Gas springs provide controlled motion and speed for elements, such as lids and doors, that open and close. They typically rely on the fluid dampening of a gas such as nitrogen in the cylinder.
Important performance specifications to consider when searching for gas springs include absorber stroke, compressed length, extended length, maximum force (P1), and maximum cycles per minute.
- Absorber or spring stroke is the difference between fully extended and fully compressed position.
- Compressed length is the minimum length of shock (compressed position).
- Extended length is the maximum length of shock (extended position).
- The maximum rated force for shock absorber or damper, referred to as the P1 force.
The maximum cycles per minute are the rated frequency of compression/extension cycles.
Compression or Extension
The absorption or damping action for gas springs can be compression or extension.
- In a compression gas spring the shock absorption or dampening occurs in the compression direction.
In an extension gas spring the shock absorption or dampening occurs in the extension direction.
Important physical specifications to consider when searching for gas springs include the cylinder diameter or maximum width, the rod diameter, mounting, and body material.
- The cylinder diameter or maximum width refers to the desired diameter of housing cylinder.
The rod diameter refers to the desired diameter of extending rod.
Mounting choices include ball and socket, rod end, clevis, eyelet, tapered end, threaded, and bumper or rod end unattached.
- A ball and socket is a spherical bearing with bore that allows for multi-axis rotation. A ball end is a ball and socket (spherical bearing) with an integral threaded stud.
- Clevis pins include mating fork mounts.
- Eyelets are round holes at the absorber ends for mounting.
- On a tapered end mounting the cylinder side has tapered end for snug fit into mounting hole.
- In a threaded mounting the ends or body have standard threads for mounting or accessory attachment.
In a bumper or rod end unattached mounting the rod is not attached to the load, but has a bumper on end to engage moving load.
Choices for body materials include aluminum, steel, stainless steel, and thermoplastic.
Common features for gas springs include adjustable configuration, reducible, locking, and valve.
- An adjustable configuration allows the user to fine tune desired damping, either continuously or at discrete settings.
- A reducible gas spring has an adjustment style for gas shocks in which gas is let out to permanently reduce force capacity.
- In a locking gas spring the position can be locked at ends or in the middle of stroke.
Valves can be included for fluid absorbers, a valve or port, which can be used to increase or decrease fluid volume or pressure.
The ISO (International Organization for Standardization) provides the standard ISO 11901-1:2003 which specifies the dimensions, nominal initial forces, and type of gas springs.