Seat Board Bending Spring Layout Without Swivel Joints

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Solution Overview

Problem

Existing seating furniture designs, such as office chairs, are complex due to the need for multiple rotary or swivel joints and longitudinally acting springs, which increase the design and assembly effort while compromising ergonomics.

Innovation Solution

A seating furniture design featuring a non-rotatable fixation of a longitudinally extended bending spring to the support arm, allowing transverse elastic deflection, eliminates the need for rotary or swivel joints, resulting in a simpler construction while maintaining good ergonomics and synchronous mechanics. The bending spring provides greater elasticity than the carrier arm, with the option of using independent components or a one-piece construction made from different materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If rotary or swivel joints are used to connect the bending spring to the support arm, then the mechanism allows relative movement between components, but the construction becomes complex with increased design and assembly effort

Engineering Contradiction:
Improverelative movement capabilityVSAvoidconstruction complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent removes the rotary or swivel joint from the system entirely. Instead of using a joint to enable relative movement, the bending spring is fixed directly to the support arm in a rotationally fixed manner, and the spring itself provides the necessary elasticity and movement capability without requiring intermediate connecting joints.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent combines the functions of the bending spring and its connection to the support arm into a single integrated arrangement. The spring is fixed directly to the support arm, merging the elastic element and the structural component into a simpler unified construction that eliminates the need for separate joint mechanisms.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If multiple individual parts are used in the spring assembly, then the mechanism achieves the required elasticity and movement, but the number of parts and assembly effort increases

Engineering Contradiction:
Improveelasticity and movement capabilityVSAvoidassembly effort
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The support arm and bending spring are designed as a one-piece continuous component, merging two separate parts into a single integrated structure. This eliminates the need for separate assembly steps while maintaining the elastic properties of the spring and the structural function of the support arm.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses a two-component material system where a fiber-reinforced plastic core area is surrounded by a plastic jacket area. This composite structure allows the single piece to exhibit both the stiffness required for structural support and the elasticity needed for spring functionality, achieving reliable movement capability while simplifying manufacturing to a single injection molding process.

Inventive Principle:
Principle #40Composite materials

3Strength

If the support arm is made rigid, then the structural stability is improved, but the elasticity required for synchronous mechanism is reduced

Engineering Contradiction:
Improvestructural stabilityVSAvoidelasticity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The support arm is constructed as a one-piece component with a composite two-component material structure: a fiber-reinforced plastic core area providing structural strength and stability, surrounded by a plastic jacket area providing elasticity and flexibility. This allows the single component to simultaneously achieve both rigidity and elastic deflection capability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different regions of the support arm have different material properties - the core area is fiber-reinforced for strength and stability, while the overall structure allows elastic deflection. This local differentiation of material quality enables the component to provide both structural stability and the necessary elasticity for the synchronous mechanism.

Inventive Principle:
Principle #3Local quality

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

This design achieves a simpler construction with effective ergonomic and synchronous movement, allowing for adjustable inclination and comfortable seating by utilizing a bending spring that is more elastically deflected than the carrier arm, enabling a stiffer support arm and a more elastic spiral spring.

Implementation Method 1

The bending spring is arranged in such a way that when the seat plate is loaded it elastically deflects transversely to its longitudinal extent

Methodology Applied
Scientific EffectElastic deflection: Elasticity

Data Source

PatentEP1989963B8Seating furniture with seat board and backrest
Publication Date: 2010.08.04 SITAG

AI summary

The furniture has a support (16), seat plate (1) and backrest (2) arranged at a support arm (3) opposite to the support. The seat plate is supported at a longitudinally extending flexible spring (4) that is connected with the support arm. The flexible spring is arranged such that the flexible spring is elastically moved during loading the seat plate transversal to the longitudinal extension. The flexible spring is fixed at the support arm in a torque-proof manner, where flexible spring includes a free end (5), in whose area the seat plate is pushed away at the flexible spring.