Hand-Held Power Tool Vibration Fault Detection and Safe Braking
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Solution Overview
Problem
Hand-held power tools require complex electronics to monitor operating currents, making them prone to defects and safety issues due to the need for precise fault detection and prevention.
Innovation Solution
The method employs an acceleration sensor to detect vibrations, comparing them to reference values to infer defects, allowing for reduced power operation and safe braking without complex monitoring devices, ensuring user safety by estimating defect presence and influencing tool operation accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex electronics are used to monitor operating currents for defect detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex electrical monitoring systems with a mechanical vibration-based detection system. An accelerometer sensor detects vibrations caused by defects in rotating components, and a evaluation unit analyzes these vibrations to identify defects. This mechanical approach substitutes the need for complex current monitoring electronics while maintaining effective defect detection capability.
2Reliability
If power output is reduced upon defect detection, then reliability is improved, but productivity decreases
Solution Approach 1:
The patent implements dynamic power management where the power output is adaptively adjusted based on defect severity. Instead of immediately shutting down the tool, the control unit reduces power output to a safe level that allows continued operation at reduced capacity. This dynamic response maintains reliability by preventing catastrophic failure while preserving partial productivity through controlled continued operation.
Solution Approach 2:
The patent applies partial action by reducing power output rather than completely shutting down the tool upon defect detection. This allows the tool to continue operating at a reduced power level, providing partial functionality that maintains some productivity while ensuring safety. The approach avoids excessive action (complete shutdown) when partial action (reduced power) is sufficient to maintain safety.
3Ease of manufacture
If vibration comparison with reference values is used for defect detection, then ease of manufacture is improved, but measurement precision may worsen
Solution Approach 1:
The patent applies preliminary action by storing reference vibration values before operation, which are obtained during manufacturing or initial setup. These reference values represent normal operating conditions and are used for comparison during actual operation. This preliminary preparation enables simple real-time defect detection through comparison without requiring complex real-time analysis systems, balancing manufacturing ease with detection precision.
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 approach simplifies defect detection, reduces the risk of overloading, and enhances user safety by reducing power and actively braking the tool when defects are detected, allowing safe completion of machining processes without sudden power loss.
Implementation Method 1
the hand-held power tool is monitored for vibrations by an accelerometer
Data Source
Figure 1~2
AI summary
The invention relates to a method for operating a hand-held power tool (1) comprising at least one acceleration sensor (9), said hand-held power tool (1) being monitored for any faults and the operating behavior thereof being influenced when a fault is sensed. The disclosed method involves the following steps: having the acceleration sensor sense vibrations of the hand-held power tool, comparing the sensed vibrations with previously stored reference vibrations, identifying a fault of the hand-held power tool (1) when the sensed vibrations differ from the reference vibrations by a predefined measure.