Asymmetric Flexible Tool for Confined Space Machining

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Solution Overview

Problem

Flexible tools used for machining and inspection in confined spaces often have insufficient work volume, limiting access to objects positioned beyond a certain angle, requiring disassembly of systems, which is time-consuming and costly.

Innovation Solution

A flexible tool design with asymmetric work volume and stiffness, achieved through uneven spacing and material variation of flexible members and control cables around a longitudinal axis, allowing greater angular reach and applicability in confined spaces without disassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If flexible tool uses symmetric uniform structure, then manufacturing is simple, but work volume is insufficient and cannot reach objects beyond 45 degrees

Engineering Contradiction:
Improvework volumeVSAvoidstructure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by unevenly distributing flexible members around the longitudinal axis. Specifically, more flexible members are positioned on one side of the axis than the other, creating asymmetric stiffness characteristics that enable the tool to reach greater angular distances in specific directions, thereby expanding the work volume beyond the conventional 45-degree limitation.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent implements local quality by varying the distribution and density of flexible members at different angular positions and radial distances from the longitudinal axis. This creates zones of different stiffness and flexibility throughout the tool structure, allowing optimized reach in specific directions while maintaining structural integrity in other areas.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If flexible tool increases angular reach, then access to confined spaces improves, but structural stability decreases

Engineering Contradiction:
Improveangular reachVSAvoidstructural stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by strategically positioning stiffer flexible members closer to the longitudinal axis and more numerous flexible members at greater radial distances. This creates a gradient structure where the tool maintains structural stability near the core while achieving greater angular reach at the periphery, resolving the contradiction between reach and stability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The asymmetric distribution of flexible members allows the tool to have different stiffness characteristics in different angular directions. Directions requiring greater reach have more flexible members, while directions requiring structural stability have fewer or stiffer members, enabling optimized performance in both aspects simultaneously.

Inventive Principle:
Principle #4Asymmetry

3Adaptability or versatility

If flexible tool uses uniform cable distribution, then manufacturing is easier, but cannot achieve asymmetric work volume for extended reach

Engineering Contradiction:
Improvework volumeVSAvoidcable distribution
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent implements asymmetry in cable distribution by positioning control cables at non-uniform angular intervals around the longitudinal axis. This asymmetric cable arrangement corresponds to the asymmetric flexible member distribution, enabling the tool to achieve extended angular reach in specific directions while maintaining controllable stiffness characteristics.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent applies local quality by varying the density and positioning of control cables at different locations along the tool's length and around its circumference. This allows localized control of flexibility and stiffness in different regions, enabling optimized asymmetric work volume while using standardized cable components that can be manufactured and installed using systematic procedures.

Inventive Principle:
Principle #3Local quality

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 machining or inspection of objects at larger angles, reducing repair time and costs by allowing access to objects within gas turbine engines and other systems without disassembly, thereby enhancing reach and applicability in confined spaces.

Implementation Method 1

a flexible tool (10) comprising: a plurality of rigid members (12) spaced along a longitudinal axis (14); and a plurality of flexible members (16) extending between the plurality of rigid members (12)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3072642B1Flexible tools and apparatus for machining objects
Publication Date: 2020.09.09 ROLLS ROYCE PLC
  • EP3072642B1 patent drawingFigure 1
  • EP3072642B1 patent drawingFigure 2~3
  • EP3072642B1 patent drawingFigure 4~5

AI summary

A flexible tool comprising: a plurality of rigid members spaced along a longitudinal axis; a plurality of flexible members extending between the plurality of rigid members and being arranged to enable the plurality of rigid members to diverge from the longitudinal axis and define a work volume for the flexible tool, at least some of the plurality of flexible members being unevenly spaced around the longitudinal axis, and/or a physical characteristic of at least some of the plurality of flexible members varying along the longitudinal axis, to cause the work volume and/or stiffness of the flexible tool to be asymmetric relative to the longitudinal axis.