Toothbrush Hinge Injection Molding Bacterial Prevention
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Solution Overview
Problem
The existing methods for manufacturing toothbrushes are inefficient in creating a robust hinge between the handle and the head that can flex under pressure while maintaining economic production and preventing bacterial accumulation.
Innovation Solution
A method involving injection molding of two thermoplastic materials in a single mold, where the first material forms either the handle or the head, and the second material is injected to fuse against the first, forming a joint covered by a softer thermoplastic component for flexibility and bacterial prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the base body has a reduced cross-section in the hinge area to allow flexing, then the head can flex relative to the handle, but bacteria and dirt can collect in the reduced cross-section area
Solution Approach 1:
The patent applies this principle by covering the hinge area with a softer thermoplastic component that is more resistant to bacterial accumulation. The softer material creates a smooth, continuous surface that prevents dirt and bacteria from collecting in the hinge region, while still allowing the necessary flexing motion. This converts the harmful effect of the reduced cross-section into a beneficial smooth surface that resists contamination.
Solution Approach 2:
The patent uses composite materials by combining a harder thermoplastic component for the base body structure with a softer thermoplastic component for the covering. The harder material provides structural integrity and hinge geometry, while the softer material provides a smooth, bacteria-resistant surface. This composite approach allows the hinge area to simultaneously achieve flexibility and bacterial prevention.
2Object-affected harmful factors
If the harder thermoplastic component is covered by a softer thermoplastic component, then bacterial accumulation is prevented, but the manufacturing process becomes more complex
Solution Approach 1:
The patent merges the base body and covering into a single integrated component made from a single thermoplastic material. This eliminates the need for separate manufacturing steps and assembly operations, reducing manufacturing complexity while maintaining the beneficial properties of the softer covering material that prevents bacterial accumulation.
Solution Approach 2:
The single thermoplastic component serves multiple functions: it provides the base body structure, creates the hinge geometry, and forms the smooth covering that prevents bacterial accumulation. This multi-functionality reduces the number of parts and manufacturing steps, simplifying the overall manufacturing process while achieving the desired bacterial prevention.
3Object-affected harmful factors
If the softer thermoplastic component is applied by injection molding around the base body, then the joint is covered and haptic properties are improved, but manufacturing time increases
Solution Approach 1:
The patent combines the base body and covering into a single injection molding operation, eliminating the need for separate molding and assembly steps. This single-step process reduces manufacturing cycle time while still providing the joint coverage and haptic property improvements associated with the softer thermoplastic component.
Solution Approach 2:
The patent incorporates the covering geometry directly into the base body design during the initial molding process. By pre-forming the covering as an integral part of the base body, the need for subsequent covering operations is eliminated, reducing manufacturing time while maintaining the protective and aesthetic benefits of the covered joint.
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 method enhances the joint's strength and flexibility, reduces manufacturing costs by using different materials for the handle and head, and prevents bacterial accumulation by covering the joint with a softer thermoplastic component.
Implementation Method 1
forming a base body by injection molding of a first thermoplastic material forming one of the handle or the head
Implementation Method 2
injection molding of a second thermoplastic material for forming the other of the handle or the head to thereby fuse the second thermoplastic material against the first thermoplastic material
Implementation Method 3
injection molding the softer thermoplastic component for covering the joint
Data Source
AI summary
A method for making a toothbrush including a handle, a head including at least one cleaning element extending therefrom, and a hinge arranged between the head and the handle, said hinge including a joint between the handle and the head of a harder thermoplastic component covered by a softer thermoplastic component is provided, the method including: forming a base body by injection molding of a first thermoplastic material forming one of the handle or the head, and injection molding of a second thermoplastic material for forming the other of the handle or the head to thereby fuse the second thermoplastic material against the first thermoplastic material; placing the base body into a further mold; and injection molding the softer thermoplastic component for covering the joint.