Shaving Razor Blade Retention via Obtuse Angles

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Solution Overview

Problem

Wet shaving razors with unitary blade members or welded blade assemblies often experience blade movement during shaving strokes, leading to inefficiency and increased nicks and cuts due to inadequate retention within the housing.

Innovation Solution

A shaving razor cartridge design featuring a housing with blade retention members forming obtuse included angles and specific contact lengths to securely position and support blade members, minimizing movement during shaving.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If unitary blade members or welded blade assemblies are used, then the blade structure is simplified and manufacturing is easier, but the blade moves during shaving strokes leading to inefficiency and nicks

Engineering Contradiction:
Improveblade assembly manufacturingVSAvoidblade stability during shaving
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The blade retention system is segmented into multiple retention members distributed across the housing, each independently securing the blade at different locations. This segmentation allows the blade to be firmly held without requiring a complex monolithic retention structure, resolving the contradiction between manufacturing simplicity and blade stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The blade retention members are nested within the housing structure, with each retention member positioned to contact the blade at specific zones. This nested arrangement allows compact integration of multiple retention functions within the housing, maintaining manufacturing simplicity while ensuring blade stability through multi-point contact.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Stability of the object's composition

If the blade retention members are positioned closer together, then blade support is improved, but the housing structure becomes more complex

Engineering Contradiction:
Improveblade positioning stabilityVSAvoidhousing structure complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

Each blade retention member is designed to perform multiple functions: securing the blade laterally, preventing rotation, and providing support during shaving strokes. This multi-functionality allows the use of fewer retention members with greater spacing, reducing housing complexity while maintaining blade stability through efficient use of each retention element.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If the blade retention members have increased contact length with the blade, then blade security is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveblade retention securityVSAvoidcontact length precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The blade retention members provide concentrated local contact at specific zones along the blade rather than distributed contact across the entire blade surface. This local quality approach ensures secure retention at critical points while allowing greater tolerance in non-critical areas, reducing overall manufacturing precision requirements while maintaining blade security.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3774212B1Shaving razor cartridge
Publication Date: 2023.12.13 THE GILLETTE CO
  • EP3774212B1 patent drawingFigure 1
  • EP3774212B1 patent drawingFigure 2
  • EP3774212B1 patent drawingFigure 3

AI summary

A shaving razor cartridge with a housing having a blade platform. A first blade retention member is positioned on the blade platform and has a front wall formed by a first wall and a second wall that define an obtuse included angle. A second blade retention member is positioned on the blade platform and has a rear wall facing the front wall of the first blade retention member. The rear wall has a first wall and a second wall that define an obtuse included angle. A blade member is positioned between the front wall and the rear wall. The second walls have a contact length of about 0.2mm to about 1.0mm.