Retractable Wheel Assembly for Appliance Stability and Mobility

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Solution Overview

Problem

Domestic appliances with permanent wheels can be unstable during operation, making them difficult to service, clean, or maneuver, while appliances without wheels are cumbersome to move.

Innovation Solution

A retractable wheel assembly that allows appliances to switch between fixed and mobile positions by using a caster wheel assembly with a rotating cam and cam follower mechanism, enabling wheels to be raised or lowered for stability or mobility as needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If an appliance is equipped with permanent wheels, then mobility is improved, but stability during operation deteriorates

Engineering Contradiction:
ImprovemobilityVSAvoidstability during operation
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The wheel assembly is designed to be dynamically adjustable between retracted and extended positions. The cam mechanism allows the wheel to be raised above the support surface for stability during operation, or lowered to contact the surface for mobility when needed. This dynamic positioning resolves the contradiction by making the mobility feature controllable rather than permanent.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If an appliance is equipped with retractable wheels, then stability during operation is improved, but ease of maneuvering deteriorates

Engineering Contradiction:
Improvestability during operationVSAvoidease of maneuvering
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The wheel is extracted from its traditional permanent contact position and integrated into a retractable mechanism. By removing the wheel from continuous engagement with the support surface and placing it on a cam-actuated carriage, the system achieves stability when retracted while maintaining maneuverability when extended, thus resolving the contradiction.

Inventive Principle:
Principle #2Taking out (Extraction)

3Stability of the object's composition

If an appliance is heavy and large, then stability is improved, but ease of moving deteriorates

Engineering Contradiction:
ImprovestabilityVSAvoidease of moving
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The heavy appliance benefits from the dynamic wheel assembly that can be positioned according to operational needs. When the wheel is retracted, the appliance maintains its stable, heavy configuration for operation. When maneuvering is required, the wheel extends to provide mobility assistance, making it easier to move the heavy appliance without compromising stability during use.

Inventive Principle:
Principle #15Dynamics

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 appliances to be stable and fixed during operation while allowing easy maneuverability by selectively engaging or disengaging wheels, facilitating servicing and movement as required.

Implementation Method 1

A compression spring 18 urges the cam follower pin 13 upward and into contact with or engagement with the cam surface 19

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

Rotation of the knob 12 causes the cam follower pin 13 to move vertically

Methodology Applied
Scientific EffectCam mechanism: Cam

Data Source

PatentEP2889156B1Improved wheel assembly
Publication Date: 2019.09.04 BREVILLE HLDG PTY LTD
  • EP2889156B1 patent drawingFigure 1
  • EP2889156B1 patent drawingFigure 2
  • EP2889156B1 patent drawingFigure 3

AI summary

A domestic appliance has an arrangement of fixed rear wheel, retractable wheel and fixed foot that enables the appliance to rest either on a stable support or to be supported on wheels. Specifically, the appliance includes a retractable caster wheel assembly, a fixed foot being located closer to a rear of the appliance than the caster wheel assembly and one or more rear wheels located closer to the rear of the appliance than the fixed foot. The rear wheels are in contact with a support surface when the caster wheel assembly is lowered and raised above it, when the caster wheel assembly is retracted.