Chamber Retaining Assembly for Reliable Bump-Fire Fastener Tools
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Solution Overview
Problem
Combustion-powered fastener-driving tools face issues such as premature unsealing of the combustion chamber, leading to improper functioning and operator fatigue due to limited operational modes, particularly when attempting to use the bump-fire mode.
Innovation Solution
Incorporation of a chamber member retaining assembly with an electromagnet controlled by a controller to maintain the combustion chamber sealed until the piston fully returns to its pre-firing position, enabling the tool to operate in both sequential and bump-fire modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the chamber member is allowed to move freely to unseal the combustion chamber when the WCE is removed, then the tool can operate in bump-fire mode, but the combustion chamber may unseal prematurely causing vacuum pressure loss and improper tool functioning
Solution Approach 1:
An electromagnet is introduced as an intermediary component between the chamber member and the unsealing mechanism. The electromagnet selectively retains the chamber member in the sealed position during piston return, preventing premature unsealing while allowing controlled unsealing when needed for bump-fire operation. This mediator resolves the conflict between maintaining reliability and enabling versatility.
Solution Approach 2:
The patent replaces a purely mechanical linkage system with an electromechanical system. The electromagnet provides precise control over chamber member retention, substituting mechanical timing mechanisms with electrically controlled retention that can reliably hold the chamber member sealed until the piston completes its return stroke, then release it for unsealing.
2Reliability
If the chamber member is retained sealed until piston return completes, then vacuum pressure is maintained for proper tool functioning, but the tool cannot operate in bump-fire mode
Solution Approach 1:
The system transitions from a static mechanical linkage to a dynamic electromechanical control system. The electromagnet can be dynamically activated and deactivated based on operational mode requirements. In sequential mode, it remains active during piston return to maintain sealing; in bump-fire mode, it can be deactivated to allow premature unsealing, providing adaptability while maintaining reliability when needed.
Solution Approach 2:
The control system changes the retention parameter (electromagnet activation state) based on operational mode. By changing the electrical control parameter of the electromagnet, the system can switch between maintaining sealed retention (for reliability) and allowing unsealing (for bump-fire versatility), resolving the contradiction through parameter adjustment.
3Adaptability or versatility
If the chamber member moves to unsealed position before piston returns to pre-firing position, then bump-fire mode becomes possible, but vacuum pressure is lost causing piston to stop before pre-firing position
Solution Approach 1:
The electromagnet serves as a mediator that controls the timing of chamber unsealing. It prevents premature unsealing that would cause vacuum pressure loss, while allowing controlled unsealing when the piston has completed its return stroke. This ensures vacuum pressure is maintained for proper tool functioning while enabling bump-fire mode operation when desired.
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
Ensures reliable tool operation in both sequential and bump-fire modes by preventing premature unsealing of the combustion chamber, enhancing operational flexibility and reducing operator fatigue.
Implementation Method 1
a chamber member retaining assembly supported by the housing and including: an electromagnetic cartridge assembly including: a cartridge, an electromagnet connected to and supported by the cartridge, the electromagnet controlled by the controller and activable to limit movement of the chamber member from the sealed position to the unsealed position
Implementation Method 2
the trigger actuates a trigger switch, thereby causing 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 from the pre-firing position
Implementation Method 3
some of the combustion gases that propel the piston exhaust through these check valves to atmosphere. This combined with heat exchange to the atmosphere and the fact that the combustion chamber remains sealed during firing generates a vacuum pressure above the piston in the combustion chamber and causes the piston to retract to the pre-firing position
Data Source
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AI summary
A combustion-powered fastener-driving tool that includes 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.