Multi-blade Razor with Varying Tip Radii

Solution Overview

Problem

Multi-blade razors often result in uneven shaving performance due to blades having different exposures and contact characteristics, leading to variations in shaving closeness, comfort, and the risk of nicks and cuts.

Innovation Solution

The implementation of blades with varying tip radii and coefficients of friction, allowing for tailored exposure and interaction with the skin, with some blades positioned at different exposures to optimize shaving performance by combining sharper and duller blades strategically.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If blades are positioned at different exposures to achieve closer shave, then shaving closeness is improved, but the risk of nicks and cuts increases

Engineering Contradiction:

Improveshaving closenessVSAvoidnicks and cuts

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by assigning different tip radii to different blades based on their specific exposure levels. Blades with higher exposure (more prominent) are given larger tip radii to reduce sharpness and minimize nicks and cuts, while blades with lower exposure (less prominent) are given smaller tip radii to maximize cutting effectiveness. This localized differentiation of blade properties resolves the contradiction by tailoring each blade's sharpness to its specific functional role in the shaving system.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If blades have different tip radii to match their exposure levels, then shaving comfort is improved, but blade wear becomes uneven

Engineering Contradiction:

Improveshaving comfortVSAvoidblade wear uniformity

Core Design Contradiction:

Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The patent applies parameter changes by systematically varying the tip radius parameter across different blades according to their exposure levels and intended functions. By adjusting this critical geometric parameter for each blade position, the system optimizes both comfort (through appropriate sharpness matching) and wear characteristics (through differentiated design that accounts for varying stress patterns). This parameter differentiation allows the system to accept non-uniform wear as a trade-off for optimized performance.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If all blades have the same sharpness, then manufacturing is simplified, but shaving performance becomes uneven

Engineering Contradiction:

Improveblade manufacturing simplicityVSAvoidshaving performance uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies local quality by assigning different tip radii to different blades based on their specific exposure levels. Blades with higher exposure (more prominent) are given larger tip radii to reduce sharpness and minimize nicks and cuts, while blades with lower exposure (less prominent) are given smaller tip radii to maximize cutting effectiveness. This localized differentiation of blade properties resolves the contradiction by tailoring each blade's sharpness to its specific functional role in the shaving system.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS7448135B2Multi-blade razors

Publication Date: 2008.11.11 THE GILLETTE CO

AI summary

Multi-blade razors are provided, having blades with differing properties. In one aspect, a razor is provided that includes a safety razor blade unit comprising a guard, a cap, and first, second and third blades with parallel sharpened edges located between the guard and cap with the first blade closest to the cap, the third blade furthest from the cap, and the second blade disposed between the first and third blades, the blades having first, second and third tip radii, respectively, at least two of the three blades having different tip radii, and at least two of the blades having different coefficients of friction.