Cross-Blade Flexural Pivot for Large-Angle Reliable Rotation

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Solution Overview

Problem

Commercially available flexural pivots face challenges with repeatable performance and reliability, especially in applications requiring high performance and large angular ranges of motion, due to manufacturing difficulties and stress limitations.

Innovation Solution

A flexural pivot design featuring three flexure support members with cantilevered extension portions and cross-configured flexible blades, allowing for rotational coupling without friction, enabling high performance, large angular travel, and reliability, while being cost-effective to produce.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional bearing designs are used to support rotational movement, then structural simplicity is maintained, but friction and lubrication requirements increase, reducing reliability in high-performance applications

Engineering Contradiction:
ImprovereliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical bearings with a flexural pivot system that uses elastic flexing of support members instead of contact surface displacement. This substitution eliminates friction and lubrication requirements, directly improving reliability in high-performance applications while maintaining structural functionality through the flexural coupling mechanism

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If flexural pivots are designed to accommodate large angular ranges of motion, then angular travel is improved, but stress concentrations increase, reducing performance reliability

Engineering Contradiction:
Improveangular travelVSAvoidstress concentration
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The patent applies local quality by creating asymmetric stress distribution within the flexure support members. The cross-configured flexible blades are positioned to concentrate flexibility in specific regions while maintaining structural integrity in other areas, allowing large angular travel without excessive stress concentrations that would compromise reliability

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs composite structural design by combining multiple flexure support members with cross-configured flexible blades. This composite arrangement distributes stresses across multiple elements and configurations, enabling large angular ranges of motion while managing stress concentrations through the collective behavior of the coupled flexural elements

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If manufacturing processes are simplified to reduce costs, then ease of manufacture is improved, but manufacturing precision deteriorates, affecting repeatable performance

Engineering Contradiction:
Improveease of manufactureVSAvoidmanufacturing precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent segments the flexural pivot into multiple discrete components including separate flexure support members and cross-configured flexible blades. This segmentation allows each component to be manufactured independently using cost-effective processes, then assembled with precise positioning features that ensure repeatable performance without requiring excessively complex or expensive manufacturing for the entire assembly

Inventive Principle:
Principle #1Segmentation

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 design provides a frictionless pivot coupling for significant loads during high accelerations, allowing large angular travel with balanced masses and reduced stress concentrations, enhancing reliability and performance.

Implementation Method 1

angular motion is accomplished through flexing of elastic flexural elements

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3589853B1Flexural pivot
Publication Date: 2021.03.24 RAYTHEON CO
  • EP3589853B1 patent drawingFigure 1A~1B
  • EP3589853B1 patent drawingFigure 2~3
  • EP3589853B1 patent drawingFigure 4~5

AI summary

A flexural pivot is disclosed. The flexural pivot can include a plurality of flexure support members, each flexure support member having a plurality of flexure openings defined at least partially by a cantilevered extension portion. The flexural pivot can also include at least one flexure to rotatably couple the plurality of flexure support members to one another. The at least one flexure can have first and second flexible blades arranged in a cross configuration. The first and second flexible blades can be disposed in the flexure openings of the flexure support members, and the cantilevered extension portions, at least in part, can couple the first and second flexible blades to the flexure support members.