Electric Razor Cutting Unit Skin Protector Mechanism

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Solution Overview

Problem

Existing electric razors with acute-angle inner blade units often cause skin irritation due to skin penetration during shaving, as they require higher pressure and are less effective in maintaining a close shave across varying user skin properties and pressure applications.

Innovation Solution

A cutting unit with an outer blade unit and an inner blade unit that oscillate relative to each other, featuring a protector element with a rounded outer contour positioned in front of the inner blade unit's edge to prevent skin bits from being cut by the acute-angle cutting edge, ensuring skin protection and optimal hair cutting without hindering the shaving process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the inner blade unit is sharpened at an acute angle to reduce cutting forces, then hair cutting efficiency is improved, but skin irritation increases due to skin penetration

Engineering Contradiction:
Improvehair cutting efficiencyVSAvoidskin irritation
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a protector element as an intermediary component positioned between the acute-angle inner blade unit and the skin. This protector element has a rounded outer contour that contacts the skin first, preventing direct contact between the sharp cutting edge and the skin, thereby eliminating skin irritation while preserving the acute-angle blade's superior hair cutting efficiency

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The cutting unit is segmented into distinct functional components: the acute-angle inner blade unit for hair cutting and a separate protector element for skin protection. This segmentation allows each component to optimize its specific function without compromising the other - the blade maintains its sharp acute angle for efficient cutting while the protector provides a rounded barrier for skin safety

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If the inner blade unit is sharpened at a 90° angle to improve skin protection, then skin irritation is reduced, but cutting forces increase and close shave quality deteriorates

Engineering Contradiction:
Improveskin protectionVSAvoidcutting forces
Core Design Contradiction:
Object-affected harmful factorsVSForce

Solution Approach 1:

The protector element serves as a mediator that decouples the relationship between blade angle and skin protection. Users no longer need to choose between 90° blades for skin protection or acute-angle blades for cutting efficiency - the protector element provides skin protection regardless of blade angle, allowing the acute-angle blade to optimize cutting forces without compromising skin safety

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If user pressure is increased to improve close shave quality with acute-angle blades, then hair cutting efficiency is improved, but skin penetration and irritation increase

Engineering Contradiction:
Improveclose shave qualityVSAvoidskin penetration
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The protector element acts as a pressure-distributing intermediary that prevents skin penetration even when users apply high pressure for close shaves. The rounded contour of the protector element distributes the applied pressure away from the sharp cutting edge, allowing users to maintain high pressure for optimal hair cutting while the protector prevents skin contact and penetration

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2448727B1Cutting unit for an electric razor with skin protectors
Publication Date: 2016.10.19 BRAUN GMBH
  • EP2448727B1 patent drawingFigure 1~3
  • EP2448727B1 patent drawingFigure 4~5
  • EP2448727B1 patent drawingFigure 6~8

AI summary

The invention relates to a cutting unit for an electric razor and to a cutting head and an electric razor equipped therewith, the cutting unit having at least one outer blade unit (12) and one inner blade unit (10) that are borne driven by a motor to oscillate relative to one another. The inner blade unit (10) has a cutting edge angle that is a maximum of 90° and a corresponding bevel (22) adjacent to the edge (24). Furthermore, at least one protector element (10) having an outer contour that is rounded at least in areas and that faces the outer blade unit (12) is in front of the edge (24) for the inner blade unit and can be moved sliding along the bevel (22) into a position that is set back relative to the edge (24).