Chair Lumbar Support Blade Adjustment With Curved Guides

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Solution Overview

Problem

Current adjustment devices for lumbar supports in chairs are difficult and laborious to adjust, making it challenging to achieve the desired position for user comfort.

Innovation Solution

A device for moving a lumbar support in a chair, featuring a flexible rectangular blade with cylindrical pins and L-shaped vertical guides, allowing the lumbar support to be easily adjusted by sliding along the blade and transforming curvilinear motion into linear motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a flexible blade with curvilinear guides is used, then the ease of operation is improved, but the device complexity increases

Engineering Contradiction:
Improveease of adjustmentVSAvoidstructure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent employs curvilinear guides (12) formed by L-shaped vertical guides on the backrest wall and corresponding guides on the flexible blade (10). The curvilinear path transforms the adjustment motion into a guided trajectory that converts small hand movements into effective lumbar support repositioning, improving ease of operation while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The flexible blade (10) is constructed as a thin, flexible rectangular element that can bend and deform as it moves along the curvilinear guides. This flexibility allows the blade to navigate the curved path defined by the guides while maintaining structural integrity, enabling smooth adjustment of the lumbar support position without requiring complex mechanical joints or actuators.

Inventive Principle:
Principle #30Flexible shells and thin films

2Ease of operation

If a curvilinear sliding mechanism is used, then the ease of operation is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveease of adjustmentVSAvoidguide alignment precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The curvilinear guides are designed with smooth, continuous curves rather than sharp angles or complex geometries. This simplifies the manufacturing process while ensuring that the flexible blade can easily follow the prescribed path. The L-shaped vertical guides on the backrest wall and corresponding guides on the blade create a well-defined but manufacturable curvilinear trajectory.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The flexibility of the blade (10) acts as a compliance mechanism that can accommodate minor variations in guide alignment during manufacturing. The blade's ability to bend and conform to the curvilinear path provides tolerance to manufacturing imperfections, reducing the stringency of precision requirements while maintaining smooth operation.

Inventive Principle:
Principle #30Flexible shells and thin films

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

Enables simple and efficient adjustment of the lumbar support to the desired position, improving user comfort and reducing the effort required for adjustment.

Implementation Method 1

thanks to the flexibility of the blades 18 which transform their curvilinear motion along the curved portion 26 into linear motion of the blade 10 in the backrest area

Methodology Applied
Scientific EffectFlexibility: Elasticity

Data Source

PatentEP4274450B1Chair back
Publication Date: 2025.01.22 BRADO
  • EP4274450B1 patent drawingFigure 1~2
  • EP4274450B1 patent drawingFigure 3~4
  • EP4274450B1 patent drawingFigure 5~7

AI summary

A chair back comprising a device for moving a lumbar support (2) provided in the back of a chair, said device being constituted by a blade (10) bound to the lumbar support and sliding along guides (12) provided in the wall of the backrest (16) of the chair, said blade (10) extending below in at least one curved blade (18) guided along at least one corresponding curved seat formed by ribs (22, 24) provided on a curved portion (26) integral with the lower edge of the backrest, the end of said at least one blade (18) being provided with an operating handle (20) characterized in that it comprises a carter (28) covering the curved portion (26) provided with at least one rib (25) having the function to constrain the curvilinear sliding of the curved blade (18) housed within the curved seat formed by the ribs (22, 24) of the backrest.