Tool-Free Backrest Frame Adjustment in Foldable Wheelchairs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Foldable wheelchairs with collapsible and angle adjustable backrest frames often require specific tools to actuate locking/unlocking means and involve dismantling of components, making them cumbersome to fold and adjust without tools.
Innovation Solution
A wheelchair design that allows stepless angle adjustment and folding of the backrest frame without tools, using a locking/unlocking mechanism that includes a threaded rod and abutment element for smooth angle adjustment and a fixed locking/unlocking element to secure the backrest in various positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional locking/unlocking means are used in foldable wheelchairs, then the backrest frame can be locked in position, but specific tools are required to actuate the locking mechanism
Solution Approach 1:
The locking mechanism is designed to be self-operating through a release cable connected to a release lever. When the user pulls the release cable, it actuates the release lever which automatically disengages the locking element from the groove, allowing the backrest to be folded or adjusted without requiring external tools.
2Adaptability or versatility
If traditional angle adjustment mechanisms are used, then the backrest can be locked at specific angles, but several components must be dismantled and reassembled to modify the inclination
Solution Approach 1:
The backrest frame is designed with a pivoting connection to the seat frame, allowing it to rotate and adjust to different inclination angles dynamically. The locking mechanism with groove and locking element enables the backrest to be locked at various positions during movement, providing continuous angle adjustment capability without requiring disassembly of components.
3Volume of moving object
If the backrest frame is made collapsible to reduce dimensions, then transportation becomes easier, but the structure becomes more complex
Solution Approach 1:
The backrest frame is divided into separable components including the backrest, backrest frame, seat, and wheel assembly. The backrest frame can be pivotally folded down from vertical to horizontal position and locked parallel to the seat, enabling compact storage and transportation while maintaining manageable structural complexity through modular design.
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 easy, tool-free folding and angle adjustment of the backrest frame, ensuring it can be locked in both folded and erected positions, enhancing user convenience and reducing assembly/disassembly complexity.
Implementation Method 1
a threaded rod and abutment element for smooth angle adjustment
Implementation Method 2
a fixed locking/unlocking element to secure the backrest in various positions
Data Source
Figure 1
Figure 2a~2d
Figure 3a~3c
AI summary
The present invention relates to a wheelchair (10) comprising a wheelchair frame (1) resting on wheels (2, 3) and supporting a seat (4), and a backrest frame (5) supporting a backrest (6), said backrest frame (5) being pivotally connected to said wheelchair frame (1) and comprising two lateral tubular elements (5a), wherein each tubular element (5a) comprises an upper end portion (5b) provided with a handle (5d) and a lower end portion (5c) pivotally mounted on an axis (7) supported on a support (11) fixedly connected to the wheelchair frame (1), characterized in that locking/unlocking means (12) are provided for preventing the lower end portion (5c) of at least one of said tubular elements (5a), and preferably of each one of said tubular elements, to pivot relative to the corresponding support (11) in a locked inclined position of the backrest frame (5), said locking/unlocking means (12) being configured so as to permit a stepless adjustment of the angle (α0) between a plane (P1) defined by the backrest (6) and a plane (P2) defined by the seat (4) in said locked inclined position.