Shaving Razor Blade Wear Sensing via Electrical Resistance

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Solution Overview

Problem

Users of shaving razors face challenges in objectively determining the wear of shaving cartridges and blades, leading to either premature replacement or poor shaving experiences due to subjective assessment.

Innovation Solution

A system and method using electrical resistance and conductance measurements, combined with notification units like light, aural, and haptic indicators, to objectively assess the wear of shaving cartridges and blades, ensuring timely replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If users replace the cartridge and/or blade too soon based on subjective feeling, then shaving effectiveness is maintained, but cost-effectiveness deteriorates due to premature replacement

Engineering Contradiction:
Improveshaving effectivenessVSAvoidcost-effectiveness
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent replaces the subjective mechanical assessment system with an electrical sensing system. Electrical sensors measure resistance or conductance changes in the blade or cartridge to objectively determine wear levels, eliminating the need for users to subjectively assess blade condition while maintaining optimal shaving performance and preventing premature replacement.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements a feedback mechanism where sensors continuously monitor blade wear through electrical property measurements and provide real-time information to the user via indicators (visual, audible, or haptic). This feedback loop enables users to replace blades at the precise moment when wear reaches critical levels, optimizing both shaving effectiveness and cost-efficiency.

Inventive Principle:
Principle #23Feedback

2Loss of substance

If users wait too long to replace the cartridge and/or blade, then cost-effectiveness is improved, but shaving quality deteriorates resulting in poor shaving experiences

Engineering Contradiction:
Improvecost-effectivenessVSAvoidshaving quality
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The patent replaces subjective mechanical assessment with objective electrical sensing to precisely determine when blade wear reaches levels that affect shaving quality. This allows users to extend blade usage to the maximum point of effectiveness without experiencing poor shaving results, thereby improving cost-effectiveness while maintaining shaving quality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The feedback system continuously monitors blade condition and alerts users at the precise moment when wear compromises shaving quality. This prevents both premature and delayed replacement, ensuring blades are changed at the optimal time to maintain shaving quality while maximizing cost-effectiveness.

Inventive Principle:
Principle #23Feedback

3Device complexity

If no wear sensing system is implemented, then device complexity is reduced, but the ability to objectively determine blade wear deteriorates

Engineering Contradiction:
Improvesystem simplicityVSAvoidblade wear determination accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces an electrical sensing system that measures resistance or conductance to objectively determine blade wear with high precision. This electrical approach is more precise than any mechanical wear indicator could achieve, as it directly measures changes in the blade's physical properties caused by wear, providing accurate quantitative data.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes changes in electrical parameters (resistance or conductance) as the blade wears. By monitoring these parameter changes, the system achieves precise measurement of wear levels without requiring complex mechanical measurement systems, thus balancing measurement precision with acceptable device complexity.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If electrical sensing components are integrated into the cartridge and/or handle, then blade wear measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveblade wear measurement accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical wear measurement mechanisms with simpler electrical sensing components. Electrical resistance or conductance sensors are inherently simpler in structure than mechanical wear indicators, achieving high measurement precision through electrical property changes rather than mechanical measurement, thus improving the precision-to-complexity ratio.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This solution allows for precise determination of blade wear, eliminating guesswork and ensuring optimal shaving performance by providing objective notifications for replacement, thereby enhancing user experience and safety.

Implementation Method 1

measuring electrical resistance and/or electrical conductance of the cartridge and/or the blade using a sensing system

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP3645225B1System and method for electrically sensing shaving razor blade wear
Publication Date: 2021.08.04 BIC VIOLEX SINGLE MEMBER SA
  • EP3645225B1 patent drawingFigure 1
  • EP3645225B1 patent drawingFigure 2~3
  • EP3645225B1 patent drawingFigure 4a~4b

AI summary

In a system and a method for determining a level of wear of at least one blade (117) of a razor cartridge (100), a sensing unit measures an electrical parameter including one of (i) a total resistance of the at least one blade (117) measured across a length of the at least one blade, and (ii) an electrical conductance of the at least one blade measured across the length of the at least one blade (117). A processing unit compares the measured electrical parameter to a reference electrical parameter and determines a level of wear of the at least one blade (117) based on an amount of deviation of the measured electrical parameter from the reference electrical parameter. Information regarding the determined level of wear of the at least one blade (117) is provided to a user by at least one of (i) a light indication, (ii) an aural indication, and (iii) a haptic indication.