Fastener Driving Device Pneumatic Piston Return Mechanism
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Solution Overview
Problem
Existing fastener driving devices often experience incomplete piston return, leading to blank fires or misfires, which cause delays and expose users to risk due to the need for manual reset.
Innovation Solution
A fastener driving device is designed with a pressure chamber, a first piston that drives fasteners, and a second piston within a sleeve that compresses gas to bias the first piston back to its original position, ensuring complete piston return.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate source of pressurised gas is used to drive the piston, then the device can operate reliably, but the device complexity increases due to additional gas storage and delivery systems
Solution Approach 1:
The patent combines the driving gas storage and the return gas storage into a single integrated gas reservoir. The gas reservoir is positioned to supply gas to both the driving chamber (for piston advancement) and the return chamber (for piston return), eliminating the need for separate gas storage systems and reducing overall device complexity while maintaining reliable piston operation in both directions
Solution Approach 2:
The gas reservoir serves multiple functions: it stores pressurised gas for driving the piston forward, stores pressurised gas for returning the piston to its initial position, and can be selectively connected to either the driving chamber or the return chamber through valve control. This multi-functional design reduces the number of components needed while ensuring reliable gas supply for both piston movements
2Device complexity
If the piston return mechanism is simplified, then the device complexity is reduced, but incomplete piston return occurs leading to blank fires or misfires
Solution Approach 1:
The patent uses a pneumatic return mechanism where pressurised gas from the gas reservoir is directed into the return chamber, which is in communication with the driving chamber. The pressurised gas creates a pressure differential that reliably forces the piston back to its initial position, ensuring complete return without requiring complex mechanical spring or cam mechanisms
Solution Approach 2:
The system incorporates a valve mechanism that automatically detects when the piston has reached its initial position and switches the gas flow from the driving chamber to the return chamber. This feedback control ensures that the piston is fully returned before the next firing cycle begins, preventing blank fires while maintaining a simple overall mechanism
3Device complexity
If manual reset is required after blank fire or misfire, then device complexity is reduced, but productivity decreases due to operational delays and safety risks
Solution Approach 1:
The patent implements an automatic reset system where the valve mechanism automatically switches between driving and return gas flow based on piston position. After the piston completes its forward stroke and returns to the initial position, the system automatically prepares for the next firing cycle without requiring manual intervention, thereby eliminating operational delays and maintaining simple device architecture
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 solution ensures complete piston return, reducing the likelihood of blank fires and misfires, thereby improving operational efficiency and user safety by eliminating the need for manual reset.
Implementation Method 1
compressed gas in the sleeve biases the first piston towards the first position
Implementation Method 2
the first piston drives the second piston and compresses gas within the sleeve
Implementation Method 3
pressurized gas in the pressure chamber causes the piston to slide from a first position to a second position
Data Source
Figure 1
Figure 2a~2c
Figure 2d~2f
AI summary
A fastener driving device (100) comprising a pressure chamber (110), a first piston (128), a fastener channel and a second piston (454). The first piston (128) is coupled to the pressure chamber such that pressurized gas in the pressure chamber causes the first piston to slide from a first position to a second position. The fastener channel is configured to receive a fastener (102), wherein when moving from the first position to the second position the first piston is configured to engage a fastener and drive it from the device. The second piston (454) is slidable within a sleeve (458) and arranged such that when the first piston slides from the first position to the second position the first piston drives the second piston and compresses gas within the sleeve. Compressed gas in the sleeve biases the first piston towards the first position.