Shaving Cartridge Lubrication Member Mechanical Interlock
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Solution Overview
Problem
Existing shaving razor cartridges face issues with securing lubrication members due to water absorption and swelling, leading to discomfort and adhesive failures under varying heat and humidity conditions, which affect shaving performance and ease of assembly.
Innovation Solution
A shaving blade unit with a housing featuring elongated apertures and protrusions from a solid polymeric lubrication member, where the protrusions' enlarged distal ends engage the housing to secure the lubrication member, and an elastomeric member with fins provides additional glide and skin stretching, ensuring secure attachment and comfort during shaving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesives are used to secure the shaving aid component to the cartridge, then the lubrication member can be attached to the housing, but the adhesive properties deteriorate under high heat and humidity conditions during shipment and storage
Solution Approach 1:
The patent replaces the chemical bonding mechanism (adhesive) with a mechanical interlocking system consisting of protrusions on the lubrication member that engage with corresponding recesses in the housing. This mechanical substitution eliminates the reliability issues associated with adhesive degradation under heat and humidity, providing consistent securement throughout the product lifecycle.
Solution Approach 2:
The patent changes the bonding mechanism from chemical (adhesive) to mechanical (interlocking protrusions and recesses), fundamentally altering how the lubrication member is secured to the housing and making the connection insensitive to environmental parameter changes such as temperature and humidity.
2Reliability
If press-fit type designs are used to secure the shaving aid composite, then the lubrication member can be attached to the housing, but the lubrication member may break or fracture due to the significant force required
Solution Approach 1:
The housing is segmented with specific recesses that receive and accommodate the protrusions on the lubrication member. This segmentation allows for localized stress distribution and reduces the risk of fracture by providing dedicated engagement points that do not require excessive assembly force.
Solution Approach 2:
The protrusions and recesses act as intermediary elements that facilitate securement without requiring direct high-force contact between the lubrication member and housing. The interlocking geometry provides a mechanical advantage that secures the component without transmitting damaging forces to the lubrication member material.
3Reliability
If increased surface contact area is used to secure the lubrication member, then the securement is improved, but the cartridge design is limited in terms of size and blade placement
Solution Approach 1:
Instead of increasing overall surface contact area, the patent employs localized protrusions and recesses at specific engagement points. This local quality approach provides securement at critical locations without requiring extended contact surfaces, thereby maintaining cartridge design flexibility for optimal size and blade placement.
Solution Approach 2:
The patent transitions from a two-dimensional surface contact approach to a three-dimensional interlocking geometry using protrusions and recesses. This dimensional change enables securement through depth and geometric engagement rather than relying on extended surface area, preserving cartridge design freedom.
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 solution effectively secures the lubrication member to the cartridge, accommodating swelling and improving shaving performance by enhancing glide and comfort without compromising the cartridge's design or manufacturing complexity, resulting in a more reliable, durable, and cost-effective assembly.
Implementation Method 1
The enlarged distal ends of the protrusions are molded from a water soluble polymer
Implementation Method 2
an elastomeric member with fins provides additional glide and skin stretching
Data Source
AI summary
A shaving blade unit with a housing having a bottom surface and a top surface defining a pair of elongated spaced apart apertures extending from the top surface to the bottom surface. At least one blade is mounted to the housing. The blade has a blade edge extending generally parallel to the pair of apertures. A solid polymeric lubrication member having an upper skin contact surface and an opposing base. A pair protrusions extend from the base. Each protrusion has an enlarged distal end. The enlarged distal ends of the protrusions each have a dimension greater than a dimension of the corresponding aperture whereby inserting the protrusion into the corresponding aperture deflects a front wall of the housing and each of the enlarged distal ends engage the bottom surface of the housing. The solid polymeric lubrication member and the enlarged distal ends are molded from a water soluble polymer.