Leaf-Spring Chair Linkage for Automatic Weight-Based Recline Resistance
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Solution Overview
Problem
Current furniture designs, particularly task chairs, face challenges in providing optimal adjustment to accommodate users of varying weights, leading to discomfort and potential health issues due to complex and time-consuming manual adjustment mechanisms that often go unoptimized.
Innovation Solution
A reconfigurable chair system featuring an adjusting assembly with a leaf spring and subassemblies that automatically adjust resistance to the backrest's angular orientation based on user weight, allowing for seamless transition from upright to reclined positions without excessive force, using a fulcrum point that moves to shorten the leaf spring's length and increase resistance as weight increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If manual adjustment mechanisms are used to accommodate users of varying weights, then adaptability is improved, but device complexity and ease of operation deteriorate due to complex and time-consuming adjustment procedures
Solution Approach 1:
The chair mechanism automatically adjusts to user weight through a self-regulating system where the user's body weight directly controls the spring compression and fulcrum position, eliminating the need for manual adjustment operations while maintaining adaptability across different weight ranges
2Adaptability or versatility
If manual adjustment mechanisms are used to accommodate users of varying weights, then adaptability is improved, but ease of operation worsens due to time-consuming adjustment procedures
Solution Approach 1:
The adjustment function is performed automatically by the system itself - the user's weight causes the seat to descend, compressing the leaf spring and moving the fulcrum point, which in turn adjusts the backrest resistance. This eliminates the need for separate manual adjustment operations, making the system both adaptable and easy to operate
3Device complexity
If fixed spring force is used in the backrest mechanism, then device complexity is reduced, but adaptability worsens as users of different weights cannot achieve optimal positioning
Solution Approach 1:
The system transitions from a static fixed-spring-force design to a dynamic system where the spring compression and fulcrum position automatically change based on the user's weight. The leaf spring's progressive compression and the moving fulcrum point create a dynamically adaptive resistance that scales with user weight, maintaining both simplicity and adaptability
4Force
If the leaf spring's working length is shortened by moving the fulcrum point, then resistance to tilting is increased for heavier users, but the mechanism complexity increases
Solution Approach 1:
The fulcrum movement mechanism is merged with the existing seat descent and spring compression mechanisms. The same structural movements that compress the leaf spring also relocate the fulcrum point along the spring's length, combining multiple functions into a unified mechanism that increases resistance without adding separate complexity
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 system ensures ergonomic support and comfort by automatically adjusting to user weight, reducing the need for manual adjustments and minimizing the effort required to change positions, thereby promoting better posture and reducing the risk of discomfort and injury.
Implementation Method 1
a leaf spring in direct contact with the linkage to provide resistance to tilting of a backrest of the chair
Data Source
AI summary
A chair, comprising, a backrest, a seat coupled with the backrest, a column coupled with the seat, a linkage statically attached to the backrest and rotatably attached below the seat, a leaf spring statically attached at one end and in direct contact with the linkage to provide a resistance to tilting of the backrest relative to the column. A first structure fixed to the column, where a portion of the first structure has an arc shape that includes one or more teeth, and a second structure in contact with the first structure, wherein a portion of the second structure includes one or more teeth. The chair is configured such that, when a weight is applied to the seat, the one or more teeth of the second structure, a pivot point at which the backrest is configured to tilt relative to the column, and the linkage are configured to move together.