Electromagnetic Setting Tool Coil Layout for Piston Acceleration

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Solution Overview

Problem

Existing setting tools for driving fasteners into substrates often lack efficiency and consistency in their operation, particularly in generating sufficient magnetic fields to effectively accelerate the working piston along the working axis.

Innovation Solution

A hand-held setting device with a stator and working piston, featuring multiple coils and a capacitor, where the first piston coil and first stator coil are oriented parallel and supplied with current in the same direction to generate aligned magnetic fields, and additional coils are used to create opposing magnetic fields to accelerate the piston, utilizing soft magnetic materials and electrical connections to enhance magnetic field interaction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a single coil configuration is used to drive the working piston, then the device structure is simple, but the acceleration efficiency and magnetic field strength are insufficient

Engineering Contradiction:
Improveacceleration efficiencyVSAvoidcoil configuration
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The drive system is segmented into multiple independent coil assemblies (first stator coil with first piston coil, second stator coil with second piston coil) that can be activated sequentially or simultaneously. Each coil assembly functions as an independent acceleration stage, allowing the piston to be accelerated through different magnetic field zones, thereby increasing overall acceleration efficiency without requiring a single complex coil system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control unit activates the coil assemblies in a periodic sequence - first activating the first stator coil and first piston coil to accelerate the piston, then activating the second stator coil and second piston coil to continue acceleration. This periodic activation of different coil pairs creates a progressive acceleration pattern that maintains high efficiency throughout the piston's travel distance.

Inventive Principle:
Principle #19Periodic action

2Ease of operation

If coils are supplied with current in opposite directions to create opposing magnetic fields, then the piston can be accelerated out of stator coils, but the energy distribution becomes less efficient

Engineering Contradiction:
Improvepiston acceleration controlVSAvoidenergy distribution
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts the current direction and activation timing of different coil assemblies based on the piston's position and acceleration requirements. The control unit switches between same-direction and opposite-direction current supply modes, optimizing the magnetic field interaction at each stage of piston movement to maintain efficient energy distribution while achieving the required acceleration control.

Inventive Principle:
Principle #15Dynamics

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 configuration ensures high efficiency and reliable acceleration of the working piston, allowing for effective driving of fasteners into substrates with reduced mechanical load and efficient energy distribution, thereby improving setting quality.

Implementation Method 1

the first stator coil and/or the first piston coil is provided to have current flowing through it and to generate a magnetic field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

generating a magnetic field to accelerate the working piston

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Implementation Method 3

the first piston coil is provided to dip into the first stator coil during a movement of the working piston relative to the stator along the working axis

Methodology Applied
Scientific EffectMagnetic field interaction: Magnetic Field

Data Source

PatentEP4076849B1Working implement
Publication Date: 2024.02.21 HILTI AG
  • EP4076849B1 patent drawingFigure 1
  • EP4076849B1 patent drawingFigure 2
  • EP4076849B1 patent drawingFigure 3

AI summary

The invention relates to a working tool for working an underlying surface, in particular a hand-held working tool, in particular a setting tool for driving securing elements into the underlying surface, having a stator and a working piston, which is designed to move relative to the stator along a working axis, and additionally having a drive, which is designed to drive the working piston from a starting position onto the underlying surface along the working axis. The drive has a first piston coil, which is arranged on the working piston, and a first stator coil, which is arranged on the stator, wherein the first piston coil is designed to be immersed into the first stator coil during a movement of the working piston relative to the stator along the working axis.