Folding Wheelchair Cross-Strut Width Adjustment

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Solution Overview

Problem

Foldable wheelchairs are often manufactured in fixed sizes, leading to logistical challenges and inefficiencies, and remain bulky even when folded due to the fixed width of the cross-strut, which limits seat width adjustment and storage convenience.

Innovation Solution

A folding wheelchair design featuring a cross-strut with pivotable bars that can be adjusted along the frame, allowing for flexible seat width adjustment by modifying the distance between the frame's side portions, enabling the same mechanism to accommodate various seat widths without the need for multiple sizes, and a foldable backrest to reduce the chair's height in the folded position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the cross-strut is designed with fixed dimensions, then the manufacturing and assembly are simplified, but the seat width cannot be adjusted and multiple sizes must be manufactured

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidseat width adjustment

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The cross-strut is designed with movable coupling connections that can be positioned at different locations along the side portions of the frame. This dynamic positioning capability allows the same cross-strut to accommodate various seat widths without requiring multiple fixed-size components, thus maintaining manufacturing simplicity while enabling adaptability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

A single cross-strut design serves multiple functions by accommodating different seat widths through adjustable coupling connections. This universal design eliminates the need for multiple differently dimensioned cross-struts, reducing manufacturing complexity and inventory requirements while providing versatility in seat width configuration.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Strength

If the cross-strut maintains fixed width, then the structural integrity is ensured, but the folded size remains bulky and storage efficiency is reduced

Engineering Contradiction:

Improvestructural integrityVSAvoidfolded size

Core Design Contradiction:

StrengthVSVolume of moving object

Solution Approach 1:

The coupling connections are designed to be movable along the side portions of the frame, allowing the cross-strut to be adjusted to a compact configuration when folded. This dynamic adjustment capability reduces the folded volume of the wheelchair while maintaining structural integrity through proper mechanical design of the coupling mechanism.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If multiple differently dimensioned cross-struts are provided for different seat widths, then the seat width requirements are met, but the logistical effort and costs increase

Engineering Contradiction:

Improveseat width varietyVSAvoidlogistical efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

A single universal cross-strut design with adjustable coupling connections replaces the need for multiple differently dimensioned cross-struts. This universal component can be used across different wheelchair configurations, significantly reducing inventory requirements, simplifying logistics, and lowering costs while maintaining the ability to meet various seat width requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Reliability

If the cross-strut is designed for robust folding mechanism, then the folding reliability is improved, but the folded configuration remains relatively large

Engineering Contradiction:

Improvefolding reliabilityVSAvoidfolded volume

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11246773B2Folding wheelchair

Publication Date: 2022.02.15 KUSCHALL RAINER

AI summary

A folding wheelchair is disclosed having a frame with two side portions, a seat and a folding mechanism. The folding mechanism has coupling connections, pivoting connections and a cross-strut with two bars crossing at a pivot point. First ends of each of the cross-strut bars are mounted rotatably on the side portions of the frame via the pivoting connections. Second ends of each of the cross-strut bars are releasably mounted on the other of the two side portions of the frame via the coupling connections. A distance between the frame side portions may be modified if the cross-strut bars second ends are released from the frame side portions. The cross-strut bars are pivoted relative to each other about the pivot point. The cross-strut extends from the first ends to the second ends of the bars in a cross-strut direction which, in the operating position, extends substantially along the seat.