Interlocked Monolithic Flexures for Compact Compliant Mechanisms

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Solution Overview

Problem

Existing compliant mechanisms, such as pivot bearings, are complex to manufacture, bulky, and suffer from axial centre shift due to asymmetry, requiring dedicated production apparatuses and limiting scalability and load capability.

Innovation Solution

A method for manufacturing compliant mechanisms using interlocked monolithic flexible elements with openings, allowing for additive manufacturing without assembly operations, reducing axial centre shift and enabling easy modification of sizes and stiffness through 3D CAD models, utilizing techniques like Selective Laser Melting or Sintering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If compliant mechanisms are manufactured using traditional methods (assembly of multiple parts, soldering, gluing), then manufacturing precision and reliability can be achieved, but device complexity and manufacturing time increase significantly

Engineering Contradiction:
Improvemanufacturing precisionVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple separate flexible elements and rigid parts into a single monolithic structure manufactured by additive manufacturing. The compliant mechanism comprises a single continuous material that forms both the rigid support structures and the flexible blades, eliminating the need for assembly operations while maintaining manufacturing precision through monolithic construction.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements nested flexible elements where one flexible blade is positioned within the structure of another flexible blade. This nested arrangement allows complex multi-element mechanisms to be integrated into a single monolithic component, reducing device complexity while preserving the functional precision of multiple independent elements.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of manufacture

If compliant mechanisms use multiple independent components assembled together, then ease of manufacture and adaptability are improved, but manufacturing time and device complexity increase

Engineering Contradiction:
Improveease of manufactureVSAvoidmanufacturing time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent combines multiple components that would traditionally be manufactured and assembled separately into a single additive manufacturing process. The monolithic structure is built layer-by-layer in one continuous operation, eliminating assembly time while maintaining the functional independence of different mechanism elements through careful structural design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The additive manufacturing process performs preliminary actions by pre-integrating support structures, flexible elements, and connection points into the monolithic design before manufacturing begins. This preliminary integration of all components into a single structure eliminates subsequent assembly operations and reduces total manufacturing time.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If asymmetric blade arrangements are used in compliant mechanisms, then manufacturing simplicity is maintained, but axial centre shift occurs reducing reliability

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidpivot reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent deliberately introduces asymmetric features into the monolithic structure to counterbalance and compensate for the axial centre shift that would naturally occur in symmetric blade arrangements. By strategically positioning blades with different dimensions or orientations within the monolithic structure, the design achieves dynamic balance and eliminates pivot instability while maintaining manufacturing simplicity through the single-piece construction.

Inventive Principle:
Principle #4Asymmetry

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 method simplifies manufacturing, reduces device size, minimizes axial centre shift, and allows for mass production of compliant mechanisms with improved mechanical properties and flexibility in size and stiffness, eliminating the need for dedicated production apparatuses.

Implementation Method 1

utilizing techniques like Selective Laser Melting or Sintering

Methodology Applied
Scientific EffectSelective Laser Melting: Selective Laser Sintering

Implementation Method 2

Selective Laser Melting or Sintering

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 3

capable of transferring force or displacement through the elastic deformation of its mechanical structure

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3690264B1Device comprising interlocked monolithic flexible elements and corresponding additive manufacturing method
Publication Date: 2021.09.29 CSEM CENTRE SUISSE D ELECTRONIQUE ET DE MICROTECHNIQUE SA
  • EP3690264B1 patent drawingFigure 1a~1c
  • EP3690264B1 patent drawingFigure 2~3
  • EP3690264B1 patent drawingFigure 4a~4h

AI summary

The invention relates to a device comprising a compliant mechanism (54, 56; 90) comprising a first monolithic flexible element (54), having first and second ends (54a, 54b) defining a first longitudinal direction, arranged such that it is able to be subjected to an elastic deformation involving a relative movement between its first and second ends (54a, 54b), and at least a second monolithic flexible element (56), having first and second ends (56a, 56b) defining a second longitudinal direction distinct from the first longitudinal direction, arranged such that it is able to be subjected to an elastic deformation involving a relative movement between its first and second ends (56a, 56b), at least one of the first and second monolithic flexible elements (54, 56) comprising at least one opening (46) located between its first and second ends (54a, 54b, 56a, 56b) and defining a passage for a portion of the other monolithic flexible element (54, 56) such that the first and second monolithic flexible elements (54, 56) are interlocked.