Electric Shaver Asymmetric Blade Coupling for Vibration Reduction
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Solution Overview
Problem
Existing electric shavers with three or four blades face issues with weight balance and vibration, particularly in three-blade shavers, which result in poor vibration reduction and difficulty in implementing functions that require different amplitudes for rough and finish shaving.
Innovation Solution
An electric shaver design with a 2:3 ratio of inner blades to drive elements, where the first drive element is coupled to two inner blades and the second drive element is coupled to three inner blades, allowing for different amplitudes and improved weight distribution, reducing vibration and enabling functions like rough and finish shaving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If inner blades are coupled to drive elements at a ratio of one to two in a three-blade shaver, then the number of blades is reduced, but weight balance deteriorates and vibration increases
Solution Approach 1:
The patent applies asymmetry by using an uneven distribution of inner blades (2:3 ratio) coupled to the first and second drive elements respectively, rather than a symmetric distribution. This asymmetric coupling ratio is specifically designed to achieve favorable weight balance and reduce vibration in the three-blade shaver configuration.
2Adaptability or versatility
If the amplitude of drive elements is made different to enable rough and finish shaving functions, then functional versatility is improved, but vibration increases due to poor weight balance
Solution Approach 1:
The patent uses asymmetric coupling ratio (2:3) of inner blades to drive elements to create favorable weight balance, which enables the system to operate with different amplitudes for rough and finish shaving functions while maintaining reduced vibration levels.
Solution Approach 2:
The patent implements dynamic amplitude control where the first and second drive elements can operate at different amplitudes. The drive source is configured to vary the amplitude of each drive element independently, allowing rough shaving with larger amplitude and finish shaving with smaller amplitude, while the asymmetric blade coupling maintains weight balance throughout the operation.
3Device complexity
If a three-blade configuration is used instead of four-blade, then device complexity is reduced, but weight balance and vibration reduction performance worsen
Solution Approach 1:
The patent resolves the vibration issue in three-blade configuration by implementing asymmetric coupling where two inner blades are coupled to the first drive element and three inner blades are coupled to the second drive element. This asymmetric distribution compensates for the reduced blade count and achieves favorable weight balance, thereby reducing vibration despite the simpler three-blade structure.
Data Source
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Figure 3A~3B
AI summary
An electric shaver (11) includes a head (13), outer blades (21-25) located next to one another in an arrangement that extends in a front to back direction of the head (13), a drive source (41) that drives a first drive element (51) and a second drive elements (52) back and forth in different directions, and inner blades (31-35) each coupled to and driven by the first drive elements (51) or the second drive elements (52) to be movable back and forth in a longitudinal direction of the outer blades (21-25), which is a widthwise direction of the head (13), at an inner side of the outer blades (21-25). The inner blades (31-35) are coupled to the first drive element (51) and the second drive elements (52) at a ratio of two to three.