Beard Trimmer Comb Teeth Elastic Modulus for Uniform Cutting
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Solution Overview
Problem
Existing electric shaving apparatuses are not suitable for maintaining hair at a stubble length, as they either require multiple orientations to achieve the desired cut or are ineffective at cutting longer hairs due to their design, leading to user discomfort and variability in cutting length.
Innovation Solution
A beard trimmer with a rotary cutting unit and a comb unit that is releasably attached, featuring a first outer cutter and a first inner cutter driven by a motor, and comb teeth that provide a consistent cutting length independent of user pressure, ensuring uniformity and comfort by allowing minimal flexing and being made of a thermoplastic material with specific Elastic Modulus for rigidity and ease of attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a comb unit with flexible comb teeth is used, then the comb teeth can adapt to skin contours, but the cutting length varies with user pressure applied
Solution Approach 1:
The comb teeth are designed with specific rigidity parameters (Elastic Modulus between 1850-3850 MPa) that balance flexibility for skin adaptation and stiffness for consistent cutting length. This parameter optimization resolves the contradiction by finding the optimal middle ground where the teeth are flexible enough to conform to skin contours but rigid enough to maintain uniform cutting regardless of pressure variations.
2Manufacturing precision
If the comb unit is made rigid, then the cutting length remains uniform, but the comb teeth cannot adapt to skin contours
Solution Approach 1:
The comb unit material is selected with specific elastic modulus values (1850-3850 MPa) that provide the optimal balance between rigidity and flexibility. This parameter control allows the comb teeth to maintain sufficient rigidity for uniform cutting while retaining enough flexibility to adapt to skin contours, resolving the contradiction between these two requirements.
3Manufacturing precision
If perforated shaving foils are used, then close shave is achieved, but hairs exceeding certain length cannot be cut effectively
Solution Approach 1:
The rotary cutting unit with comb unit attachment provides multi-functionality, enabling the device to effectively cut hairs of various lengths (from short stubble to longer beard hair) while maintaining cutting precision. The comb teeth guide hairs of different lengths into the cutting zone, making the system versatile across multiple hair length scenarios while preserving precise cutting capability.
4Productivity
If projected teeth oscillating mechanism is used, then hair cutting is achieved, but multiple orientations are required to achieve desired results
Solution Approach 1:
The rotary cutting unit with circularly arranged comb teeth creates a rotational cutting action that is effective in multiple directions simultaneously. This rotational geometry allows the device to cut hairs efficiently regardless of the direction of movement or orientation relative to hair growth, eliminating the need for multiple specific orientations required by linear oscillating mechanisms.
Data Source
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AI summary
A beard trimmer 302 having a handle 304, a motor 306 and a head portion 310. The head portion has a rotary cutting unit 348 A for trimming hair that is provided with a first outer cutter 340 and a first inner cutter. A first comb unit 370A is releasably attached to the rotary cutting unit. The first comb unit comprises comb teeth 372A wherein each of the comb teeth has a tooth skin contact surface 382. The tooth skin contact surface is at an elevated level relative to a cutter skin contact surface so that the tooth skin contact surface is suitable to be brought in a skin contact. The comb teeth are more flexible when the first comb unit is detached form the rotary cutting unit relative to the comb teeth being less flexible when the first comb unit is attached to the rotary cutting unit.