Rotary Shaver Head Unit Floating Support via Magnetic Repulsion
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Solution Overview
Problem
In rotary electric shavers, existing connection structures, whether using compression springs or repulsive magnets, fail to maintain consistent pressure on the skin surface, leading to poor followability of the outer blade over irregular skin surfaces, resulting in inadequate shaving and leaving hairs unshaven.
Innovation Solution
A rotary electric shaver design featuring a support structure with first and second magnets positioned to provide a repulsive force, allowing the head unit to float and flexibly move in multiple directions, enhancing followability by distributing pressure evenly over the skin surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a compression spring is inserted through the connecting shaft to provide restoring force, then the head unit is supported to be movable upon pushing, but the restoring force does not act effectively when the head unit is pressed at a position distant from the connecting shaft, causing poor followability on irregular skin surfaces
Solution Approach 1:
The patent divides the restoring force mechanism into multiple segments by placing multiple compression springs at different positions (including outer peripheral positions) around the connecting shaft. This segmentation allows each spring to independently support pressing forces applied at corresponding locations, ensuring effective restoring force acts even when the head unit is pressed at positions distant from the connecting shaft, thereby improving followability on irregular skin surfaces
Solution Approach 2:
The patent transitions from a single-point restoring force mechanism (one spring at the center) to a distributed multi-point mechanism by arranging springs in the radial dimension around the connecting shaft. This dimensional change enables the restoring force to be applied at multiple locations simultaneously, matching the distributed nature of pressing forces when the shaving head contacts irregular skin surfaces
2Ease of operation
If magnets are inserted through the connecting shaft to provide repulsive force, then the head unit becomes movable upon pushing, but the same problem of poor followability persists when pressed at positions distant from the connecting shaft
Solution Approach 1:
The patent segments the magnetic field support mechanism by placing multiple magnets at different radial positions around the connecting shaft instead of a single central magnet. This creates multiple localized repulsive force zones that can independently respond to pressing forces at different locations, enabling the head unit to adapt to skin surface irregularities while maintaining smooth movability
Solution Approach 2:
The patent replaces the traditional mechanical spring-based restoring force mechanism with a magnetic field-based repulsive force mechanism. This substitution eliminates mechanical contact and friction in the support structure, allowing the head unit to move more smoothly while the distributed magnet arrangement ensures adaptability to various pressing positions and skin irregularities
3Ease of operation
If the head unit is pressed with constant force by the user, then the operation is simple, but the outer blade strongly or weakly presses the skin surface depending on the position, causing poor shaving performance on irregular surfaces
Solution Approach 1:
The patent provides beforehand cushioning by pre-positioning multiple compression springs (or magnets) at strategic locations around the connecting shaft, including outer peripheral positions. These pre-positioned support elements are ready to immediately counteract pressing forces applied at any location, preventing excessive or insufficient blade pressure on irregular skin surfaces and ensuring uniform shaving performance
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 design enhances the followability of the outer blade to the skin surface, ensuring consistent pressure and improved shaving performance even over areas with significant skin irregularities.
Implementation Method 1
a first magnet disposed at a position corresponding to each of the blade units. The main body has a second magnet disposed at a position facing and repelling the first magnet
Data Source
AI summary
A rotary electric shaver includes a main body in which a first transmission mechanism, and a connecting portion is disposed; a head unit in which a plurality of blade units each having an outer blade, an inner blade being in sliding contact with an inner surface of the outer blade, and a driven shaft rotating the inner blade are disposed, and a second transmission mechanism that transmits a power of the first transmission mechanism to rotate the driven shaft is built, and which is connected to the connecting portion. The head unit has a first magnet disposed at a position corresponding to each of the blade units. The main body has a second magnet disposed at a position facing and repelling the first magnet.