In their most basic form, gas springs are essential simple mechanical systems. The main components of a gas spring---rods, pistons, tubes and gas---interact with one another to absorb shocks and jolts. Gas springs are also closed systems, as the gas used to absorb impacts is completely contained within the shock system, and the system is sealed to prevent components from entering or leaving the spring system. Depending on the brand and make, the gas spring may be lubricated by additional oil; this oil improves the spring's seal and helps ensure the gas contained within the system is unable to escape.
To facilitate its function of absorbing impact, gas springs are filled with a neutral gas that can be easily compressed with minimal risk of explosive reaction. While the precise composition of gas springs may vary from manufacturer to manufacturer, the primary component of most gas springs is nitrogen; chosen for its neutral nature, nitrogen inside a gas spring quickly returns to its natural state after being compressed. In addition, nitrogen does not react with lubricants used to keep the gas spring system sealed, and is unlikely to explode when exposed to oil under high pressures. Finally, nitrogen is both readily available and economical, making it ideal for use in gas springs.
When gas springs are exposed to impact, a rod protruding from the system is forced into the inside of the spring system. As the rod enters the system, an attached piston compresses the nitrogen inside the pressure tube. Compressed under load, the neutral nitrogen simply expands back into its original size, pushing the piston outward and extending the attached rod back into its standard position.
While the process of compression and expansion in a gas spring happens very quickly and is facilitated by simple mechanical functions, a number of complex mathematical formulas describe the spring's operation. As the rod and piston are pushed inside the gas spring tube, the nitrogen becomes compressed under a compression ratio known as the "K-Factor." In simple terms, the K-Factor describes how very high compression results in very rapid expansion of the nitrogen inside the spring. The K-Factor, expressed as the force of the spring under compression divided by the force of the spring fully extended, also helps to explain the resistance of the spring to compression.
