Collapsible Mobility Aid Folding Mechanism Anti-Fold Lock
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Solution Overview
Problem
Foldable mobility aids, such as wheelchairs, face issues with unintentional folding due to user pressure, leading to rattling and a feeling of insecurity, and existing solutions are either complex and expensive or require manual effort to adjust the folding mechanism.
Innovation Solution
A spring-loaded folding mechanism that is pretensioned in the direction of the second position, ensuring the foldable mobility aid remains locked and preventing accidental folding, with pivot axes aligned in a plane to enhance self-locking, and a locking mechanism that automatically engages when the first position is reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the folding mechanism is positioned at dead center to minimize transport distance, then the transport distance is reduced, but the mechanism becomes unstable and prone to accidental folding
Solution Approach 1:
A spring element is introduced that applies a pre-tensioning force in the unfolded direction before any user pressure is applied. This preliminary counteracting force prevents the folding mechanism from accidentally transitioning to the folded position, directly resolving the instability issue while maintaining the compact transport configuration.
Solution Approach 2:
The spring element changes the force parameter of the system by providing a continuous pre-tensioning force. This modifies the equilibrium state of the folding mechanism, creating a stable unfolded position that resists accidental folding while allowing intentional folding when needed.
2Reliability
If pressure is applied to prevent accidental folding, then stability is improved, but the mechanism cannot be folded without first moving away from dead center
Solution Approach 1:
The spring provides continuous pre-tensioning that prevents accidental folding during normal use, but does not obstruct intentional folding. When the user applies force to fold the mechanism, the spring resistance is overcome and the mechanism transitions smoothly to the folded position without requiring preliminary movements.
3Reliability
If the mechanism is moved past dead center to prevent folding, then stability is improved, but play and rattling are introduced
Solution Approach 1:
The spring element modifies the force parameters to maintain the folding mechanism precisely at dead center in the unfolded state. This eliminates play and rattling while providing the necessary stability, as the spring force continuously counteracts any tendency to move away from the dead center position.
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
The solution prevents accidental folding, reduces rattling, and allows for easy unfolding without manual force, providing a secure and cost-effective mechanism for adjusting the distance between frame elements for transport.
Implementation Method 1
the folding mechanism (6) is pre-tensioned in the direction of the second position, in particular by a spring element (30)
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
The invention relates to a collapsible mobility aid with two frame elements (2), on each of which at least one wheel is secured or can be secured, and with a folding mechanism (6) by which the frame elements (2) are connected to each other, and a distance between the frame elements (2) in a first position of the folding mechanism (6) can be adapted to a transport distance and in a second position of the folding mechanism (6) can be adapted to a use distance, wherein the folding mechanism (6) has a central element (8) with a slide (10) arranged movably with respect thereto, at least two connection arms (12) which are each articulated on a frame element (2) and on the central element (8), and at least two levers (18) which are each articulated on a connection arm (12) and on the slide (10), wherein the pivot axes (20, 22) about which the levers (18) are arranged pivotably on the connection arms (12) and on the slide (10) are situated in one plane when the folding mechanism (6) is located in the second position.