Hand-Guided Tool Hall Sensor Switching Mechanism

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Solution Overview

Problem

Existing hand-held tools with drive engines face challenges in efficient commissioning due to complex mechanical and electrical locking mechanisms, which can lead to operational inefficiencies and increased user effort.

Innovation Solution

A hand-held tool design incorporating a housing with a drive engine, a switching unit, and an electronic switch featuring a Hall sensor and a magnetically operated actuating element. This setup allows for electronic control of the drive engine's operational readiness through condition signals generated by the Hall sensor, enhancing commissioning efficiency with both mechanical and electronic security mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical locking mechanisms are used for actuating the drive motor, then operational safety is ensured, but device complexity and user effort increase

Engineering Contradiction:
Improveoperational safetyVSAvoidcomplexity of locking mechanisms
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical contact-based switching mechanisms with a Hall effect sensor-based electronic switching system. The actuating element interacts with the Hall sensor through magnetic field changes rather than direct mechanical contact, eliminating complex mechanical linkages while maintaining reliable position detection and operational safety.

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

Solution Approach 2:

The patent introduces a magnetic field as an intermediary between the actuating element and the Hall sensor. This magnetic field mediator allows the actuating element to communicate its position to the control system without requiring direct mechanical contact or complex mechanical switching mechanisms, thereby simplifying the overall device structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If mechanical switching mechanisms are used for actuating the drive motor, then operational control is achieved, but commissioning efficiency decreases

Engineering Contradiction:
Improveoperational controlVSAvoidcommissioning efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent replaces mechanical switching mechanisms with an electronic Hall effect sensor-based system that detects the position of the actuating element through magnetic field changes. This electronic approach enables faster, more precise detection of actuating element position, thereby improving commissioning efficiency while maintaining operational control.

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

Solution Approach 2:

The Hall sensor automatically detects the position of the actuating element through magnetic field changes without requiring manual intervention or complex mechanical linkages. The system self-regulates by continuously monitoring the magnetic field state and generating appropriate control signals, thereby streamlining the commissioning process.

Inventive Principle:
Principle #25Self-service

3Device complexity

If contact-based switching mechanisms are used, then simple circuit control is achieved, but reliability and user effort increase

Engineering Contradiction:
Improvesimplicity of circuit controlVSAvoidreliability of switching mechanism
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent replaces contact-based mechanical switching with a non-contact Hall effect sensor system. The Hall sensor detects the position of the actuating element through magnetic field changes without requiring physical contact, thereby eliminating wear and contact failure issues while maintaining simple circuit control through electronic signal processing.

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

Solution Approach 2:

The patent uses a magnetic field as an intermediary to transmit position information from the actuating element to the Hall sensor without requiring direct contact. This magnetic field mediator enables reliable, contactless detection while keeping the control circuit simple through electronic signal generation and processing.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution enables improved commissioning of hand-held tools by simplifying the activation process through electronic control, reducing user effort, and ensuring reliable operation through dual security mechanisms.

Implementation Method 1

The electronic switch comprises a switching element with a Hall sensor and an actuating element formed separately from the switching element, wherein the actuating element for actuating the switching element is operatively connected to the Hall sensor

Methodology Applied
Scientific EffectHall effect: Hall Effect

Implementation Method 2

If the magnet is moved relative to the Hall sensor, the magnetic field and the magnetic flux density flowing through the Hall sensor change.

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP4292767B1Hand-guided tool
Publication Date: 2025.04.09 ANDREAS STIHL AG & CO KG
  • EP4292767B1 patent drawingFigure 1
  • EP4292767B1 patent drawingFigure 2~3
  • EP4292767B1 patent drawingFigure 4

AI summary

The invention relates to a hand-held tool (1) comprising a housing (2), a tool (4), and a drive motor (3) arranged in the housing (2) for driving the tool (4), a switching unit (8) for actuating the drive motor (3) with at least one actuating element (9), wherein the at least one actuating element (9) can be switched into at least a first position (51) and a second position (52), an electronic switch (10) for detecting the switching positions of the at least one actuating element (9), wherein the electronic switch (10) generates a status signal dependent on the switching positions of the actuating element (9), and a control unit (17), wherein the control unit (17) switches the operational readiness of the drive motor (3) depending on the status signal of the electronic switch (10).wherein the electronic switch (10) comprises a switching element (11) with a Hall sensor (12) and an actuating element (13) designed separately from the switching element (11), wherein the actuating element (13) is operatively connected to the Hall sensor (12) for actuating the switching element (11) and on which at least one actuating element (9) is arranged.