Combination Gas Springs
 Different gas spring rod and body combinations are used when the K-Factor has to be lower or higher than standard (e.g., a lower or higher difference between the fully extended and fully compressed forces). Most applications requiring a low K-Factor benefit from these combination springs, while those requiring higher than standard K-Factors can be met by simply increasing the fluid fill of a standard gas spring rod and body combination.
Illustrated below are examples of applications that benefit from Low and High K-Factors.
LOW K Factor
These gas springs are most useful where a straignt lift is required (i.e.: TV monitors). The difference between the force when the gas spring is fully compressed and the force when it is fully extended will be very small, thus ensuring a near-constant hand force to be applied along its movement.
HIGH K Factor
In some cases it is in the interest of the user to have as much force as possible when the gas spring is compressed and a force as small as possible when the gas spring is extended.
A roof hatch is taken as an example here. There is almost no space available underneath the hatch to fit the gas spring, so the moment of the gas spring is small when the lid is closed. In order to help the user at the beginning of the lift this particular application requires a very strong gas spring.
On the other hand when the lid is fully open (at the point where the lid doesn't weight anything) we want to limit the gas spring force so it is not too hard to close. |
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| Using our standard size 10mm gas spring with 200mm stroke and a P1 force of 750 Newtons (K=1.3) we obtain the following curve.
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On the same application, we are using a gas spring with 750 Newtons, therefore the hand force when the lid is open remains the same (71N). This time, because we have increased the K factor, the force of the gas spring is higher when compressed and the force required to lift the lid is therefore decreased (from 98N to 66N).
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