Chair Hinge Assembly with Asymmetric Stops for Dynamic Seating

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Solution Overview

Problem

Existing chair designs with rocking mechanisms are limited in allowing dynamic sitting movements, as they often restrict rearward seat movement, which can interfere with the synchronous mechanism's functionality, and lack the ability to facilitate small movements beyond basic swiveling or tilting.

Innovation Solution

A chair with a joint arrangement that includes a support connecting part and a spring element, where the support connecting part is partially arranged in a receptacle with stops to prevent backward rocking, allowing for minimal rearward movement while enabling lateral and forward movements, thus enhancing dynamic sitting without compromising the synchronous mechanism's function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a rocking mechanism is provided to enable dynamic sitting movements, then the seat can move in multiple directions, but backward movement may interfere with the synchronous mechanism's functionality

Engineering Contradiction:
Improvedynamic sitting movementsVSAvoidsynchronous mechanism function
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The rocking mechanism is segmented into multiple independent joint arrangements: a first joint arrangement between the seat and backrest for synchronous movement, and a second joint arrangement between the seat and foot section for limited rocking movement. This segmentation allows each joint to perform its specific function without interfering with the other, enabling dynamic sitting while preserving synchronous mechanism reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second joint arrangement incorporates asymmetric movement constraints through stops that limit backward rocking movement while allowing forward and lateral movements. This asymmetric design ensures that the seat can move freely in directions that enhance comfort while preventing backward movement that would interfere with the synchronous mechanism's operation.

Inventive Principle:
Principle #4Asymmetry

2Adaptability or versatility

If the support connecting part is made movable relative to the seat, then dynamic sitting is promoted, but the structure becomes more complex

Engineering Contradiction:
Improvedynamic sitting capabilityVSAvoidjoint arrangement structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The second joint arrangement merges the support connecting part, spring element, and stops into a single integrated assembly that connects the foot section to the seat. This merging reduces the number of separate components and simplifies the overall structure while still providing the desired dynamic sitting capability through the combined functionality of these elements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The support connecting part is designed as a dynamic component that can move relative to the seat within controlled limits, rather than being a fixed rigid connection. This dynamic design enables the seat to adapt to user movements and provide comfort while maintaining a relatively simple structural configuration through the use of flexible joint arrangements.

Inventive Principle:
Principle #15Dynamics

3Reliability

If stops are added to prevent backward rocking, then synchronous mechanism function is preserved, but manufacturing complexity increases

Engineering Contradiction:
Improvesynchronous mechanism responseVSAvoidjoint arrangement assembly
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The stop mechanism is segmented into discrete stop elements that are integrated into the second joint arrangement, allowing them to be manufactured and assembled as separate components. This segmentation enables the stops to be added without requiring complete redesign of the entire joint arrangement, thus preserving synchronous mechanism reliability while minimizing manufacturing complexity.

Inventive Principle:
Principle #1Segmentation

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 solution allows for small, dynamic movements of the seat surface, ensuring the synchronous mechanism functions correctly while providing ergonomic benefits through controlled movement directions, including limited backward rocking and enhanced lateral and forward rocking capabilities.

Implementation Method 1

a support connecting part (13) which is movable relative to the seat (2) against the restoring force of a spring element (14)

Methodology Applied
Scientific EffectSpring restoring force: Spring

Data Source

PatentEP3626127B1Chair with hinge assembly
Publication Date: 2023.07.12 INTERSTUHL BUEROMOEBEL GMBH & CO KG
  • EP3626127B1 patent drawingFigure 1
  • EP3626127B1 patent drawingFigure 2
  • EP3626127B1 patent drawingFigure 3~4

AI summary

In a chair (1), in particular an office chair, with a seat (2) and a foot section, the foot section comprises a support (3) which is connected to the seat (2) via a joint arrangement (4) which allows relative movement of the seat (2) to the foot section, wherein the joint arrangement (4) comprises a support connecting part (13) which is movable relative to the seat (2) against the restoring force of a spring element (14) and both the support connecting part (13) and the spring element (14) are arranged, at least partially, in a receptacle (11) which is bounded on the upper side by a top part (10) and on the lower side by a base element (12), wherein the support connecting part (13) has a stop (17) which interacts with a corresponding stop (18) of the top part (10) to prevent a rocking movement of the top part (10) backwards.