Kneeling wheelchair frame with dynamic seat height adjustment
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Solution Overview
Problem
Wheelchair users face challenges in transitioning from a seated to a standing position due to difficulties with footrest management, which requires physical effort and can be impossible for those with limited mobility or flexibility, and there is a need for improved seat height adjustment mechanisms to facilitate daily activities and car transfers.
Innovation Solution
A wheelchair frame with dynamic seat height adjustment mechanisms that allow for independent or linked adjustment of the front and rear seat heights, enabling users to lower the front seat and raise the rear seat to facilitate standing, while also folding the chair for compact storage, using gas springs and Bowden cables for easy operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional wheelchairs with fixed seat height are used, then the structure is simple and weight is low, but the user cannot adjust seat height for different activities such as transfers or standing
Solution Approach 1:
The patent implements dynamic seat height adjustment mechanisms that allow the seat to be repositioned from a fixed state to multiple adjustable height positions. The front seat height adjustment mechanism and rear seat height adjustment mechanism enable the seat to adapt to different activities (wheeling, transfers, standing) by changing its vertical position, transforming the static wheelchair into a dynamic system that responds to user needs.
Solution Approach 2:
The patent divides the seat height adjustment function into two independent mechanisms: a front seat height adjustment mechanism and a rear seat height adjustment mechanism. This segmentation allows independent adjustment of front and rear seat heights, providing finer control over seat positioning and enabling specific configurations (such as lowering front seat for transfers while maintaining rear seat height for stability) that a single unified mechanism could not achieve.
2Adaptability or versatility
If dynamic seat height adjustment mechanisms are added, then adaptability for different activities is improved, but the wheelchair weight increases
Solution Approach 1:
The patent replaces heavy traditional mechanical adjustment systems (such as manual cranks, levers, or hydraulic systems) with spring-based mechanisms. The front seat height adjustment mechanism uses a spring assembly that provides mechanical advantage, and the rear seat height adjustment mechanism uses a spring assembly with biasing force. These spring-based systems provide the necessary adjustment capability with significantly reduced weight compared to conventional mechanical systems.
Solution Approach 2:
The patent employs spring assemblies that utilize elastic potential energy to counterbalance the weight of the seat and adjust its height. The springs are positioned and configured to provide upward biasing force that offsets the gravitational force on the seat, enabling easy height adjustment without requiring heavy motors or complex mechanical advantage systems.
3Ease of operation
If the front seat height is lowered for transfers or kneeling, then accessibility and comfort are improved, but the user cannot simultaneously raise the rear seat for standing assistance
Solution Approach 1:
The patent divides the seat height adjustment function into two independent mechanisms: a front seat height adjustment mechanism and a rear seat height adjustment mechanism. This segmentation allows independent adjustment of front and rear seat heights, providing finer control over seat positioning and enabling specific configurations (such as lowering front seat for transfers while maintaining rear seat height for stability) that a single unified mechanism could not achieve.
Solution Approach 2:
The patent designs the wheelchair to perform multiple functions through its dual adjustment mechanisms. The front seat height adjustment mechanism handles transfers, kneeling, and floor-level activities, while the rear seat height adjustment mechanism handles standing assistance and stability. This multi-functionality is achieved within a unified wheelchair system that can adapt to various activities of daily living.
4Ease of operation
If conventional footrest management is required during sit-to-stand, then the structure is simple, but users with limited mobility cannot independently perform the transition
Solution Approach 1:
The patent extracts the footrest management requirement from the sit-to-stand transition process. By lowering the front seat height using the front seat height adjustment mechanism, the seat position is reduced below the footrest level, eliminating the need for footrest movement during the transition. This extraction of the footrest management task from the transition sequence allows users with limited mobility to perform sit-to-stand independently without dealing with footrest obstacles.
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 users to transition from sitting to standing without moving footrests, improving mobility and independence, and allows for compact storage and transportation of the wheelchair by lowering the front end and raising the rear end, enhancing usability and user satisfaction.
Implementation Method 1
using gas springs and Bowden cables for easy operation
Implementation Method 2
using gas springs and Bowden cables for easy operation
Data Source
AI summary
A wheelchair frame having a seat for supporting a forward facing occupant therein, rear wheels supporting the frame thereon proximate a rear end of the frame and front wheels supporting the frame thereon proximate a front end of the frame, further includes a front seat height adjustment mechanism which permits a height of a front end of the seat relative to the front wheels to be adjusted separately from or together with a rear end height adjustment of the rear end of the seat relative to the rear wheels. The front seat height adjustment mechanism can also be operable to lower the front seat height relative to the front wheels simultaneously with a rear seat height adjustment mechanism which is biased to raise the rear seat height relative to the rear wheels to assist users in moving from a sitting position towards a more standing position.