Concave-Bevel Cutting Blade for Low-Force Durable Shaving
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Solution Overview
Problem
Conventional razor blades face challenges in achieving a balance between sharpness for low cutting force and durability, often resulting in fragility and increased wear, despite hard coatings, due to high friction and limited mechanical strength.
Innovation Solution
A cutting blade design featuring a blade body with a first and second material, where the second face includes a convex or straight primary bevel and a concave secondary bevel, with specific wedge angles and lengths, stabilizing the cutting edge while reducing contact area and friction, thereby enhancing durability and comfort during use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the cutting edge is made sharper to reduce cutting force, then the sharpness and cutting performance is improved, but the mechanical strength and durability of the cutting edge deteriorates
Solution Approach 1:
The cutting blade is divided into multiple functional zones with different wedge angles. The first zone has a smaller wedge angle for sharp cutting with low force, while the second zone has a larger wedge angle for mechanical strength and stability. This segmentation allows each zone to optimize for its specific function without compromising the other.
Solution Approach 2:
Different regions of the cutting blade are given different geometric properties. The cutting edge region has a smaller wedge angle for sharpness, while the rear region has a larger wedge angle for strength. This local differentiation of geometric quality enables simultaneous optimization of cutting performance and durability.
2Duration of action of stationary object
If hard coating materials are applied to improve mechanical strength and reduce wear, then the durability is improved, but the friction and cutting force increase
Solution Approach 1:
The invention changes the geometric parameter (wedge angle) of the cutting blade to optimize performance. By using a smaller wedge angle in the first zone, the blade achieves lower cutting force and reduced friction, eliminating the need for hard coatings that would increase friction. The parameter change addresses both durability and cutting force simultaneously.
3Ease of manufacture
If a symmetric wedge-shaped cutting edge is used, then the manufacturing process is simplified, but the cutting performance and comfort deteriorate due to high friction
Solution Approach 1:
The symmetric wedge shape is segmented into two zones with different wedge angles. This segmentation creates an asymmetric overall shape that optimizes cutting performance by reducing friction and cutting force, while still being manufacturable through conventional processes applied in sequence to different zones.
Solution Approach 2:
The cutting blade transitions from a symmetric wedge shape to an asymmetric shape with two different wedge angles. The first zone has a smaller angle for low-friction cutting, while the second zone has a larger angle for stability. This asymmetric design reduces cutting force and improves comfort while maintaining manufacturability.
Data Source
AI summary
The present invention relates to a cutting blade having a blade body with a first material joined to a second material, a first face, a second face opposed to the first face, and a cutting edge, where the first face includes a first surface, and the second face includes a primary bevel having a convex or straight cross-sectional shape and a secondary bevel having a concave cross-sectional shape with a line connecting the two bevels, the primary bevel extending from the cutting edge to the line, where cutting edge and primary bevel are shaped in the second material. A first wedge angle θ1 between the first surface and the primary bevel or the tangent of the primary bevel through the cutting edge is greater than a second wedge angle θ2 between the first surface and the tangent of the secondary bevel. A hair removal device includes this cutting blade.