Adjustable Chair Armrest Linkage for Stable Orientation
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Solution Overview
Problem
Existing multi-function chairs fail to provide adequate comfort and support for patients due to the inability to adapt the height of the armrests to individual patient sizes and body constitutions, maintaining the armrest's angular orientation 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, which maintains the armrest's angular orientation during pivotal movements of the seat and backrest, using a runner sliding along the actuator link and a pivotally connected push rod system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the armrest is pivotally arranged to the backrest to maintain angular orientation during seat and backrest movement, then the armrest maintains its angular orientation relative to the seat and backrest, but the height of the armrest above the seat cannot be adapted to individual patient sizes
Solution Approach 1:
The armrest height is made dynamically adjustable through a telescopic mechanism with movable telescopic elements that allow the armrest to change its extension along the backrest. This dynamic adjustment capability enables adaptation to different patient sizes while the link mechanism maintains the armrest's angular orientation relative to the seat and backrest during movement between seating, reclining, and standing positions.
2Adaptability or versatility
If the armrest height is made adjustable along the backrest, then the armrest can be adapted to different patient sizes, but the mechanism to maintain angular orientation during pivotal movements becomes more complex
Solution Approach 1:
The armrest is segmented into a base portion and one or more telescopic elements that can extend or retract relative to the base. This segmentation allows independent adjustment of armrest height along the backrest while the link mechanism independently maintains the angular orientation. The telescopic elements can be adjusted to different lengths to accommodate various patient sizes without affecting the orientation-maintaining function.
3Ease of operation
If a fixed armrest structure is used, then the device complexity is reduced, but poor comfort and support is offered when the armrest height does not match the patient's body constitution
Solution Approach 1:
The armrest transitions from a fixed structure to a dynamically adjustable one through telescopic elements that can be moved along the backrest. This allows the armrest height to be adapted to match different patient body constitutions, providing optimal comfort and support. The link mechanism ensures that regardless of the telescopic element's position, the armrest maintains its proper angular orientation during pivotal movements between seating, reclining, and standing positions.
Data Source
Figure 1
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AI summary
A chair is disclosed, comprising a seat (1) structure and a backrest (4) structure arranged pivotally to the seat structure. An armrest (8) is arranged pivotally to the backrest structure through a pivotal connection (9), and a link mechanism (10, 18) 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 chair is characterized in that the armrest (8) is adjustable in the length direction of the backrest through the pivotal connection (9) which is arranged displaceable on the backrest structure, and in that the pivotal orientation of the armrest (8) is controlled via a sliding engagement between a lever arm (24), adjoining the armrest at an angle thereto, and an actuator link (23) comprised 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.