Gas Spring Cylinder Weakening Zone for Overload Pressure Relief
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Solution Overview
Problem
The increased demands on gas springs due to higher forming forces and press rates in sheet metal forming lead to a risk of piston rod overloading and failure, resulting in uncontrollable piston speed and potential damage to the gas spring components.
Innovation Solution
A piston cylinder device is designed with a material weakening zone in the inner wall of the cylinder, which deforms or shears upon impact, creating a leakage gap to control gas release and reduce piston speed to zero, thereby preventing component separation and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the forming force is increased to meet higher production demands, then the productivity increases, but the risk of gas spring overload and failure increases
Solution Approach 1:
The patent implements a protection arrangement with a leakage gap and energy absorption mechanism that is pre-configured in the gas spring. When overload occurs, this pre-existing structure automatically activates to cushion the impact and prevent catastrophic failure, allowing the system to operate at higher productivity levels without proportionally increasing failure risk
2Productivity
If the press rate is increased to optimize production, then the productivity improves, but the wear on tool components increases
Solution Approach 1:
The protection arrangement with pre-configured leakage gap and energy absorption features provides automatic cushioning against overload impacts during high-rate pressing operations, reducing peak stresses on tool components and extending their operational lifespan despite increased press rates
3Reliability
If a protection arrangement is added to stop the piston rod during failure, then the safety improves, but the device complexity increases
Solution Approach 1:
The patent merges the protection functions (leakage gap, energy absorption, piston rod stopping) into the existing gas spring structure rather than adding separate external protection devices. The leakage gap is integrated into the cylinder wall, and the energy absorption features are built into the existing components, maintaining a relatively simple overall structure while providing comprehensive protection
Solution Approach 2:
The protection arrangement operates automatically using the gas spring's own internal resources - the compressed gas in the leakage gap and the elastic deformation of existing components - without requiring external power sources, control systems, or additional actuating mechanisms, thereby minimizing added 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
The solution effectively controls the piston rod's velocity to zero during overload or failure, preventing component separation and damage, while ensuring a controlled gas leakage to manage the energy release safely.
Implementation Method 1
the material weakening zone being arranged to be deformed or sheared against the lock ring at a predetermined level of impact of the piston against the guide
Implementation Method 2
the material weakening zone being arranged to be deformed or sheared against the lock ring
Implementation Method 3
gas from the pressure chamber is allowed to leave the pressure chamber through said leakage gap to the surroundings
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A piston cylinder device (1) comprising a cylinder (2) with a first and a second end and a guide (6), such that a pressure chamber (8) is formed in the cylinder. A piston (12) is moveable in the pressure chamber (8). The guide (6) is fixedly secured to the cylinder (2) by a lock ring (7). A sealing means (9) is arranged to seal between the guide (6) and an inner wall of a tubular wall (3) of the cylinder (2) to prevent fluid leakage from the pressure chamber (8) to the surroundings. The piston cylinder device (1) is provided with a material weakening zone (13) arranged in the inner wall of the tubular wall (3) of the cylinder (2) axially between the lock ring (7) and the second end (20) of the cylinder (2), the material weakening zone (13) being arranged to be deformed or sheared against the lock ring (7) at a predetermined level of impact of the piston (12) against the guide (6). A leakage gap (14) is arranged to interrupt the sealing means (9) upon deformation or shearing of the material weakening zone (13) such that gas from the pressure chamber (8) is allowed to leave the pressure chamber (8) through said leakage gap (14) to the surroundings.