Handheld Tool Torque Control via Axis Rotation Frequency
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Solution Overview
Problem
Handheld power tools with protective functions against excessive torque often interfere with operations when used with a stand, as the protective mechanisms are not effectively switched off, leading to reduced torque output and potential interference with machining processes.
Innovation Solution
A control method that detects rotational movements of the tool holder about the working axis, triggers a protective function if the movement exceeds a specific limit value, and switches it off based on a characteristic variable of the frequency spectrum of the detected rotational movement, allowing for distinction between handheld and stand-held operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the protective function is activated to protect against excessive torque in handheld operation, then user safety is improved, but torque output is reduced during stand-held operation causing interference with machining processes
Solution Approach 1:
The protective function is made dynamically controllable through frequency spectrum analysis. The system continuously monitors rotational movement characteristics and adapts the protective function's activation state based on whether the tool is handheld or stand-held, allowing optimal torque output for each operation mode while maintaining safety when needed
Solution Approach 2:
The system changes the operational parameters of the protective function based on detected frequency spectrum characteristics. By analyzing the frequency content of rotational movements, the system identifies distinct patterns between handheld and stand-held operations and adjusts the protective function's torque reduction threshold accordingly, enabling full torque output during stand-held machining while maintaining safety limits during handheld operation
2Reliability
If the protective function continuously reduces torque when rotational movement exceeds a limit value, then protection against excessive torque is improved, but the protective function cannot be switched off during stand-held operation causing unnecessary torque reduction
Solution Approach 1:
The system implements feedback control by continuously monitoring rotational movement characteristics and using frequency spectrum analysis to determine the operational mode. This feedback mechanism allows the protective function to automatically adapt its behavior - maintaining torque protection during handheld operation while switching to unrestricted torque output during stand-held operation, providing both safety and operational flexibility
Solution Approach 2:
The protective function performs self-service by automatically detecting the operational mode through frequency spectrum analysis and adjusting its own activation state without external intervention. The system monitors its own operational context and makes autonomous decisions about whether to apply torque reduction, eliminating the need for manual switching while ensuring appropriate protection in each mode
Data Source
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AI summary
The control method according to the invention for a hand-held power tool (1), which has a tool holder (2) and a motor (4) for rotating the tool holder (2) about a working axis (11), comprises the steps: detecting (S1) a rotary movement of a housing (9) of the hand-held power tool (1) about the working axis (11), triggering (S2) a protective function to reduce a torque output of the motor (4) when the detected rotary movement about the working axis (11) exceeds a certain limit value, and switching off (S3) the protective function depending on a characteristic size of a frequency spectrum of a detected rotary movement about the working axis (11).