Flexible Office Chair Backrest Structure for Adaptive Support

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Solution Overview

Problem

Existing office chairs do not adequately encourage users to change their sitting positions, which can lead to reduced flexibility and potential back problems despite having features that support pivoting movements between the seat and backrest.

Innovation Solution

A backrest with a flexible support structure made of plastic, featuring a C-shaped backrest leg and a backrest shell element with strategically placed openings and webs, allowing for relative movement and adjustable elasticity to adapt to user positions, combined with elastic fastening tabs for detachable connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the backrest is made rigid to provide stable back support, then back support stability is improved, but flexibility to adapt to user movements is worsened

Engineering Contradiction:
Improveback support stabilityVSAvoidflexibility to adapt to user movements
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The backrest shell element is divided into multiple segments separated by through-openings, allowing each segment to move independently relative to others while maintaining overall structural integrity. This segmentation enables the backrest to adapt to user movements while preserving back support stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The backrest shell element is designed as a thin-walled structure with through-openings that provides flexibility while maintaining sufficient rigidity for back support. The shell structure allows controlled deformation to adapt to user movements without compromising the stability needed for proper back support.

Inventive Principle:
Principle #30Flexible shells and thin films

2Area of stationary object

If the backrest shell element is made solid to maximize back support surface area, then back support coverage is improved, but weight and material usage are worsened

Engineering Contradiction:
Improveback support surface areaVSAvoidbackrest weight
Core Design Contradiction:
Area of stationary objectVSWeight of stationary object

Solution Approach 1:

The backrest shell element incorporates through-openings that create a porous structure, reducing material usage and weight while maintaining sufficient back support surface area. The strategically placed openings allow weight reduction without significantly compromising the back support functionality.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The backrest shell is segmented into multiple sections separated by webs and through-openings, creating a skeletal structure that provides back support coverage with minimized material usage. This segmentation maintains the necessary support surface area while reducing overall weight.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the connection between backrest shell element and support structure is rigid to ensure stability, then connection stability is improved, but relative movement capability is worsened

Engineering Contradiction:
Improveconnection stabilityVSAvoidrelative movement capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The connection system transitions from a static rigid connection to a dynamic connection that allows controlled relative movement. The elastic fastening tabs and plug-in connections enable the backrest shell element to move relative to the support structure while maintaining stable attachment, adapting to user movements in real-time.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The connection parameters are designed to allow controlled changes in position and orientation between the backrest shell element and support structure. The elastic fastening tabs provide variable connection characteristics that permit relative movement while maintaining stable attachment under different loading conditions.

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

The solution enhances user flexibility and comfort by allowing the backrest to adapt to different sitting positions while maintaining optimal back support, reducing the risk of back problems and conserving material and weight.

Implementation Method 1

the support structure is made of plastic. Due to the material properties alone, there is a certain flexibility and elasticity.

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the backrest leg is C-shaped. This results in a resilient configuration of the backrest leg.

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

The backrest shell element has elastic fastening tabs for fastening to the supporting structure, in particular in a detachable manner.

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3205236B1Backrest for an office chair
Publication Date: 2018.05.09 INTERSTUHL BUEROMOEBEL GMBH & CO KG
  • EP3205236B1 patent drawingFigure 1
  • EP3205236B1 patent drawingFigure 2~4

AI summary

A backrest (7) for an office chair (1) with a support structure (6) to which a backrest shell element (20) can be fastened is characterized in that the support structure (6) has two struts (8, 9) which are attached to their upper and lower end regions are connected to one another and are spaced apart from one another between the end regions, the struts (8, 9) being movable relative to one another at least in sections.