Rotary Hammer Mode-Based Loss-of-Control Detection
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Solution Overview
Problem
Existing rotary hammers lack effective systems for detecting loss of control during operation, particularly in modes where rotational and axial motion are concurrent, leading to potential user safety hazards.
Innovation Solution
A rotary hammer with an integrated loss-of-control detection system (LOCDS) that is activated or deactivated based on the operating mode, using a mode detection system to enable or disable protective operations such as disabling the motor or reducing power when acceleration thresholds are exceeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a loss-of-control detection system is continuously enabled, then user safety is improved, but nuisance shut-offs increase and operational reliability deteriorates
Solution Approach 1:
The loss-of-control detection system dynamically adjusts its sensitivity and operational status based on the detected operating mode. The system transitions between high-sensitivity protective mode and low-sensitivity permissive mode, allowing it to adapt to different operational contexts and reduce false positives while maintaining safety when needed.
Solution Approach 2:
The system changes the detection parameter threshold based on operating mode. In hammering mode, the acceleration threshold is set to detect genuine loss of control, while in drilling mode, the threshold is adjusted to accommodate normal operational vibrations, preventing unnecessary shutdowns.
2Reliability
If the loss-of-control detection system is highly sensitive, then safety is improved, but false positives increase causing nuisance shut-offs
Solution Approach 1:
The detection threshold parameter is dynamically adjusted based on the operating mode. The system uses different acceleration thresholds for different modes (hammering vs. drilling), allowing high sensitivity for safety in appropriate contexts while reducing sensitivity to prevent false alarms in other contexts.
Solution Approach 2:
The system dynamically adapts its detection sensitivity based on real-time operating mode detection, transitioning between protective and permissive states to balance safety with operational smoothness.
3Reliability
If protective operations are always active, then user safety is improved, but device complexity increases
Solution Approach 1:
The control system integrates multiple functions into a unified architecture that handles both normal operation control and loss-of-control detection through a single integrated controller, reducing overall system complexity while maintaining comprehensive safety protection.
Solution Approach 2:
The system performs preliminary detection of operating mode before activating the full loss-of-control detection protocol, allowing the controller to prepare appropriate response thresholds and parameters in advance, simplifying the real-time control logic.
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 system effectively reduces the risk of losing control by selectively enabling protective operations only when necessary, minimizing nuisance shut-offs and enhancing user safety.
Implementation Method 1
The mode selector can move a magnet that is detected by the operating mode detection system, the output signal generated based on detection of the magnet
Implementation Method 2
A sense element can be included. A sensor can sense a parameter corresponding to loss of control of the power tool
Data Source
AI summary
A power tool includes a housing, a motor supported by the housing, and a mode selector movable between a plurality of positions, each of the plurality of positions corresponding to one of plurality of operating modes of the power tool. The power tool further includes an operating mode detection system that detects a current operating mode of the power tool and generates an output signal corresponding to the current operating mode, and a loss-of-control detection system that performs protective operation based on an acceleration of the housing. The loss-of-control detection system is enabled or disabled based upon the output signal from the operating mode detection system.