Accelerometer-Based Anti-Kickback Control for Power Tools

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Solution Overview

Problem

Handheld power tools with self-locking functions can continue running after use, posing safety hazards, and kickback events can cause injury due to sudden torque transmission.

Innovation Solution

An anti-kickback module with an accelerometer and processor to detect acceleration changes, determining a kickback state and instructing a power controller to cease operation or actively decelerate the motor, using a braking profile or active braking mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a self-locking function is implemented to allow continuous operation, then productivity is improved, but safety deteriorates due to potential harm from uncontrolled continuous running

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoidsafety hazard from uncontrolled operation
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system continuously monitors acceleration data from the accelerometer and uses this feedback to detect kickback events. When abnormal acceleration patterns indicating kickback are detected, the system automatically triggers braking to stop the tool, thus maintaining productivity while eliminating safety hazards from uncontrolled operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces manual control mechanisms with an automated electronic control system that uses sensors (accelerometer) and processors to detect kickback events and trigger braking. This substitution allows the tool to automatically respond to kickback conditions without requiring user intervention, resolving the contradiction between continuous operation capability and safety.

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

2Device complexity

If manual control is used to stop the tool, then device complexity is reduced, but response time deteriorates during kickback events causing potential injury

Engineering Contradiction:
Improvecontrol system simplicityVSAvoidresponse time during kickback
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The system performs preliminary action by continuously monitoring acceleration data and pre-positioning the braking mechanism for immediate activation. When kickback is detected through acceleration analysis, the braking system is already ready to engage, eliminating response delay and allowing the tool to stop almost immediately, thus reducing loss of time without significantly increasing device complexity.

Inventive Principle:
Principle #10Preliminary action

3Object-affected harmful factors

If active braking is implemented to quickly stop the motor, then safety is improved, but device complexity increases due to additional braking mechanisms

Engineering Contradiction:
Improveinjury risk from kickbackVSAvoidbraking mechanism complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The processor acts as an intermediary between the accelerometer and the braking mechanism. It analyzes acceleration data to detect kickback events and triggers the braking system accordingly. This intermediary approach allows active braking to be implemented in a controlled manner, improving safety while managing device complexity through intelligent control rather than purely mechanical complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Productivity

If self-locking function is activated to maintain operation, then productivity is improved, but harmful factors worsen due to potential harm when user sets down the tool

Engineering Contradiction:
Improveoperational continuityVSAvoidharm from uncontrolled tool operation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The system uses feedback from the accelerometer to continuously monitor tool status and detect when the tool is set down or dropped. This feedback mechanism allows the system to maintain self-locking operation for productivity while automatically detecting abnormal conditions and triggering appropriate responses to prevent harm from uncontrolled operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces manual monitoring and control with an automated sensor-based system that detects when the tool is improperly positioned or set down. This substitution enables the tool to automatically respond to such conditions by triggering braking or other safety measures, maintaining productivity through self-locking while eliminating the harmful effects of uncontrolled operation.

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

Reduces the risk of injury by quickly stopping the power tool during kickback events and preventing harm from continuous operation after use.

Implementation Method 1

an accelerometer arranged to detect components of acceleration of the power tool

Methodology Applied
Scientific EffectAcceleration detection: Accelerometer

Data Source

PatentEP4613431A1Anti-kickback module and method of controlling operation of a power tool
Publication Date: 2025.09.10 TECHTRONIC CORDLESS GP
  • EP4613431A1 patent drawingFigure 1~2
  • EP4613431A1 patent drawingFigure 3A~3B
  • EP4613431A1 patent drawingFigure 4

AI summary

An anti-kickback module for a power tool comprises an accelerometer arranged to detect components of acceleration of the power tool, a power controller configured to control an operational state of the power tool, and a processor configured to determine a kickback state of the power tool based on a change in at least one component of acceleration of the power tool, and instruct the power controller to cease operation of the power tool in response to determining the kickback state.