The force of a gas spring is determined by the pressure that the nitrogen in the cylindrical body exerts on the section of the stem.
By suitably assembling stems of varying cross sections with bodies of suitable volume, by acting on the gas input pressure and adjusting the channels
on the stem or by introducing a greater quantity of oil, various operating configurations of the gas spring may be obtained in addition
to the required thrusts in order to satisfy a wide range of user requirements.
HOW TO MEASURE
The thrust force of the ATLAS spring is measured with a special dynamometer at a room temperature of approx. 20 ¡C with the stem compressed by about 10 mm and free from friction by the seal.
The measurement is given in kg and is a “static” value, which is normally referred to when defining the characteristics of a spring.
Other components interact with this basic value and become especially noticeable in the “dynamic” phase of the spring.
We are referring in particular to friction produced by the seals and the stem supporting guides. The resistance exerted by the friction acts in the opposite direction to stem movement;
it has a value of approx. 2/3 kg and is added to or subtracted from the above-mentioned “static” thrust.
The closing force is indicated in the graph below with F1 and the opening force with F2.
It can be seen that F1 and F2 are higher and lower respectively than the average line which identifies the “static” thrust force.
