Employed in a number of industrial, commercial and domestic applications,
air springs are used for the optimization of opening, closing, lifting, lowering, adjusting and damping actions. Also known as
air shocks and
dampers,
gas lifts and
gas struts are commonly used in place of or in conjunction with traditional mechanical springs. Manufacturers and suppliers often offer these well engineered devices in a number of different materials such as aluminum or
stainless steel gas springs. In addition to the body material, it is important to consider the composition of the air or gas that will be passing through the spring.
Carbon gas springs and
nitrogen gas springs are commonly used as they provide many beneficial qualities and are safe to use in most industrial applications. In addition to the material construct, the overall
gas spring design must be carefully considered. Several types, such as reducible, adjustable,
tension gas springs and
locking gas springs are commonly available to suit the vibration isolation and actuation needs placed upon these gas cylinders. The size of these devices may range from two inches to twenty inches or even several feet. The load capacity is equally variable ranging from less than one-hundred to over eighty eight thousand pounds.
The specific needs and requirements for a gas spring depend largely on the application for which it will be used. Furniture, medical and rehabilitation, aerospace, office supply, agriculture, marine, pharmaceutical, food processing and machine engineering are just a few of the many industries that make use of gas springs in regular operations. Proving the importance of these devices, the automobile industry alone uses gas springs for tailgates, hoods, trunks, supports for open doors, suspension, sunroofs, seat adjustment and steering dampening among other applications. Specific examples from other industries include the use of gas springs in tanning beds, awning extension, conveyors and landing gear for planes and jets. To suit these needs, both compression and extension gas springs are available. Compression provides dampening when a force is applied that shortens the stroke, or pushes the piston further into the main cylinder. On the other hand, extension gas springs provide isolation when the rod is fully extended either partially or fully due to high pressure within the chamber. The ability of these carefully calibrated mechanisms to endure the rigorous application of variable pressures at inconsistent velocities is of utmost importance as failure in any number of the aforementioned applications could be fatal. Proper use and maintenance is integral to product safety and longevity, the latter of which often surpasses that of traditional spring mechanisms.
Gas springs, from across the broad range of applications for which they are well suited, all function under the same basic design and principles of operation. Each spring incorporates a cylinder or body, piston and rod, o-rings or other sealing system, intake and outlet valves and gas charge or reservoir. The cylinder houses all other components and has a polished interior to reduce friction. The piston head rests perpendicular and, in conjunction with seals, creates an airtight barrier which divides the cylinder into two compartments. The rod is attached to the piston and extends out one end of the cylinder. While this design may seem relatively simple, most manufacturers use 3D CAD drawing and other design software in the construction of application specific gas springs. This is important as despite its relative simplicity, the operation of these pneumatic devices relies on precision. When force is exerted or a shock encountered, the rod attached to the external mechanisms protrudes deeper into the chamber, moving the piston head towards the opposite end. This reduces the volume of the cylinder, thereby compressing the gas. Resistance is thus created allowing the spring to absorb some of the force or at least slows the motion of the rod before it can reach other more sensitive components of the machine. A great example of this effect is in the shock absorbers or suspension system of a car or other vehicle.
Often preferred over traditional mechanical springs, gas springs offer several benefits. Air springs are often more cost effective than metal coils as well as more compact and exceedingly durable. Unlike metal coils, the air cylinders and pistons used in these springs allow for easily adjustable and controlled movement. This adjustability also provides room for correction should gas leak out of the main chamber over time whereas worn coils will need to be replaced. Like mechanical springs, however, there are several factors that must be carefully considered when selecting the proper gas spring for a given application. As aforementioned, the body material is largely important as it must endure not only the physical stresses, but also the chemical and environmental stresses of an application as well. Materials such as stainless steel, thermoplastic, aluminum and steel are often used and sometimes coated with black nitride or chrome plated for further protection. Additional physical considerations include cylinder diameter, maximum width, rod diameter and mounting style. Performance specifications to take into account include working temperatures, absorber stroke, compressed and extended lengths, maximum force and maximum cycles per minute. Gas spring and industry specific professionals can provide helpful insight when selecting the proper device for a given application in order to ensure safety and optimal performance.
Types of Gas Springs
- Air shocks are a particular type of gas spring designed for damping and vibration isolation. Also known as shock absorbers, these devices are commonly installed on a variety of vibratory or oscillating industrial equipment such as conveyors and mixers, but most closely associated with vehicle suspension systems and jet or plane landing gear.
- Air springs
utilize a contained column of air inside an elastomeric bellows or
sleeve to buffer cyclic motion, provide vibration isolation or serve as a
linear actuator.
- have
a valve that permits the flow of a pressurized fluid between two
compartments of a cylinder cavity separated by a piston. The piston rod
is blocked
during inward movement by a predetermined force applied to the piston
rod.
- Carbon gas springs have
carbon steel bodies, making them useful in rough temperature and
chemical environments.
- are
used to get specific characteristics from different types of gas
springs; they have different body and gas spring rod combinations,
and are either
combined in a parallel or serial fashion.
- have
a rod that is compressed into a cylinder, and when the compression
is removed, the rod extends. These springs cover a large range of
forces and strokes and are the most commonly used gas spring
- Dampers are
able to prevent or stop oscillations or vibrations.
- have
the damping and shock absorption occurring as the rod extends from
the cylinder.
- Gas lifts or gas lifters are simply gas springs used in lifting applications. While gas lifts more commonly refer to a method used for oil lifting or extraction, gas spring lifts are a means of producing force through the use of compressed air in order to lift, raise, push or pull a surface or component as needed.
- Gas spring design is the precision engineering and construction of pneumatic energy storage devices which provide lifting, lowering, moving, locking, opening, closing and adjusting actions in a number of industrial, commercial and domestic applications.
- utilize
a cylinder, which contains compressed gas, and a piston to exert
a force.
- Gas struts are braces or suspension units designed to resist thrust and longitudinal compression.
- Locking gas springs are pneumatic cylinders that include a stopping or bracing mechanism used to halt motion within the cylinder as needed throughout the stroke.
-
are
small in size and have low force, so they are very
versatile.
- Nitrogen gas springs have
lower pressure increase than standard gas springs, and they
have
consistent, balanced and adjustable force, with more force
per area
than other
springs.
- Stainless steel gas springs are used to prevent corrosion on the gas spring
rod, which leads to the early failure of gas springs.
- Tension gas springs,
or traction springs, retract instead of extend and the piston rod
stays in a closed position, moving opposite of other gas springs.
Used to
keep doors, hatches, lids, etc. closed.
Gas Springs Terms
- minimum
length of the spring's shock.
- is gained while regulating
the flow of gas through the valve at the orifice of a gas damper piston,
it creates a cushioning affect that slows the mechanism before it extends
fully.
- are used to
attach the gas spring to the item it will be controlling, mounting brackets
may also be used. There are different options for multiple applications
and purposes.
- maximum length
of gas spring when it is fully extended.
- measured 5mm from full
extension of the gas spring, and it is a function of the pressure in
the cylinder acting on the cross section of the rod. The larger the diameter
of the rod, the lower the force.
- ratio of compressed
force to extended force, compressed force being always larger than extended
force.
- a cylinder or disk
that displaces fluids or moves under fluid pressure within a larger cylinder.
