Rivet Retainer for Shaving Blade Cartridge Stability
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Solution Overview
Problem
Existing shaving blade cartridges face issues with retainer security, manufacturing complexity, and reduced active surface area due to snap-fitted retainers, which can lead to blade instability and increased manufacturing costs.
Innovation Solution
A rivet-based retainer system is used to securely attach the retainer to the housing, providing enhanced stability and ease of assembly while maintaining an unobtrusive design that does not compromise the shaving surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If snap-fitted retainers are used to retain cutting blades, then the assembly process is simplified, but the retainer security and blade stability are reduced
Solution Approach 1:
The patent replaces the snap-fit mechanical retention system with a rivet-based mechanical fastening system. The rivet provides permanent, secure attachment of the retainer to the housing, eliminating the insecurity and blade stability issues associated with snap-fitted retainers while maintaining manufacturing simplicity.
Solution Approach 2:
The patent changes the retention mechanism from a reversible snap-fit connection to an irreversible rivet connection. This parameter change in the fastening method transforms the retainer security from insufficient to robust, while the rivet design allows for straightforward manufacturing integration.
2Ease of manufacture
If snap-fitted retainers are used to provide retention force, then the retainer can be easily assembled, but the active surface area during shaving is reduced
Solution Approach 1:
The patent extracts the retention function from the snap-fit mechanism and implements it through rivets positioned at the corners of the housing. This extraction allows the retainer body to be minimized and positioned only where necessary for blade retention, freeing up the active shaving surface area while maintaining easy assembly through the rivet attachment process.
Solution Approach 2:
The patent moves the retention mechanism to the lateral dimensions (corner rivets on the housing) rather than occupying the longitudinal dimension (middle of top side). This dimensional relocation of the fixation points eliminates the need for a large retainer body in the shaving area, preserving active surface area while maintaining assembly simplicity.
3Strength
If multiple snap-fit fixations are provided on the housing, then sufficient retention force is achieved, but the manufacturing complexity and tolerances increase
Solution Approach 1:
The patent segments the retention function into four separate corner rivets distributed around the housing perimeter. Each rivet provides localized retention force, and collectively they achieve the necessary total retention strength. This segmentation simplifies manufacturing by using standard rivet components and reduces tolerance requirements compared to a single complex snap-fit mechanism.
Solution Approach 2:
The patent uses identical rivet components at all four corners of the housing, creating a repetitive, modular retention system. This copying of the same simple element multiple times achieves sufficient total retention force while maintaining low manufacturing complexity, as the same rivet design and installation process is used throughout.
4Reliability
If a rivet is used to join the retainer and housing, then the retainer security is enhanced, but the manufacturing cost may increase
Solution Approach 1:
The patent employs inexpensive rivet components that can be easily manufactured and installed. The rivets serve as simple, disposable fastening elements that provide robust retainer security at low cost. The simplicity of the rivet design and the ease of the riveting process keep manufacturing costs down while significantly enhancing retainer security compared to snap-fit alternatives.
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 rivet assembly enhances retainer security, simplifies manufacturing, and maintains the shaving performance by ensuring the retainer does not protrude or reduce the active surface, thus offering a robust and cost-effective solution.
Implementation Method 1
the retainer is retained on the housing by a rivet
Implementation Method 2
The fixation of the retainer on the housing by riveting is made by plastic deformation of the free end of the riveting pin by punching
Data Source
Figure 1~2
Figure 3~4
Figure 5A~7
AI summary
A shaving blade cartridge (1), which comprises a housing (9) extending along a longitudinal axis (X-X), having a top side (11), a bottom side (13) opposite to the top side (11), and two longitudinal sides (15, 17) extending longitudinally along the longitudinal axis (X-X) between the top and bottom sides (11, 13). The shaving blade cartridge also comprises a cutting blade (35) mounted in the housing (9) between the longitudinal sides (15, 17), and having a cutting edge (41) extending along the longitudinal axis (X-X), and a retainer (59, 91) retaining the cutting blade (35) in the housing (9). The retainer (59, 91) is retained on the housing (9) by a rivet (61). Method for the manufacture of shaving blade cartridges, and razor having such shaving blade cartridge.