Pivoting Four-Bar Armrest Assembly for Ergonomic Chair Support
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Solution Overview
Problem
Existing chair assemblies lack adjustable and ergonomic features that allow for optimal support and comfort for users, particularly in terms of armrest positioning and lumbar adjustment, which can lead to discomfort and reduced productivity during extended use.
Innovation Solution
A chair assembly with a four-bar linkage mechanism that allows for vertical and horizontal adjustment of armrests and a lumbar support system, enabling users to customize their seating experience by adjusting the armrests' height, tilt, and lumbar curvature to suit their needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed armrest positioning is used, then device complexity is reduced, but adaptability and user comfort deteriorate
Solution Approach 1:
The armrest assembly is made dynamically adjustable through a four-bar linkage mechanism that enables both vertical and horizontal movement. The linkage connects the armrest to the chair frame via pivot points, allowing the armrest position to be changed while maintaining mechanical stability. This dynamic configuration resolves the contradiction by providing adaptability without excessive complexity.
Solution Approach 2:
The armrest adjustment system is segmented into independent vertical and horizontal adjustment functions. The four-bar linkage separates these adjustment movements into distinct mechanical paths, with vertical adjustment controlled by one set of linkage arms and horizontal adjustment by another. This segmentation allows complex two-dimensional adjustment to be achieved through simpler, independent mechanical subsystems.
2Ease of operation
If adjustable armrests with four-bar linkage are implemented, then adaptability and comfort are improved, but device complexity increases
Solution Approach 1:
The four-bar linkage mechanism is designed to be passively actuated by user force applied directly to the armrest. When a user pushes or pulls the armrest, the linkage automatically translates this force into coordinated vertical and horizontal movement without requiring separate control mechanisms. This self-service approach improves ease of operation while keeping the mechanism relatively simple.
Solution Approach 2:
The four-bar linkage mechanism serves multiple functions simultaneously: it provides vertical adjustment, horizontal adjustment, and maintains armrest stability during movement. The same linkage structure that enables position changes also acts as the support structure and guides the movement path, eliminating the need for separate mechanisms for each function.
3Adaptability or versatility
If pivotable arm support structure is added, then armrest versatility is improved, but manufacturing complexity increases
Solution Approach 1:
The pivotable arm support structure merges multiple components into integrated assemblies. The linkage arms are designed as single-piece components that combine the pivot point, the structural arm, and the connection interfaces. This merging reduces the number of separate parts that need to be manufactured and assembled, thereby improving ease of manufacture while maintaining the desired movement versatility.
Data Source
AI summary
A chair assembly includes a back support arrangement including a back support arrangement, a seat support arrangement and a four-bar arrangement that includes a rearward end and a forward end that is adjustable between a raised and lowered positions, and an arm rest assembly adapted to support the arm of a seated user thereon and supported on the forward end of the four-bar arrangement, wherein the rearward end of the four-bar arrangement is pivotably supported from an arm support structure for pivotable movement about a substantially vertical pivot axis such that the forward end of the four-bar arrangement is moveable between a first position and second position located laterally outward from the first position, and wherein the substantially vertical pivot axis is located forwardly of a rearmost edge of an upwardly-facing surface of the seat support arrangement.