Office Chair Synchronization Mechanism Using a Bendable Seat Support Plate
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Solution Overview
Problem
Conventional office chair synchronous mechanisms fail to achieve the required seat back opening angle and effectively utilize the user's weight to increase the restoring force of the backrest support, leading to an uncomfortable sitting experience due to uneven weight distribution and inadequate angular movement of the seat surface.
Innovation Solution
The seat support plate is designed to be elastically resiliently bendable, allowing it to deform and generate an elastic restoring force when the backrest is pivoted backwards, with links oriented to pivot the seat support in an upward and downward convex curve, utilizing the user's weight to increase the restoring force on the backrest support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the seat support plate is made rigid and moves only vertically, then the structure is simple and stable, but the seat back opening angle is insufficient and the user's weight cannot be used to increase restoring force
Solution Approach 1:
The seat support plate is transformed from a rigid structure to an elastically deformable one, allowing it to bend and generate restoring force dynamically. The plate can deflect upward when the backrest is tilted backward, creating an elastic restoring force that increases with user weight, while returning to its original position when the backrest returns to upright position.
Solution Approach 2:
The mechanical properties of the seat support plate are changed by introducing elastic deformability. The plate is designed with specific material properties and geometric characteristics (thickness, span, support conditions) that allow it to exhibit controlled elastic deformation under load, converting user weight into useful restoring force.
2Force
If the seat support plate is designed to pivot upward significantly, then the restoring force increases, but the synchronous ratio (seat back opening angle) becomes inadequate
Solution Approach 1:
The solution moves from one-dimensional vertical motion to two-dimensional combined motion. The seat support plate simultaneously achieves upward vertical displacement (generating restoring force) and backward rotational movement (increasing seat back opening angle). This dual-motion capability resolves the contradiction between force generation and angular movement.
3Force
If the user's weight is applied flatly over a large area, then the seat surface is comfortable, but the center of gravity cannot be used to increase restoring force
Solution Approach 1:
The seat support plate is designed with non-uniform properties - it has greater flexibility in the central region where user weight is concentrated, allowing this area to deflect more and generate restoring force. The plate maintains sufficient rigidity at the edges to provide structural support and comfort, creating a gradient of mechanical properties that simultaneously achieves force generation and comfort.
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 enhances the ergonomic synchronous ratio by providing a significant increase in the restoring force on the backrest support, reducing pressure on the thighs and maintaining comfort while allowing the user's weight to be effectively used for additional force, resulting in improved seat and backrest movement synchronization.
Implementation Method 1
the seat support plate is designed to be elastically resiliently bendable at least in the area of the second link
Data Source
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AI summary
The mechanism has a seat support plate (5), which is elastically resilient, bendable and is raised according to pivoting movement of a backrest support (6) when a weight support is lifted by a user. The seat support plate is deformed upward against gravitational force of the user by application of an elastic restoring force. First and second steering wheels (3, 16) include longitudinal axes, which are aligned in a forward direction. A longitudinal axis of a third steering wheel (4) is positioned opposite to longitudinal axes of other wheels.