Chair Frame with L-Shaped Side Members for Simplified Assembly

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Solution Overview

Problem

Traditional reclining chairs require multiple actuators for adjustments, making them difficult to use and requiring significant labor and material for assembly and recycling, with a lack of secure connections between frame and cover components.

Innovation Solution

A chair design featuring a main transom, recline mechanism, and seat portion with a frame having L-shaped side members and a compliant support surface made of elastomeric material, such as HYTREL, which provides a secure connection between the frame and cover, reducing the need for multiple actuators and simplifying assembly and recycling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple actuators are used to provide reclining motion and adjustments, then the chair functionality is improved, but the device complexity and ease of operation deteriorate

Engineering Contradiction:
Improvechair functionalityVSAvoidnumber of actuators
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple adjustment functions (recline, seat height, seat depth) into a single integrated actuator mechanism. The resilient side members serve dual purposes as both structural support elements and adjustment actuators, eliminating the need for separate actuators for each function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The resilient side members perform multiple functions simultaneously: they provide structural support for the backrest, enable recline motion through their resilient deformation, and allow seat adjustment when manipulated by the user. This multi-functionality reduces the overall number of components needed.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple actuators are used to provide reclining motion and adjustments, then the chair functionality is improved, but the ease of operation deteriorates

Engineering Contradiction:
Improvechair functionalityVSAvoidadjustment ease
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent combines multiple adjustment functions (recline, seat height, seat depth) into a single integrated actuator mechanism. The resilient side members serve dual purposes as both structural support elements and adjustment actuators, eliminating the need for separate actuators for each function.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If separate fasteners are used to attach cover to frame, then the connection security is improved, but the manufacturing cost and labor cost worsen

Engineering Contradiction:
Improveconnection securityVSAvoidassembly labor cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent integrates the attachment function directly into the resilient side members themselves. The side members are formed with attachment features (such as integral tabs or molded-in connectors) that directly engage with the frame, eliminating the need for separate fasteners, screws, or attachment strips.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The resilient side members are designed to be self-attaching to the frame through their own structural features. The attachment mechanism is built into the side members themselves, allowing them to secure the cover to the frame without requiring external fastening components.

Inventive Principle:
Principle #25Self-service

4Object-affected harmful factors

If polymeric materials are used in chair components, then the environmental friendliness is improved, but the material usage and strength requirements worsen

Engineering Contradiction:
Improveenvironmental friendlinessVSAvoidmaterial usage
Core Design Contradiction:
Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The patent utilizes the inherent resilient properties of polymeric materials to create side members that can deform and recover, providing both strength and flexibility. This allows the use of thinner, lighter polymer sections that would not be possible with traditional rigid materials, reducing overall material usage while maintaining structural integrity.

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 design simplifies chair adjustments and reduces labor and material costs by providing a secure connection between the frame and cover, while enabling efficient recycling through the use of recyclable polymeric materials.

Implementation Method 1

a compliant support surface extending between and supported by the side members

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2939568B1chair
Publication Date: 2019.01.30 FORMWAY FURNITURE
  • EP2939568B1 patent drawingFigure 1
  • EP2939568B1 patent drawingFigure 2
  • EP2939568B1 patent drawingFigure 3a

AI summary

A chair comprising: a main transom (21), a recline mechanism, and a seat portion; and a back portion comprising a frame having at least two spaced apart side members (S1, S2), each side member (S1, S2) having an inner edge and an outer edge, wherein the inner edges of the side members (S1, S2) face towards each other and the outer edges of the side members face away from each other, each side member being generally L-shaped in cross-section and having a main frame portion (SA) comprising a front face that faces a seated occupant in use, and a flange (SB) positioned at an edge of the side member, the flange (SB) extending at least a major portion of the length of the side member and in a direction generally rearwardly from the front face of the main frame portion (SA), wherein each flange (SB) is positioned at the outer edge of the respective side member (S1, S2), and wherein the flanges (SB) are arranged to resist a majority of the loading applied to the frame by a seated occupant, the frame further comprising at least one support member (45a, 45b) extending from a lower portion thereof and mounted to at least one of the main transom (21), the recline mechanism, and the seat portion, to support the back portion in the chair; and a compliant support surface (61) extending between and supported by the side members (S1, S2).