Shaving Razor Cartridge Bridge Member Width
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Solution Overview
Problem
Conventional shaving razors often cause discomfort and skin issues such as nicks, cuts, irritation, acne, and pseudofolliculitis barbae due to close hair cutting and nerve stimulation, especially with multi-bladed systems where single hairs engage multiple blades, leading to excessive nerve stimulation and potential skin damage.
Innovation Solution
A shaving cartridge design featuring a housing with a primary guard and secondary cap, a bridge member between the blades, and blades mounted to spring-loaded clips, where the bridge member's width is greater than 50% of the interblade span, ensuring a wider spacing between blades to minimize double engagement and skin contact, thereby reducing discomfort and skin irritation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple blades are used in a shaving cartridge, then the closeness of shave is improved, but the skin irritation and discomfort increase due to multiple blades engaging the same hair
Solution Approach 1:
The patent divides the blade unit into multiple independently mounted blades spaced apart from each other. Each blade is mounted on its own clip that can independently engage and disengage from the housing, allowing each blade to operate separately rather than all blades engaging the same hair simultaneously. This segmentation reduces the harmful effect of multiple blades on a single hair while maintaining the closeness of shave benefit.
Solution Approach 2:
The patent applies different properties to different parts of the blade unit. The blades are positioned at different locations with different orientations, and each blade has its own mounting mechanism with potentially different engagement characteristics. This local differentiation ensures that while multiple blades provide close shaving, they engage hairs at different locations and times, reducing the probability of multiple blades engaging the same hair.
2Productivity
If blades are mounted close together to maximize shaving coverage, then the productivity is improved, but the interblade span becomes too small causing increased skin contact and irritation
Solution Approach 1:
The patent arranges multiple blades in a two-dimensional configuration rather than simply spacing them linearly. The blades are positioned at different lateral positions and orientations, creating an interblade span that provides sufficient spacing to reduce skin contact and irritation while still maintaining comprehensive shaving coverage across the shaving surface.
3Strength
If the bridge member width is increased to provide structural support between blades, then the strength is improved, but the interblade span is reduced causing increased double engagement of hairs
Solution Approach 1:
The bridge member is segmented into discrete portions positioned between adjacent blades rather than forming a continuous wide structure. This segmentation provides localized structural support where needed while maintaining sufficient interblade span in the critical areas where hairs pass between blades, reducing the probability of double engagement.
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 minimizes skin irritation and pseudofolliculitis barbae by maintaining hair above the skin level, reducing nerve stimulation, and preventing hair from being cut too close to the skin, resulting in a more comfortable and efficient shaving experience.
Implementation Method 1
blades mounted to spring-loaded clips
Data Source
AI summary
A shaving cartridge with a housing, having a primary guard at a front of the housing and a secondary cap at a rear of the housing. A bridge member having a primary cap surface and a secondary guard surface is positioned between the primary guard and the secondary cap. A first blade has a cutting edge. The first blade is mounted to the housing between the primary guard and the primary cap surface. A second blade having a cutting edge extending in the same direction as the cutting edge of the first blade is mounted to the housing between the secondary guard surface and the secondary cap. A width of the bridge member is greater than 50% of an interblade span between the cutting edge of the first blade and the cutting edge of the second blade and the interblade span is greater than 3 mm.