Razor Cartridge Blade Support Offset Geometry

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Solution Overview

Problem

Conventional razor cartridges with closely spaced blade assemblies can lead to nicks, cuts, and irritation due to excessive blade pressure, and also suffer from reduced rinsability due to small inter-blade span.

Innovation Solution

The razor cartridge design features blade supports with cutting edges offset relative to a support plane, allowing for negative and positive cutting edge exposures, and a larger inter-blade span for improved rinsability and reduced irritation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If blade assemblies are brought closer to each other, then nicks and cuts are avoided and glideness is enhanced, but rinsability deteriorates due to reduced water flow space

Engineering Contradiction:
Improvenicks and cutsVSAvoidrinsability
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The blade assembly is designed with movable components that allow dynamic adjustment of blade exposure and spacing. The cartridge includes a support plane tangent to front ends of blade supports, with cutting edges offset relative to this plane, enabling the blade assembly to adapt its configuration during shaving to maintain both skin contact quality and water flow channels

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent specifies precise parameter ranges: cutting edge exposure between -80μm to +80μm relative to support plane, inter-blade distance between 1.6mm to 2.2mm, and distance from cutting edge to front end between 0.3 to 0.7mm. These controlled parameter changes optimize both the reduction of nicks/cuts and maintenance of rinsability

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If cutting edge exposure is increased for closer shaving, then shaving precision is improved, but skin irritation increases

Engineering Contradiction:
Improveshaving precisionVSAvoidskin irritation
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The blade assembly incorporates movable elements that allow the cutting edge exposure to vary dynamically during shaving. The offset of cutting edges relative to the support plane (between -80μm to +80μm) creates a controlled range of motion that adapts to different skin conditions, providing precision when needed while reducing irritation on sensitive skin

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent defines specific exposure ranges (-80μm to +80μm) that allow optimization between shaving precision and skin comfort. This parameter control enables the system to achieve close shaves without excessive blade pressure that causes irritation

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If inter-blade span is reduced to prevent nicks, then skin safety is improved, but water and debris flow capability deteriorates

Engineering Contradiction:
Improvenicks and cutsVSAvoidrinsability
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The cartridge design enables dynamic adjustment of blade spacing and exposure through movable components. The support plane geometry and offset cutting edges create a configuration that maintains safe inter-blade distances (1.6mm to 2.2mm) while preserving adequate water flow channels for rinsability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent specifies optimized parameter ranges including inter-blade distance (1.6mm to 2.2mm) and distance from cutting edge to front end (0.3 to 0.7mm). These controlled parameter changes ensure both skin safety through adequate spacing and maintained rinsability through preserved water flow paths

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4257307B1Razor cartridge
Publication Date: 2025.05.07 BIC VIOLEX SINGLE MEMBER SA
  • EP4257307B1 patent drawingFigure 1~2
  • EP4257307B1 patent drawingFigure 3A~3C
  • EP4257307B1 patent drawingFigure 4A~4B

AI summary

The invention relates to a razor cartridge comprising a first blade support (120) and a second blade support (120), each of the first and second blade supports (120) include a flat portion (120b) having a lower surface (120b") and a front end (120c). A support plane S is tangent to the respective front ends (120c) of the first and second blade supports (120) and the lower surface (120b") faces away from the support plane S. A first blade (140) is attached to the lower surface (120b") of the flat portion (120b) of the first blade support (120). The first blade (140) includes a first cutting edge (140c). A second blade (140) is attached to the lower surface (120b") of the flat portion (120b) of the second blade support (120). The second blade (140) includes a second cutting edge (140c). The first and second cutting edges (140c) are offset with respect to the support plane S.