Segmented Lower Cutter Edge for Electric Razor
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Solution Overview
Problem
Existing dry shaver designs face challenges in achieving good cutting behavior with low cutting forces while maintaining cutting edge stability and service life, as acute cutting angles can lead to skin irritation and reduced stability.
Innovation Solution
The undercutter features a cutting edge with multiple sections having different angles, where a blunter leading section provides stability and a sharper trailing section reduces cutting forces, allowing for optimal compromise between cutting behavior and edge stability, with the leading section cutting the beard hair before the trailing section completes the cut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the cutting edge angle is reduced to improve cutting behavior and reduce cutting forces, then pulling behavior improves and energy consumption decreases, but cutting edge stability and service life deteriorate
Solution Approach 1:
The cutting edge is divided into multiple sections with different cutting angles. The first section has a larger cutting angle (e.g., 80-90 degrees) for stability, while the second section has a smaller cutting angle (e.g., 35-60 degrees) for reduced cutting forces. This segmentation allows each section to perform its specific function optimally.
Solution Approach 2:
Different sections of the cutting edge are given different local properties (cutting angles) according to their specific functional requirements. The leading section has a blunter angle for stability, while the trailing section has a sharper angle for efficient cutting with lower forces.
2Ease of operation
If the cutting edge angle is reduced to improve pulling behavior, then cutting forces decrease, but skin irritation risk increases
Solution Approach 1:
The cutting edge is segmented into multiple sections with progressively smaller cutting angles. The first section with the larger angle provides initial cutting stability, while subsequent sections with smaller angles complete the cut with minimal force, reducing skin irritation risk.
Solution Approach 2:
The first cutting edge section performs a preliminary cutting action with a larger angle to stabilize the cut, preparing the hair for the subsequent sharper sections that complete the cut with minimal force and reduced skin contact.
3Reliability
If the cutting edge angle is increased to improve cutting edge stability, then service life increases, but cutting forces increase and pulling behavior deteriorates
Solution Approach 1:
The cutting edge is divided into sections where the first section has a larger cutting angle for stability and the second section has a smaller cutting angle for efficient cutting. This allows the system to benefit from both high stability and high cutting efficiency simultaneously.
Solution Approach 2:
The cutting angle parameter is changed along the cutting edge length, transitioning from a larger angle at the leading section to a smaller angle at the trailing section. This parameter variation optimizes both stability and cutting efficiency.
Data Source
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AI summary
The present invention relates to a lower cutter (4) for a shaving head, equipped with an upper cutter (7), of an electric razor, comprising at least one blade (10) which has a cutting edge (11) pointing in a direction of movement. The invention also relates to a shaving head having such a lower cutter and to an electric razor equipped with it. It is proposed to no longer give the cutting edge the conventional wedge-shaped configuration in which simply two planes inclined at an acute angle define the cutting edge contour. According to the invention, the cutting edge has, one behind the other in the direction of movement (16), at least two cutting edge sections (18,19) having different cutting angles. By means of a cutting angle graduation or a changing cutting angle, an optimum compromise can be achieved between the conflicting requirements of cutting behaviour and edge stability. The cutting edge section having the more obtuse or less acute cutting angle produces the desired cutting edge stability and at the same time provides for a long service life. On the other hand, the cutting edge sections having the more acute angle reduce the cutting forces, such that an improved threading behaviour can be achieved.