Polymer Composite Wheelchair Frame Vibration Damping
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Solution Overview
Problem
Conventional wheelchairs with tubular metal frames are prone to loosening and damage due to careless handling, leading to discomfort and pain from transmitted vibrations, and require frequent maintenance.
Innovation Solution
A lightweight, foldable, and customizable wheelchair with a modular polymer matrix composite material frame that allows for adjustable seating along three axes, using fewer bolts and a novel cross-bracing structure for easy assembly and disassembly, and adjustable front and rear wheels for improved comfort and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If tubular metal frames with multiple connectors and bolts are used, then the wheelchair structure is strong, but the connectors loosen and are damaged or lost due to careless manipulation and transportation, requiring frequent maintenance
Solution Approach 1:
The patent integrates the connector and tube into a single molded polymer matrix composite piece. The tubular members are formed with integrated connectors as one unit, eliminating separate bolted joints. This merging of components removes the interface where loosening and damage occur, while maintaining structural strength through the composite material's inherent properties.
Solution Approach 2:
The patent uses polymer matrix composite material to manufacture the tubular members with integrated connectors. This composite material provides both the necessary strength and rigidity while allowing for a monolithic construction that eliminates traditional bolted connections. The composite structure maintains frame strength without requiring multiple separate connectors and bolts.
2Strength
If rigid tubular frames are used, then the frame structure is strong, but vibrations are transmitted to the user causing discomfort and pain over long term use
Solution Approach 1:
The polymer matrix composite material inherently provides vibration damping properties while maintaining structural strength. The composite construction absorbs and dissipates vibrations before they reach the user, eliminating the need for separate vibration isolation mechanisms while preserving frame integrity.
3Ease of manufacture
If traditional tubular frames with multiple connectors are used, then the frame can be assembled, but frequent maintenance is required due to loosening and damage of connectors
Solution Approach 1:
By molding the tubular members with integrated connectors as single pieces, the patent eliminates the need for separate assembly of connectors and tubes. This reduces both initial assembly complexity and ongoing maintenance requirements, as there are no separate components that can loosen or become damaged.
Data Source
AI summary
A light weight foldable and customizable wheelchair (4) is described. It is comprised of a tubular frame (9) formed at least in part of molded polymer matrix composite material tubes and connectors. The wheelchair has two side frame tubular assemblies (9, 9′) interconnected in side-by-side relationship by a pair of cross-brace (8, 8′) members. The side frame tubular assemblies define a seating section (6) therebetween. A rear wheel mounting post (80) is secured to each of the side frame assemblies adjacent a rear end section thereof for securing a rear wheel (86) to each of the side frame tubular assemblies (9, 9′) at a desired selected position. A front wheel assembly (7, 7′) is secured to a lowermost front end of each of the side frame tubular assemblies. The seating section (6) is configurable along three axes. Each of the side frame tubular assemblies (9, 9′) is adjustable in depth and in height, constituting a first and second of the three axes, by cutting tubes (70′, 70″, 71, 72) of the side frame tubular assemblies to a desired length and gluing them to associated ones of the connectors (71′, 71″, 72′, 73). Each cross-brace member (8, 8′) of the pair of cross-brace members, have a cross-brace connecting tube (30) adjustable in length to provide a width adjustment which constitutes a third of the three axes of the side frame tubular assemblies. A pair of back canes (10) is secured to the two side tubular assemblies (9, 9′).