Drilling Tool Motor Retry Control for Lock-Up and Kickback
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Solution Overview
Problem
Existing drilling devices require manual intervention to release locked states and may experience increased torque and kickback, leading to poor workability and operational inefficiencies.
Innovation Solution
A working tool with a control unit that alternates between normal and retry modes to manage torque and rotation speed, automatically adjusting motor operation to prevent lock-ups and reduce manual intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the output is increased to overcome the cause when detecting that a tool bit is about to be locked, then the drilling capability is improved, but the torque acting on the hand becomes large and kickback may be generated
Solution Approach 1:
The control unit implements periodic action by alternately repeating stop control and retry control with reduced torque when the first condition is satisfied. The motor is stopped temporarily and then restarted with reduced torque, creating a periodic on-off pattern that prevents continuous high torque application, thereby avoiding kickback while maintaining drilling capability through repeated attempts.
Solution Approach 2:
The control unit applies parameter changes by modifying the torque parameter during retry control. When the first condition is satisfied, the motor is driven at a torque smaller than the normal operating torque. This parameter adjustment reduces the harmful torque and kickback effects while still enabling the tool bit to progress through difficult material sections.
2Reliability
If a worker manually releases the locked state by operating the trigger, then the drilling device can be restarted, but the workability becomes poor due to repeated trigger operations
Solution Approach 1:
The control unit implements self-service by automatically detecting when the first condition is satisfied and executing the retry mode without worker intervention. The system autonomously performs stop control and retry control, eliminating the need for the worker to manually release the trigger and restart the drilling device, thereby significantly improving workability while maintaining reliability.
Solution Approach 2:
The control unit uses feedback by continuously monitoring the torque applied to the motor and comparing it against the first condition threshold. When the torque satisfies the first condition, the control unit automatically triggers the retry mode with reduced torque. This closed-loop feedback mechanism enables automatic adaptation to loading conditions without requiring manual input from the worker.
3Productivity
If the motor is continuously driven in normal mode, then the drilling efficiency is high, but the tool bit may become locked when torque increases excessively
Solution Approach 1:
The control unit implements feedback control by continuously monitoring torque and automatically transitioning from normal continuous driving mode to retry mode when the first condition is satisfied. This feedback mechanism detects excessive torque conditions and responds by implementing periodic stop and retry control with reduced torque, preventing tool bit lock-up while maintaining high drilling efficiency during normal operation.
Data Source
AI summary
A working tool and a drilling method capable of improving workability are provided. A working tool includes a motor, a trigger switch to instruct the driving of the motor, and a microcontroller to control the driving of the motor. The microcontroller stops the motor without transitioning to a retry mode when detecting a rapid increase of a motor current. The microcontroller transitions to the retry mode when detecting an overload without accompanying the rapid increase of the motor current. In the retry mode, the activation and stop of the motor are repeated. When the load applied to a tool bit is eliminated during execution of the retry mode, the microcontroller returns to a normal mode while the trigger switch is kept on.