Impact Wrench Reverse Control for Rusted Fastener Loosening
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Solution Overview
Problem
Existing impact tools, such as impact wrenches, struggle to loosen rusted or deformed fasteners due to their limited reverse rotation capabilities and inability to adjust torque output effectively.
Innovation Solution
An impact tool with a controller that adjusts the motor's speed and duty cycle based on the load parameter of the output shaft, allowing for a transition from a first speed to a second speed when a fastener is determined to be tightened, thereby increasing the torque output for loosening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the motor runs at full speed with a relatively large duty cycle in reverse rotation mode, then the impact tool can quickly loosen fasteners in normal conditions, but it cannot effectively loosen rusted or deformed fasteners that require higher torque
Solution Approach 1:
The patent implements dynamic speed adjustment by switching between a first speed (lower) and a second speed (higher) based on the fastener's state. The controller monitors the fastener condition and automatically adjusts the motor speed accordingly, transforming the static speed system into a dynamic one that adapts to different working conditions.
Solution Approach 2:
The patent changes the motor operating parameters (speed and duty cycle) based on the detected fastener state. When a fastener is identified as rusted or deformed, the controller adjusts the duty cycle and speed parameters to maximize torque output, thereby resolving the contradiction between speed and force.
2Adaptability or versatility
If the impact tool uses a fixed duty cycle for reverse rotation, then the control system remains simple, but the tool cannot adapt to different fastener conditions (rusted, deformed, or normal)
Solution Approach 1:
The patent employs a feedback mechanism where the controller continuously monitors the fastener's state during the loosening process. Based on this feedback, the controller automatically adjusts the motor's duty cycle and speed, enabling the system to adapt to different fastener conditions without requiring complex manual intervention.
Solution Approach 2:
The impact tool performs self-adjustment of its operating parameters based on the detected fastener condition. The controller automatically determines whether the fastener is rusted, deformed, or normal and adjusts the duty cycle and speed accordingly, making the system self-sufficient and reducing the need for external control complexity.
3Ease of operation
If the motor starts at full speed in reverse rotation mode, then the tool responds quickly to user input, but it provides poor operational feel and cannot effectively detect and respond to fastener tightness
Solution Approach 1:
The patent implements preliminary detection of the fastener's state before applying full torque. The controller first assesses whether the fastener is rusted, deformed, or normal and then determines the appropriate speed and duty cycle settings, ensuring optimal performance from the start of the loosening process.
Solution Approach 2:
The controller periodically monitors the fastener's state during the loosening process and adjusts the motor parameters accordingly. This periodic detection and adjustment mechanism ensures continuous optimization of the loosening process while maintaining good operational feel and responsiveness.
Data Source
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AI summary
An impact tool includes a controller for controlling a motor. The controller is configured to, when the direction of rotation of the motor is set to the reverse rotation direction, a drive shaft rotates at a first speed, and after an impact mechanism applies an impact force to an output shaft for a preset time, determine that a fastener is in a tightened state according to a load parameter of the output shaft and control the drive shaft to rotate at a second speed, where the second speed is greater than the first speed.