Counterweighted Main Shaft Lifting Rail for Inclined Nacelle Hoisting
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Solution Overview
Problem
Mounting and dismounting a main shaft of a wind turbine from an up-tower nacelle is challenging due to the weight of the shaft, the height of the nacelle above the ground, and the non-zero inclined angle of the shaft, which complicates the connection of a hoist over the center-of-gravity, necessitating a tool that can adjust the angle and center-of-gravity for safe lifting.
Innovation Solution
A counterweighted lifting tool with a rail, carriage, and counterweight system that allows adjustment of the center-of-gravity and angle of the main shaft, enabling secure mounting and dismounting by connecting to the rotor hub and using a lifting device to maneuver the shaft into or out of the nacelle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hoist is connected directly over the center-of-gravity of the main shaft for lifting, then the main shaft can be balanced and lifted parallel to the ground, but this connection is obstructed when using an up-tower lifting device mounted in the nacelle over the main shaft
Solution Approach 1:
The patent introduces a lifting tool as an intermediary device between the hoist and the main shaft. This tool includes a rail mounted on the main shaft, a carriage that moves along the rail, and a hoist connection point on the carriage. The intermediary tool allows the hoist to be connected at a convenient location rather than directly to the main shaft, solving the obstruction problem while maintaining lifting capability.
Solution Approach 2:
The patent employs a movable carriage system on the rail that can be positioned dynamically along the length of the main shaft. This dynamic positioning capability allows the hoist connection point to be adjusted to any convenient location on the main shaft, providing adaptability to different lifting scenarios and overcoming the obstruction issue.
2Reliability
If the main shaft is mounted in the nacelle at a non-zero angle with respect to the horizontal, then proper mounting is achieved, but any lifting tool must have the ability to adjust the angle of the main shaft
Solution Approach 1:
The patent incorporates an angle adjustment mechanism that allows the lifting tool to dynamically change the inclination angle of the main shaft during lifting operations. This dynamic adjustment capability enables the tool to accommodate the non-zero mounting angle requirement while maintaining a relatively simple overall structure, resolving the contradiction between mounting accuracy and device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables safe and efficient installation and removal of the main shaft under circumstances where a hoist cannot be connected over the center-of-gravity, maintaining the shaft's angle and balance during lifting operations.
Implementation Method 1
a counterweight movably mounted on the rail to permit moving the counterweight longitudinally along the rail
Implementation Method 2
a lug fixedly mounted on the rail proximate the first end of the rail, the lug configured to be securable to a lifting device so that the rail can be suspended from the lifting device
Data Source
AI summary
A tool for lifting a main shaft of a wind turbine has a rail having a first end and a second end, the rail configured to be fixedly mounted proximate the first end of the rail to the main shaft proximate a rotor hub mounting end of the main shaft. A counterweight is movably mounted on the rail to permit moving the counterweight longitudinally along the rail. A lug is fixedly mounted on the rail proximate the first end of the rail, the lug configured to be securable to a lifting device so that the rail can be suspended from the lifting device. Use of a counterweighted lifting tool such as the one described above permits mounting and dismounting the main shaft underneath a nacelle-mounted lift system.