A gas spring may seem simple, but improper installation can lead to rapid wear, leaking seals, and potentially dangerous malfunctions. Proper installation is crucial for optimal performance, safety, and service life.
A gas spring is a closed system containing nitrogen gas and oil. The oil serves a dual purpose: it acts as a hydraulic damper and as a lubricant for the internal seal around the piston rod. With every compression and extension stroke, the seal slides along the piston rod. Without adequate lubrication, this seal wears out quickly, resulting in gas leakage and a loss of performance.
The mounting position directly determines where the oil is located in the cylinder. This affects:
The most fundamental rule when installing a gas spring is: the piston rod must point downward. This is not a convention but a technical requirement that stems from the internal operation of the gas spring.
Inside the gas spring are two substances: nitrogen gas (under high pressure) and a small amount of oil. Due to gravity, the oil always sinks to the lowest point of the cylinder. When the piston rod is pointing downward, the seal is located exactly above this oil level. With every movement, the seal passes along the piston rod through a film of oil, keeping wear to a minimum.
If the piston rod points upward, the oil is at the bottom of the cylinder, far from the seal. The seal then runs dry and wears out considerably faster. In practice, the seal’s service life can be reduced by 40 to 70% if it is installed in the reverse position.
The rule “piston rod down” applies to the vast majority of standard gas springs. However, there are specifically designed reversible gas springs or gas springs with internal oil retention that also function correctly in other positions. Always consult the manufacturer’s datasheet for the permitted mounting positions.
The procedure below applies to the most common applications: valves, hatches, machine covers, and inspection doors. Adapt the procedure to your specific application.
A = length of the gas spring on the hinge
B = upper mounting point (on the flap)
D = vertical distance from the hinge to the mounting point
C = horizontal distance from the hinge
Attach the mounting plate to your application (the fixed frame or enclosure) according to dimensions C and D, measured from the hinge.
Attach the gas spring to the mounting plate on the frame using the provided end fittings (ball heads or other end fittings).
Attach the mounting plate to the other mounting point—this is the side that will later be mounted to the valve or hatch. Do not attach it permanently to the valve just yet.
Set the valve to the position that corresponds to the gas spring’s resting position (fully extended = open position for a gas pressure spring).
Move the free mounting plate along the flap until dimensions A and B, measured from the hinge, are reached.
Verify that the desired opening angle used in the calculation has actually been achieved.
If the opening angle is correct: permanently mount the mounting plate to the valve according to dimensions A and B.
Now carefully close the lid.
Perform a full functional test over multiple cycles:
The errors listed below are frequently observed in practice and often lead to premature failure, reduced performance, or safety risks.
| # | Error | Cause | Effect | Solution |
|---|---|---|---|---|
| 01 | Piston rod mounted in the up position | Lack of understanding of the lubrication principle | Rapid seal wear, gas leakage | Always position the piston rod in the down position |
| 02 | Misalignment (skew) | Mounting points not coplanar | Lateral load, clamping | Use ball-head fasteners |
| 03 | Stroke length too short selected | Geometry calculated incorrectly | Insufficient opening | Calculate stroke geometry |
| 04 | Overtravel in open position | Stroke too long or end stop missing | Permanent damage to cylinder | Install mechanical end stop |
| 05 | Incorrect force (F1) | Incorrect estimation of weight or geometry | Difficult operation or rapid opening | Calculate force based on geometry |
| 06 | Collisions in final position | Gas spring strikes structural components | Noise, damage, force spikes | Collision check in all positions |
| 07 | Incorrect fastening connection | Incorrect bolt size or bracket | Loosening under load | Follow the manufacturer’s specifications |
Is a gas spring designed exclusively to absorb axial forces? In other words, forces along the length of the gas spring. Lateral (radial) forces are harmful and can cause wear on the piston rod, bending, and premature seal failure. There are products available for this purpose that protect your rod
The most effective solution is to use ball joints on both sides of the gas spring. A ball joint compensates for minor misalignment errors of ±3°–5° without transmitting any radial force to the piston rod.
| Measure | Application | Compensation Range |
|---|---|---|
| Ball Joint | Standard industrial applications | ±3° – 5° in all directions |
| Brackets with a longitudinal hole (keyway) | Requires a small axial tolerance | Axial compensation ±5 mm |
| Pivot bracket | Wide design tolerances | Rotation in a single plane |
| Precise Positioning | Precision Engineering, OEM | <0.5° deviation required |
Gas springs are virtually maintenance-free, but following a few basic precautions can significantly extend their service life.
Dirt that accumulates on the piston rod is dragged past the seal with every movement, causing abrasion damage. Wipe the piston rod clean periodically with a dry, lint-free cloth. Do not use abrasive cleaners or solvents.
Store gas springs upright (with the piston rod pointing down) in a dry, temperature-controlled area between 10°C and 40°C. Never store gas springs horizontally for extended periods—the oil will seep away from the seal.
A properly installed gas spring performs reliably, safely, and durably. The four pillars of a successful installation are:
If you take the time to install it properly, you will significantly extend its service life, avoid unplanned downtime, and ensure the user’s safety.
Do you have a specific application for which you’d like to select the right gas spring or have an installation calculation performed? Our technical specialists can assist you with custom configurations for machine building, vehicles, and industrial applications.
