Synchronisation mechanism

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Solution Overview

Problem

Existing synchronous mechanisms for office chair seat-backrest movement are complex, require large installation space, and often compromise on adjusting pivoting resistance, making them inefficient in design and assembly.

Innovation Solution

A compact synchronous mechanism with a coupling device featuring a tension coupling, support coupling, and spring arrangement that allows for adjustable pivoting resistance without increasing installation space, utilizing a track element for precise spring force adjustment and leveraging a compression spring mechanism to induce a defined synchronous movement between the seat and backrest.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional synchronous mechanism is used to ensure correlated seat-backrest movement, then the kinematic coupling is achieved, but the installation space requirement increases and the structure becomes more complex

Engineering Contradiction:
Improvecorrelated seat-backrest movementVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent combines the synchronous mechanism and the pivoting resistance adjustment device into a single integrated unit. The spring arrangement is positioned within the base support structure, and the coupling device simultaneously provides both the synchronous motion coupling and the adjustment functionality, eliminating the need for separate components and reducing installation space.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The base support is designed to serve multiple functions: it provides the structural foundation, houses the spring arrangement for pivoting resistance adjustment, and integrates the coupling device for synchronous motion. This multi-functional design reduces the overall number of components and minimizes the space required for installation.

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

2Area of stationary object

If the structure is simplified to reduce installation space, then the footprint is reduced, but the ability to adjust pivoting resistance is lost

Engineering Contradiction:
Improveinstallation spaceVSAvoidpivoting resistance adjustment
Core Design Contradiction:
Area of stationary objectVSAdaptability or versatility

Solution Approach 1:

The adjustment mechanism is merged with the base support structure. The track element is positioned within the base support, and the spring arrangement is integrated into the same structure, allowing adjustment functionality to be incorporated without increasing the external dimensions of the mechanism.

Inventive Principle:
Principle #5Merging (Combining)

3Area of stationary object

If a flat design is implemented to reduce installation space, then the mechanism becomes more compact, but the complexity of assembly increases

Engineering Contradiction:
Improveinstallation spaceVSAvoidassembly complexity
Core Design Contradiction:
Area of stationary objectVSEase of manufacture

Solution Approach 1:

The coupling device is divided into distinct modular components: the first coupling element, the second coupling element, and the track element. Each component can be manufactured separately and then assembled together, simplifying the manufacturing process while maintaining the compact flat design. The modular nature allows for easier quality control and assembly.

Inventive Principle:
Principle #1Segmentation

4Adaptability or versatility

If more components are added to enable pivoting resistance adjustment, then the adjustability is improved, but the device complexity increases

Engineering Contradiction:
Improvepivoting resistance adjustmentVSAvoidnumber of components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The spring arrangement shares the connection point with the coupling device, eliminating the need for separate mounting structures. The track element is positioned within the base support, and the spring arrangement is integrated into the same structure, allowing adjustment functionality to be incorporated without increasing the external dimensions or the number of discrete components.

Inventive Principle:
Principle #5Merging (Combining)

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 mechanism achieves a flat design with adjustable pivoting resistance, ensuring comfortable seating by synchronizing the angle of the seat and backrest without the 'shirt-taking effect, while maintaining a small footprint and easy assembly.

Implementation Method 1

a spring arrangement for fixing the pivoting resistance of the backrest support, wherein the spring arrangement has at least one spring element, the spring element having a stationary end and a free end

Methodology Applied
Scientific EffectSpring mechanism: Spring

Implementation Method 2

the spring element acting as a compression spring. The first coupling element is articulated to the backrest support at a distance from the connection point and, when the backrest support pivots, pulls the connection point of the two coupling elements forward as seen in the longitudinal direction of the seat, thereby acting on the spring element acting as a compression spring

Methodology Applied
Scientific EffectCompression spring: Spring

Data Source

PatentEP3741256B1Synchronisation mechanism
Publication Date: 2023.11.08 BOCK 1
  • EP3741256B1 patent drawingFigure 1~2
  • EP3741256B1 patent drawingFigure 3~4
  • EP3741256B1 patent drawingFigure 5

AI summary

The invention relates to a synchronous mechanism (100) for a correlated seat-backrest movement of an office chair, comprising a base support (1) placeable on a chair column, a seat support (3), and a backrest support (4). Furthermore, the invention relates to a piece of seating furniture, in particular an office chair, with a synchronous mechanism (100). In order to enable a piece of seating furniture that requires only a comparatively small installation space for the use of a synchronous mechanism, and is in particular particularly flat, yet still allows the swivel resistance of the backrest to be adjusted with the synchronous mechanism used, a synchronous mechanism (100) for a correlated seat-backrest movement of an office chair is proposed, comprising a base support (1) placeable on a chair column (10), a seat support (3), and a backrest support (4), wherein the backrest support (4) is pivotably connected to the base support (1).thereby defining the main axis of rotation (11) of the synchronous mechanism (100), with a coupling device (20) comprising a first coupling element (21) operatively connected to the backrest support (4) and a second coupling element (22) operatively connected to the base support (1), wherein the first coupling element (21) and the second coupling element (22) are pivotally connected to each other at a connection point (16), and with a spring arrangement (19) for defining the pivoting resistance of the backrest support (4), wherein the spring arrangement (19) comprises at least one spring element (30), wherein the spring element (30) has a fixed end (27) and a free end (28), wherein the free end (28) of the spring element (30) engages the connection point (16) of the coupling device (20).