Gas Springs & Struts

Explained

Gas Springs

This page aims to provide basic information about gas spring components and how it works.

Compression Gas springs or lift type gas struts are self-contained, force generating, maintenance-free cylinders. They are used to move and position lids, chairs, table-tops, and host of other assemblies. body is pre-charged with nitrogen gas to provide a specific output force. Pressure is applied to the piston and diameter area, which provides the output force in push-type gas springs.

GAS SPRING COMPONENTS

a – Tube Side End Fitting
M4, M6, M8, M10, M14 thread options acording to item diameter. Check End Fittings Collection for appropriate mounting options.

b – Pressure Tube
Seamless ST14 Steel tube covered with electro – static powder paint in order to provide corrosion resistance.

c – Nitrogen
Pressurized pure Nitrogen.

d – Oil
Specific amount of oil for lubrication and damping.

e – Piston Assembly
Specially designed labyrinth piston with o-ring provides speed control and rod guide.

f – Sealing and Guidance Package
The seal that prevents the pressurized gas from escaping and ensures the highest level of functional safety.

g – Piston Rod
Induction Hardened and 3 times stoned QBQ black piston rods provides protection against impacts and corrosion.

h – Rod Side End Fitting
M4, M6, M8, M10, M14 thread options acording to item diameter. Check End Fittings Collection for appropriate mounting options.

SPRING CHARACTERISTIC

The spring characteristic curve shows the force path of the gas spring over the stroke, from the extended to the retracted state and back. The spring characteristic illustrates the balance of power of F2/F1 which called force ratio (x).

x = F2/F1

For the design of gas springs, the force F1 is, in addition to the dimensions, the most important criterion. The force F1 is measured 5mm before the end of the extension movement and thus defines the value of the spring force. The resulting friction force F is generated between the lines of force in the insertion and extension direction.

PRESSURE BEHAVIOURS

In general, the gas spring is intended for a maximum operating temperature of 80°C. This accounts for the real properties of nitrogen (N2) in respect to temperature and pressure changes.
Considering pressured gas inside gas spring tube, pressure rate varies according to environment temprature. In order to get most certain results, test environment should be 20 C° (±3°)
The force change of the gas spring as a function of pressure and temperature is also represented in diagram.

GAS STRUT FORCE CALCULATION

The pressure required for the gas spring is calculated by substituting the value used in the following formula:

F1 = ((m* LT)/(2* N* LA) +5)* 9.81 = gas spring pressure  (Newton)

F1 = gas spring pressure/force
N = number of gas springs required
m = weight of the tailgate/object to be lifted, operated (kg)
LT = length of the tailgate object to be lifted, operated (meter)
LA = the distance (in meters) between the application point of the gas spring on the tailgate and the rotation axis of the tailgate.
The number 5 represents a constant force of 5 kg/p, which is equivalent to friction.

force calculation gas strut

TECHNICAL INSTRUCTIONS

Storage:

After longer periods of storage, a slight oil film may occur at the piston rod side of the product. Such surface film is system-specific and has no impact on the function. Storage of the parts should be piston rod downward. Please activate the parts at least once after six months of storage.

Handling:

MS Products may stand under high pressure. In order to avoid reduction of service life, safety and function, piston rods are not to be damaged, painted, or treated with aggressive materials. Keep away foil and paper packaging (statical charging). Radial stress effects, impact effects, any type of alteration or manipulation (f. e. opening), tensile load, heating, re-painting, removal of imprints, bulk handling, as well as extreme influence of wastewater, splash or salt water are not permissible. The outer tube is not to be deformed or damaged. Products that were modified or damaged in any kind should not to be put into operation and have to be exchanged.
Utilization:
Your specific application is the basis for the technical design of MS Products. Please discuss your particular requirements with our
application technicians in advance. Our products fulfil the specifications shown in MS drawings. Unless otherwise specified, the products are to be used with the piston rods pointing down within a temperature range of –25°C up to +60°C.

Assembly:

MS gas springs are under high pressure, should not be exposed to high temperatures, nor should they be opened. MS gas springs should be assembled only with specified end fittings supplied by MS. Fixed mounting is to be avoided. Standard safety protection applicable. The gas springs are to be mounted with the rod pointing down, unless otherwise agreed upon.