Rotary Shaver Blade Height Adjustment Mechanism
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Solution Overview
Problem
Commercially available rotary electric shavers with uniformly positioned or tilted outer blades often result in unwanted skin contact during use, leading to poor usability and incomplete hair cutting, especially when trying to trim areas like the nose or sideburns.
Innovation Solution
A rotary electric shaver with a lock mechanism that allows at least one outer blade to be adjusted in height, using a fulcrum plate, turning plate, and spring system to reduce skin contact by changing the blade's position between two predetermined heights, thereby minimizing unwanted contact with the skin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If all outer blades are positioned at the same height or tilted together, then the structure is simple and manufacturing is easy, but unwanted skin contact occurs and usability deteriorates
Solution Approach 1:
The head is divided into multiple blade units (first blade unit, second blade unit, third blade unit), each with independent height adjustment capability through the lock mechanism. This segmentation allows selective positioning of individual outer blades to prevent unwanted skin contact while maintaining simple overall structure
Solution Approach 2:
The lock mechanism enables dynamic height adjustment of outer blades between a first height position and a second height position. The spring-loaded turning plate with sloped parts allows easy transition between positions, transforming the static blade structure into a dynamically adjustable one that adapts to different shaving needs
2Ease of operation
If the head is tilted to make one outer blade contact the skin, then partial hair cutting is achieved, but skin enters the slit groove causing tingling and other outer blades still contact the skin
Solution Approach 1:
Different outer blades can be positioned at different heights based on local shaving requirements. The lock mechanism allows each blade unit to be independently adjusted, so only the desired blade contacts the skin while others remain elevated, eliminating both tingling from skin entry and unwanted contact from other blades
3Ease of operation
If the outer blade is pressed down to change height position, then skin contact is reduced, but the mechanism becomes more complex
Solution Approach 1:
The spring-loaded turning plate mechanism automatically engages and disengages the sloped parts of the fulcrum plate when the outer blade is pressed down or released. This self-service mechanism eliminates the need for additional actuators or complex control systems, achieving height adjustment with simple user action while maintaining mechanism simplicity
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 adjustable outer blade mechanism effectively reduces skin contact and enhances usability by allowing precise control over hair cutting, even when the shaver is used with the head parallel to the skin, ensuring better hair cutting performance.
Implementation Method 1
a spring disposed in the fixing plate to press the turning plate in a pressing-up direction
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
There is provided a rotary electric shaver which can easily prevent an outer blade which is undesirable to be brought into contact with a skin from coming into contact with the skin, by reducing the number of contact times of the outer blades in a head with the skin, even when the shaver is used in a state where the head is substantially parallel to the skin. A rotary electric shaver (1) includes a main body (2) having a drive shaft (4), and a head connected to the main body (2). At least one of a plurality of blade units (19) has a fulcrum plate (21), a turning plate (22), a spring (23), and a fixing plate (24), and has a lock mechanism (6) capable of changing a height position of at least one of outer blades (12) corresponding one-to-one to the blade units (19).