Folding tower

Abstract

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.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]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.BACKGROUND[0002]1. Field[0003]The invention relates to tower support structures and methods for erecting them.[0004]2. Description of the Related Art[0005]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.[0006]Tower structures for wind turbines are constructed to accommodate and withstand the weight of the wind ...

AI Technical Summary

Benefits of technology

[0017]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.

[0019]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.

Problems solved by technology

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.

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.

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.

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