Reverse Coil Head Innerspring Structure for Stable Intercoil Engagement

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Solution Overview

Problem

Existing mattress innerspring designs face challenges in achieving optimal intercoil engagement and stability while minimizing material usage and manufacturing costs, with high tensile strength wire increasing wear on forming equipment and material costs.

Innovation Solution

The Reverse Coil Head Coil design features helical and cylindrical body with offset coil ends that facilitate inter-engagement through lacing wires, allowing for independent movement and adjustable spring rate, made from a single piece of wire with specific dimensions and tensile strength to reduce material usage and enhance stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If high tensile strength wire is used to minimize the number of convolutions and material usage, then material usage is reduced, but wear on wire forming equipment increases and material costs increase

Engineering Contradiction:
Improvematerial usageVSAvoidwear on wire forming equipment
Core Design Contradiction:
Loss of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent changes the key parameter of wire tensile strength from high to moderate levels (e.g., using wire with tensile strength in the range of 150,000-250,000 psi rather than higher strength wires). This parameter change allows the coil to achieve the required performance with more convolutions while using less extreme material properties, thereby reducing wear on forming equipment and lowering material costs while still minimizing sufficient material usage

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces adjustable spring rates through varied coil configurations (different numbers of convolutions, pitch variations, diameter changes) to dynamically achieve the desired performance characteristics without relying solely on high tensile strength wire. This dynamic approach allows optimization of both material usage and equipment wear by adjusting geometric parameters rather than material properties

Inventive Principle:
Principle #15Dynamics

2Reliability

If high tensile strength wire is used to maintain performance characteristics with fewer convolutions, then coil performance is maintained, but material costs and handling costs increase

Engineering Contradiction:
Improvecoil performanceVSAvoidmaterial and handling costs
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the material parameter from high tensile strength wire to moderate tensile strength wire, and compensates by adjusting geometric parameters (increasing number of convolutions, modifying pitch and diameter). This parameter substitution maintains coil performance while reducing material and handling costs associated with expensive high-strength wire

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent incorporates design features such as offset portions and specific convolution configurations that are built into the coil structure during manufacturing. These preliminary design actions ensure proper interengagement and stability without requiring post-manufacturing adjustments or special handling procedures, thereby reducing handling costs while maintaining performance

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If offset portions are added to coil ends to improve interengagement and stability, then intercoil stability is improved, but device complexity increases

Engineering Contradiction:
Improveintercoil stabilityVSAvoidcoil structure complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent segments the coil end structure into distinct functional portions: the main helical body and the offset portion. This segmentation allows the offset portion to be specifically designed for interengagement functions while keeping the main body simple and manufacturable. The offset portion acts as a separate functional element that improves stability without complicating the overall coil structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of adding complex interengagement mechanisms to the main coil body, the patent inverts the approach by extending the coil end itself to form the offset portion. This inversion simplifies the overall structure by using the coil's own geometry to provide the interengagement feature, rather than adding separate complex components

Inventive Principle:
Principle #13The other way round (Inversion)

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 Reverse Coil Head Coil design improves intercoil stability and ease of assembly, reduces material usage, and allows for adjustable firmness, enhancing the overall performance and comfort of mattress innersprings while minimizing manufacturing costs.

Implementation Method 1

The coil body (12c) can be of any design, including asymmetric designs, and can have varying pitch and/or diameter. The coil ends (12a, 12b) can be in any form, and have one or more segments which are generally in the same plane and generally perpendicular to an axis of the coil body.

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2665392B1Reverse coil head coils and innersprings
Publication Date: 2018.11.21 SEALY TECHNOLOGY LLC
  • EP2665392B1 patent drawingFigure 1
  • EP2665392B1 patent drawingFigure 2~3
  • EP2665392B1 patent drawingFigure 4

AI summary

A reverse coil head coil and innerspring has a generally cylindrical and helical wire form coil body and opposing coil ends which terminate on opposite sides of a reference plane that passes through the coil body. The reverse coil head coils are interconnected in a matrix to form an innerspring wherein only one terminal end of each coil is located at a perimeter of the innerspring. Variations in the number and pitch of helical turns of the coil body are also disclosed.