Power Tool Control Device Using 3D Hall Sensor
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Solution Overview
Problem
Conventional mechanical switches in power tools are prone to poor contact due to oxidation or contamination, leading to malfunctions.
Innovation Solution
A control device for power tools using a 3D Hall sensor to detect the position of magnets on the control trigger and direction-switching button, generating signals to activate and control the motor without mechanical switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mechanical switches with metal contacts are used, then the control device can detect trigger activation and direction switching, but the metal contacts are prone to oxidation or contamination resulting in poor contact and malfunction
Solution Approach 1:
The patent replaces mechanical switches with Hall sensors to detect trigger activation and direction switching. The Hall sensor detects the position of magnets attached to the trigger and direction-switching button through magnetic field changes, eliminating the need for mechanical contacts that are susceptible to oxidation and contamination. This substitution of mechanical detection with magnetic field-based detection resolves the reliability issue caused by environmental degradation of metal contacts.
2Reliability
If multiple separate sensors or switches are used to detect trigger activation and direction switching, then each function can be detected independently, but the circuit complexity increases
Solution Approach 1:
The patent employs a single 3D Hall sensor that performs multiple detection functions simultaneously. The Hall sensor detects both trigger activation (along the first axis) and direction switching (along the second axis) by measuring magnetic field changes in different spatial dimensions. This multi-functional approach eliminates the need for separate sensors or switches for each function, thereby reducing circuit complexity while maintaining reliable detection of all control operations.
Solution Approach 2:
The patent utilizes the three-dimensional capability of the Hall sensor to detect magnetic field changes along multiple axes (first axis for trigger activation, second axis for direction switching). By leveraging the spatial dimensionality of the magnetic field, a single sensor can distinguish between different control operations that occur in different directions, achieving multi-functionality without increasing the number of sensors.
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
The solution eliminates the issue of poor contact in mechanical switches, simplifies the circuit by using a single 3D Hall sensor to detect multiple operations, and enhances the reliability and performance of power tool control systems.
Implementation Method 1
a 3D Hall sensor is disposed on the control circuit board. A first magnet is disposed on the control trigger. The control trigger is movable on the trigger mounting bracket along a first axis, allowing the first magnet to approach or move away from the 3D Hall sensor along the first axis. The 3D Hall sensor detects a position of the first magnet and correspondingly generates a first signal.
Data Source
AI summary
A control device of a power tool includes a trigger mounting bracket, a control circuit board, a control trigger, and a direction-switching button. The control circuit board is disposed on the trigger mounting bracket and has a 3D Hall sensor. The control trigger has a first magnet and is disposed on the trigger mounting bracket to approach or move away from the 3D Hall sensor along a first axis. The direction-switching button has a second magnet and is disposed on the trigger mounting bracket to approach or move away from the 3D Hall sensor along a second axis. By detecting a variation of a magnetic field generated by different magnets in the first axis and the second axis when approaching or moving away from the 3D Hall sensor through the 3D Hall sensor, the power tool could be controlled to activate and switch directions.