Piston Cylinder Weakening Zone for Controlled Gas Spring Overload Relief
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Solution Overview
Problem
The increased demands on press tools due to higher production speeds and forming forces in sheet metal forming lead to risks of gas spring overload and failure, resulting in uncontrollable piston rod acceleration, which can cause damage to the gas spring components and surrounding equipment.
Innovation Solution
A piston cylinder device 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 rod velocity to zero, preventing component separation and material cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If higher forming forces are applied to meet increased production demands, then the forming capability is improved, but the risk of gas spring overload and failure increases
Solution Approach 1:
A material weakening zone is pre-formed in the cylinder wall at a specific location. This zone acts as a predetermined failure point that will deform or shear under excessive load, absorbing energy and preventing complete gas spring failure. The weakening zone is created during manufacturing by reducing material density or creating a structural defect at the desired location.
2Loss of energy
If the piston rod is allowed to freely accelerate during failure, then the energy release is immediate, but uncontrollable speed and energy cause damage to components and surroundings
Solution Approach 1:
The material weakening zone serves as a pre-prepared energy absorption mechanism. When the piston rod accelerates uncontrollably, the weakening zone deforms or shears, creating a leakage path that allows gas to escape in a controlled manner, thereby dissipating energy gradually rather than instantly and preventing catastrophic damage.
Solution Approach 2:
The potential harmful effect of uncontrolled piston rod acceleration is converted into a beneficial controlled energy release. The material weakening zone transforms the destructive kinetic energy into controlled gas leakage and localized deformation, protecting the surrounding components and environment.
3Object-affected harmful factors
If the piston rod velocity is reduced to zero through controlled gas leakage, then component damage is prevented, but the protection mechanism requires additional structural elements
Solution Approach 1:
The protection function is merged with the existing cylinder structure by incorporating the material weakening zone directly into the cylinder wall. This eliminates the need for separate protection devices while achieving the same safety function. The weakening zone is integrated during manufacturing, combining structural and protective roles.
Solution Approach 2:
The cylinder structure itself provides the protection function through the material weakening zone. When overload occurs, the weakening zone automatically deforms or shears to create the leakage path, without requiring external control systems or additional active components. The structure serves both its primary containment function and the secondary protection function.
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 reduces piston rod velocity to zero during overload or failure, minimizing damage and ensuring controlled gas leakage, thus enhancing the robustness and protection of gas springs against overload.
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
A sealing means is arranged to seal between the guide and the inner wall of the tubular wall to prevent fluid leakage from the pressure chamber to the surroundings
Implementation Method 4
the gas in the gas chamber in the gas cylinder is compressed and the pressure increases in the gas spring
Implementation Method 5
After being released from such a compressed position the piston freely accelerates in the gas spring, i.e., travels with high speed
Data Source
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.