A design engineers guide to gas springs - gas spring overview

F = P x A

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Often used but seldom fully understood, gas springs are often the last thing to be considered on an application. The first thing to understand is that gas springs are used within a wide range of applications for lowering of weights, lifting, damping and general safe manoeuvring of applications.

Principally, a gas spring is the same as a mechanical coil spring in so far as it is a device which stores energy. However, whereas a coil springs energy comes from straining material, a gas spring stores energy by containing compressed Nitrogen gas inside.

A gas spring is supplied as a closed system which is charged with inert Nitrogen gas. The rod always extends because the pressure on either side of the piston remains equal no matter where it is positioned; this is due to the small cross-sectional area of the rod where the gas is unable to exert any pressure.

As the rod is pushed into the tube, the Nitrogen gas contained in the spring is compressed increasing the pressure giving the gas spring its non-linear force characteristics. The piston attached to the rod allows the flow of gas across the piston. This also provides the means of controlling the flow of gas and oil as the rod is compressed and extended.