Electromagnetic Setting Tool Piston Contacts for Fast 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 sufficient magnetic fields for effective acceleration of working pistons.

Innovation Solution

A hand-held setting device with a stator and working piston, utilizing a drive system that includes a capacitor and coils to generate opposing magnetic fields through rapid electrical discharge, with sliding contacts and springs to facilitate efficient energy transfer and movement along a working axis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a drive system with capacitor and coil is used to generate magnetic field for accelerating working piston, then acceleration effectiveness is improved, but waste heat generation increases

Engineering Contradiction:
Improveworking piston accelerationVSAvoidwaste heat
Core Design Contradiction:
SpeedVSLoss of energy

Solution Approach 1:

The drive system is segmented into two independent coils: a first coil for generating the primary magnetic field to accelerate the working piston, and a second coil for generating a counteracting magnetic field. This segmentation allows the system to achieve effective acceleration while reducing waste heat by canceling out thermal effects through the opposing second coil.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If magnetic field strength is increased to improve acceleration, then setting quality is improved, but load on drive system increases

Engineering Contradiction:
Improvesetting qualityVSAvoiddrive system load
Core Design Contradiction:
Manufacturing precisionVSForce

Solution Approach 1:

A second coil acts as an intermediary element that generates a counteracting magnetic field to reduce the overall load on the drive system. This allows the first coil to maintain strong magnetic field strength for high-quality setting while the second coil compensates for excessive force requirements, effectively mediating between acceleration needs and system load constraints.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Use of energy by moving object

If electrical contacts are designed for rapid discharge, then energy transfer efficiency is improved, but risk of electrical issues increases

Engineering Contradiction:
Improveenergy transfer efficiencyVSAvoidelectrical system stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The electrical contact system is extracted and specifically designed with sliding contacts that separate the high-current discharge path from the control circuitry. This extraction allows rapid energy discharge for efficient piston acceleration while isolating sensitive electrical components from the high-stress discharge conditions, thereby maintaining reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

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 device achieves high efficiency and improved setting quality by generating strong magnetic fields that effectively accelerate the working piston, reducing the load on the drive and user, while also reducing waste heat and the risk of electrical issues.

Implementation Method 1

the piston coil is electrically connectable to the capacitor in order to have current flow through it when the capacitor is rapidly discharged and to generate the magnetic field that accelerates the working piston relative to the stator

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the stator has a first electrical stator contact and the working piston has a first electrical piston contact which slides on the first electrical stator contact

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4076854B1Working implement
Publication Date: 2024.04.24 HILTI AG
  • EP4076854B1 patent drawingFigure 1
  • EP4076854B1 patent drawingFigure 2
  • EP4076854B1 patent drawingFigure 3~5

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 stator has a first electric stator contact, and the working piston has a first electric piston contact which contacts the first electric stator contact and which is arranged on a radially outer circumference of the working piston with respect to the working axis.