Bi-stable Compliant Switch With Single Fixed End

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Solution Overview

Problem

Bi-stable switches with fixed ends at both ends face issues of instability, overloading, and inconsistent movement between stable positions, requiring additional components and complex manufacturing processes.

Innovation Solution

A compliant buckling switch mechanism with a single fixed end and a free end, utilizing residual stress and friction forces to maintain stable positions, allowing for easy manufacturing and operation without the need for additional components like hinges or latches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If both ends of the structural member are fixed to enable buckling-type bi-stable mechanism, then the device can maintain stable positions without energy input, but the device experiences instability, overloading, and inconsistent movement between stable positions

Engineering Contradiction:

Improvestability of switch positionsVSAvoidconsistent movement between positions

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent removes one fixed end constraint from the structural member, extracting the problematic dual-fixed-end configuration. By having only one fixed end and one free end, the structural member can buckle between stable positions without the instability and overloading issues caused by dual fixed ends, while maintaining the energy-free stable position capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the constraint application by fixing only one end of the structural member while leaving the other end free. This segmentation of constraints allows the structural member to achieve reliable buckling behavior and consistent movement between stable positions without the harmful effects of dual fixed-end constraints

Inventive Principle:

Principle #1Segmentation

2Reliability

If additional components like hinges or latches are added to improve switch stability, then the stable positions can be maintained more reliably, but the device complexity and manufacturing complexity increase

Engineering Contradiction:

Improveswitch position stabilityVSAvoidnumber of components

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent enables the structural member to maintain its stable positions through its own buckling behavior and residual stress, without requiring external latches or hinges. The single fixed end configuration allows the structural member to self-stabilize at its buckled positions, eliminating the need for additional stabilizing components

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent merges the functions of stability maintenance and position holding into the structural member itself through its buckling behavior. By combining the structural member's geometric configuration with its material properties, the system achieves reliable stable positions without separate stabilizing components, reducing overall device complexity

Inventive Principle:

Principle #5Merging (Combining)

3Ease of operation

If transition force is applied to move the switch between stable states, then the switch can change positions, but energy is consumed and the switch may move past the desired stable state

Engineering Contradiction:

Improveswitching between positionsVSAvoidenergy for position transition

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent utilizes the dynamic buckling behavior of the structural member to enable transitions between stable positions. By applying minimal transition force to initiate buckling, the structural member dynamically snaps to the opposite stable position, minimizing energy consumption while ensuring precise position change without overshooting

Inventive Principle:

Principle #15Dynamics

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 switch mechanism consistently and reliably moves between two stable positions with reduced energy requirements, increased durability, and simplified manufacturing, avoiding overloading and instability issues.

Implementation Method 1

the device utilizes a mode of failure (i.e., buckling) that results from structural instability from forces, such as compression acting on a structural member, to create the necessary residual stress

Methodology Applied

Scientific EffectResidual stress: Stress Relaxation

Implementation Method 2

Buckling is an instability or failure mode that may occur when a structural member is placed under sufficient compressive stress

Methodology Applied

Scientific EffectBuckling: Compression

Implementation Method 3

A compliant buckling switch mechanism with a single fixed end and a free end, utilizing residual stress and friction forces to maintain stable positions

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS10546703B1Bi-stable compliant switch system

Publication Date: 2020.01.28 THE GOVERNMENT OF THE UNITED STATES AS REPRESENTED BY THE SECRETARY OF THE AIR FORCE

AI summary

A switch mechanism has a compliant buckling bar that includes a single fixed end mounted to a mounting surface and a free end that is displaced with respect to the fixed end. The mounting of the fixed end to the mounting surface may constitute the only fixed connection between the bar and the mounting surface. The bar moves between two stable positions in response to a transition force applied transversely to the free end. Residual stress in the bar may be higher when the free end is at each of the stable positions than when the free end is at a neutral position located between the stable positions.