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Your Guide to Gas Struts


Have you ever thought why your car boot doesn't fall on your head when you are getting something out of it? The reason it stays put is due to gas struts…the unsung heroes in everyday life. Gas struts not only spare you a bump on the head but they also spare your car damage when you close the boot by controlling the force with which the car boot shuts.

Gas struts or gas springs can be used for any application where there’s a need to control the speed of movement – they can be found in objects such as garage doors, luggage holders, extendable arms on a lamp and height adjustable furniture. According to Wikipedia, ‘Much larger gas springs are found in machines that are used in industrial manufacturing (the press tooling industry), where the forces they are required to exert often range from 2500N to 400,000N (Forty tonnes).’

The basic gas spring consists of three parts…

The rod – this is where force will be applied to the spring. The rod is attached to the piston so the energy applied to the rod will control the piston.

The piston – like the plunger on a syringe, it pushes the gas in the gas strut causing it to compress. The piston has holes in it so that gas can flow either side of it.

The housing tube – contains the piston and is filled with compressed gas, in most cases nitrogen. This tube is completely sealed to prevent any loss of gas.

How does a gas spring work?

With a car boot, when you push down on it you apply pressure on the rod, which pushes the piston forward. By having holes in the piston the gas flows on both sides, however the gas is still being compressed by the rod now occupying the space that was filled with gas. The gas being compressed on both sides of the piston means that it controls the rate you shut the boot. When you open the boot, the compressed gas pushes the rod out of the housing and helps you lift the boot door.