Telescoping Hoist Arm Adjustment for Wheelchair Lift Reach

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Solution Overview

Problem

Existing hoist mechanisms for motorized wheelchairs and scooters face challenges in versatility across varying vehicle types and packaging constraints, with limitations in reach and stowage of the spreader bar, particularly in vehicles with large lips or ledges, and require complex adjustments.

Innovation Solution

A stepless adjustment system using a telescoping arrangement with interlocking engagement features and clamping means, allowing for adjustable and reliable operation, combined with a hoist mechanism featuring a pivotable lifting arm and a spreader bar with a secure hook formation for easy attachment and detachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a telescoping arrangement with interlocking engagement features is used, then adjustability and versatility are improved, but device complexity increases

Engineering Contradiction:

ImproveadjustabilityVSAvoidcomplexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The lifting arm is divided into multiple telescoping sections (first section, second section, third section) that can be independently adjusted. Each section has engagement features that allow selective locking at different positions, enabling stepless adjustment of the arm length to adapt to various vehicle types and load requirements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The telescoping sections are nested within each other, with the second section received within the first section and the third section received within the second section. This nested arrangement allows compact stowage when not in use and enables variable length adjustment by extending sections as needed, providing versatility without excessive complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Strength

If clamping means with bolts are used to force body portions together, then connection strength is improved, but ease of operation deteriorates

Engineering Contradiction:

Improveconnection strengthVSAvoidease of adjustment

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The clamping mechanism uses movable clamping blocks that can be positioned along the lifting arm sections. The blocks are forced together using bolts to create strong connections, but the entire assembly can be quickly released and repositioned by loosening the bolts, allowing rapid adjustment between different configuration strengths.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The engagement features including projections and recesses are pre-formed on the lifting arm sections. When the clamping blocks are forced together using bolts, these pre-formed features automatically align and interlock, ensuring proper engagement without requiring precise manual alignment, thus maintaining ease of operation while achieving strong connections.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If a gap is provided between engagement features, then ease of rotation is improved, but manufacturing precision deteriorates

Engineering Contradiction:

Improveease of rotationVSAvoidprecision

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The gap between engagement features is designed with specific dimensions that allow sufficient clearance for rotation during adjustment operations. The gap size is optimized to provide ease of rotation while maintaining adequate manufacturing tolerances, balancing operational ease with manufacturing precision requirements.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The engagement features include projections and recesses that act as intermediaries between the clamping blocks and the lifting arm sections. These features facilitate controlled rotation and positioning while the gap provides necessary clearance, mediating between the need for ease of rotation and manufacturing precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If multiple engagement points are used, then reliability is improved, but device complexity increases

Engineering Contradiction:

ImprovereliabilityVSAvoidcomplexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Multiple engagement features (projections and recesses) are integrated into the telescoping sections of the lifting arm. These features work together to provide redundant engagement points that enhance reliability, while being combined within the same structural components rather than adding separate mechanisms.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11078055B2Hoist mechanism and a stepless adjustment system

Publication Date: 2021.08.03 AUTOCHAIR

AI summary

The invention relates to a hoist mechanism (20) intended primarily, but not exclusively, for moving a motor driven wheelchair or scooter into and/or out of the load carrying space of a vehicle. The hoist mechanism (20) comprises a lifting arm having, at least in part, a generally U-shaped cross section, and an actuator (28). A mounting point (56) for the actuator (28) is provided within the generally U-shaped cross section. The invention also relates to a stepless adjustment system suitable for use in such a hoist mechanism (20). The adjustment system comprises an inner section (34) received within an outer section (24) in a telescoping arrangement. The outer section (24) comprises first and second body portions (44A, 44B) provided with features for engaging corresponding features (48A, 48B) provided on the inner section (34).