IP Verse

Main Shaft Fixture

Patent No. US12104578 (titled "Main Shaft Fixture") was filed by Liftra Ip Aps on Jan 24, 2024.

What is this patent about?

’578 is related to the field of wind turbine maintenance, specifically addressing the challenge of safely and efficiently servicing heavy components within the nacelle. Traditional methods of fixing the main shaft during these operations often require halting turbine operation and using inflexible fixtures, leading to energy production losses and logistical difficulties due to varying shaft geometries. The patent aims to overcome these limitations.

The underlying idea behind ’578 is to provide a modular main shaft fixture that can be installed on existing nacelle structures without stopping the turbine. This fixture uses adjustable pressure mandrels with tap shoes to accommodate different shaft geometries. Furthermore, the fixture incorporates mounting points for both lightweight and self-hoisting cranes, streamlining the process of lifting and replacing heavy components.

The claims of ’578 focus on a main shaft fixture designed for wind turbine maintenance. The fixture is characterized by adjustable pressure mandrels with tap shoes that can be moved between a retracted position (away from the shaft) and an engaged position (contacting the shaft). Crucially, the fixture also includes mounting facilities for anchoring a crane within the nacelle.

In practice, the fixture is assembled in sections onto the nacelle's bottom frame. The adjustable mandrels are then extended to contact and secure the main shaft, providing stability for maintenance work. The integrated crane mounting points allow for efficient hoisting of tools and components, reducing the need for large external cranes and minimizing downtime. The adjustability of the mandrels allows the same fixture to be used on different turbine models.

The key differentiation from prior solutions lies in the combination of adaptability and integration. The adjustable mandrels eliminate the need for custom fixtures for each shaft geometry. The integrated crane mounting points streamline the maintenance process, reducing setup time and reliance on external equipment. Some embodiments also include a rotor lock and actuators to allow for controlled vertical displacement of the main shaft, facilitating bearing replacement without complete disassembly.

How does this patent fit in bigger picture?

Technical landscape at the time

In the mid-2010s when ’578 was filed, wind turbine maintenance at a time when fixing the main shaft during repairs was typically implemented using external fixtures. These fixtures were mounted after halting the turbine and locking the rotor, which caused downtime and energy production losses. Furthermore, the fixtures were often inflexible, requiring different fixtures for different shaft geometries. The increasing use of self-hoisting cranes with ground-based winches also created a need for anchoring facilities in the nacelle.

Novelty and Inventive Step

The examiner approved the application because the prior art does not teach a main shaft fixture that also includes mounting facilities adapted for anchoring a crane on or in a wind turbine nacelle.

Claims

This patent includes 17 claims, with independent claims numbered 1, 15, and 16. The independent claims generally focus on a main shaft fixture used for fixing a wind turbine's main shaft during installation and repair, incorporating adjustable pressure mandrels and crane mounting facilities. The dependent claims elaborate on specific features and variations of the main shaft fixture described in the independent claims.

Key Claim Terms New

Definitions of key terms used in the patent claims.

Term (Source)Support for SpecificationInterpretation
Adjustable pressure mandrels with tap shoes
(Claim 1, Claim 15, Claim 16)		“Thus, it is the purpose of the invention to specify a main shaft fixture that provide a more universal application in relation to shaft geometry, which moreover does not require halting and fixing of the wind turbine main shaft, but which may however comprise the means for such. It is further the purpose of the invention to provide a main shaft fixture that in addition offers facilities for the mounting of a self-hoisting crane, with a ground-based winch. It is by the invention realized that this is possible by a main shaft fixture of the nature specified in the introduction, which is characterised by that the main shaft fixture comprises adjustable pressure mandrels with tap shoes, and said pressure mandrels being displaceable between a passive, withdrawn lockable position where the tap shoes are configured to be located at a distance from the surface of the main shaft and an advanced lockable position where the tap shoes are configured to be engaged with the main shaft and mounting facilities suitable for a lightweight crane.”A component of the main shaft fixture that includes mandrels that can be adjusted to move tap shoes. The tap shoes can be moved between a passive position, where they are not in contact with the main shaft, and an active position, where they are engaged with the main shaft.
Beam-shaped brackets extending parallel with, and on each side of the main shaft
(Claim 16)		“In a preferred embodiment of the rotor lock, it is comprised of a flange, whose bolt circle geometry corresponds to a bolt circle geometry on the rotor, said flange element being fastened at the ends to the first end of two first beam-shaped brackets extending parallel with, and on each side of the main shaft, said beam shaped brackets belonging to the main shaft fixture, and where the other end of the brackets are pivotally mounted with horizontally oriented bolt connections, on other brackets belonging to the main shaft fixture, which are anchored on the bottom frame of the nacelle.”Two brackets shaped like beams that run alongside the main shaft, forming part of the rotor lock mechanism.
Mounting facilities adapted for anchoring a crane on/in a nacelle
(Claim 1, Claim 15, Claim 16)		“With the intent of being able to use a self-hoisting crane with a ground-based winch together with the main shaft fixture according to the invention, it may comprise mounting facilities for a self-hoisting crane whose winch is placed on the ground surface ground near the foot of the wind turbine. The advance thereof is that the establishment of facilities for the fixing of the wind turbine's main shaft, as well as the establishment of mounting facilities for the self-hoisting crane with a ground-based winch, take place simultaneously, which saves work processes, and space, which are of great importance, as the space in the nacelle in a wind turbine are most often narrow, and furthermore the main shaft fixture as well as the mounting facilities for a self-hoisting crane in the nacelle normally utilize the same permanent structural parts in the nacelle for anchoring.”Features of the main shaft fixture that allow a crane to be secured to the nacelle, either inside or on it.
Rotor lock for fixation of a rotor
(Claim 16)		“With the intent of being able to fix the rotor on the wind turbine after it has been braked to a stop, the main shaft fixture according to the invention, may comprise a rotor lock, for fixing the wind turbine rotor. In a preferred embodiment of the rotor lock, it is comprised of a flange, whose bolt circle geometry corresponds to a bolt circle geometry on the rotor, said flange element being fastened at the ends to the first end of two first beam-shaped brackets extending parallel with, and on each side of the main shaft, said beam shaped brackets belonging to the main shaft fixture, and where the other end of the brackets are pivotally mounted with horizontally oriented bolt connections, on other brackets belonging to the main shaft fixture, which are anchored on the bottom frame of the nacelle.”A component of the main shaft fixture used to secure the wind turbine's rotor in place.
Threaded bolts whose opposing free ends facing the main shaft are furnished with tap shoes
(Claim 15)		“In a more simple form of embodiment of the main shaft fixture according to the invention, the pressure mandrels may be comprised of threaded bolts whose free ends facing the main shaft are furnished with tap shoes, where the threaded bolts work together with threaded holes in relevant sections of the fixture. The pressure mandrels with the tap shoes are hereby displaced by manual turning of the threaded bolts between the passive position and the active position.”A specific configuration of the adjustable pressure mandrels, where the mandrels are threaded bolts with tap shoes attached to the ends that face the main shaft. The bolts engage with threaded holes in the fixture.

Patent Family

Patent Family

File Wrapper

The dossier documents provide a comprehensive record of the patent's prosecution history - including filings, correspondence, and decisions made by patent offices - and are crucial for understanding the patent's legal journey and any challenges it may have faced during examination.

  • Date

    Description

  • Get instant alerts for new documents

US12104578

LIFTRA IP APS
Application Number
US18420859
Filing Date
Jan 24, 2024
Status
Granted
Expiry Date
Oct 6, 2035
External Links
Slate, USPTO, Google Patents