Combustion-Powered Fastener Driver with Positive Piston Return
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Solution Overview
Problem
Combustion powered fastening devices often experience incomplete piston return, leading to blank fires or misfires, which require manual resets and pose safety risks.
Innovation Solution
A fastener driving device with a combustion chamber and a positive air return system, featuring a return chamber connected to the sleeve via vents with one-way valves, which increases gas pressure to reliably return the piston to its original position, and a nose leak channel to equalize pressure, ensuring consistent fastener firing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a combustion powered fastening device is used, then fastener driving capability is achieved, but incomplete piston return occurs leading to blank fires or misfires
Solution Approach 1:
The patent applies pneumatic principles by using combustion gas pressure differentials to drive piston motion. The combustion chamber generates high pressure gas that drives the piston forward, while the return chamber uses controlled gas flow through vents to create pressure differential that pushes the piston back to its initial position, ensuring complete return and preventing misfires
Solution Approach 2:
The patent implements a feedback mechanism where the state of the piston (position and motion) is continuously monitored through the interaction between combustion chamber pressure and return chamber pressure. The vent system provides feedback control by regulating gas flow based on pressure differential, ensuring the piston completes its return stroke before the next firing cycle begins
2Reliability
If manual reset is implemented after blank fire or misfire, then device can be reset, but user safety risk increases and firing delays occur
Solution Approach 1:
The device performs self-service through automatic piston return mechanism. The return chamber and vent system automatically restore the piston to its initial position after firing, enabling the device to prepare for the next firing cycle without user intervention. This eliminates the need for manual resetting and reduces user exposure to safety risks
3Productivity
If piston return speed is increased, then cycle time is reduced, but gas pressure control becomes more difficult
Solution Approach 1:
The patent employs dynamic pressure control through the vent system that adjusts gas flow based on real-time pressure differential between combustion chamber and return chamber. The vents are positioned and sized to provide optimal gas flow control during different phases of piston motion, enabling fast return while maintaining pressure control
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 enhances piston return reliability, reduces cycle time, and minimizes safety risks by preventing misfires and ensuring consistent fastener firing.
Implementation Method 1
combustion powered fastening devices use the expansion of gases generated during an explosion within a combustion chamber to drive a piston
Implementation Method 2
combustion gas expansion in the combustion chamber causes the piston to slide from a first position to a second position
Implementation Method 3
Gas returning from the return chamber to the sleeve via the first vent may be configured to bias the piston towards the first position
Data Source
AI summary
A fastener driving device comprising a combustion chamber, a piston and a fastener channel. The piston is coupled to the combustion chamber and slidable within a sleeve such that combustion gas expansion causes the piston to slide from a first position to a second position. The fastener channel is configured to receive a fastener, wherein when moving from the first to the second position, the piston is configured to engage the fastener. In one embodiment the device comprises a return chamber for receiving gas from the sleeve via a first vent, and a second vent coupled to the return chamber and for supplying combustion gas from the combustion chamber to the return chamber. In another embodiment, the combustion chamber comprises a housing portion, wherein combustion gas expansion acts on the housing portion such that the housing portion moves to open the combustion chamber and exhaust combustion gases.