Rotatable Chair Foot Ring With Leg-Clearance Arc
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Solution Overview
Problem
Conventional adjustable-height chairs with fixed foot rests obstruct users when the seat is lowered, as the foot rests do not swivel around the seat post, requiring users to exit the chair to reposition or remove them.
Innovation Solution
A rotatable foot-rest chair ring with a convex-ring-shaped section for elevated configurations and a recessed, concave arc section for lowered configurations, mounted on a pentaradially symmetric rotation hub with angularly displaced spokes, allowing the ring to rotate and adjust to avoid leg obstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed foot rest is mounted on an adjustable-height chair, then foot support is provided in elevated configurations, but the foot rest obstructs user legs when the seat is lowered to desk configuration
Solution Approach 1:
The foot rest is transformed from a fixed structure to a dynamic, rotatable structure that can change its position relative to the seat. The rotatable ring allows the foot rest to rotate 360 degrees around the seat post, enabling it to move from an obstructing position to a non-obstructing position as the seat height changes, thus adapting to different chair configurations without harming the user.
Solution Approach 2:
The foot rest is divided into functional sections: a convex-ring-shaped section for supporting feet and a recessed concave arc section that clears the user's legs. This segmentation allows different parts of the ring to serve different purposes at different times, with the convex section providing support when needed and the concave section eliminating obstruction when the seat is lowered.
2Ease of manufacture
If a conventional fixed foot rest is used, then manufacturing is simple, but the user must exit the chair to reposition or remove the foot rest
Solution Approach 1:
The rotatable ring with foot rest is designed to rotate freely around the seat post, allowing users to easily reposition the foot rest by simply rotating it while seated. This eliminates the need to exit the chair to adjust or remove the foot rest, significantly improving ease of operation while maintaining relatively simple manufacturing through the use of a rotatable mounting mechanism.
3Adaptability or versatility
If the foot rest extends fully around the seat post, then maximum foot support is provided, but it always obstructs legs when the seat is lowered
Solution Approach 1:
The foot rest ring is segmented into a convex-ring-shaped section that provides foot support and a recessed concave arc section that clears the user's legs. This segmentation allows the foot rest to provide maximum support coverage when the seat is elevated while eliminating leg obstruction when the seat is lowered, as the concave section rotates into the clearance position.
Solution Approach 2:
Different sections of the foot rest ring have different geometries optimized for different functions: the convex-ring-shaped section provides ergonomic foot support with its outward-curving surface, while the recessed concave arc section provides leg clearance with its inward-curving, low-profile geometry. This local quality differentiation resolves the contradiction between support coverage and leg obstruction.
Data Source
AI summary
An ergonomic, rotatable foot-rest chair ring for an adjustable-height chair is provided. The chair ring comprises a rotation hub configured to be rotatably mounted on the seat post of an adjustable height chair and angularly displaced spokes extending radially from the rotation hub to a modified foot-supporting ring. The modified ring has a perimeter defined by a convex-ring-shaped section that extends more than half way around the hub and a recessed, concave arc section that completes the perimeter.