Elastomeric Guard with Debris Passages for Shaving

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Solution Overview

Problem

Safety razor cartridges with larger guard contact areas often experience accumulation of shave prep and debris, which can reduce skin stretch and lead to hydroplaning, compromising the closeness of the shave.

Innovation Solution

Incorporation of an elastomeric member with passages and channels that direct shave prep and debris away from the skin, combined with flexible fins that conform to the skin and enhance skin stretch, reducing hydroplaning and improving shave closeness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If the guard contact area is increased to enhance skin stretching and hair preparation, then skin stretch and shave prep accumulation increase, but shave prep and debris accumulate between the guard and skin, restricting frictional engagement and causing hydroplaning, which reduces closeness of shave

Engineering Contradiction:
Improveguard contact areaVSAvoidcloseness of shave
Core Design Contradiction:
Area of moving objectVSReliability

Solution Approach 1:

The guard surface is segmented into multiple discrete skin stretching elements (fins, ribs, fingers) rather than a continuous surface. This segmentation allows shave prep and debris to pass through the spaces between elements, preventing accumulation while maintaining skin stretching functionality. The segmented structure resolves the contradiction by enabling both large effective contact area for skin stretch and adequate clearance for debris removal.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The guard incorporates a porous or perforated structure with channels and openings that allow shave prep and debris to pass through. This porous design prevents the accumulation problem while maintaining sufficient skin contact area for stretching. The porous structure enables simultaneous achievement of skin stretch enhancement and debris evacuation, resolving the technical contradiction.

Inventive Principle:
Principle #31Porous materials

2Area of moving object

If the guard contact area is increased to provide greater skin stretching, then skin stretch improves, but hydroplaning increases due to accumulation of shave prep, lifting the cartridge blades away from the skin

Engineering Contradiction:
Improveguard contact areaVSAvoidhydroplaning
Core Design Contradiction:
Area of moving objectVSObject-affected harmful factors

Solution Approach 1:

The design extracts or removes the harmful accumulation of shave prep and debris from the interface between the guard and skin by providing escape pathways through channels and openings in the guard structure. This extraction of the harmful factor (accumulated shave prep) prevents hydroplaning while maintaining the beneficial large contact area for skin stretching.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The solution adds a third dimension to debris management by creating channels that extend through the thickness of the guard, allowing shave prep and debris to be evacuated in the depth direction rather than just laterally. This dimensional approach enables effective debris removal while maintaining large surface area contact for skin stretch, preventing hydroplaning.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Area of moving object

If the guard contact area is increased to enhance hair preparation, then hair preparation improves, but frictional engagement of the guard with the skin is restricted due to accumulation, lessening skin stretch

Engineering Contradiction:
Improveguard contact areaVSAvoidfrictional engagement
Core Design Contradiction:
Area of moving objectVSEase of operation

Solution Approach 1:

The guard surface is divided into multiple discrete skin stretching elements with spaces between them. This segmentation maintains large effective contact area for skin stretch and hair preparation while allowing shave prep and debris to pass through the gaps, preventing accumulation that would restrict frictional engagement. The segmented design simultaneously achieves both goals.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The guard incorporates flexible elastomeric elements that can dynamically adapt to skin contours and maintain frictional engagement. The flexible material allows the skin stretching elements to conform to the skin surface, ensuring consistent frictional engagement and skin stretch even during movement, while the open structure prevents accumulation.

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 elastomeric member effectively directs shave debris away from the skin, maintaining skin stretch and reducing hydroplaning, resulting in a closer and more efficient shaving experience.

Implementation Method 1

The guard has an elastomeric member forming at least one passage extending between an upper surface and a lower surface of the elastomeric member

Methodology Applied
Scientific EffectFluid flow direction through passages:

Implementation Method 2

The elastomeric member has a leading portion extending beyond a leading edge of the plastic housing front portion and a following portion supported by the plastic housing front portion

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2178681B1Safety razor with improved guard
Publication Date: 2021.06.16 THE GILLETTE CO
  • EP2178681B1 patent drawingFigure 1~2
  • EP2178681B1 patent drawingFigure 3
  • EP2178681B1 patent drawingFigure 4A

AI summary

A shaving blade unit has a plastic housing having a front portion and a rear portion' and two side surfaces extending from the front portion to the rear portion. A shaving blade is disposed between the front portion and the rear portion and has a blade length extending along a blade axis. A guard (22) is disposed at the front portion of the housing. The guard includes an elastomeric member (100) forming at least one passage extending between an upper surface (132) and a lower surface (134) of the elastomeric member.