Razor Cartridge Guard Structure for Low-Friction Skin Gliding
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Solution Overview
Problem
Existing razor cartridges experience excessive friction between the guard and skin, leading to discomfort during shaving due to high friction materials like rubber or silicone, which deteriorate gliding performance.
Innovation Solution
A razor cartridge design featuring a guard portion with a first flexible guard and a rigid guard, where the rigid guard has a three-dimensional surface roughness of 20 µm to 200 µm, reducing friction and enhancing gliding by removing foreign substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a guard made of high friction material (rubber, silicone) is used to improve close contact with skin, then skin contact quality is improved, but gliding performance deteriorates and user comfort decreases
Solution Approach 1:
The guard is divided into multiple segments with different materials and surface properties. The front surface has a first material with specific friction characteristics, while the rear surface has a second material with different properties. This segmentation allows each surface to perform its specific function - the front surface provides controlled friction for skin contact while the rear surface maintains gliding performance
Solution Approach 2:
Different portions of the guard have different material compositions and surface roughness values. The front surface portion has a first surface roughness value optimized for skin contact, while the rear surface portion has a second surface roughness value optimized for gliding. This local quality differentiation resolves the contradiction by providing high friction only where needed for skin contact while maintaining low friction for gliding surfaces
2Ease of operation
If a rigid guard with smooth surface is used to improve gliding performance, then gliding performance is improved, but foreign substances on skin are not effectively removed
Solution Approach 1:
The guard surface is differentiated into regions with different roughness characteristics. The rear surface has a smoother finish optimized for gliding performance, while the front surface has a controlled roughness that enables effective removal of foreign substances. This local quality approach allows the guard to simultaneously achieve good gliding performance and effective foreign substance removal
3Ease of manufacture
If a single material is used for the guard to simplify manufacturing, then manufacturing complexity is reduced, but the guard cannot provide both high friction for skin contact and low friction for gliding
Solution Approach 1:
The guard is constructed using composite materials with different friction characteristics in different regions. The first material on the front surface provides high friction for skin contact, while the second material on the rear surface provides low friction for gliding. This composite material approach enables the guard to provide both high friction and low friction performance simultaneously, achieving dual friction performance that a single material cannot provide
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 design prevents excessive friction, allows smoother gliding, and effectively removes foreign substances, improving the shaving experience.
Implementation Method 1
a rigid guard disposed in front of the first flexible guard with respect to the shaving direction, and formed with unevenness having a three-dimensional surface roughness (SA) of 20 μm to 200 μm on a surface thereof
Implementation Method 2
a first flexible guard disposed adjacent to the blade to come into contact with skin of a user
Data Source
Figure 1
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AI summary
A razor cartridge, according to an embodiment of the present invention, comprises: at least one blade having a cutting edge; a blade housing accommodating the blade in a longitudinal direction; and a guard unit disposed in front of the blade accommodated in the blade housing with respect to the shaving direction, wherein the guard unit comprises a first flexible guard, disposed adjacent to the blade, for contacting the skin of a user, and a hard guard, disposed in front of the first flexible guard with respect to the shaving direction and having recesses and protrusions formed on the surface thereof, the recesses and protrusions having a three-dimensional surface roughness (SA) in the range of 20 µm-200 µm.