Chair Caddie Roller Design for Mobility Without Stability Loss
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Solution Overview
Problem
There is a need for a mobility solution that allows individuals with limited mobility to be easily moved to tables without the use of a wheelchair, as traditional options are either conspicuous, costly, or compromise the stability and integrity of the chair.
Innovation Solution
A chair caddie with a central hub and four arms, each supported by surface-engaging rollers, that elevates the chair legs above the surface, allowing for easy movement while maintaining stability and avoiding structural modifications that could void warranties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If casters or wheels are attached to chair legs, then mobility is improved, but the stability and integrity of the chair deteriorates
Solution Approach 1:
The mobility function is segmented from the chair structure itself. Instead of attaching wheels directly to the chair legs, a separate caddie unit with rollers is positioned beneath the chair. This segmentation allows the chair to maintain its original stable structure while the independent caddie provides mobility through rollers that contact the floor surface.
Solution Approach 2:
The caddie unit acts as an intermediary between the chair and the floor. Rather than modifying the chair legs directly, the caddie's rollers serve as the mediating contact point with the floor, enabling movement without compromising the chair's structural integrity or stability.
2Speed
If a rolling caddie is placed beneath the chair, then mobility is improved, but the risk of tripping hazards increases
Solution Approach 1:
The caddie is designed to operate in the vertical dimension beneath the chair seat, utilizing the space below the seating surface. By positioning rollers vertically underneath the chair rather than extending horizontally outward, the design enables mobility while keeping the mechanism concealed and out of the path of potential tripping hazards at floor level.
3Speed
If the chair is elevated on rollers, then mobility is improved, but the arms cannot pass under the table
Solution Approach 1:
The elevation function is applied locally only to the chair legs through the caddie unit, while the main chair body and seat remain at their original height. The rollers are positioned to elevate only the support structure beneath the seat, preserving the local quality of the seating surface height and ensuring arms can still pass comfortably under the table.
4Speed
If structural modifications are made to the chair, then mobility is improved, but the manufacturer's warranty is voided
Solution Approach 1:
The caddie unit serves as an intermediary mobility solution that does not require direct modification of the chair structure. By positioning the caddie beneath the chair and using rollers that contact the floor independently, the system provides mobility without drilling holes, mounting hardware, or altering the chair in ways that would void the manufacturer's warranty.
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
Enables the easy and stable transfer of individuals with limited mobility to tables without compromising the chair's stability or integrity, accommodating various chair configurations and weights, and avoiding tripping hazards.
Implementation Method 1
Each arm is supported by a surface-engaging roller, and the surface-engaging rollers cooperate to elevate the arms and the central hub above a planar surface engaged by the surface-engaging rollers
Data Source
AI summary
A chair caddie, comprises a central hub and four arms. Each of the four arms is coupled to and extends outwardly from the central hub and is adapted to support a chair leg. Each arm is supported by a surface-engaging roller. The surface-engaging rollers cooperate to elevate the arms and the central hub above a planar surface engaged by the surface-engaging rollers. Each arm carries a chair foot receptacle adapted to receive and support a chair foot, and each roller is positioned inboard of the chair foot receptacle on its respective arm. The chair foot receptacles define a notional chair footprint circumscribing the chair foot receptacles, and the surface-engaging rollers have centers of rotation that are inside the chair footprint.