Gas Springs - How they work, what types are
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
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
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.
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.
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