Power Tool Acceleration Sensing for Loss of Control Braking
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Solution Overview
Problem
Existing power tools lack effective mechanisms to prevent loss of control during operation, which can lead to accidents and inefficiencies.
Innovation Solution
A power tool equipped with a brushless DC motor, a switching network, an acceleration sensor, and an electronic processor that detects loss of control events by measuring acceleration thresholds and controls the motor to brake in response, ensuring safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acceleration sensors and electronic processors are added to detect loss of control events, then safety and operational stability are improved, but device complexity increases
Solution Approach 1:
The acceleration sensor serves multiple functions: it detects loss of control events, monitors operational stability, and provides data for both safety interventions and performance optimization. The electronic processor integrates multiple control functions including loss of control detection, motor control, and safety intervention coordination into a single unit, reducing overall system complexity despite adding capability.
Solution Approach 2:
The electronic processor acts as an intermediary between the acceleration sensor and the motor control system. It processes sensor data, determines loss of control events, and coordinates braking interventions, thereby managing the complexity of integrating safety features with existing motor control architecture.
2Reliability
If the motor is braked in response to exceeding acceleration thresholds, then loss of control is prevented, but productivity decreases due to operational interruptions
Solution Approach 1:
The system applies preliminary anti-action by detecting acceleration patterns that precede complete loss of control and initiating progressive braking interventions. This prevents catastrophic failure while minimizing operational disruption through staged rather than abrupt stoppages.
Solution Approach 2:
The braking intervention is dynamic rather than static. The electronic processor adjusts braking force and duration based on the severity and persistence of acceleration threshold exceedances, allowing the system to maintain productivity when conditions are marginal while ensuring safety when loss of control is imminent.
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 prevents loss of control by braking the motor when acceleration thresholds are exceeded, enhancing safety and operational stability.
Implementation Method 1
The acceleration sensor is configured to measure an acceleration of the housing of the power tool with respect to at least two axes
Implementation Method 2
The brushless direct current ('DC') motor is within the motor housing portion and has a rotor and a stator. The rotor is configured to rotationally drive a motor shaft about a rotational axis
Implementation Method 3
The switching network is electrically coupled to the brushless DC motor
Implementation Method 4
control the switching network to brake the brushless DC motor in response to the one or more signals exceeding the acceleration threshold
Data Source
AI summary
A power tool includes a housing, a motor, a switching network electrically coupled to the motor, and a printed circuit board positioned at an angle within the housing. The power tool further includes a user input configured to receive a sensitivity level for loss of control detection, a sensor configured to measure an acceleration of the housing with respect to at least two axes, and an electronic processor coupled to the switching network. The electronic processor is configured to receive one or more signals related to the acceleration of the housing of the power tool from the acceleration sensor, determine that the one or more signals exceed an acceleration threshold corresponding to the sensitivity level for loss of control detection, and control the switching network to brake the brushless DC motor in response to the one or more signals exceeding the acceleration threshold.