Spheroidal Coupling for Wind Vane Backlash Elimination

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Solution Overview

Problem

Existing mechanical coupling devices for rotary components, such as wind vanes and anemometers, face issues with backlash, inaccurate axial location, and reliance on friction forces, making them unsuitable for applications requiring precision and tool-free operation.

Innovation Solution

A spheroidal coupling system with resilient elements providing two or three point contacts ensures defined rotational and axial alignment, eliminating backlash and friction dependence, and allowing tool-free locking and release through gravity action.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ball and groove coupling mechanism is used, then the coupling can be locked in position, but backlash occurs making the instrument inaccurate

Engineering Contradiction:
Improvecoupling lock reliabilityVSAvoidinstrument accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces the traditional ball-and-groove mechanism with a spheroidal (egg-shaped) coupling member that has a curved surface profile. This spheroidal shape engages with corresponding curved surfaces in the coupling chamber, eliminating the clearance and backlash inherent in ball-and-groove designs. The curved contact surfaces ensure continuous positive engagement while maintaining rotational alignment, thereby improving measurement precision without compromising coupling reliability.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Power

If a chuck with threaded or tapered bore is used, then torque transmission is achieved, but the device is large and provides substantial inertial resistance

Engineering Contradiction:
Improvetorque transmissionVSAvoidinertial resistance
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The patent extracts the essential torque transmission function from the bulky chuck design and implements it through a minimalistic spheroidal coupling member. The spheroidal shape with its curved engagement surfaces provides sufficient torque capacity while reducing the overall size and mass of the coupling device. This extraction of the core function eliminates unnecessary material and structure, thereby reducing inertial resistance while maintaining adequate torque transmission capability for the application.

Inventive Principle:
Principle #2Taking out (Extraction)

3Manufacturing precision

If a pin arrangement with annular groove is used, then axial location is provided, but the system requires tools for assembly and disassembly

Engineering Contradiction:
Improveaxial location precisionVSAvoidassembly ease
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent implements a self-servicing coupling mechanism where the spheroidal coupling member's curved surface profile enables automatic alignment and engagement. The geometry of the spheroidal shape provides self-centering action that ensures precise axial and rotational location without requiring external tools or complex alignment procedures. The coupling can be assembled and disassembled by simple insertion and removal motions, making the system user-friendly while maintaining manufacturing precision.

Inventive Principle:
Principle #25Self-service

4Power

If traditional coupling devices are used, then torque transfer is achieved, but friction forces are relied upon reducing accuracy

Engineering Contradiction:
Improvetorque transferVSAvoidaccuracy
Core Design Contradiction:
PowerVSMeasurement precision

Solution Approach 1:

The patent employs curved contact surfaces on the spheroidal coupling member that engage with corresponding curved surfaces in the coupling chamber. This geometric design creates positive mechanical engagement through surface contact rather than relying on friction between mating surfaces. The curved profiles ensure consistent contact geometry that maintains precise rotational alignment and torque transfer without the slippage and variability associated with friction-based coupling, thereby improving measurement accuracy.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

The spheroidal coupling system ensures precise alignment and secure torque transmission without tools, reducing inertial resistance and improving accuracy in meteorological applications.

Implementation Method 1

allowing tool-free locking and release through gravity action

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 2

a resilient element operable to provide an axial force of separation

Methodology Applied
Scientific EffectResilient element force: Spring

Data Source

PatentEP2921733B1Improvements in or relating to mechanical coupling devices
Publication Date: 2019.11.27 WINDSPEED
  • EP2921733B1 patent drawingFigure 1~5
  • EP2921733B1 patent drawingFigure 3a~4
  • EP2921733B1 patent drawingFigure 5~7c

AI summary

The present invention relates to rotary devices, such as wind vanes and the like. Specifically, the present invention relates to a mechanical coupling for the same, whereby a wind vane or other rotary tool, can be replaced without the use of a tool. The present invention seeks to provide a coupling device which makes a mechanical coupling between a first and a second member such that the locking together and release action is positive, without likelihood of failure, and can be conducted simply and quickly without the use of a tool. Further objects of the invention are to provide couplings in which a positive axial and rotational location of shaft as first member and mating bore in a second member are obtained without reliance on friction forces, and which do not cause damage to either of the sliding surfaces when excessive force is applied, and which are capable of transmitting a torque, such couplings being suitable for attaching a rotor to an anemometer or the fin to the shaft of a wind vane. In accordance with a general aspect of the invention, the invention provides a coupling arrangement for a rotary device and a spindle supported for rotation, the coupling being enabled by a resilient body which acts upon a spheroidal locking member such as a ball bearing. In particular, the present invention provides a coupling arrangement for a wind vane or an anemometer rotating body comprising impellor cups, which impellor cups and rotating body are required for removable fitment, ideally without the use of tools.