Power Tool Motion Sensing for Automatic Inactivity Shutoff
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Solution Overview
Problem
Electric power tools, such as chainsaws and hedge cutters, pose safety risks when left unattended in an active state, as they may not be easily recognizable as operational, leading to potential accidents, and existing solutions either fail to distinguish between inactivity and carrying the tool for later use or are not easily understood by all users.
Innovation Solution
Incorporating a movement sensor, like an accelerometer, into the power tool to detect absence of movement and inactivate the tool after a predetermined time period, ensuring safety without unnecessarily switching off the tool during intended pauses in use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power tool is switched off after a time period of inactivity, then safety is improved by preventing accidental activation, but the tool may be switched off when carried around for later use causing frustration and potential risk
Solution Approach 1:
The patent replaces the simple time-based inactivity detection with a movement sensor-based detection system. The controller monitors movement signals from the sensor to determine whether the tool is being carried or is truly inactive, substituting mechanical carrying detection with electronic sensor-based movement detection throughout the power tool system.
Solution Approach 2:
The movement sensor acts as an intermediary between the physical state of the tool (being carried or stationary) and the controller's decision-making process. The sensor provides objective movement data that mediates the controller's determination of tool activity status, preventing direct but potentially erroneous interpretation of mere time elapsed since activation.
2Loss of information
If LED or light indicators are used to show active state, then the active state is indicated, but the indicators are difficult to see and understand especially for children
Solution Approach 1:
The patent replaces visual light-based indication systems with movement sensor-based detection. Instead of relying on optical indicators that may not be visible or understood, the system uses movement sensors to detect physical carrying actions, substituting optical information transmission with mechanical movement detection that is universally understandable regardless of visual acuity or literacy.
3Ease of operation
If the power tool remains active indefinitely, then ease of use is improved by avoiding frequent reactivation, but safety is reduced as unattended active tools pose accident risks
Solution Approach 1:
The patent implements a dynamic safety mechanism that adapts the tool's active state based on real-time movement detection. Rather than a static time-based cutoff, the system dynamically adjusts between remaining active (when movement indicates carrying) and switching off (when no movement indicates unattended), allowing the operational state to flex according to actual usage conditions.
Solution Approach 2:
The movement sensor provides continuous feedback to the controller about the tool's physical state. This feedback loop allows the system to make real-time decisions about whether to maintain or terminate operation, with the sensor's movement signals serving as ongoing information that feeds back into the controller's active/inactive state determination process.
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 solution provides enhanced safety and ease of handling by accurately distinguishing between tool inactivity and intended pauses, preventing accidental activation while allowing continued use without frequent reactivation, thus addressing the limitations of prior art solutions.
Implementation Method 1
Incorporating a movement sensor, like an accelerometer, into the power tool to detect absence of movement
Data Source
Figure 1~2
Figure 3
AI summary
A power tool (100), such as a chainsaw, comprising means (230) for driving said power tool (100) and a controller (210). The power tool comprises a movement sensor (220) and the controller (210) is configured to receive a signal from said movement sensor (220), determine if said signal is a signal indicating a movement, determine a time wherein no signal indicating a movement is received, determine if said time exceeds a time period, and if so, disable said driving means (230).