Multi-Layer Erodible Razor Strip for Wear Indication

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Solution Overview

Problem

Existing razor cartridges lack an effective indication for when they are nearing the end of their optimal shave performance, with two-color lubrication strips only providing a distinction between optimal and sub-optimal performance, failing to alert users before the cartridge reaches the end of its effective life.

Innovation Solution

A skin engaging member with multiple erodible layers of different colors and thicknesses, where each layer contains a combination of water-soluble and water-insoluble polymers, is used to indicate the cartridge's remaining lifespan through color changes as the layers wear away during shaving.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If a two-color lubrication strip is used to indicate cartridge performance status, then the user can distinguish between optimal and sub-optimal performance, but the user cannot receive advance warning before the cartridge reaches end of life

Engineering Contradiction:
Improveinformation about cartridge performance statusVSAvoidtime for user to replace cartridge
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The lubrication strip is divided into three distinct colored layers (first color, second color, third color) with different thicknesses, where each layer represents a different performance stage. This segmentation allows the indicator to provide multiple stages of warning rather than a single binary state, enabling the user to see progressive degradation and plan replacement accordingly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The third color layer is positioned below the second color layer to provide advance warning before the cartridge reaches end of life. This preliminary indication allows the user to acquire and locate a replacement cartridge before the current one becomes completely ineffective, preventing unexpected shaving failures.

Inventive Principle:
Principle #10Preliminary action

2Loss of information

If the skin engaging member uses multiple erodible layers with different colors and thicknesses, then progressive indication of cartridge lifespan is provided, but the device structure becomes more complex

Engineering Contradiction:
Improveinformation about remaining cartridge lifeVSAvoidstructure of skin engaging member
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The indicator function is merged with the lubrication function by combining the colored layers with the lubricating composition. The skin engaging member serves dual purposes: providing lubrication during shaving and simultaneously indicating cartridge performance status through color progression, eliminating the need for separate indicator mechanisms.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The skin engaging member is constructed as a composite structure with multiple erodible layers containing different colored lubricating compositions. Each layer combines pigment or dye with lubricating agents in a compatible matrix, creating a multi-functional composite material that both lubricates and indicates wear progression.

Inventive Principle:
Principle #40Composite materials

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 color change from green to yellow and then to red provides a progressive indication to the user that the razor cartridge is approaching and has reached the end of its optimal performance, allowing ample time to replace it, enhancing user experience by providing a pre-alert for maintenance.

Implementation Method 1

Upon exposure to water, the water-soluble shaving aid leaches from the skin engaging member onto the skin

Methodology Applied
Scientific EffectLeaching: Diffusion

Implementation Method 2

As the user shaves the lubrication member wears away

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentEP2365898B1Skin engaging member for razor cartridge
Publication Date: 2013.03.27 THE GILLETTE CO
  • EP2365898B1 patent drawingFigure 1~4
  • EP2365898B1 patent drawingFigure 5~7

AI summary

The present invention is directed to a skin engaging member (22) in the form of a narrow elongated strip of dimensions suitable for placement on a razor cartridge (14). The skin engaging member includes a first uppermost erodible layer (24), a second erodible layer (26) positioned below the first layer and a third erodible layer (28) positioned below the second layer. The first layer has a first color and a first thickness dimension. The second layer has a second color different from said the color and a second thickness dimension that is less than the first thickness dimension. The third layer has a third color different from the first color and the second layer and has a third thickness dimension.