Separable Drive-Train Coupling for Quiet, Low-Wear Personal Care Heads

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Solution Overview

Problem

Personal care devices with separable drive trains face issues with noise and wear due to decoupling of coupling elements during operation, which can lead to inefficient power transfer and component damage.

Innovation Solution

A separable coupling system with resilient elements that bias coupling elements against each other in the motion direction, ensuring gap-free engagement and reducing decoupling, utilizing force transmission surfaces that are not resilient in the motion direction, and an overload clutch to manage excessive forces, allowing for efficient power transfer and minimizing noise and wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If separable coupling elements are used in the drive train, then the head portion can be detached for cleaning or replacement, but the coupling elements may decouple during operation causing noise and wear

Engineering Contradiction:
Improvedetachability of head portionVSAvoidcontinuous engagement of coupling elements
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces a resilient element that changes the engagement parameter from rigid to elastic, allowing the coupling elements to maintain continuous contact through elastic deformation while remaining separable for cleaning and replacement

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The resilient element acts as a cushioning mechanism that anticipates and prevents decoupling during operation, absorbing shocks and maintaining engagement without causing noise or wear

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Object-affected harmful factors

If resilient elements are added to bias coupling elements against each other, then noise and wear are reduced, but device complexity increases

Engineering Contradiction:
Improvenoise and wearVSAvoidstructure of separable coupling
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The resilient element is implemented as a flexible component that can be integrated into the existing coupling structure, reducing the increase in complexity while effectively eliminating noise and wear through elastic deformation

Inventive Principle:
Principle #30Flexible shells and thin films

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 solution effectively reduces noise and wear by maintaining continuous contact between coupling elements during operation, ensuring efficient power transfer and extending the lifespan of the device components.

Implementation Method 1

a resilient element that biases the first coupling element and the second coupling element against each other

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3733118B1Personal care device with separable coupling in drive train
Publication Date: 2022.08.24 BRAUN GMBH
  • EP3733118B1 patent drawingFigure 1A~1B
  • EP3733118B1 patent drawingFigure 2~3

AI summary

The present disclosure is concerned with a personal care device having a head portion having a driven treatment head, a handle portion having a drive unit for providing a motion having a motion direction, and a drive train extending between the drive unit and the driven treatment head for transmitting the motion from the drive unit to the driven treatment head, the drive train having a separable coupling. The separable coupling has a first coupling part having a first coupling element, a second coupling part having a second coupling element, the first and the second coupling elements being separably engaged with each other, and a resilient element biasing the first coupling element and the second coupling element against each other so that the first and second coupling elements are engaged in a gap-free manner along the motion direction.