Hand-held Tool Load Detection via Current and Position Sensors
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Solution Overview
Problem
Existing hand-held tools, such as electric hammers and drills, struggle to accurately detect load conditions, particularly when the load change is small due to insufficient or excessive pressing, which can lead to inefficient operation and potential damage from excessive loads.
Innovation Solution
A hand-held tool equipped with multiple detecting sensors, including a current sensor for load current detection and a microswitch position sensor, along with an indicating device and driving control system, to accurately identify no-load, normal load, and heavy load conditions, providing visual and audio feedback to the user and adjusting the tool's operation accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single type of sensor is used to detect load conditions, then the device complexity is low, but the measurement precision of load conditions is insufficient
Solution Approach 1:
The patent divides the load detection function into multiple specialized sensors: a current sensor for detecting motor load current and a position sensor for detecting hammer bit position. Each sensor is optimized for its specific detection task, enabling accurate differentiation between no-load, normal load, and heavy load conditions without requiring a single complex sensor system.
Solution Approach 2:
The patent combines the outputs of multiple sensors (current sensor and position sensor) through a controller that integrates their signals to comprehensively determine load conditions. This merging of sensor data allows the system to accurately detect load states by cross-referencing multiple measurement sources, resolving the contradiction between using simple individual sensors and achieving precise overall detection.
2Measurement precision
If multiple detecting sensors are used to accurately detect load conditions, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The controller serves multiple functions: it processes signals from both the current sensor and position sensor, determines load conditions based on their combined outputs, controls motor driving accordingly, and activates the indicating device. This multi-functionality reduces the need for separate dedicated components for each task, thereby managing system complexity while maintaining high measurement precision.
Solution Approach 2:
The controller acts as an intermediary that coordinates between the multiple sensors and the final control actions. It integrates the measurement data from sensors, processes the information to determine load conditions, and then drives both the motor control and indication systems. This intermediary role simplifies the overall system architecture by providing a central coordination point.
3Measurement precision
If load current detection alone is used, then the ease of operation is simple, but the measurement precision of small load changes is insufficient
Solution Approach 1:
The patent dynamically adjusts the detection strategy based on operating conditions by combining real-time data from both current sensors and position sensors. The controller continuously monitors both parameters and adapts its load condition determination accordingly, enabling precise detection of small load changes while maintaining smooth, automatic operation without requiring user intervention or complex manual adjustments.
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 enables precise detection of load conditions, preventing excessive load usage and enhancing tool durability by providing users with real-time feedback and controlling the tool's operation to match the detected load, thus ensuring efficient and safe operation.
Implementation Method 1
a means for detecting load current of the motor
Implementation Method 2
a position sensor for detecting relative positional displacement of two members which move relative to each other when the tool bit is pressed against the workpiece
Data Source
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AI summary
An effective technique for detecting several load conditions different in presence or absence and magnitude of load applied to a tool bit is provided in a hand-held tool. A hand-held tool 101 performs a predetermined operation while pressing a tool bit 119 mounted in a front end region of a tool body 103 against a workpiece. A plurality of detecting sensors 161 of different kinds detect several load conditions different in presence or absence and magnitude of load applied to the tool bit 119. The hand-held tool 101 includes at least one of an indicating device 171 which indicates the load conditions based on a result detected by the detecting sensors 161, and a driving control device 135 which controls driving of the tool bit 119 based on the detected result.