Eccentric Angle Adjustment Assembly for Wheelchair Stability

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Solution Overview

Problem

Existing angle adjustment assemblies for wheelchairs fail to accurately and readily adjust angles, particularly affecting the camber angle of rear wheels and caster stems, which compromises stability and steering precision.

Innovation Solution

An angle adjustment assembly comprising a first member that pivots about a first axis and at least a second member that rotates about a second axis transverse to the first axis, with an eccentric configuration between the members allowing for pivotal movement, enabling precise adjustment of caster stems and axle receivers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the camber angle of rear wheels is adjusted to lower the profile and provide a wider footprint, then stability and control are improved, but the footprint becomes too wide for narrow environments

Engineering Contradiction:

ImprovestabilityVSAvoidadaptability to narrow environments

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic adjustability of the camber angle through an angle adjustment assembly that allows the camber angle to be changed from a first position to a second position. This enables the wheelchair to adapt its footprint width according to environmental requirements, providing both stability in open areas and maneuverability in narrow spaces.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If the camber angle is adjusted to narrow the footprint for narrow pathways, then maneuverability is improved, but strain on wheel bearings increases

Engineering Contradiction:

ImprovemaneuverabilityVSAvoidstrain on wheel bearings

Core Design Contradiction:

Ease of operationVSForce

Solution Approach 1:

The angle adjustment assembly enables dynamic adjustment of the camber angle to optimize the balance between maneuverability and bearing strain. The system allows selection between different camber angles depending on whether the priority is narrow pathway navigation or reduced bearing strain.

Inventive Principle:

Principle #15Dynamics

3Shape

If the caster stem tilts when the frame is tilted during camber adjustment, then the frame angle changes, but the caster stem fails to maintain vertical orientation causing steering issues

Engineering Contradiction:

Improveframe angleVSAvoidsteering reliability

Core Design Contradiction:

ShapeVSReliability

Solution Approach 1:

The patent separates the adjustment of frame angle from caster stem orientation by introducing an independent caster angle adjustment mechanism. This allows the frame camber angle and caster stem angle to be adjusted independently, ensuring the caster stem maintains vertical orientation for reliable steering while the frame achieves the desired camber angle.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system independently adjusts two parameters: the camber angle of the rear wheels and the caster angle of the front casters. By changing these parameters separately through independent adjustment assemblies, the patent ensures that steering reliability is maintained while achieving the desired frame orientation.

Inventive Principle:

Principle #35Parameter changes

4Ease of operation

If existing angle adjustment assemblies are used, then basic adjustment is possible, but accurate and ready adjustment of angles is not achieved

Engineering Contradiction:

Improveadjustment easeVSAvoidangle adjustment precision

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces conventional mechanical adjustment mechanisms with a cam-based adjustment system. The cam mechanism provides precise angular positioning through its profile design, enabling accurate and ready adjustment of both camber and caster angles without relying on traditional mechanical linkages that lack precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables accurate and efficient adjustment of wheelchair components, maintaining proper steering and stability by allowing for precise control of camber angles and caster orientations, suitable for various environments and uses.

Implementation Method 1

The first member is eccentrically supported in relation to the second member so that rotation of the second member produces pivotal movement of the first member

Methodology Applied

Scientific EffectEccentric mechanism: Eccentric

Data Source

PatentUS10085903B1Angle adjustment assembly

Publication Date: 2018.10.02 KI MOBILITY LLC

AI summary

An angle adjustment assembly comprises a first member configured to pivot about a first axis. A second member is configured to rotate about a second axis transverse to the first axis. The first member is eccentrically supported in relation to the second member so that rotation of the second member produces pivotal movement of the first member. A third member may be configured to rotate about a third axis transverse to the first axis. The second member may be eccentrically supported in relation to the third member so that rotation of the third member further produces pivotal movement of the first member. The second member may comprise an inner cam member. The third member may comprise an outer cam member. The first member may be a caster stem for supporting a wheelchair caster assembly, or alternatively, an axle receiver for supporting an axle of a wheelchair drive wheel.