Articulated Chair Back Structure for Balanced Tilt Support
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Solution Overview
Problem
Conventional office chairs lack individual adjustability of the seat and backrest, leading to inadequate support and comfort for users of varying sizes and postures, with tilting mechanisms that do not provide a balanced ride throughout the range of motion.
Innovation Solution
A seating structure with an articulated seat and backrest, featuring a linkage assembly that allows the rear portion of the seat to pivot independently, an adjustable seat depth mechanism, and a biasing system with a leaf spring and cam surfaces to provide balanced torque and visual indicia for adjusting the return force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the seat and backrest are made as rigid fixed components, then structural strength is improved, but adaptability to different users and postures deteriorates
Solution Approach 1:
The seat is divided into front and rear portions that can articulate relative to each other, allowing independent movement. The backrest is segmented into multiple sections with different articulation capabilities. This segmentation enables both structural integrity and adaptability to different user sizes and postures.
Solution Approach 2:
The patent introduces dynamic articulation mechanisms that allow the seat and backrest to move and adjust during tilting. The seat portions can rotate relative to each other, and the backrest sections can independently articulate, providing continuous adaptation to user needs while maintaining strength through controlled mechanical movements.
2Adaptability or versatility
If the seat depth is adjusted by moving the entire rigid seat, then seat depth adjustability is improved, but structural complexity and risk of pinching deteriorates
Solution Approach 1:
The seat is segmented into front and rear portions connected by an articulation mechanism. Adjusting seat depth involves moving only the front portion relative to the rear portion, rather than moving the entire seat. This reduces the complexity of the adjustment mechanism and eliminates pinch points that would occur with full-seat movement.
3Ease of manufacture
If the backrest is made as a rigid fixed component, then manufacturing simplicity is improved, but user comfort and range of motion deteriorates
Solution Approach 1:
The backrest is divided into multiple sections that can articulate independently. The lower, middle, and upper portions can move relative to each other, allowing users to stretch and arch their backs while maintaining a relatively simple overall structure that is easier to manufacture than a fully complex mechanism.
4Ease of operation
If conventional springs are used to bias the seat and back, then tilting function is achieved, but device complexity and adjustment difficulty increases
Solution Approach 1:
The patent combines the biasing function with the articulation mechanism itself. The linkage assembly that enables seat portion movement also provides the restoring force through its geometric configuration, eliminating the need for separate complex spring mechanisms and reducing overall device 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 solution ensures comfortable support for users by reducing hip drop, allowing customizable fit, and providing a balanced ride and easy adjustment, eliminating the need for additional support members and simplifying the tilting mechanism.
Implementation Method 1
The mechanisms used to adjust the load on the spring(s), or the load capability of the spring(s)
Implementation Method 2
The spring and body support structure have cam surfaces that contact one another
Data Source
AI summary
A seating structure includes a central spine and an upper back structure having a pair of arms extending upwardly and outwardly from the central spine. The upper back structure is pivotally connected to the central spine about a first horizontal axis. A back support structure is pivotally connected to the spine about a second horizontal axis and is pivotally connected to the ends of each of the arms about a third horizontal axis.