Impact Tool Shutoff Control by Sensed Impact Progression
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Solution Overview
Problem
Existing power tools like impact wrenches and drivers struggle to consistently apply a predefined torque and number of impacts, leading to over-tightening and difficulty in replicating recommended torque settings.
Innovation Solution
A power tool equipped with an impact sensor and motor controller that senses impact events and measures progression, transitioning between smooth rotation and impacting modes based on predefined criteria, ensuring consistent torque application and impact count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If impacts are delivered very rapidly to improve efficiency, then productivity increases, but manufacturing precision deteriorates due to difficulty in judging correct number of impacts and over-tightening
Solution Approach 1:
The system uses impact sensors to detect each impact event and provides feedback to the controller, which then deactivates the motor after a predefined number of impacts. This closed-loop feedback mechanism ensures precise control of impact count while maintaining high-speed operation, resolving the contradiction between productivity and manufacturing precision.
Solution Approach 2:
The patent replaces the mechanical judgment system (user visually and tactilely judging impact count) with an electronic sensing and control system. The impact sensors and controller automatically count and limit impacts, eliminating human judgment errors while maintaining rapid impacting capability.
2Ease of operation
If user judgment is used to control impact number, then ease of operation is maintained, but manufacturing precision deteriorates due to inability to consistently replicate torque
Solution Approach 1:
The system performs self-monitoring and self-control through integrated impact sensors and a controller that automatically deactivates the motor after the predefined impact count. The tool serves itself by autonomously controlling the impacting process without requiring user judgment or intervention, thereby maintaining ease of operation while achieving precise torque replication.
3Device complexity
If motor runs continuously without automated control, then device complexity is reduced, but manufacturing precision deteriorates due to inability to control impact progression
Solution Approach 1:
The patent replaces simple continuous motor operation with an electronic control system that uses impact sensors to detect impacting events and a controller to manage motor activation and deactivation. This substitution of mechanical control with electronic sensing and control enables precise impact progression control while keeping the overall device complexity manageable through integration.
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
Enables predictable and repeatable tightening operations by automatically controlling the number of impacts and torque, eliminating user judgment errors.
Implementation Method 1
The impact sensor may include an accelerometer
Implementation Method 2
The impact sensor may include one or more Hall-effect sensors arranged to sense an angular position of the one or more magnets about a rotation axis of the output shaft
Data Source
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AI summary
A power tool, comprises an activation trigger, an impact assembly comprising a hammer and an output shaft, a motor arranged to drive the hammer of the impact assembly, an impact sensor configured to sense one or more impact events of the impact assembly, and a motor controller configured to activate the motor in response to a user input via the activation trigger, determine an impacting state of the impact assembly based on the impact sensor output, in response to determining the impacting state of the impact assembly, to measure an impact progression of the impact assembly based on the impact sensor output, and deactivate the motor in response to measuring a predefined impact progression.