Safety Razor Blade Unit With Displacement Limiting Protrusions

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Solution Overview

Problem

Safety razors with flexible blades face damage due to excessive flexing during shaving, leading to reduced shaving efficacy and blade deformation.

Innovation Solution

A blade unit design with a blade housing, a blade carrier, and protrusions that limit the downward displacement of blades, allowing flexibility to adjust to skin contours while preventing excessive deformation, featuring a rack and flexible legs with connecting members and protrusions to control displacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If flexible blades are used to adjust to skin contours, then adaptability is improved, but blade strength deteriorates due to excessive flexing and deformation

Engineering Contradiction:
Improveadaptability to skin contoursVSAvoidblade strength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The blade carrier is designed with flexible legs that allow controlled dynamic movement and downward displacement during shaving, enabling the blades to adapt to skin contours while maintaining structural integrity through elastic deformation within safe limits

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces protrusions that limit the downward displacement parameter to a specific range (0.25mm to 0.75mm), changing the physical state of blade flexing from uncontrolled excessive deformation to controlled elastic deformation within optimal parameters

Inventive Principle:
Principle #35Parameter changes

2Strength

If downward displacement is limited by protrusions, then blade strength is improved, but adaptability deteriorates due to restricted flexibility

Engineering Contradiction:
Improveblade strengthVSAvoidadaptability to skin contours
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent optimizes the displacement parameter by introducing protrusions that limit downward movement to 0.25mm-0.75mm, changing the physical state from uncontrolled excessive flexing to controlled elastic deformation within optimal parameters that maintain both strength and adaptability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The flexible legs with connecting members create a dynamic system that allows controlled movement within the limited displacement range, enabling the blades to adapt to skin contours through elastic deformation while the protrusions prevent excessive movement that would cause damage

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 solution prevents or reduces blade damage by limiting downward displacement, maintaining optimal flexibility and shaving performance, and incorporates a galvanic cathodic protection system to enhance blade longevity.

Implementation Method 1

the flexible legs that allow the downward displacement of the plurality of blades and the rack

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

an amount of downward displacement of the plurality of blades and the blade carrier is limited by one or more protrusions extending upwards from the base of the blade housing

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP3347176B1Safety razor and blade unit for safety razor
Publication Date: 2019.11.27 BEIERSDORF AG
  • EP3347176B1 patent drawingFigure 1
  • EP3347176B1 patent drawingFigure 2
  • EP3347176B1 patent drawingFigure 3~4

AI summary

The present disclosure describes a blade unit (10) for a safety razor (8). The blade unit comprises a blade housing (12), a plurality of blades (18) disposed within the blade housing (12) to expose respective cutting edges (20) suitable for shaving, and a blade carrier supporting the plurality of blades (18). The blade housing (12) has a base on which the blade carrier is supported. The plurality of blades (18) and the blade carrier being dispiaceabie downwards towards the base of the blade housing (12) during shaving, wherein an amount of downward displacement of the plurality of blades (18) and the blade carrier is limited by one or more protrusions extending upwards from the base of the blade housing (12).