Power Tool Vector Sensing for Early Kickback Detection
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Solution Overview
Problem
Existing power tools lack effective early detection of kickback and other operational states due to reliance on scalar quantities, which can lead to delayed recognition of potential hazards and increased risk of injury.
Innovation Solution
The use of a sensor device to detect mechanical vector quantities such as force, acceleration, speed, deflection, or deformation, allowing the control device to recognize events like kickback, forward sawing, or backward sawing by monitoring changes in direction, thereby enabling earlier and more accurate event detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If scalar quantities are used for detection, then the device complexity is reduced, but the measurement precision and early detection capability deteriorate
Solution Approach 1:
The patent transitions from scalar quantity detection to vector quantity detection by incorporating directional information. The sensor device measures both magnitude and direction of mechanical quantities, enabling the control device to detect kickback events through direction changes rather than relying solely on magnitude thresholds. This dimensional enhancement improves measurement precision without requiring overly complex sensor systems.
Solution Approach 2:
The patent changes the detected parameter from scalar to vector quantities. By monitoring directional parameters alongside magnitude, the system can identify kickback events through direction reversal, providing earlier and more accurate detection. This parameter transformation allows the use of relatively simple sensor devices while achieving high measurement precision.
2Loss of time
If scalar threshold comparison is used, then the device complexity is reduced, but the loss of time for early detection increases
Solution Approach 1:
The system performs preliminary detection by continuously monitoring the direction of mechanical quantities during normal operation. When a direction change indicative of kickback is detected, the system can trigger protective actions before the kickback fully develops. This preliminary action reduces detection time while the control device complexity remains manageable through algorithmic processing of vector data.
Solution Approach 2:
The control device continuously receives feedback from the sensor device regarding the direction and magnitude of mechanical quantities. By analyzing direction changes in real-time feedback, the system can detect kickback events earlier and respond promptly. This feedback mechanism reduces detection time while maintaining reasonable control device complexity through efficient data processing.
3Reliability
If vector quantities are detected, then the measurement precision and early detection capability are improved, but the device complexity increases
Solution Approach 1:
The patent adds directional information to the detection system by measuring vector quantities instead of scalar values. This dimensional enhancement allows the system to distinguish between normal operation and kickback events based on direction changes, significantly improving operational safety. The increased reliability is achieved without requiring overly complex sensor devices, as the vector measurement can be implemented with standard sensors capable of directional detection.
Solution Approach 2:
The system transforms the detected parameters from scalar to vector quantities, incorporating directional information. This parameter change enables more reliable kickback detection through direction reversal identification. The overall system complexity increases only moderately, as the vector measurement approach can utilize existing sensor technology with enhanced signal processing capabilities in the control device.
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
This approach allows for improved and earlier detection of power tool events and states, particularly anticipating kickbacks before significant acceleration occurs, enhancing operational safety by providing timely warnings or interventions.
Implementation Method 1
a sensor device (2) for detecting a mechanical vector variable 3 which depends on a force emanating from the tool (1)
Implementation Method 2
The mechanical vector variable is, for example, a force, an acceleration, a speed, a deflection, a deformation, and/or a mechanical stress
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The invention relates to an electric tool (10; 20; 30; 40; 0; 60) with a rotatable tool (1) formed as a saw blade or milling cutter, comprising a sensor device (2) for detecting a mechanical vector (3), wherein the mechanical vector (3) comprises a force, an acceleration, a velocity, a deflection, a deformation and/or a mechanical stress and the mechanical vector (3) depends on a force coming from the tool (1), and a control device (4) coupled to the sensor device (2) for communication, which control device is designed to identify an event and/or a state of the electric tool (10; 20; 30; 40; 0; 60) in accordance with a direction and/or change in direction of the mechanical vector (3) detected by the sensor device (2).