Mobility Aid Footrest Locking Mechanism for Stability
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Solution Overview
Problem
Foldable wheelchairs with separate footrests lack stability, especially for users with limited mobility or amputations, and existing folding mechanisms can lead to unsafe impressions due to excessive joints and pivoting options, along with issues like rattling and manufacturing tolerances.
Innovation Solution
A mobility aid with a locking device that secures the footrest in the use position, allowing it to be automatically or manually locked, and a mechanical spring to bias the footrest towards the transport position, ensuring stability and preventing accidental folding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If separate footrests are used in foldable wheelchairs, then the folding mechanism achieves compact transport size, but the wheelchair lacks stability and gives an unsafe impression due to excessive joints and pivoting options
Solution Approach 1:
The patent merges the two separate footrests into a single footrest structure that connects both frame elements (first frame element and second frame element) simultaneously. This unified footrest reduces the number of separate folding mechanisms and joints, thereby improving stability while maintaining compact transport capability.
Solution Approach 2:
The footrest is designed with a specific segmentation that allows it to connect to both frame elements independently through separate mounting points. This segmentation enables the footrest to provide stabilizing connections without requiring a single complex folding mechanism, thus improving reliability while allowing compact folding.
2Reliability
If the footrest is positioned to provide stabilization by loading from above, then wheelchair stability improves, but users with lower leg amputations cannot utilize this stabilization method
Solution Approach 1:
The footrest is designed to provide stabilization through its structural connection to both frame elements rather than relying on user loading. The footrest itself acts as a stabilizing element through its rigid connection, eliminating the need for user weight loading and making it accessible to users with lower leg amputations.
Solution Approach 2:
Instead of relying on user loading from above to create stabilization, the patent inverts the approach by having the footrest structure itself provide stabilization through its connection to both frame elements. The stabilization comes from the footrest's structural integrity and dual connection points rather than external loading.
3Manufacturing precision
If the folding mechanism uses exact dead center positioning, then manufacturing precision is required, but this increases device complexity and sensitivity to tolerances
Solution Approach 1:
The footrest is pre-configured with connection points and mounting structures that automatically align with the frame elements during folding. This preliminary configuration eliminates the need for precise dead center positioning during operation, reducing sensitivity to manufacturing tolerances and simplifying the folding mechanism.
Solution Approach 2:
The patent introduces intermediary connection elements (such as mounting brackets or alignment features) between the footrest and frame elements that facilitate automatic alignment during folding. These intermediaries mediate the positioning process, eliminating the need for exact dead center positioning and reducing device complexity.
4Reliability
If the footrest is locked in use position, then stability is improved, but manual operation becomes more complex
Solution Approach 1:
The footrest incorporates an automatic locking mechanism that engages the footrest in the use position through its own structural configuration when the frame elements are in the correct position. This self-locking feature improves stability without requiring manual intervention, maintaining ease of operation.
Solution Approach 2:
The locking mechanism is pre-configured to automatically engage when the footrest reaches the use position during the folding/unfolding process. This preliminary setup ensures stability is achieved automatically without requiring the user to perform additional locking actions.
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
Enhances the stability of the mobility aid without the drawbacks of prior art, allowing for safe and space-efficient folding, and enabling one-handed operation by preventing re-locking of the footrest in the use position.
Implementation Method 1
Between the first folding element (8) and the second folding element (12) there is a spring element (20) which was preloaded when the footrest (6) was moved into the use position shown in Fig. 1 and now preloads the footrest (6) into the transport position.
Data Source
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AI summary
The invention relates to a mobility aid with a first frame element (2), a second frame element (4), and at least one body contact surface which is arranged between the first frame element (2) and the second frame element (4), wherein a distance between the first frame element (2) and the second frame element (4) is adjustable to a use distance, wherein the body contact surface is brought to a use position, and adjustable to a transport distance, wherein the body contact surface is brought to a transport position, wherein the mobility aid has at least one locking device (18) by means of which the body contact surface can be locked in the use position.