Power Tool Material Detection for Pre-Contact Motor Interruption
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Solution Overview
Problem
Power tools lack effective mechanisms to safely interrupt operation when detecting certain objects in their operating path, potentially leading to unsafe conditions, especially when encountering human presence or specific materials.
Innovation Solution
A power tool system that includes an object detection sensor and a controller to determine the presence and type of objects in its operating path, allowing for real-time adjustment of motor power to prevent accidents, such as interrupting power when flesh or specific materials are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power tools operate continuously without object detection, then productivity is maintained, but safety risks increase when hazardous objects are present in the operating path
Solution Approach 1:
The object detection sensor detects hazardous objects in advance before the power tool's output component reaches them. The controller receives detection signals and interrupts power to the motor proactively, preventing contact between the output component and hazardous objects. This preliminary detection and response mechanism ensures safety without requiring continuous monitoring during operation.
2Reliability
If object detection sensors and controllers are added to power tools, then safety is improved, but device complexity increases
Solution Approach 1:
The controller serves multiple functions: it controls motor operation during normal use and simultaneously acts as a safety system by receiving signals from the object detection sensor and interrupting power when hazardous objects are detected. This multi-functionality reduces the need for separate dedicated safety components, thereby limiting the increase in device complexity while maintaining improved safety.
3Reliability
If power is interrupted when objects are detected, then safety is enhanced, but operating time is reduced when objects are present
Solution Approach 1:
The interruption of power when hazardous objects are detected, while reducing operating time, converts a potentially harmful situation into a beneficial safety outcome. The system prioritizes preventing accidents over maintaining continuous operation, transforming the limitation into a protective feature that safeguards users and prevents damage to equipment or workpieces.
Data Source
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AI summary
A power tool and methods are provided for detecting objects (e.g., flesh or other materials) in the operating path of a power tool's output component (e.g., saw blade or drill bit). An object detection sensor in the power tool generates an output signal indicative of a type of material detected in the operating path of the power tool. A power tool controller receives the object detection sensor output and determines when a material in the operating path of the power tool changes. The controller changes operation of a motor of the power tool (e.g., increasing or decreasing speed or stopping the motor) in response to the detected material change. The object detection sensor may include, for example, an RF sensor, a capacitive sensor, a camera, a conductivity probe, or an ultrasound probe.