Nested Torsion Bar Spring for Compact Energy Storage

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Solution Overview

Problem

Conventional torsion springs face limitations in space-constrained applications due to insufficient energy storage per unit volume and/or unit mass, leading to performance issues in achieving desired angular displacement and torque.

Innovation Solution

A torsion bar spring design comprising nested elongated spring bars made of resiliently flexible materials, where each bar is directly coupled at coupling interface portions to allow relative rotation, optimizing geometry for increased energy storage and compactness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional torsion springs are used, then the structure is simple, but the energy storage per unit volume and per unit mass is insufficient

Engineering Contradiction:
Improveenergy storage per unit volumeVSAvoidstructure complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent applies nesting by placing multiple torsion bars (at least two) concentrically within each other, where each torsion bar is positioned inside the hollow cross-section of the outer torsion bar. This nested configuration increases the energy storage capacity per unit volume by utilizing the internal hollow space of each bar for additional bars, while maintaining a compact overall structure that does not significantly increase device complexity

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent employs composite construction by combining multiple torsion bars with different wall thicknesses and material properties within the same assembly. Each torsion bar can be made from materials optimized for its specific function, creating a composite system that achieves superior energy storage density compared to a single homogeneous bar

Inventive Principle:
Principle #40Composite materials

2Use of energy by moving object

If conventional torsion springs are used, then the structure is simple, but the energy storage per unit mass is insufficient

Engineering Contradiction:
Improveenergy storage per unit massVSAvoidstructure complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The nested configuration of multiple torsion bars within hollow cross-sections maximizes the use of material volume for energy storage while minimizing unused hollow space. This arrangement increases the amount of active material per unit mass, thereby improving energy storage per unit mass without requiring a proportionally complex support structure

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from a single-bar one-dimensional structure to a multi-bar three-dimensional nested arrangement. By utilizing the hollow cross-sectional space and arranging bars in concentric layers, the design adds spatial dimensionality that increases mass utilization efficiency for energy storage

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of operation

If the torsion bar length is increased to achieve desired angular displacement, then the angular displacement is sufficient, but the volume increases

Engineering Contradiction:
Improveangular displacementVSAvoidspring volume
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

By nesting multiple torsion bars concentrically, the patent achieves the desired angular displacement through the combined torsional capacity of multiple bars rather than requiring a single longer bar. This nested arrangement provides the necessary rotational flexibility while maintaining a compact volume equivalent to the outermost bar's dimensions

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent divides the torsional function into multiple separate bars instead of using one large bar. Each bar contributes to the total angular displacement capability, allowing the system to achieve the required rotation range in a more compact configuration than a single segmented bar would require

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 enhances energy storage density by increasing angular displacement and potential energy storage in a compact volume without altering the overall size, providing a multifunctional hinge pin for spring-loaded mechanisms.

Implementation Method 1

each spring bar can be made of a resiliently flexible material... uncoupled portions of the first and second elongated spring bars are rotatable relative to one another about the longitudinal axis

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3542083B1Torsion bar spring
Publication Date: 2025.07.30 RAYTHEON CO
  • EP3542083B1 patent drawingFigure 1A~1B
  • EP3542083B1 patent drawingFigure 2
  • EP3542083B1 patent drawingFigure 3A~3B

AI summary

A torsion bar spring is disclosed. The torsion bar spring can include a first elongated spring bar made of a resiliently flexible material. The first elongated spring bar can have a first coupling interface portion at a distal end and an interior opening oriented along a longitudinal axis. The torsion bar spring can also include a second elongated spring bar made of a resiliently flexible material. The second elongated spring bar can have a second coupling interface portion at the distal end. The second elongated spring bar can be disposed at least partially in the interior opening of the first elongated spring bar. The first and second elongated spring bars can be directly coupled to one another at the first and second coupling interface portions such that uncoupled portions of the first and second elongated spring bars are rotatabie relative to one another about the longitudinal axis.