Ultrasonic Sonotrode Insulation for Safe Contact Detection
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Solution Overview
Problem
Ultrasonic tools used for welding and sealing thermoplastic materials face a safety issue where electrical contact detection between the sonotrode and an anvil is hindered by grounding requirements, which prevents the detection of mechanical contact due to the risk of electric shock.
Innovation Solution
The implementation of electrical insulation between the sonotrode and the piezo unit's electrical contacts allows for the detection of electrical contact between the sonotrode and the anvil without grounding the converter housing, using insulating materials or coatings to ensure galvanic isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the converter housing is grounded for safety reasons, then the risk of electric shock is reduced, but electrical contact detection between the sonotrode and anvil becomes impossible
Solution Approach 1:
The electrical insulation system segments the electrical circuit by introducing insulating elements (insulating connecting elements, insulating coatings, or insulating material applications) that divide the conductive path between the sonotrode and the converter housing, allowing the housing to remain grounded while enabling contact detection through the insulated electrical connections
Solution Approach 2:
Insulating materials act as intermediaries between the sonotrode and the converter housing components, allowing electrical contact detection to occur through the insulated connections while maintaining the safety ground on the housing. The insulating materials mediate between the need for safety grounding and the need for contact detection
2Difficulty of detecting and measuring
If the converter housing is not grounded to enable electrical contact detection, then contact detection becomes possible, but the risk of electric shock increases
Solution Approach 1:
The electrical circuit is segmented into isolated sections through insulating connecting elements and coatings, allowing the converter housing to remain grounded for safety while enabling electrical contact detection through the insulated signal paths. This segmentation creates separate electrical domains that can serve different functions simultaneously
Solution Approach 2:
Insulating materials serve as intermediaries that enable electrical contact detection while maintaining safety grounding. These intermediaries allow the system to achieve both safety (through grounding) and functionality (through contact detection) simultaneously by mediating between conflicting requirements
3Difficulty of detecting and measuring
If electrical insulation is provided between the sonotrode and converter components, then contact detection becomes possible, but the device complexity increases
Solution Approach 1:
The patent employs relatively simple and inexpensive insulating materials (such as insulating connecting elements, coatings, or potting compounds) that can be easily applied during manufacturing. These insulating components are straightforward to implement and maintain, minimizing the increase in device complexity while effectively enabling contact detection
Solution Approach 2:
The insulating materials act as simple intermediary components that can be integrated into existing ultrasonic tool designs without requiring major structural changes. By using straightforward insulating solutions like coatings or insulating connecting elements, the patent minimizes the complexity increase while achieving the desired contact detection functionality
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
Enables safe electrical contact detection between the sonotrode and anvil, even when the converter housing is grounded, reducing the risk of electric shock and allowing for effective mechanical contact sensing.
Implementation Method 1
a piezo unit controllable via electrical contacts is provided
Implementation Method 2
providing electrical insulation between the sonotrode and the electrical contacts of the piezoelectric unit
Data Source
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AI summary
An ultrasonic tool comprises a sonotrode made of electrically conductive material and a converter connected to it, which contains a piezoelectric unit that can be controlled via electrical contacts. Electrical insulation is provided between the sonotrode and the electrical contacts of the piezoelectric unit.