Razor Guard Structure with Curved Protrusions for Skin Contact
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Solution Overview
Problem
Current guard structures in razor cartridges are costly and time-consuming to manufacture due to the use of thermoplastic or elastomeric materials requiring complex injection molding processes, while also lacking in providing optimal shaving performance and comfort.
Innovation Solution
A guard structure comprising rows of elongated hard plastic protrusions with rounded tips and varying heights, arranged on a curved profile, which extends beyond the housing for improved skin contact and shaving aid distribution, manufactured using a single material via injection molding for reduced costs and enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermoplastic or elastomeric materials with acute tips are used for guard structure, then skin engagement and hair positioning are improved, but manufacturing cost and time increase due to complex two-color injection molding processes
Solution Approach 1:
The patent extracts the flexible guard material from the housing structure, making the guard a separate removable component. This allows the housing to be made of simple thermoplastic via standard injection molding, while the guard can be made of elastomeric material separately, eliminating the need for complex two-color injection molding and reducing manufacturing complexity
Solution Approach 2:
The guard structure is segmented into a separate component from the housing, allowing independent manufacturing and assembly. This segmentation enables each component to be optimized for its specific function and manufactured using the most appropriate process for that material and function
2Ease of manufacture
If constant height fins are used for guard structure, then manufacturing simplicity is improved, but shaving performance and comfort deteriorate due to inability to manage varying skin contours
Solution Approach 1:
The guard fins are designed with asymmetric varying heights rather than uniform constant heights. This asymmetry allows different portions of the guard to contact the skin at different elevations, accommodating the natural contours and variations in skin surface, thereby improving skin engagement and shaving performance
Solution Approach 2:
Different portions of the guard structure are given different heights and properties tailored to local skin contact requirements. This local variation in fin height allows optimal skin engagement at each location while maintaining overall structural integrity
3Ease of manufacture
If hard plastic material is used for guard structure, then manufacturing cost and time are reduced through single-material injection molding, but skin comfort and flexibility deteriorate
Solution Approach 1:
The patent uses composite construction by combining hard plastic housing material with elastomeric guard material. The hard plastic provides structural support and cost-effective manufacturing, while the elastomeric material provides flexibility and skin comfort, achieving both manufacturing efficiency and performance requirements
Data Source
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AI summary
A novel guard structure of a razor is shown including rows of elongated hard plastic protrusions having rounded (e.g., not sharp or pointed) tips arranged on a tip curved profile. The rounded valleys between the protrusions are also arranged on a curved profile which may be different than that of the tip curved profile. The valleys encompass an inner protrusion volume which increases going back to front end of the guard structure. Preferably, the front end volumes are larger than the back end inner protrusion volumes to assist in trapping and distributing having aid. In one embodiment having six protrusions, the inner protrusion volume between a second and third protrusion is the largest, while a volume between first and second protrusion is the second largest volume. The guard structure is disposed in front of the blades which are formed within the housing and may desirably extend past the front end of the housing.