Gas Springs - How they work, the types available,
and their applications
Gas springs are also known as gas struts or gas
dampers and are used in very wide range of applications. Here we look at the
operation of gas springs, the different kinds of gas springs that exist and some
information on where they may be used.
How does a gas spring work?
A gas spring is a sealed energy source containing an inert gas
(nitrogen) and oil. Being self-contained units gas springs require no power source or
maintenance.
Nitrogen is forced under pressure into the cylinder
of the gas spring. The
internal pressure exceeds atmospheric pressure and generates an outward force on
the rod, making the gas spring extend.
With the pressure being equal on both sides of the piston,
there is more force acting in direction ‘B’ than in direction ‘A’. This forces
the rod of the gas spring out.
When the rod is compressed into the cylinder, the internal
pressure and the output force increase according to the volume displaced by the
rod. On extension or compression, gas is metered from one side of the piston to
the other via a small orifice.
At the end of the extension stroke, oil damping occurs
within the gas spring due to
a hydraulically cushioned zone.
What gas spring types are available and how are they used?
Swift & Sure Gas Springs
At JET PRESS, 'Swift & Sure' are a standard range of
compression gas spring providing constant force output and a controlled rate of
movement. The example below shows two Swift & Sure gas springs in a food counter
application.
Econoloc Gas Springs
The JET PRESS Econoloc gas spring includes a locking safety
shroud. This feature eliminates the need for separate safety rods in critical
lift-assist applications. The Econoloc gas springs positively lock, when fully
extended, by a spring loaded locking shroud moving into place. The example blow
show the Econoloc gas spring used in an engine bay cover application.
Stop & Stay Gas Springs
The 'Stop & Stay' gas spring from JET PRESS
incorporates friction control. This enables multi-position holding of a
counterbalanced weight over the entire 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
JET PRESS to cope with 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 JET PRESS 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.
Contact JET PRESS on 01623 - 551 800 to find the right
gas spring for your application, or buy on-line now at
www.comdir.co.uk