Active Safety Sensor for Fastener Tools
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Solution Overview
Problem
Nail guns pose a significant safety risk due to misuse or disablement of existing safety features, leading to frequent injuries, with a higher risk associated with multi-shot contact triggers and accidental firings into human tissue or open air.
Innovation Solution
A two-part sensor system and two-stage driving system are implemented, utilizing capacitive touch sensors and a neural network to differentiate between hazardous and non-hazardous targets, locking out the trigger and employing a high-speed catch system to prevent unintended firings, ensuring safe operation and accurate fastener placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional safety features (pressure plates, sequential triggers) are implemented, then basic safety is improved, but these features are frequently misused or disabled leading to injuries
Solution Approach 1:
The patent replaces mechanical safety features (pressure plates, sequential triggers) with an optical sensing system using time-of-flight sensors to detect skin contact. This substitution eliminates the reliance on user compliance with mechanical safety mechanisms while maintaining protective functionality through automatic optical detection.
Solution Approach 2:
The patent introduces an intermediary sensing system that detects skin contact through optical time-of-flight measurements before the fastener can contact the user. This intermediary detection layer prevents direct contact between the fastener and skin, resolving the contradiction by providing safety through detection rather than relying on user adherence to mechanical safety features.
2Productivity
If multi-shot contact triggers are used to improve ease of operation, then firing speed is improved, but the risk of injury is twice as high compared to single-shot sequential triggers
Solution Approach 1:
The patent implements continuous optical feedback during the fastening operation. Time-of-flight sensors monitor for skin contact in real-time, and the system provides immediate feedback by disabling further firing upon detection. This allows multi-shot capability for productivity while ensuring safety through continuous monitoring that prevents harmful accidental contact.
3Reliability
If pressure plates are used to prevent firing into open air, then basic safety is improved, but users can circumvent by holding down the trigger for bump firing
Solution Approach 1:
The patent replaces mechanical pressure plate restrictions with optical sensing that detects skin contact regardless of trigger state. This substitution maintains the ability to fire in various modes (including bump firing for versatility) while ensuring safety through optical detection that prevents firing into open air or accidental contact with skin.
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 significantly improves safety by preventing hazardous unintentional firings and enhances performance by accurately driving fasteners, reducing the risk of injury and ensuring precise placement, while maintaining reliable operation.
Implementation Method 1
A capacitive sensor in the pressure plate detects skin contact
Implementation Method 2
An ultrasonic sensor detects skin contact
Implementation Method 3
An RF sensor detects skin contact
Implementation Method 4
A neural network has been trained on sensor data from the contact detection system to classify various types of materials including skin of a user
Data Source
AI summary
An active safety device and method for fastener tools that includes a first sensor that detects a hazardous target; a first driver that drives the fastener a minimal distance into the material, the fastener being conductive and acting as a second sensor; a second driver that drives the fastener into the material; a processor that receives information from the first sensor and determines if a hazardous target is detected by said first sensor and engages a trigger interlock if the hazardous target is not detected the first driver is engaged and said second sensor provides information on the composition of the material to the processor; wherein the processor engages the trigger interlock when it determines if the composition of the material is classified as a hazardous target and otherwise initiates the second driver to drive the fastener into the material.