Oscillating Hand Tool Vibration Control via Automatic Drive Restart
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Solution Overview
Problem
Existing hand tools that oscillate and monitor vibrations do not effectively limit vibrations to physiologically safe levels during operation, as they either shut down only after cumulative exposure or allow users to bypass vibration reduction measures.
Innovation Solution
An oscillating hand tool with a control unit that calculates a vibration characteristic from sensor signals and automatically switches off the drive when the characteristic exceeds a maximum value, then restarts after a short period, ensuring vibrations are limited to safe levels without user notice.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive is switched off when vibration limit is exceeded, then user safety is improved, but continuous operation is interrupted
Solution Approach 1:
The control unit implements periodic monitoring of vibration values and periodic restart of the drive after shutdown. The drive operates continuously with periodic interruptions only when vibration limits are exceeded, creating a cycle of operation-shutdown-restart that ensures safety while maintaining overall continuous functionality.
Solution Approach 2:
The control unit continuously monitors vibration sensor data and uses this feedback to automatically control the drive state. When vibration values exceed the threshold, the control unit shuts down the drive; when values return to acceptable levels, the control unit automatically restarts it, creating a closed-loop safety system.
2Productivity
If the drive restarts immediately after shutdown, then productivity is improved, but user may notice the interruption
Solution Approach 1:
The control unit is programmed with predetermined restart timing that automatically restarts the drive after a specific time interval following shutdown. This preliminary programming of restart action ensures minimal interruption while maintaining productivity, as the restart occurs automatically without user awareness or manual intervention.
3Reliability
If vibration monitoring is continuously performed, then vibration limitation is improved, but device complexity increases
Solution Approach 1:
The control unit autonomously performs vibration monitoring, comparison with threshold values, shutdown decisions, and automatic restart operations without requiring external intervention. The system serves itself by using its own computational resources to manage vibration control, eliminating the need for additional complex control mechanisms.
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
Effectively limits vibrations to physiologically acceptable levels by automatically restarting the drive after shutdown, ensuring user safety without noticeable interruption.
Implementation Method 1
with at least one vibration sensor for monitoring vibrations, whose output signals are supplied to a control unit
Data Source
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AI summary
An oscillating hand tool is described, with a drive (28) for the oscillating drive of a tool, with at least one vibration sensor (32) for monitoring vibrations, the output signals (vx, vy, vz) of which are supplied to a control unit (30) which is designed to derive a vibration characteristic value (vk) from the output signals (vx, vy, vz) of the vibration sensor (32) and then, when the vibration characteristic value (vk) exceeds a maximum value (vkmax), to switch off the drive (28) and subsequently restart it automatically.