Progressive Over-Guard Razor Cartridge for Reduced Skin Irritation
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Solution Overview
Problem
Existing razor cartridges often cause skin irritation and exacerbate conditions like pseudofolliculitis barbae (PFB) and acne, and fail to maintain a desired '5 o'clock shadow' appearance during shaving.
Innovation Solution
A razor cartridge with an over-guard design featuring angled blades and progressively decreasing heights of longitudinal members, along with enhanced blade sharpness, to provide comfort and controlled beard trimming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional razor cartridges are used to achieve a close shave, then shaving efficiency is improved, but skin irritation and worsening of PFB/acne conditions occur
Solution Approach 1:
The cartridge is divided into functional zones: a guard section that segments and distributes hair across multiple blades, preventing concentrated stress on single skin areas. The guard segments hair into portions that can be cleanly cut by individual blades rather than dragging across skin
Solution Approach 2:
The guard acts as an intermediary element between the blades and skin, maintaining optimal spacing to prevent blades from直接接触 skin while still effectively cutting hair. This intermediary structure eliminates direct blade-skin contact that causes irritation
2Object-affected harmful factors
If blades are angled and over-guard is used to reduce skin contact, then skin irritation is reduced, but shaving closeness is compromised
Solution Approach 1:
Different portions of the blade assembly have different orientations and functions: blades are angled relative to the cartridge axis to optimize cutting geometry, while the guard maintains a different orientation to control hair presentation. Each element has localized properties optimized for its specific function
Solution Approach 2:
The blade angle parameter is optimized at 20.5 degrees relative to the reference plane, and the guard-to-blade spacing parameter is precisely controlled to maintain hair within the cutting zone. These parameter changes achieve both reduced skin contact and maintained shave effectiveness
3Productivity
If multiple blades are used to improve shave quality, then cutting performance is improved, but complexity of the cartridge structure increases
Solution Approach 1:
Multiple blades are merged into a single integrated cartridge assembly with common mounting structure and shared guard element. The guard serves as a unifying component that simultaneously supports and positions all blades, reducing overall structural complexity despite multiple cutting elements
Data Source
AI summary
A razor cartridge has a housing with a blade mounting region between a guard and a cap. A first, second and third razor blade are sequentially mounted in the blade mounting region. An over-guard is secured over the blades. The cutting edges of the blades have an as-defined increased sharpness. The blades are mounted at a reduced angle between each blade portion bearing the cutting edge and a reference plane tangential to the cutting edges of the first and third blade. Individual longitudinal members of the over-guard that lie over each blade and have a progressively decreasing height above the reference plane in a front to back direction of the razor cartridge. A further longitudinal member is forward of the first blade and has a height above the reference plane.