Grooved Cylindrical Foam Spring for Load-Bearing Formability

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Solution Overview

Problem

Existing methods for producing foam springs, such as cutting foam blocks or using molds, result in low load-bearing capacity, high material costs, and inefficiencies due to waste generation and non-homogeneous structures caused by bending stress, limiting diameter adjustment and automated production.

Innovation Solution

A cylindrical foam body with a central cavity formed from a curved, flexible foam strip with grooves extending over its height, reducing external stress and allowing for adjustable diameter and hardness by varying groove number and depth, and potentially incorporating cuts or a wave pattern for efficient production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If foam strips are cut through in multiple places to create passages, then the foam spring can be formed, but the load bearing capacity is significantly reduced

Engineering Contradiction:
Improvefoam spring formationVSAvoidload bearing capacity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The foam strip is divided into multiple segments by creating grooves that extend partially through the thickness. These grooves segment the foam structure without completely separating it, allowing the strip to be formed into a spring while maintaining structural integrity and load bearing capacity through the continuous foam material between grooves.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The grooves are positioned specifically on the outer surface of the foam strip where they are needed to facilitate forming, while the inner surface and bulk material remain intact. This local modification allows easy formation without compromising the overall strength of the foam spring.

Inventive Principle:
Principle #3Local quality

2Strength

If a non-perforated foam strip is bent around into a foam spring, then the load bearing capacity is maintained, but high internal stresses cause deformation and non-homogeneous structure

Engineering Contradiction:
Improveload bearing capacityVSAvoidstructural homogeneity
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

By introducing grooves that partially divide the foam strip, the structure can accommodate bending stresses more evenly. The grooves act as stress relief features that prevent excessive internal stress concentration, allowing the foam to be formed into a spring while maintaining structural homogeneity and preventing uncontrolled deformation.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If the diameter of the foam spring is adjusted by adapting the size of the foam strip, then different diameters can be produced, but the production process becomes laborious and complex

Engineering Contradiction:
Improvediameter adjustmentVSAvoidproduction process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The diameter of the foam spring is adjusted by changing the number, depth, and spacing of grooves cut into a standard foam strip, rather than changing the strip dimensions themselves. This parameter-based approach allows versatile diameter adjustment while maintaining a standardized production process and foam strip inventory.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If foam strips with cuts are used to form springs, then the springs can be produced, but a relatively high density foam must be used which is expensive and heavy

Engineering Contradiction:
Improvespring productionVSAvoidfoam spring weight
Core Design Contradiction:
Ease of manufactureVSWeight of moving object

Solution Approach 1:

The grooves provide structural segmentation that enables spring formation in lower density foams. The partial divisions created by grooves maintain sufficient structural integrity without requiring high density material, thereby reducing weight while still enabling successful spring production.

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

This approach minimizes deformation, reduces waste, and enables cost-effective, efficient production of foam springs with consistent properties across different diameters and hardness levels, suitable for use in mattresses and pillows.

Implementation Method 1

the foam body is formed by a curved, and thus under bending stress, flexible foam strip

Methodology Applied
Scientific EffectBending stress:

Implementation Method 2

the inside of the foam spring can be compressed in an uncontrolled and irreproducible way due to the stress on the outside

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3253258B1Cylindrical foam body, use thereof and method for producing this
Publication Date: 2018.09.12 ROMERIKA NV
  • EP3253258B1 patent drawingFigure 1~2
  • EP3253258B1 patent drawingFigure 3~5
  • EP3253258B1 patent drawingFigure 6~7

AI summary

Cylindrical foam body (1) with a central cavity (9), whereby the foam body (1) is formed by a curved flexible foam strip (2) of which two opposite ends (3) are fastened together, whereby the foam body has a height (H), whereby the strip 2 has a length (L), a height (h) and a width (b), whereby after forming the foam body (1) the longitudinal direction (L) of the strip 2 is the height direction (H) of the foam body (1), whereby the foam body (1) has an outside (5) and an inside (8), characterised in that the foam body (1) is provided on its outside (5) with two or more grooves (7) that extend over the height (H) of the foam body (1) and which only cut into the foam body (1) over a part of the distance between the outside (5) and the inside (8).