A Gas Spring is an energy-storage device similar in function to mechanical coil springs. Mechanical coil springs store energy by straining the material composing the spring. A Gas Spring stores energy by compressing the nitrogen gas within the Gas Spring. As a mechanical coil spring is compressed, additional strain is placed within the spring, which adds to the spring’s stored energy. Likewise, as a Gas Spring is compressed, the gas chamber volume is reduced due to the intrusion of the shaft into the Gas Spring tube; thereby causing the gas pressure to rise, storing more energy.
The goal is the same with either type of spring; to move or resist the movement of some object. Typically for Gas Springs, the object to be moved is an engine cover, access panel or even a hospital bed. Gas Springs are not limited to just these uses, and in fact can be used in many applications where mechanical springs are applied.
One of the significant differences between mechanical springs and gas springs is the force provided at their free length. Gas Springs always require some initial force to begin compression, while mechanical springs have a characteristic known as free length. This is the length of the spring with no force applied. The force required to move the spring begins at zero and increases according to the spring rate. Gas Springs in their “free length” require some initial force before any movement takes place. After the full initial force is applied the Gas spring will begin to compress. This force can range from 15 to 1,000 pounds. In mechanical springs this initial force is called pre-load and requires additional hardware to achieve.
Another significant difference is the spring rate. Gas Springs can be designed with a very low spring rate utilizing a small package. A similar mechanical spring would require as much as twice the package space.
The ability to have a controlled rate of extension is another major difference. Gas Springs can provide a rate of extension (controlled release of the stored energy) that can be set to a prescribed velocity. Mechanical springs do not have this ability. In fact, Gas Springs can have multiple extension rates within the same gas spring (typically two: one through the majority of the extension stroke, another at the end of the extension stroke to provide dampening). When designing a Gas Spring one must allow for between 1% and 2% force loss per year, and understand the force variation due to temperature..
Dynamic Damped Gas Springs (VMX) -Dynamic dampening is available on AVM’s full range of Gas Springs. These Gas Springs are referred to as “VMX”. Standard gas spring shafts will extend from the tube at a steady speed with VMX we can vary the rate at which the shaft moves based on its position as it extends. View Specifications
Gas Spring with a Multi-Lobe Seal -AVM is the only company to build Gas Springs with a multi-lobe seal. The seal provides superior durability in dirty, wet environments over a standard lip seal but does require a more complex manufacturing process.
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Off the Shelf Gas Springs -While AVM Industries is a “Build To Order” Manufacturer, we do offer a Standard Line of Gas Springs that we have Material more readily available and can be manufactured with a reduced lead time. View Specifications
Gas Spring - Lip Seal - AVM Gas Springs are custom-engineered and manufactured beyond industry standards to provide smooth operation and durability. The Lip Seals used in our Gas Springs are ideal for general use and in particular, for high-frequency applications.
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Locking Gas Springs -AVM locking Gas Springs allow the user to lock the unit in any position during operation of the Gas Spring. This is achieved by depressing a control pin, inside the shaft, that actuates a valve inside the assembly.
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Paint Assist Gas Springs -AVM gas springs are an industry first in their ability to survive high temperature paint ovens used in the automotive industry. The standard front bushing is replaced with a powdered metal design and all of the internal plastic components are made with a Thermo-set material. View Specifications
Temperature Compensation (TCM) -Temperature plays a big part with Gas Springs. Output force will increase as the temperature rises and decrease as it drops. Gas Springs function by utilizing compressed nitrogen gas to provide the force to extend the shaft via a differential in surface area of the piston. View Specifications