Razor Cartridge Blade Geometry for Longer Hair Shaving Comfort
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Solution Overview
Problem
Shaving razor cartridges designed for daily shaving have not kept up with changing consumer habits, leading to inefficiencies and discomfort when used by individuals who shave less frequently, such as longer hair trapping, miss cuts, and decreased shaving performance.
Innovation Solution
A razor cartridge design with a specific blade arrangement and geometry, including a 3:1 to 6:1 ratio of total blade spans to primary span, optimized blade angles, and reduced rinse gaps, to enhance cutting efficiency and comfort for less frequent shavers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional blade arrangement is used, then daily shaving performance is maintained, but longer hairs trap and cause discomfort for less frequent shavers
Solution Approach 1:
The patent applies local quality by creating different blade span configurations for different blade positions. The first blade has a longer primary span (1.0-1.5mm) to handle longer hairs, while subsequent blades have progressively shorter spans. This localized variation in blade geometry allows each blade to be optimized for its specific function in the shaving sequence, resolving the contradiction between adaptability to infrequent shaving and operational comfort.
2Productivity
If blade spans are increased to cut longer hairs, then cutting efficiency improves, but blade exposure decreases
Solution Approach 1:
The patent segments the total blade span into multiple discrete blade units with different individual spans. Instead of one long blade, the system uses multiple blades (first, second, third, fourth blades) with progressively shorter spans. This segmentation allows the first blade to provide extended reach for longer hairs while subsequent blades maintain appropriate exposure for their position, resolving the contradiction between cutting efficiency and blade exposure control.
3Reliability
If multiple blades are added to improve closeness, then shaving closeness improves, but device complexity increases
Solution Approach 1:
The patent applies dynamics by making the blade unit pivotable relative to the handle, allowing the cartridge to adjust its angle dynamically to follow skin contours. Additionally, the blades are arranged in a sequential, overlapping configuration where each blade engages hair at a different position and angle. This dynamic arrangement achieves multiple levels of closeness shaving while managing structural complexity through functional integration.
Data Source
AI summary
A shaving razor cartridge with a housing, a guard at a front of the housing and a cap at a rear of the housing. A first blade mounted to the housing. The first blade having a cutting edge with primary span measured from the cutting edge of the first blade to the guard. A second blade mounted to the housing. The second blade having a cutting edge. A third blade mounted to the housing. The third blade having a cutting edge. A blade plane defined by the cutting edges of the first blade, the second blade and the third blade. A ratio of the primary span to a guard height is 9.5:1 to 15:1. The guard height is measured from a top surface of the guard to the blade plane.