Wheelchair Back Support Assembly for Independent Three-Axis Adjustment

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Solution Overview

Problem

Existing wheelchair back support devices are overly complex, making it difficult for physical therapists and seating professionals to achieve optimal support and positioning along three mutually perpendicular axes, often requiring disassembly and additional parts, which can lead to instability and aesthetic issues.

Innovation Solution

A three-axis adjustable back support assembly that allows independent longitudinal and pivotal adjustments along and about the three axes without disassembling parts, featuring a rigid and lightweight design with minimal components, ensuring secure and aesthetically pleasing support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If prior three-axis back support devices are used to provide maximum adjustment capability, then adjustment flexibility is improved, but device complexity increases significantly

Engineering Contradiction:

Improveadjustment flexibilityVSAvoidmechanical complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The back support device is divided into three independent adjustment mechanisms, each responsible for one axis (longitudinal, transverse, vertical). Each mechanism operates independently without interfering with the others, allowing complex three-axis adjustment capability while maintaining simplicity in each individual mechanism. The segmentation isolates the complexity into manageable, non-interdependent modules.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If prior back support devices with multiple moving parts are used to achieve three-axis adjustment, then adjustment capability is improved, but ease of operation deteriorates due to interdependent positioning

Engineering Contradiction:

Improveadjustment capabilityVSAvoidadjustment ease

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

Each axis adjustment is handled by a separate mechanism that operates independently. The longitudinal adjustment mechanism does not affect transverse or vertical positioning, and vice versa. This segmentation eliminates the need for therapists to understand complex interdependent relationships, making each adjustment straightforward and intuitive.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each adjustment mechanism is designed to be self-contained and self-explanatory, requiring minimal training to operate. The mechanisms automatically maintain their positions without requiring complex coordination between multiple parts, allowing therapists to make adjustments independently and efficiently.

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If prior mechanical back support devices are used to provide adjustment functionality, then positioning capability is improved, but reliability deteriorates due to susceptibility to slip and loose assembly

Engineering Contradiction:

Improvepositioning capabilityVSAvoidassembly stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces traditional mechanical fastening systems (screws, bolts, clips) with a vacuum-based holding system. The vacuum cup creates a secure attachment between the back support and the wheelchair backrest through atmospheric pressure, eliminating mechanical wear, slippage, and loosening problems. This substitution maintains full positioning capability while dramatically improving reliability and stability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If prior back support devices with numerous components are used to achieve three-axis adjustment, then adjustment versatility is improved, but ease of manufacture deteriorates due to assembly complexity

Engineering Contradiction:

Improveadjustment versatilityVSAvoidassembly simplicity

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The device is manufactured as three separate adjustment mechanisms that can be produced independently using standard manufacturing processes. Each mechanism is simpler to manufacture than a fully integrated complex mechanism, allowing for better quality control, easier assembly, and reduced manufacturing costs while maintaining full three-axis adjustment versatility.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS8517469B1Three-axis adjustable back support assembly and method

Publication Date: 2013.08.27 SUNRISE MEDICAL US LLC

AI summary

The back of a wheelchair user is independently supported along and about three mutually perpendicular axes. Two elongated adjustment arms are pivotally connected to extension arms which telescope into opposite ends of a hollow connecting tube. The support positions along and about the three axes is achieved by pivoting the arms and the connected relationships of a back shell and cushion to the connecting tube, while the adjustment arms remain pivotally connected to the wheelchair and the extension arms are telescopically retained in the connecting tube.