Circuit Breaker Conductor Overmolding With Internal Sprue Gating
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Solution Overview
Problem
Existing methods for conductor overmolding in circuit interrupters face challenges such as distortion, weld line formation, and reduced strength due to cooling and pressure from arcs, especially when using external gates.
Innovation Solution
The method involves extending the sprue from the cavity through which the conductor passes, allowing molten plastic to flow from the sprue to the conductor overmolding through a sprue manifold, thereby reducing warping and maintaining material heat during injection molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If external gates are used for conductor overmolding, then the conductor overmolding can be produced, but distortion and weld line formation occur due to cooling and pressure from arcs
Solution Approach 1:
The patent inverts the conventional injection molding approach by using internal gates instead of external gates. The sprue extends from the cavity through which the conductor passes, allowing molten plastic to flow from the inside outward. This inversion eliminates the cooling and weld line issues associated with external gates, as the material flows directly from the hot sprue to the conductor overmolding through a sprue manifold, maintaining material heat and preventing distortion.
2Ease of manufacture
If material flows through external gates to the conductor overmolding, then the overmolding can be formed, but material cools down considerably before reaching the arc area, reducing strength
Solution Approach 1:
The sprue is extended from the cavity through which the conductor passes before the injection molding process begins. This preliminary arrangement ensures that the molten plastic flows directly from the hot sprue through a sprue manifold to the conductor overmolding, maintaining material heat throughout the flow path. The material reaches the arc area still hot and pliable, ensuring strong connection without the cooling problems of external gates.
3Strength
If the sprue extends from the cavity through the conductor, then material heat is maintained during flow, but the sprue manifold structure becomes more complex
Solution Approach 1:
The sprue manifold serves as an intermediary structure between the extended sprue and the conductor overmolding. It distributes the molten plastic from the sprue to the overmolding while maintaining material heat. The manifold is integrated into the injection mold and designed to flow material efficiently without requiring complex external gating systems, balancing structural complexity with thermal maintenance.
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 reduces distortion and strengthens the connection between the conductor overmolding and the sprue, enhancing the overall integrity and performance of the circuit interrupter.
Implementation Method 1
molten plastic being injected through a sprue of an injection mold holding the conductor
Data Source
AI summary
The aim of the invention is to produce a conductor (14) for a circuit breaker (11), said conductor having a printed circuit board (14c) to be separated between two conductor ends and additionally having a conductor encapsulation (15) that has a cavity (20) in which the printed circuit board (14c) is located. This is achieved in that a plastic melt is injected, via at least one gate (21), into an injection mold, in which the conductor (14) is located. According to the invention, the gating process (21) is carried out from out of the cavity (20), through which the conductor passes, wherein the plastic melt flows from the gate (21) to the actual conductor encapsulation (15) through a runner (22; 24a-24d; 26a, 26b). In the process, the gate (21) can remain in the completed circuit breaker (11).