Synchronous chair mechanism and chair with such
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Solution Overview
Problem
Existing synchronous chair mechanisms have limited adjustability of the supporting force for the backrest, requiring complex and unstable mechanisms to achieve sufficient support, often necessitating large forces to pre-tension linear springs, which complicates operation and reduces the range of motion.
Innovation Solution
A synchronizing chair mechanism with a spring element connected to multiple basic elements, featuring a detent structure and slide coupling piece that adjusts the effective lever length, allowing for precise and stable adjustment of the supporting force by changing the distance between pivot axes, enabling easy and ergonomic tilting of the seat and backrest.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If linear springs are used to provide supporting force for the backrest, then the backrest can be supported, but the range of motion is reduced due to pre-tensioning and complex setting mechanisms are required
Solution Approach 1:
The patent applies the dynamics principle by making the lever arm length adjustable rather than fixed. The lever arm connected to the spring element can be extended or retracted, allowing the system to adapt its mechanical advantage dynamically. This enables the spring to provide adequate supporting force while maintaining sufficient range of motion, as the lever arm length can be optimized for different operating conditions without requiring excessive pre-tensioning.
2Force
If pre-tensioning is applied to linear springs to provide sufficient support, then the supporting force is adequate, but large forces are required and setting mechanisms become complicated to operate
Solution Approach 1:
The adjustable lever arm provides a dynamic mechanical advantage system that reduces the need for high pre-tensioning forces. By extending the lever arm, the system amplifies the spring force output, allowing adequate supporting force with lower pre-tensioning requirements. This eliminates the need for complex threaded spindle mechanisms and makes operation simpler.
Solution Approach 2:
The patent changes the physical parameter of lever arm length to optimize the force output. By adjusting this geometric parameter, the system can achieve the required supporting force without increasing spring pre-tensioning, thereby simplifying the overall mechanism and reducing operational complexity.
3Adaptability or versatility
If known adjusting mechanisms are used for backrest support, then adjustment is possible, but the mechanisms are not sufficiently stable and can change position abruptly
Solution Approach 1:
The adjusting mechanism is segmented into discrete detent positions along the adjustment slot. The detent structure with its multiple engagement positions provides stable, predetermined adjustment steps. This segmentation prevents continuous or abrupt position changes while maintaining adjustability, as the mechanism naturally settles into discrete stable positions rather than allowing intermediate unstable positions.
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 mechanism allows for simple, comfortable, and reliable adjustment of the backrest's supporting force, ensuring stable and efficient synchronous movement of the seat and backrest, reducing operational complexity and enhancing ergonomic adjustability.
Implementation Method 1
The suspension is designed as a torsion spring that generates a torque about the third axis of rotation on the seat support
Data Source
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AI summary
A synchronous chair mechanism (10) for simultaneously altering a seat and a backrest of a chair from a zero position, in which the backrest has been tilted to a minimum extent in relation to the seat, into an end position, in which the backrest has been tilted to a maximum extent in relation to the seat, comprises a base (20), which can be connected to a substructure provided for setting up. It also comprises a backrest carrier (30), on which the backrest can be fitted, a seat carrier (40), which is designed for accommodating a seat, and a spring element (8) having a front end and a rear end. The backrest carrier (30) is mounted on the base (20) such that it can be pivoted about a first axis of rotation (710). The seat carrier (40) is connected in an articulated manner to the backrest carrier (30) for movement about a second axis of rotation (720) and to the front end of the spring element (80) for movement about a third axis of rotation (730). The rear end of the spring element (80) is articulated on the backrest carrier (30) for movement via a fourth axis of rotation (740). A latching structure (310) is formed on the backrest carrier (30). The synchronous chair mechanism (10) comprises a sliding coupling piece (60), which is fitted at the rear end of the spring element (80) such that it can be pivoted about the fourth axis of rotation (740). Outside the zero position of the synchronous chair mechanism (10), the sliding coupling piece (60) engages in the latching structure (310) of the backrest carrier (3; 30), and therefore the sliding coupling piece (60) and the backrest carrier (30) are connected to one another in a fixed position. In the zero position of the synchronous chair mechanism (10), the sliding coupling piece (60) has been uncoupled from the latching structure (310) of the backrest carrier (30), and therefore the sliding coupling piece (60) can be moved in relation to the latching structure (310), as a result of which it is possible to alter a distance between the fourth axis of rotation (740) and the first axis of rotation (710).