Chamber Member Retaining Assembly for Combustion Fastener Tools
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Solution Overview
Problem
Certain combustion-powered fastener-driving tools face issues where the chamber member moves and the combustion chamber unseals before the piston returns to the pre-firing position, leading to vacuum pressure loss and improper tool function, and they typically operate only in sequential firing mode, causing operator fatigue.
Innovation Solution
A chamber member retaining assembly, controlled by an electromagnet, is used to maintain the chamber member in a sealed position until the piston fully returns to its pre-firing position, enabling the tool to operate in both sequential and bump-fire modes by selectively energizing the electromagnet to prevent undesired movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the chamber member is allowed to move freely to unseal the combustion chamber, then the tool can operate in bump-fire mode, but the combustion chamber may unseal before the piston returns to pre-firing position causing vacuum pressure loss
Solution Approach 1:
The chamber member retaining assembly dynamically adjusts its retention state based on piston position. The electromagnet engages to hold the chamber member in the sealed position when the piston is in the firing position, and disengages when the piston returns to the pre-firing position, allowing the chamber member to move to the unsealed position. This dynamic control enables the system to adapt to different operational requirements while maintaining reliability.
Solution Approach 2:
The system uses feedback from the piston's position to control the chamber member retaining assembly. The controller monitors the piston's movement and accordingly activates or deactivates the electromagnet, creating a closed-loop control system that ensures the combustion chamber remains sealed during firing and allows unsealing when appropriate, thus preventing vacuum pressure loss while enabling bump-fire mode operation.
2Reliability
If the chamber member retaining assembly is added to prevent premature unsealing, then vacuum pressure is maintained, but the device complexity increases
Solution Approach 1:
The patent replaces complex mechanical linkages with an electromagnet-based retaining assembly. Instead of using purely mechanical springs or latches to hold the chamber member, the system uses an electromagnet that can be controlled by the controller, simplifying the overall mechanism while providing reliable sealing control. This substitution reduces mechanical complexity while maintaining or improving reliability.
Solution Approach 2:
The chamber member retaining assembly serves multiple functions: it holds the chamber member in the sealed position during firing, allows controlled unsealing when the piston returns to pre-firing position, and enables the tool to operate in both sequential and bump-fire modes. This multi-functionality reduces the need for separate mechanisms, thereby limiting the increase in device complexity.
3Device complexity
If the tool operates only in sequential firing mode, then the mechanism is simple, but operator fatigue increases due to slower operation
Solution Approach 1:
The system dynamically switches between sequential and bump-fire operational modes based on the operator's needs. In bump-fire mode, the chamber member retaining assembly holds the chamber member sealed during each firing cycle, allowing rapid successive firings without manual intervention between shots. This dynamic mode switching enables the tool to adapt to different working conditions, improving ease of operation while maintaining reasonable mechanism complexity.
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 ensures the combustion chamber remains sealed until the piston is fully retracted, allowing the tool to function in bump-fire mode and reducing operator fatigue by enabling rapid switching between operational modes.
Implementation Method 1
the chamber member retaining assembly includes an electromagnet configured to hold the chamber member in a retained position
Implementation Method 2
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 3
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
Figure 1
Figure 2A~2B
Figure 2C
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.