Non-Contact Trigger System for Impact Tools

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Solution Overview

Problem

Contact-type triggers in impact tools fail frequently due to erosion and repeated use in high-cycle applications, leading to increased maintenance needs and production delays.

Innovation Solution

A multiple position non-contact trigger system with a magnetically actuated sensor system that allows for controlled actuation of the power tool, using Hall Effect sensors to manage the movement of a trigger member and adjust the drive mechanism's speed and function based on trigger position, reducing wear and enhancing durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If contact-type triggers are used in impact tools, then the trigger system can detect and control tool operation, but the trigger components are prone to wear and failure due to repeated use and electrical arcing

Engineering Contradiction:
Improvetrigger system reliabilityVSAvoidtrigger component service life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent replaces the mechanical contact-type trigger switch with a non-contact magnetic sensor system. The trigger member includes a magnet that interacts with Hall effect sensors without physical contact, eliminating wear from both mechanical friction and electrical arcing. This substitution directly resolves the reliability issue by removing the worn components inherent in contact-type systems.

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

Solution Approach 2:

The patent introduces a magnetic field as an intermediary between the trigger member and the sensor system. The magnet on the trigger member creates a magnetic field that is detected by the Hall effect sensors, allowing trigger position detection without direct contact. This intermediary approach enables reliable signal transmission while eliminating the wear mechanisms present in contact-type systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If non-contact sensors are used to detect trigger position, then trigger durability is improved, but the system complexity increases due to additional sensors and control logic

Engineering Contradiction:
Improvetrigger system durabilityVSAvoidsensor system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent achieves multiple functions with a single magnetic sensor system. The Hall effect sensors not only detect trigger position but also enable multiple trigger modes (single-shot, continuous, semi-automatic) through different signal processing logic. This multi-functionality approach reduces the need for separate mechanical switches for different modes, thereby managing system complexity while maintaining enhanced durability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent utilizes changes in magnetic field parameters (strength, position) as the trigger member moves through different positions. The Hall effect sensors detect these parameter changes to determine trigger state, enabling a simple sensor design that can distinguish between multiple trigger positions and modes without requiring complex sensor arrays or mechanical linkages.

Inventive Principle:
Principle #35Parameter changes

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 system significantly increases the durability and reliability of impact tools by minimizing wear and tear, reducing maintenance needs, and ensuring consistent performance in high-cycle applications.

Implementation Method 1

The plurality of non-contact sensors are Hall Effect sensors and sense movement of the magnet on the trigger member

Methodology Applied
Scientific EffectHall Effect: Hall Effect

Data Source

PatentEP4491333A1Multiple position non-contact trigger system for a power tool
Publication Date: 2025.01.15 INGERSOLL RAND IND US INC
  • EP4491333A1 patent drawingFigure 1
  • EP4491333A1 patent drawingFigure 2
  • EP4491333A1 patent drawingFigure 3

AI summary

An impact tool having a multiple position non-contact trigger system. The trigger system includes a trigger member having at least one magnet moveable along a plurality of non-contact sensors when the trigger member moves from a non-actuated position to a fully actuated position. The plurality of non-contact sensors sense the movement of the trigger member and output a corresponding signal to a controller. The controller may command the impact tool to perform a function from a plurality of functions based on the position of the trigger element, where each position of the trigger element may correspond to a different mode of the power tool system.