Handheld Power Tool Work Status Detection Without Extra Sensors
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Solution Overview
Problem
Existing handheld power tools, such as rotary impact drivers, face challenges in automating operations to ensure reproducible and high-quality screwing and unscrewing processes, as users often struggle to react quickly to changes in machine characteristics, leading to issues like overtightening or screws dropping due to insufficient automation and reliance on fixed threshold values or additional sensors.
Innovation Solution
A method for operating handheld power tools that involves providing a model signal shape associated with the work status, determining and comparing operating variable signals with this model shape to ascertain the work status, and executing routines based on the determined status, thereby reducing user workload and improving operation accuracy without the need for additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed threshold values are used for determining operating modes, then the determination is simple, but it cannot function reliably across different applications and speed ranges
Solution Approach 1:
The patent transitions from static fixed threshold values to dynamic adaptive threshold values that automatically adjust based on detected operating parameters such as motor current, speed, and vibration patterns. This allows the system to maintain reliable operating mode determination across different applications and speed ranges without requiring manual reconfiguration.
Solution Approach 2:
The system changes the threshold parameters dynamically based on the operating conditions. Instead of using fixed thresholds, the system adapts threshold values according to the detected motor current, speed, and vibration characteristics, enabling reliable operation across diverse applications while maintaining determination simplicity.
2Measurement precision
If additional sensors like acceleration sensors are installed to determine operating modes, then measurement accuracy improves, but device complexity and cost increase
Solution Approach 1:
The system uses existing sensors (motor current, speed sensors) to perform multiple functions including operating mode determination. By analyzing vibration patterns and operating parameters from already-installed sensors, the system achieves accurate mode detection without requiring additional acceleration sensors, thereby maintaining measurement precision while avoiding increased device complexity.
Solution Approach 2:
Existing sensors are made multi-functional by using them not only for their primary purposes but also for operating mode determination. The motor current and speed sensors serve dual purposes: controlling motor operation and detecting operating modes through pattern analysis, eliminating the need for dedicated additional sensors.
3Ease of operation
If the user manually monitors and reacts to machine characteristics, then operation flexibility is maintained, but response time is insufficient leading to overtightening or screw dropping
Solution Approach 1:
The system implements automatic feedback control by continuously monitoring operating parameters and automatically adjusting motor operation based on detected work status. When the impact mechanism status changes or when screw fastening status is detected, the system automatically responds by adjusting speed or stopping the motor, eliminating the time delay associated with manual user reaction while maintaining operational flexibility through programmable response strategies.
Solution Approach 2:
The control system acts as an intermediary between the motor and the user, automatically interpreting operating parameters and executing appropriate responses. This intermediary function bridges the gap between manual control flexibility and automated rapid response, allowing the system to react instantly to changing conditions while preserving the user's ability to override or adjust parameters as needed.
Data Source
AI summary
The disclosure relates to a method for operating a handheld power tool having an electric motor, the method comprising: S1 providing at least one model signal waveform that is associated with a work progress of the handheld power tool; S2 determining a signal of an operating variable of the electric motor; S3 comparing the signal of the operating variable with the model signal waveform and determining a conformity evaluation on the basis thereof; S4 identifying the work progress at least partially using the conformity evaluation; S5 executing a first routine of the handheld power tool at least partially on the basis of the work progress identified in method step S4. The disclosure also relates to a handheld power tool, in particular an impact driver, comprising an electric motor and a control unit, wherein the control unit is designed to carry out a method according to the disclosure.