Pocket Spring Core With Fully Active End Turns for Lower Wire Use

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Solution Overview

Problem

Conventional pocket spring cores require a significant amount of wire to achieve desired firmness, increasing manufacturing costs and not effectively utilizing end turns for spring force contribution.

Innovation Solution

The use of fully active springs with unknotted end turns having a finite pitch angle, which contribute to spring force and reduce wire requirements, along with end extensions that mitigate pocket material wear, are integrated into the pocket spring core manufacturing method.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional springs with flat end turns are used to provide comfort and luxury feel, then the end turns define flat surfaces normal to the spring axis, but the flat end turns do not contribute to spring force, requiring greater wire length and increasing costs

Engineering Contradiction:
Improvecomfort and luxury feelVSAvoidwire length
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The invention changes the geometric parameter of the end turns from flat (perpendicular to spring axis) to inclined (at finite pitch angle). This parameter change allows the end turns to contribute to spring force while maintaining the comfort characteristics, thereby reducing the required wire length for achieving the same firmness level.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The end turns are designed to serve dual functions: providing comfort through their geometric configuration and contributing to spring force through their inclined orientation. This multi-functionality eliminates the need for separate components and reduces overall wire consumption.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Force

If greater wire length is used to achieve desired firmness with conventional springs, then the firmness requirement is met, but manufacturing costs increase

Engineering Contradiction:
ImprovefirmnessVSAvoidwire length
Core Design Contradiction:
ForceVSQuantity of substance

Solution Approach 1:

By changing the pitch angle parameter of the end turns from zero (flat) to a finite value, the spring force contribution is enhanced without increasing wire length. This allows achieving the same firmness with less wire, directly addressing the cost reduction goal.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If unknotted end turns with finite pitch angle are used to reduce wire length, then wire requirements are reduced and costs decrease, but the end turns must maintain shape memory within bounds

Engineering Contradiction:
Improvewire lengthVSAvoidshape memory
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The pitch angle is optimized to a specific range that balances two competing requirements: providing sufficient spring force contribution while maintaining shape memory stability. This parameter optimization allows the spring to retain its functional properties without requiring excessive wire length.

Inventive Principle:
Principle #35Parameter changes

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 reduces the amount of wire needed for comparable firmness to conventional springs, lowering manufacturing costs while maintaining comfort and luxury feel, and addresses wear issues with pocket material.

Implementation Method 1

a resilient core assembly including a plurality of resilient elements respectively disposed in said pockets

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2689695B1Spring core
Publication Date: 2016.06.08 L& P SWISS HLDG AG
  • EP2689695B1 patent drawingFigure 1
  • EP2689695B1 patent drawingFigure 2~3
  • EP2689695B1 patent drawingFigure 4~5

AI summary

A pocket spring core for a bedding or seating cushion comprises an array of pocket springs. The array of pocket springs comprises fully active springs (10) respectively enclosed in an associated pocket (35) of fabric. Each fully active spring (10) respectively has a central spiral portion (20) with at least one turn and defining a spring axis (13), an unknotted first end turn (21) defining a first end of the fully active spring (10), and an unknotted second end turn (22) defining an opposing second end of the fully active spring (10). Each fully active spring (10) has a rest shape in which the first end turn (21) and the second end turn (22) have a finite pitch angle, so that the first end turn (21) and the second end turn (22) contribute to a spring force of the fully active spring (10).