Capacitor-Driven Setting Tool Frame for Eddy Current Suppression
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Solution Overview
Problem
Existing setting tools for driving fastening elements into substrates lack efficiency and quality, particularly in the acceleration mechanism using electrical capacitors and squirrel-cage rotors, due to inefficiencies in magnetic field generation and eddy current suppression.
Innovation Solution
A setting tool with a soft-magnetic and electrically conducting frame surrounding the excitation coil, featuring interruptions that extend significantly over the radial and axial extent, suppressing eddy currents and enhancing magnetic field intensity, combined with a switching circuit for rapid capacitor discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a continuous frame is used, then the magnetic field is intensified through the soft-magnetic material, but eddy currents are generated that reduce efficiency
Solution Approach 1:
The continuous frame is divided into multiple segments by introducing interruptions (gaps or non-conductive barriers) that extend radially through the frame. This segmentation breaks the eddy current paths while maintaining the soft-magnetic material's ability to intensify the magnetic field in the circumferential direction, thereby reducing energy loss from eddy currents while preserving field intensity.
2Object-generated harmful factors
If interruptions are added to the frame, then eddy currents are suppressed, but the magnetic field intensity may be reduced
Solution Approach 1:
The interruptions are strategically positioned and dimensioned to affect only the radial eddy current paths while leaving the circumferential magnetic field path intact. The gaps or non-conductive barriers are configured to block eddy currents without significantly interfering with the soft-magnetic material's ability to conduct and intensify the magnetic field in the circumferential direction around the working axis.
3Area of stationary object
If the frame extends fully in radial direction, then magnetic field coverage is maximized, but eddy current paths are longer
Solution Approach 1:
The frame's radial extent is maintained for adequate magnetic field coverage, but interruptions are introduced that extend radially through the frame to break eddy current paths. This segmentation allows the frame to cover the necessary radial area while preventing continuous eddy current circulation by dividing the conductive path into isolated segments.
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 tool achieves improved efficiency and setting quality by intensifying the magnetic field and reducing parasitic magnetic fields, leading to enhanced acceleration of the working piston and precise fastening element insertion.
Implementation Method 1
an excitation coil, which during rapid discharge of the capacitor is flowed through by current and generates a magnetic field that accelerates the working piston
Implementation Method 2
a frame of a soft-magnetic and electrically conducting material, which surrounds the excitation coil and extends in a circumferential direction with respect to the working axis
Implementation Method 3
an electrically conducting material should be understood as meaning a material that has a high specific electrical conductivity, so that a magnetic field passing through the material generates eddy currents in the material
Data Source
AI summary
A tool having a working piston that moves along a working axis, a drive, for driving the working piston along the working axis, the drive having an electrical capacitor, a squirrel-cage rotor arranged on the working piston and an excitation coil, wherein current flows through the coil during rapid discharge of the capacitor and generates a magnetic field that accelerates the working piston, the tool having a frame of a soft-magnetic and electrically conducting material surrounding the excitation coil and extending in a circumferential direction with respect to the working axis, the frame having one or more at least partial interruptions, which extend over a significant part of a radial extent of the frame with respect to the working axis.