Cross flexure suspension

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Solution Overview

Problem

Existing suspension systems for supporting objects like mirrors fail to provide two degrees of rotational freedom while minimizing translational movement, which is crucial for high-scanning frequency applications like optical scanning systems.

Innovation Solution

A cross flexure suspension system that uses a monolithic structure with flexure blades to allow rotation about two perpendicular axes, minimizing translational movement and eliminating the need for welded or brazed joints through an EDM process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If prior suspension systems use multiple separate components with welded or brazed joints to provide two degrees of rotational freedom, then rotational freedom is achieved, but manufacturing precision and reliability deteriorate due to joints and assembly inconsistencies

Engineering Contradiction:
Improverotational freedomVSAvoidmanufacturing inconsistencies
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent merges multiple separate suspension components into a single monolithic flexure structure. This integration eliminates welded or brazed joints that cause manufacturing inconsistencies, while maintaining two degrees of rotational freedom through carefully designed flexure blades within the unified structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Within the monolithic structure, the patent segments the flexure into multiple blades arranged in specific patterns. These segmented blades provide the necessary rotational degrees of freedom while remaining part of a single integrated component, avoiding the need for external joints.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If suspension systems use traditional multi-component designs to allow large angular motions, then rotational range is improved, but device complexity and risk of mechanical failure increase due to multiple joints and connections

Engineering Contradiction:
Improveangular travel rangeVSAvoidstructural complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple functional elements into a single monolithic flexure structure, reducing device complexity while maintaining the capability for large angular tip-tilt motions. The integrated design eliminates multiple joints and connections that would increase structural complexity and failure risk.

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If suspension systems use flexible elements to minimize friction for high scanning frequency, then scanning frequency is improved, but translational movement control deteriorates

Engineering Contradiction:
Improvescanning frequencyVSAvoidtranslational movement control
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by designing specific regions of the monolithic flexure with different stiffness characteristics. Certain areas are made more flexible to reduce friction and enable high scanning frequency, while other regions maintain higher stiffness to control translational movement and maintain positioning accuracy.

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 large angular tip-tilt motions with minimal decenter, high operational frequency, and increased load capacity, while reducing the risk of mechanical failure and manufacturing inconsistencies.

Implementation Method 1

a first flexure structure including a first set of flexure blades... allows the connecting structure to rotate relative to the base mounting structure about the first axis of rotation

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The suspension system can be provided as a monolithic flexure, and can be made by an Electrical Discharge Machining (EDM) process, allowing manufacturing of thin flexure blades

Methodology Applied
Scientific EffectElectrical Discharge Machining: Electrical Discharge Machining

Data Source

PatentEP3566087A2Cross flexure suspension
Publication Date: 2019.11.13 BAE SYST SPACE & MISSION SYST INC

AI summary

Suspension system structures and methods are provided. A system as disclosed allows for rotation of a supported object in two axes, with very little translational movement of the supported object. The system can include a base mounting structure that is joined to an intermediate or connecting structure by a first set of flexure blades. The connecting structure is in turn joined to a supported element structure by a second set of flexure blades. The first set of flexure blades can include four blades that intersect along a line that is coincident with an X axis of rotation, and the second set of flexure blades can include four blades that intersect along a line that is coincident with the Y axis of rotation. The components of the suspension system can comprise a monolithic structure that is formed from a single piece of material.