Chamber Member Retaining Assembly for Combustion Fastener Tools
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Solution Overview
Problem
Certain combustion-powered fastener-driving tools face issues with operator fatigue due to limited operational modes, as they typically operate in sequential firing mode and not in bump-fire mode, and there is a risk of the chamber member unsealing before the piston returns to the pre-firing position, leading to vacuum pressure loss and tool malfunction.
Innovation Solution
A chamber member retaining assembly is introduced, controlled by a suitable controller, which includes a gas-assisted actuation member and an electromagnet to maintain the chamber member in a sealed position until the piston fully returns, enabling the tool to operate in both sequential and bump-fire modes by preventing undesired movement of the chamber member and ensuring the combustion chamber remains sealed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the chamber member is allowed to move freely to unseal the combustion chamber, then the tool can operate in bump-fire mode with rapid successive firings, but the chamber member may unseal before the piston returns to the pre-firing position causing vacuum pressure loss and malfunction
Solution Approach 1:
The chamber member retaining assembly dynamically controls the chamber member position based on piston location. The electromagnet activates when the piston is in the firing position to retain the chamber member in the sealed position, preventing premature unsealing. When the piston returns to the pre-firing position, the electromagnet deactivates and the chamber member is released to move to the unsealed position, enabling bump-fire mode operation.
Solution Approach 2:
The system uses feedback from the piston position to control the chamber member retaining assembly. The controller monitors piston location and accordingly activates or deactivates the electromagnet, creating a closed-loop control system that ensures the chamber member is retained only when necessary to maintain vacuum pressure, while allowing unsealing when the piston is ready for the next cycle.
2Reliability
If the chamber member is retained in the sealed position during piston retraction, then vacuum pressure is maintained and tool malfunction is prevented, but the tool cannot operate in bump-fire mode with rapid successive firings
Solution Approach 1:
The chamber member retaining assembly dynamically controls the chamber member position based on piston location. The electromagnet activates when the piston is in the firing position to retain the chamber member in the sealed position, preventing premature unsealing. When the piston returns to the pre-firing position, the electromagnet deactivates and the chamber member is released to move to the unsealed position, enabling bump-fire mode operation.
Solution Approach 2:
The system performs preliminary retention of the chamber member in the sealed position during piston retraction to ensure vacuum pressure is maintained before the next firing cycle. This preliminary action prevents potential malfunction and ensures the combustion chamber is ready for the next ignition event, while still allowing rapid successive firings through controlled timing.
3Reliability
If the tool operates only in sequential firing mode, then vacuum pressure loss is prevented, but operator fatigue increases due to limited operational modes
Solution Approach 1:
The chamber member retaining assembly enables the tool to operate in multiple firing modes: sequential mode (single actuation per trigger pull) and bump-fire mode (rapid successive firings). By dynamically controlling the chamber member retention based on piston position, the system provides both operational flexibility and maintains vacuum pressure integrity, allowing operators to select the appropriate mode for different application requirements.
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
This solution allows the tool to operate efficiently in bump-fire mode, reducing operator fatigue and ensuring consistent performance by maintaining the combustion chamber sealed until the piston returns, thus preventing vacuum pressure loss and enabling rapid mode selection between sequential and bump-fire modes.
Implementation Method 1
an electromagnet to hold the actuation member in a retained position
Implementation Method 2
The tool provides gas that causes the actuation member to move from an unretained position to a retained position
Implementation Method 3
a spark plug to spark and ignite the fuel/air mixture in the combustion chamber. This generates high-pressure combustion gases that expand and force the piston to move through the cylinder
Implementation Method 4
the piston passes exhaust check valves defined through the cylinder, and some of the combustion gases that propel the piston exhaust through the check valves to atmosphere
Data Source
AI summary
A combustion-powered fastener-driving tool that include a chamber member retainer assembly configured to enable the controller of the tool to prevent the chamber member of the tool from moving to an open unsealed position and to ensure the tool's combustion chamber remains sealed until the piston fully returns to its pre-firing position.