Rotating Cylindrical Screen Shaving Head With Intermittent Brake

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Solution Overview

Problem

Existing electric razors cause skin irritation and reduced closeness of shave due to mechanical abrasion and friction heat transfer from foil screens and inner blades.

Innovation Solution

A shaving apparatus with a cylindrical screen that rotates about a rotational axis, featuring a brake sub-system to intermittently reduce rotational velocity and a cutting component with blades for hair cutting, allowing for reduced friction and improved skin contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a foil screen is used to cover the blades in an electric razor, then the blades are protected and the user's hairs can pass through to be cut, but mechanical abrasion and friction heat transfer cause skin irritation

Engineering Contradiction:
Improveblade protectionVSAvoidskin irritation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies the dynamics principle by making the screen rotatable rather than stationary. The screen rotates in the same direction as the blade movement, creating a dynamic system where the relative motion between the screen and skin is reduced. This rotational motion allows the screen to follow the contours of the skin more effectively while minimizing mechanical abrasion and friction heat transfer, thereby reducing skin irritation while maintaining blade protection.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies the spheroidality principle by using a curved or contoured screen surface that follows the natural contours of the skin. This curved geometry allows the screen to adapt to the skin's surface topology, reducing the mechanical abrasion caused by flat screens and improving overall comfort while maintaining effective hair cutting.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Productivity

If the screen rotates continuously at high speed, then hair cutting efficiency is improved, but friction and heat generation increase causing skin irritation

Engineering Contradiction:
Improvehair cutting efficiencyVSAvoidfriction and heat
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies the periodic action principle by implementing intermittent rotation of the screen rather than continuous rotation. The screen rotates periodically in synchronization with the blade movement cycles, creating periods of high-speed rotation for efficient hair cutting followed by periods of reduced speed or pause. This periodic motion maintains cutting efficiency while allowing heat dissipation and reducing cumulative friction on the skin.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies dynamics by varying the rotational speed of the screen based on operational requirements. The screen rotates at higher speeds during active cutting phases to maintain productivity, then reduces speed or pauses during transitions. This dynamic speed control optimizes the balance between hair cutting efficiency and heat/friction management.

Inventive Principle:
Principle #15Dynamics

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 reduces skin irritation and achieves a closer shave by minimizing friction and heat transfer, while allowing for effective hair cutting through controlled rotational motion.

Implementation Method 1

reduces skin irritation and achieves a closer shave by minimizing friction and heat transfer

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a brake sub-system configured to reduce a rotational velocity of the cylindrical screen to cause relative motion between the cylindrical screen and the skin surface

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3914427B1Shaving apparatus
Publication Date: 2024.11.06 HYBRID RAZOR
  • EP3914427B1 patent drawingFigure 1
  • EP3914427B1 patent drawingFigure 2
  • EP3914427B1 patent drawingFigure 3A

AI summary

A shaving apparatus having a head portion intended for contact with a skin surface to cut hairs growing therefrom. The head portion may include a cylindrical screen and a cutting component located within a cavity defined by the cylindrical screen. The cylindrical screen includes a plurality of openings so that a user's hairs can pass therethrough to be cut by blades of the cutting component. The cylindrical screen may be rotatable about a rotational axis so that as the cylindrical screen is placed into contact with a skin surface and moved therealong, the cylindrical screen is made to rotate about the rotational axis. The shaving apparatus may include a brake sub-system to intermittently reduce a rotational velocity of the cylindrical screen.