Power Tool Bog-Down Control for Excessive Load Feedback
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Solution Overview
Problem
High-powered electric motor driven power tools do not provide innate bog-down feedback to users, leading to potential damage from excessive loading, which can cause rapid battery depletion.
Innovation Solution
Implementing an electronic processor to detect load thresholds and control a power switching network to simulate bog-down conditions, mimicking the feedback experienced in gas engine-powered tools, including speed reduction and oscillation to provide tactile and audible feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-powered electric motor driven power tools operate without bog-down feedback mechanism, then power and productivity are improved, but reliability deteriorates due to potential damage from excessive loading and battery depletion
Solution Approach 1:
The system implements a feedback mechanism where the electronic processor continuously monitors motor current draw and compares it against predefined thresholds. When excessive current is detected, the system provides simulated bog-down feedback by reducing motor speed through the power switching network, alerting the user to reduce loading. This closed-loop feedback prevents damage while maintaining high power capability during normal operation.
2Ease of operation
If electric motor driven power tools lack resistive force feedback, then ease of operation is improved, but harmful factors increase due to excessive current draw and battery depletion
Solution Approach 1:
The electronic processor monitors motor current and provides feedback control through the power switching network. When current exceeds safe thresholds, the system automatically reduces motor speed to limit current draw, preventing battery depletion and overheating while maintaining simple operation for the user.
Solution Approach 2:
The patent replaces the mechanical resistive feedback mechanism of gas engine-powered tools with an electronic control system. The power switching network electronically modulates motor speed to simulate bog-down conditions, eliminating the need for mechanical resistance while achieving the same protective effect.
3Reliability
If power switching network continuously monitors and controls motor speed to simulate bog-down, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical feedback mechanisms with an electronic control system. The electronic processor and power switching network provide precise control over motor speed and current, achieving reliable bog-down simulation with simpler, more controllable electronic components rather than mechanical linkages.
Solution Approach 2:
The system dynamically changes motor operating parameters (speed, current) based on real-time conditions. The electronic processor adjusts power delivery through the switching network to simulate bog-down conditions only when needed, maintaining simple operation during normal conditions while providing protection when thresholds are exceeded.
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
Simulates bog-down conditions in electric motor driven tools, providing users with feedback on excessive loading, preventing potential damage and conserving battery power.
Implementation Method 1
a motor selectively coupled to the power source. The motor includes a rotor and stator windings
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
Simulated bog-down system and method for power tools. One power tool according to an example embodiment includes a power source and a motor selectively coupled to the power source. The motor includes a rotor and stator windings. The power tool includes an actuator configured to generate a drive request signal and a power switching network configured to selectively couple the power source to the stator windings of the motor. The power tool includes an electronic processor coupled to the power source, the actuator, and the power switching network. The electronic processor is configured to detect a load on the power tool and compare the load to a threshold. The electronic processor is configured to determine that the load is greater than the threshold, and to control the power switching network to simulate bog-down in response to determining that the load is greater than the threshold.