Inductive Resonant Contact Detection in Rotary Wire Stripping
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Solution Overview
Problem
Existing devices for detecting contact between an electrically conductive tool and an electrical conductor in rotary stripping machines are limited by precision requirements for capacitive coupling, which restricts sensitivity and accuracy, especially for short cables with small cross-sections, and cannot reliably detect minor injuries or damages.
Innovation Solution
A device using a parallel resonant circuit with inductive elements on both the rotor and stator sides, allowing for contactless detection of tool-conductor contact through changes in oscillation parameters, enabling reliable and sensitive knife-conductor contact detection without the need for precise mechanical implementation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If capacitive coupling is used for contactless detection in rotary stripping machines, then the detection can be performed without direct electrical connection, but the mechanical implementation requires very precise concentric capacitor rings with controlled air gaps to avoid capacitance fluctuations that would be interpreted as incorrect knife-wire contact
Solution Approach 1:
The patent replaces the mechanical capacitive coupling system with an inductive coupling system using magnetic fields. Instead of requiring precise mechanical alignment of capacitor rings and air gaps, the invention uses inductive elements (coils) that can be positioned more tolerantly, substituting a mechanically sensitive system with one that is less sensitive to mechanical precision requirements.
Solution Approach 2:
The patent changes the detection parameter from capacitive coupling to inductive coupling. By using magnetic field coupling instead of electric field coupling, the system achieves contactless detection while being less sensitive to mechanical tolerances. The inductive elements are designed with specific winding configurations and positioning that provide more stable coupling characteristics under rotational conditions.
2Ease of manufacture
If capacitive coupling with large basic capacitances is used, then the system can be implemented with existing components, but the sensitivity is severely restricted making it difficult or impossible to detect knife-conductors of short cables with small cross-sections
Solution Approach 1:
The patent substitutes the capacitive detection system with an inductive detection system. The inductive elements (coils) generate and detect magnetic field changes, which provide higher sensitivity for detecting small conductors. This substitution allows the system to detect knife-conductor contacts on short cables with small cross-sections that were previously undetectable with capacitive coupling.
Solution Approach 2:
The patent utilizes electromagnetic oscillation and resonance principles through the inductive coupling system. The inductive elements are designed to operate at specific frequencies where the magnetic coupling is optimized, enhancing the detection sensitivity. The oscillating magnetic fields allow for more sensitive detection of small changes in coupling conditions compared to static or low-frequency capacitive systems.
3Device complexity
If direct electrical connection between the stripping knife and circuit device is used, then the detection circuit can be simplified, but the device cannot be used for rotary stripping heads where the tool rotates around the conductor
Solution Approach 1:
The patent replaces direct electrical connection with inductive coupling using magnetic fields. This allows the detection system to function with rotary stripping heads where the tool rotates around the conductor, as the magnetic coupling can accommodate rotational movement without requiring sliding contacts or complex rotary connectors. The inductive elements can be positioned on the rotary component and the stationary component, maintaining electrical isolation while enabling signal transmission.
Solution Approach 2:
The patent introduces magnetic field coupling as an intermediary between the rotating tool and the stationary circuit device. The inductive elements act as mediators that transfer detection signals across the air gap without direct electrical contact. This intermediary coupling method enables the system to bridge the rotating and stationary components while maintaining electrical isolation and simplifying the overall device architecture.
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 solution provides a compact and reliable method for detecting tool-conductor contact, enhancing the sensitivity and accuracy of contact detection, particularly for small conductors, and preventing injuries during the stripping process.
Implementation Method 1
The inductive elements on the rotor and stator sides are inductively coupled to one another
Implementation Method 2
a parallel resonant circuit with at least one partial circuit on the rotor side and at least one partial circuit on the stator side
Data Source
Figure 1
Figure 2
Figure 2b~3
AI summary
The present invention is directed at a device for identifying contact with an electrical conductor by at least one electrically conductive tool (2ra, 2rb). The device comprises a tool holder (lr) which is rotationally mounted about a rotation axis (X), wherein the tool (2ra, 2rb) is arranged on this tool holder (lr). The device additionally comprises an electrically conductive body (ECB) and a rotor-side inductive element (L1) which is arranged on the electrically conductive body (lr), a parallel resonant circuit comprising at least one rotor-side circuit element (A) and at least one stator-side circuit element (B), a stationary circuit arrangement (28) and a stator-side inductive element (L2). The rotor-side inductive element (L1) and the stator-side inductive element (L2) are arranged in relation to one another in such a way that the characteristic oscillation parameters (φ, Am, f) of the parallel resonant circuit can be measured independently of the rotation speed of the tool holder (lr). The invention further relates to an insulation-stripping machine and to a method for identifying contact with an electrical conductor by at least one electrically conductive tool.