Toothbrush Head Over-Molding for Mixed Bristle Materials
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Solution Overview
Problem
Existing toothbrush head manufacturing methods lack design flexibility, material flexibility, and support flexibility, particularly in combining different types of bristle tufts and cleaning elements with varying properties, as hot-tufting methods struggle to melt ends of differently composed tufts without affecting adjacent tufts and integrating diverse bristle materials and soft plastic strips effectively.
Innovation Solution
A method involving over-molding cleaning elements, such as bristle tufts, at their ends using different plastic materials in separate injection-molding sections, allowing for varied support properties and anchoring, using a carrier part with movable slides and mold parts to create distinct injection-molding sections without moving the elements to different molds, enabling the use of different materials and designs in different areas of the brush head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hot-tufting methods are used to melt ends of bristle tufts, then anchoring is achieved, but different types of bristle tufts with different materials cannot be effectively combined
Solution Approach 1:
The patent divides the bristle field into multiple sections, each containing bristle tufts of the same material type. By segmenting the diverse bristle field into homogeneous subsections, the manufacturing process can treat each section uniformly with appropriate melting parameters, while the overall brush head achieves versatility through the combination of different material types in different sections.
Solution Approach 2:
The patent applies local quality by allowing different physical or chemical properties in different sections of the bristle field. Each section can be optimized for specific cleaning needs with appropriate bristle materials, and the manufacturing process can be locally adapted to melt and anchor each material type appropriately without affecting other sections.
2Strength
If a flat support structure is created by melting adjacent bristle tufts together, then pull-out resistance increases, but mold cavity filling speed decreases
Solution Approach 1:
The patent applies partial melting rather than complete melting of bristle tuft ends. The bristle tufts are melted to a degree sufficient to provide adequate anchoring and pull-out resistance, but not to the extent of creating a thick flat support structure. This partial action maintains mold cavity filling speed while achieving the necessary anchoring strength.
3Reliability
If bristle tufts are arranged in a bristle field and then melted, then anchoring is achieved, but design flexibility for different cleaning elements is reduced
Solution Approach 1:
The patent segments the bristle field into multiple sections that can be independently designed and manufactured. Each section can contain different types of cleaning elements (bristle tufts, soft plastic strips, or combinations) with different material properties. This segmentation allows design flexibility while maintaining reliable anchoring through the over-molding process applied to each section.
Solution Approach 2:
The patent employs composite materials by allowing different bristle materials and soft plastic materials to be combined in different sections of the bristle field. Each material type can be selected and arranged according to specific cleaning requirements, and the over-molding process anchors these composite structures reliably.
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
This approach allows for a complex bristle field design with optimal support properties, enabling the use of different materials and designs in various sections of the toothbrush head, enhancing cleaning efficiency and hygiene by providing flexible and customizable bristle configurations.
Implementation Method 1
cleaning elements, in particular bristle tufts, are over-molded at one of their ends using a plastic material, from which a bristle carrier is formed at least partially in the process
Implementation Method 2
the bristle tufts are melted at their ends to form thickenings and then are over-molded with plastic
Data Source
Figure 1
Figure 2A~3
Figure 4A~4B
AI summary
A brush head, particularly a toothbrush head, may have a plurality of cleaning elements, in particular bristle tufts, which are anchored by an end section in a brush carrier, wherein the cleaning elements may be cast with positive engagement in blind-hole shaped retaining recesses. For producing such a brush head different cleaning elements may be placed successively or simultaneously in different mold cavities and may be over-molded using different plastic materials from which injection-molding sections of the bristle carrier are formed in the process. In doing so, a first cleaning element is over-molded in a first mold cavity using a first plastic material, while a second cleaning element is over-molded in a second mold cavity using a second plastic material.