Chair Synchronous Deflection Mechanism with Integrated Base Support

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Solution Overview

Problem

Existing chair mechanisms for synchronous deflection between the backrest and seat inclination are complex, costly, and do not allow for efficient ergonomic optimization and aesthetic design.

Innovation Solution

A chair mechanism with a minimized design featuring a spring unit, a U-shaped base support with articulated axes, and a locking system using crown elements and guide pins to achieve synchronous deflection between the backrest and seat, allowing for adjustable ergonomic settings and aesthetic shaping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing chair mechanisms for synchronous deflection are used, then synchronous adjustment between backrest and seat is achieved, but the mechanism becomes complex and costly

Engineering Contradiction:
Improvesynchronous adjustmentVSAvoidmechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the synchronous deflection mechanism and the height adjustment mechanism into a single integrated structure. The base support serves dual functions: it provides the articulation axes for synchronous backrest and seat movement while simultaneously supporting the gas spring for height adjustment. This merging eliminates separate mechanisms and reduces overall complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The base support is designed as a multi-functional component that performs multiple tasks: it articulates the backrest on the first axis, supports the moving third axis for the seat, and provides the mounting structure for the height adjustment gas spring. This universal component approach reduces the total number of parts and simplifies the overall mechanism.

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

2Reliability

If existing chair mechanisms for synchronous deflection are used, then synchronous adjustment is achieved, but material and assembly costs increase

Engineering Contradiction:
Improvesynchronous adjustmentVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By merging the synchronous deflection mechanism with the height adjustment mechanism into the base support structure, the patent reduces the total number of components that need to be manufactured and assembled. This integration lowers material costs and assembly expenses while maintaining the synchronous adjustment function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The multi-functional base support reduces the overall part count, leading to fewer manufacturing operations and assembly steps. This universal component design simplifies production processes and reduces both material and labor costs associated with manufacturing complex synchronous mechanisms.

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

3Adaptability or versatility

If complex mechanisms are used for synchronous deflection, then adjustment functionality is achieved, but aesthetic design is compromised

Engineering Contradiction:
Improveergonomic adjustmentVSAvoidaesthetic design
Core Design Contradiction:
Adaptability or versatilityVSShape

Solution Approach 1:

The integration of the synchronous mechanism into the base support structure allows for cleaner lines and fewer visible mechanical components. The compact design enables the mechanism to be housed within or behind aesthetic chair elements, maintaining visual appeal while providing full ergonomic adjustment functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The multi-functional base support consolidates multiple mechanisms into a single structural element, reducing visual clutter and enabling more flexible aesthetic design options. This universal component can be integrated into various chair styles without compromising appearance, as it eliminates the need for separate visible adjustment mechanisms.

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

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 provides efficient ergonomic adjustment, reduced material and assembly costs, and an aesthetically pleasing design while ensuring secure locking and smooth operation of the synchronous deflection.

Implementation Method 1

The mechanism causing the synchronous deflection has a spring unit arranged therein

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3197319B1Chair having a deflection that is mutually synchronous between backrest and a seat
Publication Date: 2021.01.06 VITRA
  • EP3197319B1 patent drawingFigure 1A~1B
  • EP3197319B1 patent drawingFigure 1C~1D
  • EP3197319B1 patent drawingFigure 1E~1F

AI summary

The invention relates to a chair which functions by means of a deflection that is mutually synchronous between a backrest (9) and a seat (25) over a range between a respective zero position of back inclination (R0) and of seat inclination (S0) and a respective maximum back inclination (Rmax) and maximum seat inclination (Smax). The mechanism (2) that causes synchronous deflection has a spring unit (6) arranged therein. The base support (50) of a carrier unit (5) is rigidly fastened to the underframe (1), which is intended to be set on the floor. A stationary first axis of rotation (D1) and a stationary second axis of rotation (D2) extend through the base support (50). A back carrier (91) is articulated on the first axis of rotation (D1). A third axis of rotation (D3), which moves around the first axis of rotation (D1) when the mechanism (2) is adjusted, extends through the back carrier (91). A base plate (3) lies movably on the base support (50) at the front of the base plate and is articulated on the third axis of rotation (D3) at the rear of the base plate. The base support (50) is designed in the shape of a U, having a center part (54) and two arms (53) extending upward from the center part, which arms each have a shaped piece (55) protruding upward, which shaped pieces each engage in an associated opening (34) in the base plate (3). When the mechanism (2) is deflected, a relative displacement between the stationary shaped pieces (55) and the openings (34) arises. The two openings (34) are oriented in the direction of the seat depth (T) and thus at right angles to the transversely extending axes of rotation (D1, D2, D3).