Wheelchair Backrest Adjustment via Parallel Slots and Flexible Straps
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Solution Overview
Problem
Existing wheelchair backrests lack quick and easy adjustability, are not cost-effective to manufacture, and cannot deform to fit anatomical curves, limiting user comfort.
Innovation Solution
A backrest with parallel slots and flexible, length-adjustable straps that allow easy adjustment of the cushion support's position and shape to conform to the user's morphology, using bolts or screws in threaded holes for quick adjustments and clamping elements for secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple separate adjustment mechanisms are used for backrest depth, width, and height, then adjustment precision is improved, but adjustment time and operational complexity increase
Solution Approach 1:
The patent combines multiple adjustment functions (depth, width, height) into a single integrated adjustment mechanism. The attachment member with multiple parallel slots allows one adjustment operation to simultaneously modify multiple dimensions of the backrest, eliminating the need for separate adjustment mechanisms for each dimension.
Solution Approach 2:
The attachment member serves multiple functions: it provides depth adjustment through vertical slots, width adjustment through horizontal slots, and height adjustment through threaded holes. This single component performs what would traditionally require multiple separate mechanisms, reducing adjustment time while maintaining precision.
2Strength
If rigid backrest parts are used, then structural strength is improved, but adaptability to anatomical curves decreases
Solution Approach 1:
The patent introduces adjustability and flexibility to the backrest structure. The attachment member can be positioned at multiple locations along the slots, and the lateral supports can be independently adjusted, allowing the rigid structure to adapt to different user anatomies while maintaining its structural integrity.
Solution Approach 2:
The backrest is divided into adjustable segments including the attachment member and lateral supports. These segmented components can be independently positioned to conform to anatomical curves, while the overall rigid structure maintains strength. The segmentation allows flexibility without compromising structural integrity.
3Measurement precision
If complex adjustment mechanisms are used, then adjustment precision is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The attachment member is designed as a universal component that handles depth, width, and height adjustments through its integrated slot system. This multi-functional design reduces the total number of components needed while maintaining precise adjustment capabilities, thereby simplifying the overall device.
Solution Approach 2:
The patent uses uniform parallel slots throughout the attachment member for different adjustment directions. This homogeneous design approach simplifies manufacturing compared to complex irregular slot patterns, reducing production costs while providing precise multi-directional adjustment capabilities.
Data Source
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AI summary
A backrest (1) for a wheelchair, comprising: - an adjustable cushion support (10), for supporting a backrest cushion, said cushion support (10) defining substantially a plane P1; - a backrest frame (20), for holding said cushion support (10), said backrest frame having two substantially parallel side posts (21a, 21b) defining substantially a plane P2; - attachment members (3), for attaching said cushion support (10) to said backrest frame (20); characterised in that: - said cushion support (10) comprising two side bars (11a, 11b) and a plurality of transversally extending and vertically spaced apart flexible straps (14) each interconnecting said two side bars (11a, 11b), each strap having length-adjusting means for adjusting the length of said straps; - said cushion support (10) comprising at least two connecting plates (12a, 12b), each plate (12a, 12b) being integral with one of said side bars (11a, 11b) and being provided with at least two parallel adjustment slots (13, 13', 13"), said slots defining an angle α, α>0, with said plane P1; - said attachment members (3) being slidably mounted on said slots (13, 13', 13"), enabling depth, width and angular adjustment of said cushion support (10) on said backrest frame (20).