Wheelchair Backrest Adjustment Mechanism for Seated Positioning
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Solution Overview
Problem
Existing wheelchair backrest adjustment mechanisms require users to be moved away from the seat to make adjustments, which is inconvenient and may not accommodate users with different sizes or physical impairments effectively.
Innovation Solution
An angle adjustable backrest support system that allows for angular and lateral positioning of the seat back relative to the seat base, featuring a strut with a torque transmitting profile, an adjuster ring, and a backrest reclining mount with a clamp and limiter slot, enabling adjustments while seated, with a backrest riser for height adjustment and a compound angle seat back mount for enhanced positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed backrest support is used, then the structural simplicity is maintained, but the adaptability to different user sizes and impairments deteriorates
Solution Approach 1:
The backrest support structure is transformed from a fixed rigid structure to a dynamic adjustable structure. The strut with torque transmitting profile allows rotational movement, and the adjuster ring with limit slots enables lateral positioning, creating a system that can adapt to different user needs while maintaining structural integrity through controlled degrees of freedom.
Solution Approach 2:
The backrest support is divided into separable functional components: the strut for angular adjustment, the adjuster ring for lateral positioning, the clamp for securing, and the limit slots for range control. This segmentation allows each component to perform its specific function independently while contributing to the overall adaptability of the system.
2Ease of operation
If an adjustable backrest mechanism is provided, then the adaptability to user needs is improved, but the ease of operation deteriorates because users must be moved away from the seat to adjust
Solution Approach 1:
The adjustment mechanism is designed to be operable by the user themselves while seated in the wheelchair. The clamp and adjuster ring configuration allows the user to easily manipulate the adjustment components without requiring assistance or repositioning, making the system self-serviceable and improving ease of operation.
Solution Approach 2:
The adjuster ring acts as an intermediary component between the user's manual input and the backrest positioning. It translates simple rotational or linear movements into precise angular and lateral adjustments of the backrest, mediating the interaction between the user and the complex adjustment mechanism.
3Measurement precision
If multiple adjustment degrees of freedom are provided, then the positioning precision is improved, but the device complexity increases
Solution Approach 1:
The system provides two degrees of freedom: angular adjustment through the strut's rotational capability and lateral positioning through the adjuster ring's movement along the strut. This dynamic multi-degree-of-freedom system achieves precise positioning while managing complexity through coordinated mechanical design of the interacting components.
Solution Approach 2:
The adjuster ring is nested within the clamp structure and interacts with the strut, creating a compact hierarchical arrangement. The limit slots are integrated into the clamp, and the entire adjustment mechanism is contained within the backrest support assembly, nesting multiple functional elements to reduce overall complexity.
Data Source
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AI summary
The present invention refers to a wheelchair comprising a frame (20) having spaced apart side frame tubes; a strut (30, 130, 230, 330) connected to the frame; and an adjustable backrest support (10, 10', 10", 400) engaging the strut (30, 130, 230, 330) such that the adjustable backrest support (10, 10', 10", 400) pivots angularly about the strut (30, 130, 230, 330) and being configured to be fixed in one of a plurality of angled positions and moveable along the strut (30, 130, 230, 330) and configured to be fixed in one of a plurality of lateral positions between the side frame tubes. It also refers to an adjustable wheelchair backrest assembly and an adjustable backrest support.