Back support for a chair

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Solution Overview

Problem

Existing office chairs with upholstered backrests face challenges in incorporating user-adjustable lumbar support while maintaining an aesthetically pleasing design and ease of manufacturing.

Innovation Solution

A back support system for office chairs featuring a support frame, rear and front shells, a cushion, and a cover, with a vertically adjustable lumbar pad and lumbar enhancement ribs, allowing for easy assembly and enhancing user experience through flexible central sections and convoluted cushioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a lumbar support is incorporated into an upholstered backrest, then user comfort and support characteristics are improved, but manufacturing complexity and difficulty increase

Engineering Contradiction:

Improveuser comfortVSAvoidmanufacturing difficulty

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

The backrest is divided into separate functional components: front shell, rear shell, lumbar pad, and cushion. This segmentation allows each component to be manufactured independently using different processes (injection molding for shells, foam molding for cushion and lumbar pad), then assembled together, thereby maintaining manufacturing simplicity while enabling enhanced lumbar support functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The lumbar pad is positioned and retained within the lumbar region by the front and rear shells, with the cushion positioned in front of the front shell. This nested arrangement integrates the lumbar support feature within the existing backrest structure without requiring separate complex mechanisms, achieving enhanced support while maintaining manufacturing simplicity.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If a lumbar support is incorporated into an upholstered backrest, then support characteristics are improved, but device complexity increases

Engineering Contradiction:

Improvesupport characteristicsVSAvoidstructural complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The front and rear shells serve multiple functions: they provide the structural framework of the backrest, define the lumbar region, retain the lumbar pad in position, and contribute to the overall aesthetic appearance. This multi-functionality reduces the need for additional specialized components, thereby reducing overall device complexity while maintaining reliable support characteristics.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If vertical adjustability of the entire upholstered back is provided, then lumbar adjustment capability is improved, but aesthetic appearance and ease of operation deteriorate

Engineering Contradiction:

Improvelumbar adjustment capabilityVSAvoidadjustment convenience

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The lumbar pad is designed to be vertically adjustable within the lumbar region defined by the front and rear shells, allowing users to adjust only the lumbar support portion independently of the entire backrest. This dynamic adjustment capability provides targeted lumbar support customization while maintaining the static, aesthetically pleasing appearance of the overall upholstered backrest.

Inventive Principle:

Principle #15Dynamics

4Adaptability or versatility

If vertical adjustability of the entire upholstered back is provided, then lumbar adjustment capability is improved, but aesthetic appearance deteriorates

Engineering Contradiction:

Improvelumbar adjustment capabilityVSAvoidaesthetic appearance

Core Design Contradiction:

Adaptability or versatilityVSShape

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The adjustment mechanism is localized to the lumbar region only, with the lumbar pad movable within the lumbar region defined by the front and rear shells. This localized adjustment preserves the overall aesthetic appearance of the backrest while providing functional adaptability where needed, avoiding the visual disruption that would result from adjusting the entire backrest structure.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12440031B2Back support for a chair

Publication Date: 2025.10.14 HAWORTH INC

AI summary

An office-type chair includes a back support having a support frame, front and rear shells, a cushion and a cover. The perimeter edge of the cover wraps around the side of the cushion and the front shell and is inserted between the front and rear shells to form a finished edge for the cover. The front shell may include a central flex section, and a lumbar pad may be positioned between the front shell and the rear shell and adjacent to the central flex section. One or more lumbar enhancement ribs on the front shell may augment the pressure distribution of the lumbar pad as it is vertically adjusted.