Chair Back Control Linkage for Recline and Tension Adjustment
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Solution Overview
Problem
Existing chair mechanisms lack efficient control over the recline and tension adjustment of back support structures, limiting user comfort and adaptability.
Innovation Solution
A chair assembly with a control link assembly and actuator system that allows a seated user to adjust the back tensioning assembly between low-tension and high-tension positions, and move the back support structure between upright and reclined positions, using a universal joint assembly and damper structure for smooth movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional chair mechanism is used, then the structure is simple, but the user control over recline and tension adjustment is inefficient
Solution Approach 1:
A control link assembly acts as an intermediary mechanical system between the user's manual input and the actuator mechanisms. This assembly includes links, joints, and levers that translate user input into controlled movement of the back support structure, enabling efficient user control while maintaining a mechanically straightforward design without requiring electronic controls or complex systems.
2Reliability
If high-tension settings are applied to the back tensioning assembly, then the back support stability is improved, but the input force required by the user increases
Solution Approach 1:
The control link assembly incorporates mechanical advantage through lever arms and linkages that balance and counteract the high tension forces in the back tensioning assembly. When the user adjusts the tension, the linkage system distributes and counterbalances the required input force, allowing high-tension settings to be achieved and maintained with reduced user effort while preserving back support stability.
3Strength
If a rigid back support structure is used, then the structural strength is improved, but the movement smoothness and user comfort decrease
Solution Approach 1:
The back support structure combines rigid structural elements with dynamic, movable joints and linkages. The control link assembly includes pivot joints and sliding connections that allow controlled movement between upright and reclined positions. This dynamic design maintains structural strength while enabling smooth, controlled transitions and adjustable positioning for user 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
Enhances user control over chair position and tension, improving comfort and adaptability by allowing precise adjustment of back support, reducing the input force required for high-tension settings, and ensuring smooth movement.
Implementation Method 1
a first universal joint assembly and a second universal joint assembly each operably coupling the first end of the first shaft member to the first end of the second shaft
Implementation Method 2
ensuring smooth movement
Data Source
AI summary
A chair assembly including a first chair structure, a second chair structure, an actuator assembly coupled to the second chair structure to move the second chair structure between the first and second positions, a control input assembly coupled to the first chair structure, and a control link assembly coupling the control input assembly with the actuator assembly to move the second chair structure between first and second positions, and including a first shaft operably coupled to the control link, and rotatable about a second axis that is substantially orthogonal to the first axis and to the first direction, and first and second universal joint assemblies coupling the first shaft member to the second shaft, wherein actuation of the control input moves the second chair structure between the first and second positions.