Power Tool Safety Control Circuit for Pre-Start Switch Failure Detection
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Solution Overview
Problem
Power tools lack a mechanism to detect circuit failures before the motor is turned on, leading to potential hazards due to undetected transistor damage or static electricity, which can cause control abnormalities and safety issues.
Innovation Solution
A safety control circuit module that includes a control processing device with switch signal output pins and an examination signal input pin, connected to switch control circuits and diodes, allowing for pre-detection of switch unit failures before enabling the motor, ensuring safe operation by preventing continuous motor operation in case of switch unit burnout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If no pre-detection mechanism is implemented, then the device complexity is reduced, but the reliability deteriorates due to undetected circuit failures
Solution Approach 1:
The patent implements preliminary detection of switch unit status before motor operation begins. The control processing device checks whether switch units are in a normal or failed state prior to enabling motor control, preventing unsafe operation from the outset
Solution Approach 2:
The patent introduces an intermediary examination signal transmission mechanism between the control processing device and switch units. This signal pathway enables indirect detection of switch unit status without requiring direct physical inspection, resolving the contradiction between simple structure and reliable detection
2Object-affected harmful factors
If pre-detection of switch unit failures is implemented, then the safety is improved, but the device complexity increases due to additional control circuits
Solution Approach 1:
The patent extracts the safety detection function as a separate examination signal transmission mechanism independent from the main motor control pathway. This allows failure detection without integrating complex interlocking mechanisms into the primary control circuit
Solution Approach 2:
The control processing device performs self-diagnosis by examining the status of its own switch units through the examination signal mechanism. The system monitors its critical components without requiring external monitoring equipment, achieving safety functionality while minimizing additional circuit complexity
3Loss of information
If switch unit status is not monitored, then the ease of operation is maintained, but the loss of information occurs regarding circuit failure states
Solution Approach 1:
The patent establishes a feedback loop where the control processing device sends examination signals to switch units and receives status information in return. This automatic feedback mechanism provides continuous information about switch unit health without requiring manual inspection or complex user interaction
Solution Approach 2:
The control system automatically monitors and detects switch unit failure states without user intervention. The examination signal mechanism enables the system to self-diagnose critical component status, eliminating information loss while maintaining operational simplicity for the user
Data Source
AI summary
A power tool and a safety control circuit module and a safety control method thereof are provided. The power tool includes a power supply device, a control processing device, a safety control circuit module, and a power output device. The control processing device is electrically connected with the power supply device. The safety control circuit module includes a first switch control circuit, a second switch control circuit, a third switch control circuit, a first resistor, and a first diode. The power output device includes a first power connection terminal and a second power connection terminal. Before switch units of the control circuits are controlled, the control processing device detects whether the switch unit has failed, so as to increase safety.