Gas Springs – Design, Function, Calculation and Installation

This guide provides a complete overview of gas springs, including their design, functional principle, force calculation, installation rules, and maintenance requirements. It explains key components, the role of pressurized gas in generating lifting force, and the formula for selecting the correct spring force. The document also highlights proper mounting practices, safety instructions, and maintenance tips to ensure long service life and reliable operation.

Construction of a Gas Spring

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The gas spring consists of several precisely designed components that ensure its functionality and long service life:

Piston rod (1) – smoothly machined rod guided through the sealing system.
Mounting eye (2) – end fitting for installation into the mechanical assembly.
Sealing system (3) – ensures gas-tightness between the cylinder and the atmosphere.
Piston (4) – guides the piston rod, limits its extension, and acts as a shock absorber.
Cylinder (5) – the main body filled with pressurized gas.
End cap (6) – closes the cylinder and allows spring mounting.

The external ends of the piston rod and cylinder are typically fitted with mounting eyes. Other mounting elements can be supplied on request.

Operating Principle

The gas spring is filled with gas under defined pressure, which generates the required lifting force F. When the piston rod is compressed, the gas pressure increases, which results in higher spring force. This effect ensures stable operation during the opening and closing of doors, lids, or other moving parts.

Calculation of Gas Spring Force

Accurate calculation is crucial for safe and efficient operation. The following formula is used:

F = (G × L × S) / b

Variables in the Formula

G = weight of the door or lid [N]
L = distance of the center of gravity from the pivot axis [mm]
S = safety factor (usually 1.1)
b = distance of the gas spring mounting point on the door from the pivot axis [mm]

Example Calculation

For a lid weighing 350 N, with the center of gravity at 500 mm and spring mounting point at 200 mm:

F = (350 × 500 × 1.1) / 200 = 963 N

The result shows the required gas spring force for the given application.

Installation of Gas Springs

For long service life and correct function, the following rules must be observed:

Install with piston rod facing downwards – ensures lubrication of seals and full damping effect at the end of the stroke.
Avoid misalignment – incorrect mounting causes bearing wear and increased seal load.
Use retaining clips – recommended for increased safety under external influences (wind, snow).
Select mounting point carefully – affects opening speed and closing behavior through the dead point.

Maintenance of Gas Springs

Lubricate the eyes of mounting and bearing fittings with oil (not grease) occasionally.
Protect the piston rod from scratches, wear, and dirt.
Gas springs operate reliably within a temperature range of -30 to +80 °C.
Always store with the piston rod facing downwards.

Safety Instructions

Do not disassemble gas springs – the cylinder is under high pressure.
Do not expose to heat and do not weld near the spring.
Do not damage the piston rod surface or use unsuitable lubricants or paints.

Summary

Gas springs are an essential structural element for safe and convenient opening of doors, lids, and covers. Their correct selection, installation, and maintenance ensure long service life and reliable operation. Accurate calculation of the spring force according to the given formula is crucial for efficient use.