Through special protection tubes and locking devices HAHN gas springs can be used in difficult environments. For extreme situations our technical specialists will develop intelligent solutions for almost any requirement.
The Wiper ring for piston rod is integrated into the sleeve to prevent the intrusion of foreign matter into the gas spring as the piston rod moves inward, effectively protecting the sleeve itself as well as the seals and other elements.
Fluorocarbon rubber: a sealing material with high thermal and chemical resistance (used for gas springs exposed to high temperatures or on stainless steel models).
NBR: the most commonly used material due to its advantageous mechanical properties and resistance against mineral oil based lubricants.
The side valve allows direct installation into the application and force adjustments on site. This eliminates the time-consuming installation and removal of the gas spring as is necessary for force adjustment via the standard valve. A horizontal valve connection is also used for pressure monitoring (manometer).
The piston rod sealing can only be integrated into lockable gas springs and are installed on the threaded end of the rod. They prevent the intrusion of moisture, cleaning agent and other foreign matter into the actuation system of a locking gas spring.
Locking gas springs with a piston rod seal are mainly used in medical applications, such as hospital beds, which, for reasons of hygiene, are cleaned in automated washing machines, using a detergent emulsion.
The oil chamber permanently lubricates the piston rod / sleeve. This reduces friction and makes it possible to install the gas spring in any orientation, while preventing the seal from drying out. When selecting the right gas spring for a specific application, please take into account that the usable stroke may be shorter than normal.
Just as the side valve, the schraeder valve allows the precise force adjustment of the gas spring to local conditions. Unlike the horizontal valve, the regular valve is located on the threaded end of the base. In case of a pneumatic tension spring the valve takes the form of a valve top on the piston rod. The connector must be unscrewed to provide access to the threaded end. There is a 2.5 mm hole in the center of the threaded end. Insert a flattened pin with a diameter of less than 2.5 mm into the hole. Using a 200-gram hammer or similar, strike the top of the pin, allowing the hammer to rebound. Never push on the pin for extended periods of time (caution: gas and oil can escape through the valve. Observe safety rules!). Strikes with excessive force or an excessive number of strikes can damage the valve beyond repair. Pressing down the valve pin too long will lead to an uncontrolled escape of gas and can even result in a complete loss of pressure. When adjusting two gas springs at the same time, we recommend that you keep count of your strikes, in order to achieve a similar extension force on both springs. It is advisable to limit yourself to no more than five strikes. Afterwards, the spring should be tested for tightness by placing a drop of oil on the valve hole and monitoring the oil for about one minute to see if there is any leakage. In case of leakage, you should actuate the valve again briefly and repeat the test. If necessary, repeat the entire process. If released pressure should have resulted in insufficient extension force, the gas spring can be refilled by HAHN Gasfedern.
The protection tube for piston rod protects the gas spring against physical and mechanical damage, while also reducing the risk of buckling during longer strokes. The protection tube also reduces the influence of weather on the piston rod. A typical application would be a horse trailer on which the piston rod is protected against damage. The protection tube can also be retrofitted.
Independent of its installation position, the floating piston functions as a hydraulic damper. It dampens the speed across the entire stroke of the gas spring.
The mechanical locking device is a physical and mechanical locking mechanism used when the spring’s piston rod is extended. It prevents a sudden retraction of the spring. The mechanism is attached to the piston rod in an off-center position. When the rod is extended, the support tube on the flat side of the sleeve can be pressed. This engages a mechanical lock that prevents retraction. The safety lock is often used on vendor stands and must be disengaged manually.
The short release for locking gas springs is 0.1 to 0.2 mm as opposed to the standard 2 – 5 mm. In case of a short actuation the actuation stroke of the trigger plunger is only 0.1 to 0.2 mm (standard value: 2 – 5 mm). Thereby, a lockable gas spring responds to small actuation inputs, as opposed to requiring at least a 3mm input to respond.
The HAHN reducer safely and comfortably reduces the force of a gas spring fitted with a valve. It is screwed onto the thread of the base valve. If the handle is pressed, the pressure release plunger opens the valve, allowing gas to escape. The handle must not be pressed for extended periods of time, but instead must be pressed in short intervals.
The Hahn reducer is available in 5 different sizes:
If you have a gas spring with an end-position damper, the gas spring must be held in an upright position with the valve pointing up while the spring is relaxed. This causes the oil of the damping mechanism to flow away from the valve, preventing it from escaping when the spring is emptied. The HAHN reducer is manufactured in compliance with RoHS and Reach guidelines.
The HAHN clean cap is a retrofit item. It protects the piston rod seal by removing dirt from the rod as it plunges into the housing, thereby preventing the intrusion of foreign matter to the inside of the gas spring. It consists of an aluminum disk with a rubber wiper and a plastic cap, which is placed over the gas spring, holding the disk and wiper in position. Applying this retrofit wiper precludes the use of the standard protection tube and the standard safety lock. The HAHN clean cap is often used in construction machines to prevent the intrusion of dust, sand, etc. into the gas spring. Caution: employing the HAHN clean cap results in stroke and force losses (friction). The amount of force loss is dependent upon the ambient temperature and the actuation frequency.
Stroke and force losses:
|Model||Stroke loss (mm)||Force loss (N)|
There are 5 different sizes of gas springs:
The HAHN clean cap is manufactured in compliance with RoHS and Reach guidelines.
The B3 sealing system is used for gas springs experiencing high forces and increased stress (vibration), e.g. in construction machines. It allows the spring to be installed in any position. When selecting the correct size of the spring for the application at hand, please take into account that the usable stroke may be reduced.
The NT low temperature design is used for ambient temperatures of up to -40°C. It allows the spring to be installed in any position. When selecting the correct spring size for the application at hand, please take into account that the usable stroke may be reduced.
The HT high temperaturedesign is used for ambient temperatures of up to 200°C. It allows the spring to be installed in any position. When selecting the correct spring size for the application at hand, please take into account that the usable stroke may be reduced.
The friction element increases the friction force of gas springs used for safe positioning of windows and hatches, etc. An elastic foam ring is mounted on the piston. The ring’s diameter is significantly larger than the inner diameter of the pressure tube. This compresses the foam ring inside the pressure tube, which in turn creates higher friction forces.