U-Shaped Razor Retainer With Deformable Legs

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Solution Overview

Problem

Conventional wet shaving systems face challenges in maintaining secure blade assemblies, preventing corrosion, and ensuring consistent geometry and electrical conductivity, particularly due to issues with retainer design and processing, which can lead to assembly integrity loss and undesirable sharp features during use.

Innovation Solution

A U-shaped retainer with deformable legs that are inserted into cartridge housing openings, featuring protrusions and a domed central portion to enhance stability and electrical connectivity, allowing for secure blade retention and improved manufacturing processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional retainers are used to secure blades in cartridge housing, then blade retention is achieved, but assembly integrity is lost when subjected to stresses during use

Engineering Contradiction:
Improveassembly integrityVSAvoidretainer holding strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The retainer is divided into distinct functional segments: a head portion that contacts the blade, a neck portion that provides structural transition, and leg portions that engage the housing. This segmentation allows each portion to be optimized for its specific function, with the neck portion acting as a reinforcement that distributes stress and prevents retainer deformation under load, thereby maintaining assembly integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The retainer employs a composite structural design combining rigid portions (head and legs for engagement) with a reinforced neck portion that acts as a stress-distributing element. This composite approach allows the retainer to maintain strength while reducing sharp features, as the neck portion absorbs and distributes stresses that would otherwise concentrate at sharp corners.

Inventive Principle:
Principle #40Composite materials

2Reliability

If retainer processing is performed to create retention features, then blade retention is improved, but undesirable sharp features are created that affect user comfort

Engineering Contradiction:
Improveblade retentionVSAvoidsharp features during shaving
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The retainer head portion features a domed configuration with a rounded apex instead of sharp corners or edges. This curvature eliminates harmful sharp features that could contact the user during shaving, while the domed shape maintains effective blade retention through its contact geometry. The rounded surfaces distribute contact pressures and prevent concentration at sharp points.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Ease of manufacture

If retainer shape is distorted during forming or assembly, then manufacturing is simplified, but electrical conductivity to blades is reduced causing loss of corrosion protection

Engineering Contradiction:
Improveretainer formingVSAvoidcorrosion protection
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The retainer neck portion is designed with pre-formed reinforcement geometry that anticipates and compensates for potential distortion during manufacturing and assembly. This preliminary structural reinforcement ensures that even if some shape change occurs during forming, the critical electrical contact surfaces remain intact and conductive, maintaining corrosion protection. The neck portion acts as a buffer that absorbs dimensional changes without affecting the blade-contacting surfaces.

Inventive Principle:
Principle #10Preliminary action

4Ease of manufacture

If metal clips are used to retain blade assemblies, then assembly is simplified, but consistent cartridge geometry cannot be maintained

Engineering Contradiction:
Improveassembly simplicityVSAvoidcartridge geometry consistency
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The retainer is designed as a self-aligning component where the leg portions automatically position themselves within the housing openings during assembly. The neck portion provides a self-centering effect that ensures consistent geometric relationships between the blade, retainer, and housing without requiring additional alignment fixtures or complex assembly procedures. This self-service capability maintains manufacturing precision while keeping the assembly process simple.

Inventive Principle:
Principle #25Self-service

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 provides enhanced assembly integrity, reduced drag during shaving, improved comfort, and consistent shave geometry, while maintaining electrical connectivity and preventing corrosion, thus addressing the limitations of conventional retainer designs.

Implementation Method 1

each leg comprises an elastically compressible distal end portion wider than the opening when uncompressed, the distal end portion being compressible to fit into the opening during insertion, and expandable after insertion to restrict movement of the retainer relative to the cartridge housing

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

Retainers can be constructed using anodic materials based on galvanic activity such as aluminum, magnesium, beryllium, zinc, etc. or combinations thereof, to protect the blades from corrosion

Methodology Applied
Scientific EffectGalvanic corrosion protection:

Data Source

PatentEP3222395B1Shaving razor cartridge
Publication Date: 2019.07.24 EDGEWELL PERSONAL CARE BRANDS LLC
  • EP3222395B1 patent drawingFigure 1A~1B
  • EP3222395B1 patent drawingFigure 2A~2F
  • EP3222395B1 patent drawingFigure 3A~3B

AI summary

A retainer 50 for retaining a blade 40 in a razor cartridge housing 20 is disclosed. The retainer has a central portion 60 for extending across a minor axis of a blade, and a pair of legs 70 extending from respective distal ends of the central portion to form substantially a U-shape with the central portion. The cartridge housing has a pair of openings 30 for respectively receiving the pair of legs. The legs are engaged by the opening to restrict movement of the retainer relative to the cartridge housing.