Temperature-Responsive Coupling for Low-Force Personal Care Attachments

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Solution Overview

Problem

Current personal care devices, such as power toothbrushes, face challenges in coupling mechanisms that allow easy removal and replacement of attachments while preventing vibration and ensuring efficient power transfer, which is compromised by loose or too-tight clearances, and require high attachment and detachment forces, particularly for elderly users.

Innovation Solution

A coupling mechanism utilizing materials that change shape with temperature changes, allowing for adaptive fitting and reduced attachment forces through heating or cooling, enabling efficient torque and vibration transfer while maintaining a secure hold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If mechanical coupling mechanisms with clearance tolerances are used to allow easy removal and replacement, then ease of operation is improved, but power transfer efficiency deteriorates due to rattling and vibrations

Engineering Contradiction:
Improveease of removal and replacementVSAvoidpower transfer efficiency
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent applies shape memory materials that change their physical parameters (shape, stiffness) in response to temperature changes. During attachment, the material is heated to become soft and adaptable, allowing easy insertion. During operation, it cools to become rigid, ensuring tight coupling and efficient power transfer without rattling or vibrations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The coupling mechanism performs preliminary heating of the shape memory material before the actual attachment operation. This preliminary thermal action prepares the material to be soft and formable, enabling easy insertion and adaptation to the coupling partner, after which cooling locks the position for secure operation.

Inventive Principle:
Principle #10Preliminary action

2Loss of energy

If tight coupling is used to prevent rattling and vibration, then power transfer efficiency is improved, but attachment and detachment forces increase

Engineering Contradiction:
Improvepower transfer efficiencyVSAvoidattachment and detachment forces
Core Design Contradiction:
Loss of energyVSForce

Solution Approach 1:

The shape memory material's mechanical properties are dynamically changed through temperature control. When heated above its transition temperature, the material becomes soft and requires minimal force for attachment. When cooled below the transition temperature, it becomes rigid and maintains tight coupling with minimal detachment force required.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The coupling mechanism transitions from a static rigid connection to a dynamic system where the material's stiffness can be adjusted on-demand through temperature changes. This allows the system to be soft during attachment/detachment operations and rigid during power transfer operations.

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

The temperature-sensitive coupling mechanism ensures secure attachment and easy detachment of components, reducing rattling and vibration, and lowering the force required for attachment and detachment, enhancing user experience and efficiency in personal care devices.

Implementation Method 1

a first coupling interface comprising a portion of shape memory material to change shape in response to a change in temperature

Methodology Applied
Scientific EffectShape memory effect: Shape Memory Alloy

Implementation Method 2

a heating element to heat the portion of shape memory material

Methodology Applied
Scientific EffectThermal heating: Heating

Data Source

PatentEP3558158B1Coupling for personal care device
Publication Date: 2021.05.05 KONINKLIJKE PHILIPS NV
  • EP3558158B1 patent drawingFigure 1
  • EP3558158B1 patent drawingFigure 2~3
  • EP3558158B1 patent drawingFigure 4

AI summary

A first component (16) for a personal care device comprises a first coupling interface for allowing the first component (16) to be releasably and repeatably coupled to a second component for the personal care device via a second coupling interface of the second component. The first coupling interface comprising a portion of material (38) that can change shape with changes in temperature to couple the first coupling interface to the second coupling interface. The portion of the material (38; 60) is configured to deform during coupling and uncoupling, and to revert towards an original shape after the first coupling interface and the second coupling interface have been coupled or uncoupled. The invention also provides a personal care device (10) comprising the first component (16; 12), and the second component (12; 16) having the second coupling interface.