Electromagnetic Setting Tool Coil Layout for Piston Acceleration

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Solution Overview

Problem

Existing setting tools for driving fasteners into substrates lack efficiency and consistency in their operation, particularly in generating effective magnetic fields to accelerate the working piston for precise and effective fastener insertion.

Innovation Solution

A hand-held setting device with a stator and working piston, utilizing a drive system that includes a piston coil and multiple stator coils oriented parallel to each other, where current flow generates aligned or opposing magnetic fields to accelerate the piston, and a capacitor for rapid energy discharge to enhance the magnetic field generation, along with a detection device for position-based control of current application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single stator coil and piston coil configuration is used, then the device structure is simple, but the efficiency and consistency of magnetic field generation are insufficient

Engineering Contradiction:
Improveefficiency of fastener drivingVSAvoidcoil configuration complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The stator coil system is segmented into multiple coils (first stator coil, second stator coil, third stator coil) arranged at different positions along the working axis. Each coil can be independently controlled to generate magnetic fields at specific stages of piston movement, enabling optimized acceleration throughout the entire stroke while maintaining manageable system complexity through modular architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control system activates different stator coils in a periodic sequence based on the piston's position. As the piston moves along the working axis, different coils are energized in succession to provide continuous and consistent magnetic field generation, ensuring efficient acceleration throughout the entire movement cycle rather than relying on a single continuous field.

Inventive Principle:
Principle #19Periodic action

2Speed

If magnetic fields are always aligned to accelerate the piston, then acceleration is maximized, but the piston cannot be decelerated or stopped precisely

Engineering Contradiction:
Improvepiston accelerationVSAvoidprecise positioning control
Core Design Contradiction:
SpeedVSEase of operation

Solution Approach 1:

The magnetic field configuration is dynamically adjusted based on the piston's real-time position and the operational phase. During the acceleration phase, coils are energized to create aligned magnetic fields that maximize piston speed. During the deceleration and positioning phase, the control system adjusts coil activation patterns to create opposing or reduced magnetic fields, enabling precise stopping and positioning of the piston at the desired location.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system can invert the magnetic field direction by reversing the current flow through the stator coils. This allows the same coil configuration to serve dual purposes: accelerating the piston when fields are aligned and decelerating/stopping it when fields are opposed, providing comprehensive control over the piston's motion profile throughout its entire cycle.

Inventive Principle:
Principle #13The other way round (Inversion)

3Force

If high current is continuously applied to generate strong magnetic fields, then piston acceleration is improved, but energy consumption and heat generation increase

Engineering Contradiction:
Improvemagnetic force on pistonVSAvoidenergy consumption
Core Design Contradiction:
ForceVSUse of energy by moving object

Solution Approach 1:

The control system applies current to stator coils in advance of when the piston reaches their optimal position, based on detected piston location. This preliminary activation ensures that magnetic fields are ready to act on the piston immediately when needed, maximizing acceleration efficiency without requiring continuous high current application throughout the entire cycle, thereby reducing overall energy consumption.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

By using multiple stator coils positioned along the working axis and activating them in sequence as the piston moves, the system maintains continuous useful magnetic action on the piston throughout its entire travel. This eliminates gaps in magnetic field application that would occur with single-coil systems, ensuring consistent energy transfer and efficient piston acceleration without requiring excessive current in any single coil.

Inventive Principle:
Principle #20Continuity of useful action

4Power

If the piston coil dips into the stator coil during movement, then magnetic coupling is enhanced, but mechanical interference and friction increase

Engineering Contradiction:
Improvemagnetic field couplingVSAvoidmechanical friction
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The system replaces direct mechanical contact between piston and stator components with magnetic field interaction. The piston coil and stator coils generate magnetic fields that act across a small air gap, eliminating the need for physical contact that would cause friction and wear. This electromagnetic coupling mechanism maintains strong power transfer while avoiding the harmful effects of mechanical friction and contact interference.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 quality in driving fasteners into substrates by optimizing the magnetic field generation and energy transfer, reducing mechanical loads and waste heat distribution, while allowing for precise control and effective fastener insertion.

Implementation Method 1

the first stator coil and/or the 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

generate a magnetic field to accelerate the working piston

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Implementation Method 3

the drive has a first capacitor, wherein the first stator coil and/or the piston coil can be electrically connected to the first capacitor in order to have current flow through it and generate the magnetic field when the first capacitor is quickly discharged

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP4076851B1Working implement
Publication Date: 2024.05.22 HILTI AG
  • EP4076851B1 patent drawingFigure 1
  • EP4076851B1 patent drawingFigure 2
  • EP4076851B1 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 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.