Gas Springs - How they work, what types are there, and where are they used

Gas springs are also referred to as gas struts or gas dampers. They are a common sight in very wide range of applications. This article gives a little more information on the operation of a gas spring, the different sorts of gas springs that are available and also details some information on applications where they can be used.

How does a gas spring do its job?

A gas spring comprises of a sealed energy source containing an inert gas (nitrogen) and oil. As they are self-contained items, gas springs require no maintenance and no extra source of power.

During manufacture nitrogen is forced under pressure into the gas spring cylinder and this is then sealed. The pressure inside the cylinder exceeds atmospheric pressure and this results an outward force on the rod and the gas spring is extended. (The press on the B face is higher than the A face.)

When extra external pressure is applied to the rod, the piston is compressed into the cylinder. The pressure internally from the compressed gas, and the output force, increase according to the volume displaced by the rod. On compression or extension, the nitrogen gas is moved from one side of the piston to the other side through a small hole in the piston face.

There is a hydraulically cushioned zone at the end of the extension stroke. Here, oil damping smoothes the end of the stroke within the gas spring.

What gas spring types are there and where are they used?

Swift & Sure Gas Springs

At Components Direct, 'Swift & Sure' are a standard range of compression gas spring. These provide constant force output and a controlled movement rate. The example below shows two Swift & Sure gas springs in a food display cabinet.

Econoloc Gas Springs

The Components Direct Econoloc gas spring has the added feature of a locking safety shroud. This can eliminate the need for separate safety rods in critical lift-assist applications. When fully extended, these Econoloc gas springs automatically lock in place as a spring loaded shroud moves into place. A typical application example below shows the Econoloc gas spring used on an engine bay cover.

Stop & Stay  Gas Springs

The 'Stop & Stay' gas spring from Components Direct has a friction control function which enables multi-position staying of a counterbalanced weight over the whole stroke by means of a simple adjustment nut. The example below shows two 'Stop & Stay' gas springs on a sunbed application.

Stainless Steel Gas Springs

A range of stainless steel gas springs are available from Components Direct where the application exposes the gas spring to harsh environments.

Their features include:

~ 316 Stainless Steel
~ High corrosion resistance for external applications
~ Tested to 1000 hours salt spray
~ Special surface finish for additional hardness and corrosion resistance enabling cycle life of 100K+
~ Variable force option available
~ Wide range of connectors

Vari Lift Gas Springs

All styles of gas springs at Components Direct listed above are available with 'Vari-lift'. These are adjustable gas springs, charged to their maximum force, which can be simply adjusted down to meet individual application requirements - even whilst fitted in position. The image below shows the Allen Key screw release valve on a 'Vari-lift' gas spring.

Bloc Lift Gas Springs

The 'Bloc Lift' gas spring can be locked at any desired position via an internal locking mechanism but works like a standard gas spring when the lock is released. 'Bloc lifts' are excellent way of moving an application to any position at the discretion of the operator. The 'Bloc Lift' gas spring will also allow a load to be applied to the application while it is locked in any of the infinite locked positions. It is available in stainless steel with a wide range of connectors and actuators.

Dampers

Gas springs technology can also be used in dampers. The dampers from JET PRESS provide velocity or time controlled movement. They provide deceleration and momentum control to prevent sudden shock or impacts. As for gas springs, dampers are available in stainless steel and can be supplied with a wide range of connectors and actuators.

Buy on-line now at www.comdir.co.uk