Razor Cartridge With Stepped Front Supporters to Reduce Skin Irritation

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Solution Overview

Problem

Existing razor cartridges with linear motion blades cause significant skin irritation during shaving due to the forward and backward movements.

Innovation Solution

The razor cartridge design includes a guard frame with a movable blade housing and front and rear supporters, where the topmost portion of the first front supporter is higher than the second front supporter, reducing skin contact irritation during forward movement, and adjusting the shaving plane to minimize blade protrusion and angle changes during both forward and backward movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the blade moves in linear motion during shaving, then shaving efficiency is improved, but skin irritation increases

Engineering Contradiction:
Improveshaving efficiencyVSAvoidskin irritation
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The front supporter is divided into two distinct parts: a first front supporter attached to the guard frame and a second front supporter attached to the blade housing. This segmentation allows each part to serve different functions - the first provides a stable reference plane while the second adjusts with blade motion, thereby maintaining shaving efficiency while reducing skin irritation from excessive blade protrusion

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second front supporter acts as an intermediary element between the blade and the first front supporter. It mediates the interaction by providing a dynamic reference plane that adjusts with blade housing position, controlling blade protrusion relative to the skin and reducing direct harmful contact while preserving cutting effectiveness

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the blade housing is fixed relative to the guard frame, then structural simplicity is maintained, but shaving efficiency decreases

Engineering Contradiction:
Improvestructural simplicityVSAvoidshaving efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The blade housing is designed to move linearly relative to the guard frame during shaving operation. This dynamic configuration allows the blade to maintain optimal contact with the skin across different strokes, improving shaving efficiency. The front supporters are designed to accommodate this motion while maintaining their functional relationship

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Different parts of the system have different degrees of freedom: the blade housing moves linearly within the guard frame, while the front supporters maintain fixed relative positions. This local differentiation of motion characteristics allows the system to achieve both structural simplicity and improved shaving efficiency through controlled local movement

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If the topmost portions of both front supporters are at the same height, then manufacturing simplicity is maintained, but skin contact optimization is reduced

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidskin contact irritation
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The first and second front supporters are designed with asymmetric heights - the second front supporter has its topmost portion lower than that of the first front supporter. This asymmetric configuration optimizes skin contact by creating a stepped reference plane that better conforms to skin topology, reducing irritation while maintaining manufacturability through simple geometric differentiation

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP4620639A1Razor cartridge
Publication Date: 2025.09.24 DORCO CO LTD
  • EP4620639A1 patent drawingFigure 1
  • EP4620639A1 patent drawingFigure 2
  • EP4620639A1 patent drawingFigure 3

AI summary

A razor cartridge according to an embodiment of the disclosure includes: at least one blade having a cutting edge; a blade housing accommodating the at least one blade in a longitudinal direction; and a guard frame accommodating the blade housing to be movable forwards and backwards, the guard frame comprising a first front supporter that is provided in front of the blade housing and comes into contact with skin during a shaving process, the blade housing comprising a second front supporter that is provided between the blade and the first front supporter and comes into contact with skin during the shaving process, and, a topmost portion of the first front supporter is higher than a topmost portion of the second front supporter so that the first front supporter can come into contact with skin in a state that the blade housing is at a foremost position relative to the guard frame, and the second front supporter can come into contact with skin in a state that the blade housing is at a rearmost position relative to the guard frame, during shaving the shaving process.