Personal Care Device with Dynamic Stiffness Control

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Solution Overview

Problem

Existing hair removal devices, such as electric shavers, often fail to self-adjust effectively to different user preferences and skin contours, leading to suboptimal performance and potential skin irritation due to inadequate adjustment of working head stiffness and contact pressure.

Innovation Solution

The device incorporates an adjustment actuator controlled by an electronic control unit, which adjusts the pivoting and floating stiffness of the working head in response to real-time skin pressure and other treatment parameters detected by sensors, allowing for automatic variation of torque and force to enhance user control and comfort during hair removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the working head is made pivotable to compensate for angular displacement, then the shaver can maintain full contact with skin contour, but the device becomes more complex and harder to control

Engineering Contradiction:
Improveskin contour adaptationVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The working head is made dynamically pivotable relative to the handle through a support structure with pivot axes, allowing automatic adaptation to skin contours during operation. This dynamic adjustment mechanism enables the shaver to maintain optimal contact angle without requiring complex manual control systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The pivotable working head design allows the device to self-adjust its orientation automatically during use, compensating for angular displacement and maintaining full skin contact without requiring active user intervention or complex control systems.

Inventive Principle:
Principle #25Self-service

2Object-affected harmful factors

If the cutter elements are allowed to float or dive into the shaver head structure, then they can compensate for excessive forces, but the control precision over the working head position is reduced

Engineering Contradiction:
Improveskin irritation from excessive forceVSAvoidposition control precision
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

A biasing device is pre-configured to apply a predetermined biasing force to the working head, cushioning against excessive user pressure before it can cause skin irritation. This pre-loaded mechanical spring system provides automatic force limitation without requiring active sensing or control.

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

Solution Approach 2:

The biasing force parameter is adjusted based on detected skin contact pressure, allowing the system to dynamically modify the working head's resistance to movement. This parameter adjustment enables the device to maintain optimal contact force while preventing excessive pressure that would cause skin irritation.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If fuzzy logic control is used to automatically adjust multiple parameters, then shaving performance and skin irritation are balanced, but the adjustment precision is insufficient for different user preferences

Engineering Contradiction:
Improveautomatic parameter adjustmentVSAvoidadjustment precision
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

A sensor system provides real-time feedback on skin contact pressure and device orientation, which is processed by a control unit to automatically adjust working parameters. This closed-loop feedback mechanism enables precise adaptation to different skin types and user preferences, going beyond fixed fuzzy logic rules.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3546148B1Personal care device
Publication Date: 2022.01.12 BRAUN GMBH
  • EP3546148B1 patent drawingFigure 1
  • EP3546148B1 patent drawingFigure 2~3
  • EP3546148B1 patent drawingFigure 4~5

AI summary

The present invention relates to a personal care device, in particular skin treatment device such as electric shaver, comprising an a working head attached to a handle for moving the working head along a skin surface, said working head including at least one working tool defining a skin contact contour of the working head, wherein said at least one working tool is moveable relative to said handle under a skin contact pressure by means of a support structure to allow for pivoting of the working head's skin contact contour relative to the handle, wherein a biasing device is provided for biasing said working tool. According to an aspect, an adjustment device including an adjustment actuator is controlled by an electronic control unit to adjust pivoting and/or floating stiffness of the working head in response to at least skin contact pressure of the working head detected by at least one detector during handling the personal care device when effecting the personal care treatment.