Rigid Rectangular Tine Plastic Lice Comb
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Solution Overview
Problem
Current plastic lice combs are ineffective and require multiple passes to remove lice and nits due to flexible tines with rounded cross-sections and tapering, which leads to incomplete removal and increased manufacturing costs compared to metal combs.
Innovation Solution
A plastic lice comb design with rigid, rectangular tines and a unique injection molding process using an elongated plastic flow ridge and flow restriction channel to ensure complete filling of tines, allowing for single-pass nit removal and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plastic is used to manufacture lice combs to reduce costs, then manufacturing cost decreases, but the comb becomes flimsy and ineffective requiring significantly longer use time
Solution Approach 1:
The patent changes the cross-sectional geometry parameter of the tines from rounded to rectangular, and modifies the dimensional parameters (thickness, width, length) to optimize rigidity. The rectangular cross-section with specific thickness-to-width ratio provides significantly higher moment of inertia and rigidity compared to traditional rounded tines, enabling plastic combs to achieve metal-comb-level effectiveness while maintaining low manufacturing cost
Solution Approach 2:
The patent employs a composite structure combining rigid rectangular tines with a flexible grip portion. The tines are designed with specific thickness (0.030-0.060 inches) and width (0.020-0.040 inches) to provide rigidity, while the grip portion uses standard plastic flexibility for user comfort. This composite approach optimizes both structural performance and manufacturability
2Ease of manufacture
If plastic lice combs are designed with traditional rounded tines to reduce manufacturing complexity, then ease of manufacture increases, but the combs require multiple passes and significantly longer usage time
Solution Approach 1:
The patent modifies the tine cross-sectional shape parameter from rounded to rectangular, which dramatically improves lice and nit removal efficiency. The rectangular geometry provides sharper edges for more effective nit scraping while maintaining the same basic injection molding process, thus achieving high productivity without significantly increasing manufacturing complexity
Solution Approach 2:
The patent incorporates flow ridges and flow restrictions in the mold design to pre-condition the plastic flow before it reaches the tine cavities. This preliminary action ensures complete and uniform filling of the rectangular tine cross-sections, eliminating voids and ensuring consistent rigidity, which enables single-pass lice removal effectiveness
3Ease of manufacture
If injection molding is used to manufacture plastic lice combs, then manufacturing cost decreases, but the rectangular tines with close spacing are difficult to fill completely
Solution Approach 1:
The patent introduces flow ridges and flow restrictions as intermediary features in the injection molding process. The flow ridge acts as a mediator to redirect and concentrate plastic flow toward the closely spaced rectangular tine cavities, ensuring complete filling. The flow restriction features mediate the flow rate to allow adequate filling time for the thin-walled rectangular sections, achieving complete filling without increasing manufacturing complexity
Solution Approach 2:
The patent applies local quality modifications to the mold cavity by adding flow ridges specifically at critical locations where plastic flow tends to stagnate. These localized features improve filling of the rectangular tine cross-sections without requiring changes to the overall molding process or tooling, maintaining cost-effectiveness while achieving complete filling
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 improved comb effectively removes lice and nits in a single pass with minimal user effort and reduced manufacturing costs, maintaining rigidity and efficiency comparable to metal combs while being cost-effective.
Implementation Method 1
The ridge is created by machining an elongated channel into the mold which creates a temporary reservoir of molten plastic, which can then flow into the narrow cavities forming the tines
Implementation Method 2
The flow restriction depression is formed by machining an elongated projection into one half of the mold which extends into the mold cavity thereby restricting and slowing the flow of molten plastic toward the grip end of the comb during an injection molding shot
Implementation Method 3
The tines of the comb of the invention have a substantially rectangular cross-section which helps ensure that the tines are sufficiently rigid to resist excessive flexing when making contact with nits and lice
Data Source
AI summary
Example embodiments relate to an improved plastic lice treatment comb as well as methods of manufacture and use of the comb. The lice plastic comb may have a front surface, a back surface, a grip portion, and a plurality of rigid plastic tines extending from the grip portion. The front surface of the grip portion includes an elongated plastic flow ridge which is adjacent to the base ends of the tines. The back surface of the grip portion includes a plastic flow restriction channel, which is spaced slightly back from the base ends of the tines.