Pocketed Spring Tension Member for Non-Linear Mattress Support

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Solution Overview

Problem

Conventional mattress springs, such as wire coil springs and foam mattresses, either provide a firm and rigid surface or a comfortable but degrading non-linear support, failing to offer both characteristics simultaneously at a cost-effective price.

Innovation Solution

A pocketed spring design incorporating a compression spring enclosed in a flexible fabric with an elastic cable or tension member that extends along a central axis, allowing the spring to exhibit a non-linear response to force loading by transitioning from a combined spring constant to that of the compression spring alone, providing increased support without pre-compression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a foam mattress is used to provide non-linear support, then comfort and support are improved, but cost increases and mechanical properties degrade over time

Engineering Contradiction:
Improvemechanical properties stabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The mattress is divided into multiple independent pocketed springs rather than using a continuous foam structure. Each spring is individually enclosed in a fabric pocket, allowing independent operation. This segmentation enables the use of durable metal springs instead of degrading foam material while maintaining the desired non-linear support characteristics.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention combines metal compression springs with fabric enclosures to create a composite structure that replicates foam's non-linear behavior. The metal spring provides structural integrity and durability, while the fabric pocket allows controlled deflection, together achieving foam-like performance without the degradation issues.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If wire coil springs are used to provide firm support, then structural stability is improved, but comfort deteriorates due to rigid surface

Engineering Contradiction:
Improvestructural stabilityVSAvoidcomfort
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The mattress structure is segmented into individual pocketed springs that can deflect independently. This segmentation allows the firm metal springs to provide structural stability while the individual pockets enable localized comfort adjustments, eliminating the rigid surface effect of traditional wire coil mattresses.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A flexible fabric pocket encloses each metal spring, allowing the rigid spring to maintain structural stability while the flexible fabric enables comfort-oriented deflection. The fabric acts as an intermediary that translates the firm spring support into a comfortable, conforming surface.

Inventive Principle:
Principle #30Flexible shells and thin films

3Force

If pre-compression is applied to pocketed springs to provide initial support, then support level is improved, but device complexity increases

Engineering Contradiction:
Improveinitial support forceVSAvoidspring configuration complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The fabric pocket is pre-formed with a specific geometry that creates initial tension, which in turn applies pre-compression to the spring. This preliminary configuration of the fabric pocket provides the desired initial support force without requiring complex mechanical pre-loading mechanisms or additional components.

Inventive Principle:
Principle #10Preliminary action

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 pocketed spring design offers a mattress with non-linear support similar to foam mattresses, maintaining comfort and support over time while being cost-effective and durable, as the elastic cable relaxes before maximum compression, allowing the compression spring to provide additional support.

Implementation Method 1

the elastic cable is configured such that it will enter a relaxed state prior to the compression spring reaching a maximum compression

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3302179B1Pocketed spring
Publication Date: 2021.08.18 SEALY TECHNOLOGY LLC
  • EP3302179B1 patent drawingFigure 1~1D
  • EP3302179B1 patent drawingFigure 2~2D
  • EP3302179B1 patent drawingFigure 3~3D

AI summary

A pocketed spring, such as that used in a mattress, comprises: a compression spring having an upper end convolution and a lower end convolution opposite the upper end convolution, and a plurality of helical intermediate convolutions between the upper end convolution and the lower end convolution; a flexible enclosure including a top wall positioned adjacent to the upper end convolution of the compression spring, a bottom wall positioned adjacent to the lower end convolution of the compression spring, and a side wall that extends from the top wall to the bottom wall; and a tension member connected to the flexible enclosure. The tension member acts in opposition to the compression spring until the pocketed spring is compressed to a point at winch the tension member no longer applies any force. Thus, the pocketed spring exhibits a non-linear response when compressed.