Gas Combustion Driving Tool Lock Piston Sealing Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In gas combustion type driving tools, the combustion chamber sealing state is often lost prematurely due to the urging force of a spring, leading to insufficient striking force in subsequent operations, as the contact arm moves downward before the pressure within the combustion chamber is fully reduced.
Innovation Solution
A combustion chamber holding mechanism that includes a lock cylinder and lock piston, coupled via a gas path with a check valve and an electromagnetic or manually-operated valve, which maintains the sealing state by preventing backward gas flow and controlling the opening of the combustion chamber after a predetermined time, ensuring consistent sealing regardless of trigger operation timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the trigger is released immediately after pulling or the body separates instantaneously from the driven member, then the operation speed is improved, but the contact arm moves downward due to spring urging force causing the combustion chamber sealing state to be lost
Solution Approach 1:
A holding member is introduced as an intermediary component between the movable sleeve and the combustion chamber sealing mechanism. This holding member engages with the movable sleeve to maintain its upper position and prevent downward movement, thereby preserving the combustion chamber sealing state even when the trigger is released early or the body separates from the driven member.
Solution Approach 2:
The holding member is designed to engage with the movable sleeve in advance before the trigger is released or before body separation occurs. This preliminary engagement ensures that the movable sleeve is prevented from moving downward, maintaining the sealing state proactively before any potential sealing loss can occur.
2Stress or pressure
If the combustion chamber is opened at early timing, then the pressure within the combustion chamber is not reduced sufficiently, but the striking piston cannot return to the top dead center resulting in insufficient striking force
Solution Approach 1:
The holding member acts as a mediator that decouples the trigger release action from the movable sleeve position. By maintaining the movable sleeve in the upper position regardless of trigger release timing, the combustion chamber remains sealed, allowing complete pressure reduction and ensuring the striking piston can return to the top dead center with full striking force.
3Speed
If a spring is used to urge the contact arm downward, then the reset speed is improved, but the combustion chamber sealing state is lost prematurely
Solution Approach 1:
The holding member serves as a mediator that overrides the spring's urging force on the contact arm. By engaging with the movable sleeve, the holding member prevents the sleeve from moving downward even when the spring urges the contact arm downward, thus maintaining the sealing state while allowing the spring to continue providing fast reset speed.
Solution Approach 2:
The holding member provides a counteracting force against the spring's urging force. When the holding member engages with the movable sleeve, it counterbalances the downward force from the spring, preventing premature movement of the sleeve and maintaining the combustion chamber sealing state despite the continuous spring pressure.
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 mechanism effectively maintains the sealing state of the combustion chamber, ensuring consistent striking force by preventing pressure reduction in the lock cylinder, allowing the combustion chamber to open only when necessary, thus maintaining operational efficiency.
Implementation Method 1
A check valve is provided at the gas path
Implementation Method 2
an electromagnetic valve is provided at the lock cylinder. The electromagnetic valve is opened upon the lapse of a predetermined time period after the combustion within the combustion chamber
Implementation Method 3
mixed gas of the combustible gas and the air is burnt within the combustion chamber to generate high-pressure combustion gas
Implementation Method 4
explosively burn mixed gas of combustible gas and the air within a combustion chamber
Implementation Method 5
The high-pressure combustion gas acts on a striking piston housed within a striking cylinder to impulsively drive the striking piston within the striking cylinder
Data Source
AI summary
When a movable sleeve 11 on a cylinder moves upward, a combustion chamber 5 in a sealed state is formed. Mixed gas is explosively burnt within the combustion chamber 5 so as to drive a fastener out. A lock cylinder 22 is disposed beneath the movable sleeve 11. A lock piston 23 is housed within the lock cylinder 22 so as to be movable in an up/down direction. The upper end of the lock piston 23 is capable of being engaged with a holding member 12 which is interlocked with the movable sleeve 11. The lower portion of the lock cylinder is coupled to the combustion chamber via a gas tube 24. The gas tube 24 is provided with a check valve 25. The lock cylinder 22 is provided with an electromagnetic valve 27. The electromagnetic valve 27 opens upon the lapse of a predetermined time period after the combustion within the combustion chamber.