1. A tower for supporting heavy loads above a tower Foundation, said tower comprising a plurality of elongated tubular tower sections including at least an outer lower tower section and an inner upper tower section each including a substantially cylindrical peripheral wall, said tower sections being telescopically nestable in a generally vertical position, said outer tower section having a lower end supported from said tower foundation to enable the inner tower section to be extended vertically, said inner tower section supporting said heavy load at an upper end thereof when nested in said outer tower section, a lift mechanism interconnecting said outer and inner tower sections to telescopically extend said inner tower section and lift said heavy load to an extended tower height, and coacting mating wedge surfaces on said outer tower section and said inner tower section to form a rigid wedge joint between a lower end of said inner tower section and an upper end of said outer tower section when said tower sections are vertically extended.

2. The tower as defined in claim 1, wherein fasteners rigidly interconnect said wedge surfaces when said tower sections are extended to tower height.

3. The tower as defined in claim 1, wherein at least one of said tower sections includes guide rollers to guide movement of said inner tower section when raised to an extended tower height.

4. The tower as defined in claim 1, wherein said lift mechanism includes a plurality of circumferentially spaced jackrods mounted on said outer tower section, a crawler jack on each jackrod for vertical movement thereon, said crawler jacks engaging said inner tower section to raise said inner tower section to an extended tower height.

5. The tower as defined in claim 1, wherein said lift mechanism includes a plurality of circumferentially spaced rope, pulley and winch assemblies associated with said tower sections to raise said inner upper tower section to an extended tower height.

6. The tower as defined in claim 1, wherein said wedge structure on an upper end of said outer lower tower section includes a peripheral upwardly and inwardly inclined wedge ring, said wedge structure on said inner upper tower section including a downwardly and outwardly inclined wedge surface engaging the wedge ring on said outer lower tower section when the inner upper tower section is lifted vertically, said fasteners interconnecting said wedge ring and wedge surfaces to secure said tower sections in said extended tower height.

7. The tower as defined in claim 1, wherein an upper end portion of said outer lower tower section and a lower end portion of said inner upper tower section each include inter-engaging wedge structures to limit upward movement of said inner upper tower section and align said sections when said inner upper section is in an elevated position, said fasteners interconnecting said wedge structures by extending through said wedge structures.

8. A tower for supporting a heavy load from a tower foundation comprising at least two elongated, telescopically associated tower sections including a lower tower section supported vertically on said tower foundation and an upper tower section telescopically nestable in relation to said lower tower section, a lift mechanism interconnecting said lower tower section and said upper tower section, said lift mechanism including a plurality of generally parallel vertical jackrods and crawler jack assemblies interconnecting said lower tower section and said upper tower section to move said upper tower section vertically to an elevated position in relation to said lower tower section, an upper end portion of said lower tower section and a lower end portion of said upper tower section each including peripheral mating wedge assemblies which are interconnected to retain said upper tower section in said elevated position and in vertical alignment with said lower tower section.

9. A tower for supporting heavy loads above a tower foundation which comprises a plurality of elongated tower sections including at least an outer tower section and an inner tower section nested in a vertical telescoped position with said inner tower section nested within said outer tower section, said outer tower section having a lower end mounted on said tower foundation to enable the nested vertically telescoped tower sections to be extended vertically, said inner tower section supporting said heavy load when nested in said outer tower section, and a lift mechanism interconnecting said outer and inner tower sections to telescopically raise said inner tower section and said heavy load to an extended tower height.

10. The tower as defined in claim 9, wherein at least one of said tower sections includes upper sway rollers and lower sway rollers to guide movement of the inner tower section when raised to an extended tower height.

11. The tower as defined in claim 9, wherein said lift mechanism includes a plurality of circumferentially spaced jackrods mounted in said outer tower section, a crawler jack on each jackrod for vertical movement thereon, said crawler jacks raising said inner tower section to an expanded tower height.

12. A tower for supporting a heavy load from a tower foundation comprising at least two elongated, telescopically associated tower sections including a lower tower section supported vertically on said tower foundation and an upper tower section telescopically positioned in said lower tower section, a lift mechanism interconnecting said lower tower section and said upper tower section, said lift mechanism including a plurality of generally parallel vertical jackrod and crawler jack assemblies interconnecting said lower tower section and said upper tower section to move said upper tower section vertically to an elevated position in relation to said lower tower section, a lower end portion of said upper tower section including a plurality of peripheral low sway rollers guidingly engaged with a peripheral surface of said lower tower section, said lower tower section including a plurality of upper sway rollers to guide relative vertical movement of said tower sections.

13. The tower claimed in claim 11, further comprising a second upper tower section telescopically positioned in said upper tower section positioned in said lower tower section, a second lift mechanism interconnecting said upper tower sections to simultaneously move said second upper tower section vertically in relation to said upper tower section positioned in said lower tower section when said jackrod and crawler jack assemblies move said upper tower section positioned in said lower tower section upwardly thereby simultaneously moving both upper tower sections vertically in response to vertical movement of said upper tower section positioned in said lower tower section by said jackrod and crawler jack assemblies.

14. The tower as claimed in claim 12, wherein each of said jackrod and crawler jack assemblies includes a vertical jackrod fixed interiorly of said lower tower section, and a crawler jack vertically moveable on said jackrod, said jackrods being mounted vertically and generally parallel within said lower tower section, said crawler jacks engaging a lower end of said upper tower section for lifting it to said elevated position.

15. The tower as claimed in claim 12, wherein said upper tower section includes a vertical guide bar depending therefrom, said lower tower sections including opposed rollers engaging said guide bar to prevent rotation of said upper tower section during vertical movement in relation to the said lower tower section.

16. The method of erecting a tall support tower having a plurality of elongated telescopic tower sections above a tower foundation comprising the steps of mounting an outer tower section in vertical position on said foundation, vertically inserting an inner tower section downwardly into said outer tower section, elevating said inner tower section vertically to an expanded tower height, limiting vertical movement of said inner tower section by coacting wedge structures on the upper end of said outer town section and lower end of said inner tower section and extending fastening members through the coacting wedge structures to secure said tower sections in expanded tower height.

17. The method as claimed in claim 16, wherein said step of elevating the inner tower section includes the step of engaging a lift mechanism with a lower end portion of said inner tower section and lifting the inner tower section to an expanded tower height.

18. A tower for supporting heavy loads above a tower foundation, said tower comprising a plurality of elongated tubular tower sections including at least a lower tower section and an upper tower section each including a substantially cylindrical peripheral wall, said tower sections being telescopically nested and disposed in a generally vertical position, said lower tower section having a lower end supported from said tower foundation to enable said upper tower section to be extended vertically, said upper tower section supporting said heavy load at an upper end thereof when nested in said lower tower section, and a lift mechanism interconnecting said lower and upper tower sections to telescopically extend said upper tower section and lift said heavy load to an extended tower height, coacting structures on a lower end of said upper tower section and an upper end of said lower tower section, said coacting structures being rigidly connected when said upper tower section is vertically extended by fasteners interconnecting said coacting structures.

19. The tower as defined in claim 18, wherein at least one of said tower sections includes guide rollers to guide movement of said upper tower section when raised to an extended tower height.

20. The tower as defined in claim 18, wherein said lift mechanism includes a plurality of circumferentially spaced composite rope and pulley assemblies associated with said tower sections to raise said upper tower section to an extended tower height.

21. The tower as defined in claim 18, wherein said coacting structures include a peripheral upwardly and inwardly inclined wedge ring on one of said tower sections and a downwardly and outwardly inclined wedge ring on the other of said tower sections for rigid engagement with said wedge ring when said one tower section is elevated to its extended tower height.

22. A tower for supporting heavy loads above a tower foundation, said tower comprising a plurality of elongated tubular tower sections including at least a lower tower section and an upper tower section each including a perimeter structure, said tower sections being telescopically nested and disposed in a generally vertical position, said lower tower section having a lower end supported from said tower foundation to enable said upper tower section to be extended vertically, said upper tower section supporting said heavy load at an upper end thereof when said tower sections are nested and a lift mechanism interconnecting said lower and said upper tower sections to telescopically extend said upper tower section and lift said heavy load to an extended tower height, coacting connecting structures on a lower end of said upper tower section and an upper end of said lower tower section, said connecting structure being matingly and rigidly engaged when said tower sections are vertically extended, and fasteners interconnecting said connecting-structures when said tower sections are extended to tower height.