Adjustable Chair Armrest Linkage for Height and Orientation Control
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Solution Overview
Problem
Existing multi-function chairs fail to provide adaptable armrest height for patients of varying sizes, leading to poor comfort and support due to fixed angular orientation of the armrest relative to the seat and backrest.
Innovation Solution
A link mechanism that allows the armrest to be adjustable in height through a sliding engagement between a lever arm and an actuator link, maintaining its angular orientation with the backrest across different pivotal positions, utilizing a runner and actuator link system that enables parallel or near-parallel displacement, and a sliding sleeve on a guide bar for height adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the armrest is fixed to the backrest at a specific height, then the structure is simple and stable, but the armrest height cannot be adapted to patients of varying sizes, leading to poor comfort and support
Solution Approach 1:
The armrest structure is transformed from a fixed static configuration to a dynamic adjustable system. The armrest can be positioned at multiple heights along the backrest through a guide mechanism with positioning holes, allowing adaptation to different patient sizes while maintaining structural stability through the mechanical guide-and-pin system.
Solution Approach 2:
The armrest assembly is segmented into movable and fixed components. The armrest can slide along the backrest structure and be locked at discrete positions, dividing the adjustment function into separate movable (armrest) and guiding (backrest with holes) elements, thereby enabling height adaptability without excessive overall complexity.
2Adaptability or versatility
If the armrest is pivotally arranged to the backrest to maintain angular orientation, then the armrest maintains its angular orientation in any pivotal position of the backrest, but the armrest height above the seat is not adaptable to different patient sizes
Solution Approach 1:
The armrest adjustment mechanism is designed to be self-servicing through its mechanical nature. The armrest can be manually positioned and locked into place using the guide holes and positioning pins without requiring external power sources, complex controls, or assistance from operators, thereby maintaining ease of operation while enabling height adaptability.
3Adaptability or versatility
If a link mechanism is used to actuate the armrest for pivoting motion, then the armrest maintains its angular orientation relative to the undercarriage in any pivotal position, but the armrest height cannot be adjusted for individual patient needs
Solution Approach 1:
The armrest system transitions from a completely fixed link mechanism to a dynamic configuration where the armrest can be repositioned vertically along the backrest. This is achieved through guide holes and positioning pins that allow the armrest to slide and lock at different heights, enabling customization for individual patients while preserving the angular orientation function.
Solution Approach 2:
The link mechanism is segmented to allow relative movement between the armrest and backrest. The connection is divided into a movable component (armrest with positioning pin) and a guiding component (backrest with holes), enabling height adjustment while maintaining the structural integrity and angular control provided by the link mechanism.
Data Source
AI summary
A chair, includes a seat structure and a backrest structure arranged pivotally to the seat structure. An armrest is arranged pivotally to the backrest structure through a pivotal connection, and a link mechanism is journalled to the structures of the seat and the backrest, respectively, the link mechanism actuating and controlling the armrest to maintain its pivotal orientation in any pivotal position of the backrest relative to the seat. The armrest is adjustable in the length direction of the backrest through the pivotal connection which is arranged displaceable on the backrest structure, and the pivotal orientation of the armrest is controlled via a sliding engagement between a lever arm, adjoining the armrest at an angle thereto, and an actuator link included in the link mechanism and displaceable thereby with respect to the backrest so as to extend substantially in the length direction of the backrest in all its positions of displacement.