Bellows Spring Element Geometry for High Deflection and Low Wear

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Solution Overview

Problem

Existing spring elements with bellows in the shape of truncated pyramids or cones suffer from reduced spring deflection and accelerated mechanical wear when compressed, leading to a shortened service life.

Innovation Solution

The spring element features bellows folds where inner tips extend into the lower bearing surface and outer tips are parallel, allowing maximum spring deflection without mutual loading, resulting in a lightweight component with optimized service life and adjustable spring rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the bellows is compressed very strongly, then the spring deflection is reduced, but the mechanical wear and destruction of the spring element occur

Engineering Contradiction:
Improvespring deflectionVSAvoidservice life
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The bellows folds are arranged with outer tips in a plane parallel to the lower bearing surface instead of stacking vertically. This spatial reconfiguration from vertical stacking to lateral arrangement in parallel planes allows the folds to compress without overlapping, maintaining reliability while preserving spring deflection capacity.

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

Solution Approach 2:

The bellows structure utilizes curved, tapered folds with specific geometric shaping where outer tips extend further than inner tips. This curved geometry enables the folds to deform and compress along their natural curvature, allowing maximum compression without mutual interference between adjacent folds.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Force

If the bellows folds are arranged in parallel planes, then the spring deflection is increased, but the structural complexity increases

Engineering Contradiction:
Improvespring deflectionVSAvoidbellows configuration
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The bellows is divided into multiple discrete folds, each acting as an independent spring element. These segmented folds are arranged in parallel planes with outer tips extending further than inner tips, allowing each fold to deform independently without interfering with others, thus increasing spring deflection while maintaining manageable structural complexity.

Inventive Principle:
Principle #1Segmentation

3Force

If the outer tips of bellows folds extend further than inner tips, then the spring rate is optimized, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvespring rateVSAvoidfold geometry
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

Each bellows fold is designed with asymmetric geometry where the outer tip extends further from the central axis than the inner tip. This asymmetric configuration optimizes the spring rate by distributing deformation forces more effectively across the fold structure, allowing greater deflection while maintaining structural integrity. The asymmetric design is consistently applied to all folds, creating a predictable and manufacturable pattern.

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

This configuration maximizes spring deflection while preventing mechanical wear, offering excellent spring properties and a long service life, suitable for various applications including mattresses and upholstered furniture.

Implementation Method 1

made of a rubber-elastic circular or mirror-symmetrical bellows

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP1889709B1Spring element
Publication Date: 2008.11.05 HARTMANN SIEGBERT
  • EP1889709B1 patent drawingFigure 1~4

AI summary

The spring element, especially for installing in mattresses, is in the form of a rubber-elastic bellows (2), the internal points (5) of the folds (7) of which, with the spring element in its maximum compressed state, extend into the region of the lower support surface (4) or are supported there, and as a result of which the external points (6) of the folds are arranged in a plane lying above it and parallel to it. The maximum distance of the plane from the lower support surface corresponds to the width measurement of a completely compressed fold.