Electric Grinder Grip Sensing for Automatic Drop Shutoff
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Solution Overview
Problem
Existing electric grinders lack effective safety measures to prevent accidents caused by inadvertent or unconscious tool dropping, and existing safety features are inadequate in varying work environments and grip positions, with additional issues in user convenience and post-accident response.
Innovation Solution
An electric grinder with a sensing mechanism to detect user contact or non-contact, a control unit to stop the motor upon non-contact, and a mode setting unit to switch between safety, operating, and reset modes, with emergency notification to external institutions if the safety mode is not released within a set time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light sensor or piezoelectric sensor is used to detect user grip, then the tool can detect whether the user is holding it, but the sensing accuracy varies depending on work environment or grip position, causing the power to not be turned off when necessary
Solution Approach 1:
The grip detection function is divided into multiple independent sensing zones (first grip sensing zone and second grip sensing zone) along the longitudinal direction of the handle. Each zone has its own sensor, allowing the system to detect grip status at different positions independently, thereby improving overall detection reliability and precision across various grip positions and work environments.
2Reliability
If an automatic power interruption unit with mechanical operation is used, then the electronic switch can be controlled, but the user must operate the power interruption unit while maintaining grip on the tool, reducing convenience
Solution Approach 1:
The system automatically detects grip status through the sensing zones and autonomously controls the power interruption without requiring user operation. When the sensor detects that the user has released the grip (no contact in both sensing zones), the control unit automatically interrupts power to the motor, eliminating the need for manual operation of the power interruption unit and improving ease of operation while maintaining reliability.
3Reliability
If safety measures are added to detect and respond to dropped tools, then safety accidents can be prevented, but the device complexity increases
Solution Approach 1:
The sensing zones serve multiple functions: they detect both grip status (whether the user is holding the tool) and drop status (whether the tool has been dropped). The same sensor system is used for normal operation safety monitoring and emergency drop detection, eliminating the need for separate detection systems and thereby reducing overall device complexity while providing comprehensive safety protection.
4Productivity
If the tool operates continuously without time limits, then work efficiency is maintained, but safety risks increase during prolonged operation
Solution Approach 1:
The control unit is configured to automatically interrupt power to the motor after a predetermined period of continuous operation. This periodic power interruption forces the user to release and re-grasp the tool, preventing fatigue-related accidents during prolonged operation while minimizing impact on overall work efficiency through brief, automatic safety pauses.
Data Source
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AI summary
The present invention relates to an electric grinder with safety measures, and includes a housing provided with a sensing means for sensing a human contact or a non-contact state in a grip part; a driving unit provided with a blade operating through a driving motor and a power transmission shaft on one side of the housing; a power supply unit provided on the other side of the housing and supplying power to the driving motor; and a control unit configured to control the driving motor to stop driving when the sensing means receives a signal of a human non-contact state.