TECHNICAL GUIDELINES
Protempo supplies a wide range of gas springs from HAHN Gasfedern. Below you can read the technical guidelines that apply to these gas springs from HAHN Gasfedern GmbH.
To be observed for assembly, construction, or storage:
- If gas compression springs, gas tension springs, and dampers are installed in applications where product failure could lead to health risks or danger to life, safety elements must be installed. The installation and removal of gas compression springs, gas tension springs, and dampers must be carried out in accordance with safety regulations.
HAHN products may not be used in the aerospace and shipbuilding industries without written permission from HAHN Gasfedern GmbH. - Position of the piston rod during installation and storage of gas compression springs and dampers: pointing downwards. Position of the piston rod during installation and storage of gas tension springs: pointing upwards. Pressure loss during storage according to the regulations is not to be expected. Storage for more than a year is not recommended. Upon first use after a long storage period, sticking effects (slip-stick) of the piston rod may occur. Higher forces may be required to operate the piston rod. The plastic film must be removed before installation.
- Gas compression springs, gas tension springs, and dampers are not safety products! They are subject to wear and have a limited lifespan. They must be protected against corrosion to extend their lifespan and durability. Leakage of small quantities of hydraulic oil may occur; this oil must not come into contact with food or groundwater.
- The products may only be refilled with the written permission of HAHN Gasfedern GmbH.
- Pivot points at the mounting should be secured with some play. Rigid mounting and radial loads must be avoided. Lubrication of the pivot points reduces wear and extends the lifespan.
- Attached connections (e.g., eyes, clevises) must be fully tightened and lie flat. Any loose connections must be fully screwed on. In the event of vibrations, these must be secured against loosening.
- Loading the piston rod at an angle must be avoided (for a long stroke and/or products, extra bearing/guidance must be installed). Sagging/bending/buckling of the piston rod must also be avoided. This can be prevented by installing a protection tube.
- The products are only suitable for axial loads. Lateral or torsional forces must not occur (risk of buckling).
- Gas compression springs must not be subjected to tensile forces. Gas tension springs must not be subjected to compressive forces.
- Gas compression springs, gas tension springs, and dampers may be used as an end stop, provided the nominal force + 30% is not exceeded (do not overstretch or compress). For large forces, a mechanical end stop must be installed to prevent compressing and stretching of the product.
- The products may be used briefly in a temperature range between –20°C and +80°C. Temperature variations affect the expansion and compression forces, as well as the viscosity of the oil (the damping changes, especially with dampers).
- Minor damage, corrosion, or paint residues on the piston rod will lead to the failure of the gas spring. The cylinder tube must not be damaged or deformed. The warranty becomes void if changes are made to the product by third parties.
- Gas tension springs are open systems. Therefore, it must be avoided that dirt or other substances enter the ventilation hole at the cylinder end (installation with the piston rod pointing upwards). During installation, care must be taken that the gas tension springs are not installed in closed systems, but in open systems where condensation due to temperature fluctuations does not occur.
- Lockable gas compression springs have a pin in the piston rod with which the locking mechanism is operated. It must be avoided that dirt or certain substances (e.g., cleaning agents) enter the piston rod bore. This can lead to corrosion and jamming of the pin.
Lockable gas springs should preferably be installed with the piston rod pointing downwards. In applications where lockable gas springs are to be used and these may come into contact with cleaning agents (hospital beds), the manufacturer must be informed. Max. number of actuations approx. 30,000. - HAHN Gasfedern GmbH is excluded from any liability for assembly proposals and drawings of gas compression springs, gas tension springs, and dampers. It must be taken into account that not all theoretical data may be included. The utmost care must be taken during assembly, as friction values or accelerations can only be taken into account approximately.
- Assembly and use must in principle be tested in practice under operating conditions by the installer, because application and installation conditions vary greatly. Therefore, not all data can be simulated or tested by HAHN. It must be specified whether the application takes place under normal conditions (20°C, natural environment = air) or is exposed to influences such as hot water vapor (+80°C), chemicals, or cleaning agents.
Tolerances / characteristics / disposal:
- Maximum pressure 160 bar (20°C).
- Max. extension speed 300 mm/s in installed condition. Attention: high speeds can lead to overheating and damage to the seals and thus to defects in the product. Overloading due to high extension or retraction speeds and acceleration must be avoided.
- Length tolerance of the products +/- 2 mm.
- Tolerance for extension or pulling forces in general: minimum +/- 3 Newton +/- 5% of the nominal force; maximum +/- 10% of the nominal force (20°C). Nominal force is measured statically during the outward stroke (for tension springs: inward stroke) 5 mm before the end of the stroke (standard).
- Actuation force for pressing the pin on lockable gas springs: approx. 18% of the nominal force F1 of the gas spring.
- Lifespan: gas compression springs, dampers approx. 10 km stroke; tension springs approx. 2 km stroke (under optimal conditions).
- Processing as residual material: Gas compression springs, gas tension springs, and dampers are under pressure. They must not be opened or overheated.
- Installation instructions and environmentally friendly disposal instructions are included with every delivery.
- Opening the products is only permitted with instructions from HAHN Gasfedern GmbH (available upon request from your supplier). All products are filled with oil, which must be treated as chemical waste.
Attention:
Do not open gas springs – high pressure!
Do not heat gas springs above 80°C.
Failure to comply with these guidelines will void any liability/warranty.