Adjustable Chair Lumbar Assembly With Secure Smooth Positioning

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Solution Overview

Problem

Existing lumbar support devices for chairs lack optimal comfort, ease of manufacturing, smooth adjustability, durability, and security in their adjusted positions, while providing effective lumbar support.

Innovation Solution

A vertically adjustable lumbar assembly with a flexible lumbar device and an overlap joint connection between the chair back support and lower frame, featuring a 'ZIP-LOCK' type bottom connection and wave ridges for smooth adjustment, ensuring secure positioning and structural stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a lumbar support device is made adjustable and comfortable, then user comfort is improved, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:
ImproveadjustabilityVSAvoiddevice complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The lumbar support device is divided into multiple wire segments arranged in a grid pattern, allowing independent adjustment of each section to provide customized lumbar support without requiring a complex overall structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The device uses a dynamic adjustment mechanism where the basculating arm can pivot between multiple positions, enabling the wire array to transition between different support configurations while maintaining structural simplicity

Inventive Principle:
Principle #15Dynamics

2Reliability

If a lumbar support device provides secure positioning, then reliability is improved, but the adjustment smoothness and ease of operation deteriorate

Engineering Contradiction:
Improvesecure positioningVSAvoidadjustment smoothness
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The wave ridges on the guide channel are pre-configured to provide progressive resistance during adjustment, preventing overshot and ensuring the device settles securely at each position while maintaining smooth movement throughout the adjustment range

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The guide channel acts as an intermediary mechanism between the basculating arm and the wire array, mediating the adjustment motion to provide both smooth movement and secure positioning through its shaped geometry

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If the chair back support uses a robust connection to the lower frame, then structural strength is improved, but the manufacturing and assembly complexity increase

Engineering Contradiction:
Improvestructural strengthVSAvoidassembly simplicity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The overlap joint combines the back support and lower frame into a single integrated connection structure, providing robust structural strength while simplifying manufacturing and assembly by eliminating the need for separate mounting operations

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The overlap joint is designed to be pre-assembled during frame construction, with the back support overlapping the lower frame in a configuration that automatically provides structural reinforcement without requiring additional fastening steps

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2160119B1Chair back construction with adjustable lumbar device
Publication Date: 2013.05.29 STEELCASE INC
  • EP2160119B1 patent drawingFigure 1~2
  • EP2160119B1 patent drawingFigure 3~4
  • EP2160119B1 patent drawingFigure 5

AI summary

A chair includes a lower back frame, a back construction, including a back support attached to the lower back frame, a cushion assembly attached to the back support, and a vertically adjustable lumbar. The lumbar frame includes a transition shell and a vertically sliding lumbar device having a plurality of horizontal flexible wires. A lower edge of the transition shell is positioned on top of an uppermost horizontal flexible wire of the lumbar device. The lumbar device is operably slidably mounted between the outer shell and cushion assembly and the transition shell upper edge slides between the outer shell and the upholstery cushion assembly. Another chair includes a Y-shaped lower back frame having two uprights and a cross-piece attached to the back support. An overlap flange and channel-shaped flange mate to form an overlap joint, including a box beam for added structural support.