Shaving Razor Cartridge Blade Registration and Retention
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Solution Overview
Problem
Existing shaving razor cartridges face challenges in designing a simple and reliable mechanism to establish shaving geometry with increased blade numbers or closer spacing, while also addressing the limitations of spring finger biasing members, which are difficult to mold and provide insufficient force to maintain blade position during shaving.
Innovation Solution
The use of blade registration members, such as metal or plastic clips, which are strategically positioned within the housing to secure blades and establish the shaving plane, eliminating the need for spring fingers by distributing force effectively and allowing for closer blade spacing and increased blade count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spring finger biasing members are used to maintain blade position, then blade geometry can be established, but the mechanism becomes complex and costly
Solution Approach 1:
The patent removes the spring finger biasing members from the cartridge mechanism entirely. Instead of using separate spring components to maintain blade position, the invention integrates the blade retention function directly into the blade holder structure, which is formed as a single-piece molded component with built-in retention features that engage with the blades without requiring additional spring elements.
Solution Approach 2:
The blade holder is designed as an integrated structure that combines multiple functions: it holds the blades, maintains their position, and provides retention features all in one component. This merging of functions eliminates the need for separate spring finger biasing members and other discrete retention mechanisms, simplifying the overall cartridge design while maintaining reliability.
2Reliability
If spring finger biasing members are used to secure blades, then blade geometry is established, but manufacturing difficulty increases
Solution Approach 1:
The invention eliminates spring finger biasing members from the design, removing the manufacturing challenges associated with forming and assembling these difficult-to-mold components. The blade retention function is achieved through integrated features in the single-piece molded blade holder, which can be manufactured more easily using standard injection molding processes.
Solution Approach 2:
The blade holder is designed to be self-retaining through its integrated structure. The molded-in retention features automatically engage with the blades during assembly without requiring additional adjustment or complex manufacturing steps, making the entire cartridge easier to manufacture and assemble.
3Reliability
If spring finger biasing members are used, then blade position is maintained, but valuable cartridge space is consumed
Solution Approach 1:
The blade holder integrates blade retention and position maintenance functions into the same structural features that hold the blades, eliminating the need for separate spring finger components. This merging allows the cartridge to accommodate more blades or achieve closer blade spacing without consuming additional space for separate retention mechanisms.
4Device complexity
If fixed blade construction is used, then simplicity is achieved, but sufficient blade force during shaving is difficult to provide
Solution Approach 1:
The blade holder is designed as an integrated structure that combines blade mounting, retention, and force transmission functions. The molded-in retention features and structural design of the single-piece holder provide sufficient force to maintain blade position and pressure during shaving, achieving this without the complexity of separate spring finger biasing members.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A shaving razor cartridge (10) with a housing (12) having a guard (14) and a cap (18). At least one blade (22) is mounted to the housing. The at least one blade has a cutting edge (32). At least one blade registration member (54, 56) is mounted to the housing. A blade retention member (42, 44) secures the at least one blade between the blade registration member and the blade retention member. The blade registration member has an unsupported region (76) having a span of 0.25mm to 5mm between a pair of supported regions (77, 79).