Gas Spring Overtravel Pressure Relief Vent Path
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Solution Overview
Problem
Conventional gas springs in forming equipment can experience overtravel, leading to undesirable gas overpressure and adverse conditions due to the piston rod extending beyond its design-intent retracted position, which existing safety devices fail to adequately address.
Innovation Solution
Incorporating an overtravel pressure relief feature with a vent path and seal mechanism that allows pressurized gas to be released when the piston rod overtravels, reducing pressure in the pressure chamber and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the piston rod is allowed to reciprocate freely between extended and retracted positions, then the gas spring can perform its cushioning function, but the piston rod may overtravel beyond the design-intent retracted position causing gas overpressure and adverse conditions
Solution Approach 1:
The patent applies preliminary anti-action by providing a vent path that is pre-configured to become active when overtravel occurs. The vent path includes a vent passage through the casing wall and a seal that normally blocks it, but which automatically opens when the piston rod housing displaces into the casing during overtravel. This pre-positioned safety mechanism counteracts the harmful gas overpressure before it can cause damage.
Solution Approach 2:
The patent uses an intermediary mechanism - the seal (such as an O-ring) that normally blocks the vent passage but automatically moves out of the way when overtravel occurs. This seal acts as a mediator that allows the system to maintain pressure during normal operation while automatically releasing pressure when the piston rod housing displaces into the casing beyond the design-intent position.
2Object-affected harmful factors
If a vent path is provided through the casing wall to release pressurized gas during overtravel, then gas overpressure can be relieved, but the vent path must be sealed during normal operation to maintain pressure
Solution Approach 1:
The patent applies self-service by designing a system where the piston rod housing itself performs the sealing and venting functions. During normal operation, the housing position keeps the seal in place to maintain pressure. During overtravel, the housing displacement automatically moves the seal out of the vent passage, opening the vent path without requiring external control mechanisms. The system serves itself through its own motion.
Solution Approach 2:
The patent extracts the sealing function from a separate controlled mechanism and integrates it into the piston rod housing structure itself. The seal is positioned such that the housing's own displacement during overtravel automatically extracts the seal from the vent passage opening, simplifying the overall device by eliminating the need for separate vent control mechanisms.
3Object-affected harmful factors
If the piston rod housing is displaced into the casing during overtravel, then the vent path opens to release pressure, but this displacement must be prevented during normal operation
Solution Approach 1:
The patent uses preliminary anti-action by pre-positioning the seal in the vent passage to prevent premature opening. The seal is configured to remain in place during normal housing displacement within the design-intent range, only allowing vent path opening when the housing displaces beyond this range during overtravel conditions.
Solution Approach 2:
The patent applies dynamics by making the vent path sealing status dynamic rather than static. The seal's position relative to the vent passage changes automatically with the housing displacement, transitioning from a blocked state during normal operation to an open state during overtravel. This dynamic behavior allows the system to adapt its pressure containment based on operational conditions.
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 overtravel pressure relief feature effectively depressurizes the gas spring during overtravel conditions, preventing damage and ensuring safe operation by releasing pressurized gas, thus extending the useful life and reliability of the gas spring.
Implementation Method 1
a seal that sealingly interrupts the vent path
Implementation Method 2
a vent path that is disposed between the pressure chamber and the outside of the gas spring and that includes a vent passage through the side wall of the casing
Data Source
Figure 1
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Figure 4
AI summary
A gas spring (310) for forming equipment. A casing (312) includes an axially extending side wall (320), an open end, a transversely extending closed end wall (322) axially spaced from the open end (324), and a pressure chamber (317) established in part by the side and end walls (320) to receive a gas under pressure. A piston rod (316) is received at least partially in the casing for reciprocation between extended and retracted positions. A piston rod housing (344) is received at least in part in the casing between the piston rod and the casing. An overtravel pressure relief feature (318) includes a vent path that is disposed between the pressure chamber and the outside of the gas spring and that includes a vent passage (363) through the side wall of the casing and a seal that sealingly interrupts the vent path, wherein displacement of the housing into the casing results in opening of the vent path.