Rigid blockable in extension gas spring

Less widely known, but long-produced gas telescope variety. The lockable, positionable… etc. names are also cover this type. Normally open, compression needs strenght. Can be positioned freely along the full stroke. In blocked state in extension force is rigid, in compression force can be flexible

Size range:

Within the range shown in the table below, we produce flexible blockable gas springs, even in individual sizes.
The ends of the gas springs are threaded in principle, but can be chosen from a large variety of end fittings as required.


Type A B C Stroke x F1 max. D E
Rod Ø [mm] Cylinder Ø [mm] Stroke [mm] Basic lenght calculation [mm] Extended lenght calculation [mm]
FBCH10 10 22 20 – 500 300 000 (C x2,5) +80 (C x2,5) +80 +G
FBCH10/27 10 27 50 – 500 300 000 (C x2,5) +80 (C x2,5) +80 +G

For each type, the stroke and the maximum value of F1 are determined to avoid bending of the rod. If the gas spring you are looking for exceeds this value, it can only be made with a smaller stroke or force, or it can be made only from bigger type.

The value of G and H are different for each fitting type.

Force characteristics and dampering:

The force of the rigid blockable in extension gas spring is not constant, depending on the position of the piston rod and the direction of movement. The force is required for compression is always greater than the extension froce of the gas spring.

Of the 4 different forces, only one can be definite, preferably the the smallest thrust, F1. This force is called as the force of the gas spring, this is indicated on the nameplate. The F2, F3, F4 force are indicative, may differ from the theoretical values. The force of the gas spring can be affacted by the ambient temperature. When fabricated, the F1 is measured at 20±2 °C. With the change of the temperature, the force change rate is about 3,3% for every 10 °C deviation.


Type P Fs max F1 Max. blocking force Possible damperings
Progression Friction force max [N]. Smallest extension force [N]

Extension [N]

Compression [N]

Extension Compression Both direction Without dampering
FBCH10 1,50 40 50 – 1200 7 000 4x F1 X
FBCH10/27 1,35 50 100 – 1200 10 000 6x F1 X

During the damping of the gas springs, it is the stroke end damping, braking can be mean, which is slows down the speed of movement before reaching the entire open and/or closed lenght, thus saving the structure and the telescope. The rigid blockable in extension gas springs can be ordered with both direction dampering only, due to their internal structure.

The gas spring cannot pick up higher load in extension direction then the maximum load, in compressionn direction becomes flexible above the specified value. The maximum load in compression direction is the same as the maximum blockin force in extension direction.

Function and structure:

The rigid blockable in extension gas spring is a cylinder filled with high pressure nitrogen, which is divided by the piston rod into two interlocked internal chambers. The piston valve is normally closed. The two sides of the piston, due to the different size surfaces, has differnt force of the gas charge, lower on the lower side than the top. The difference of the two forces is the force of the gas telescope,which pushes the rod outwards. When the valve is closed, the gas does not flow between the chambers, so the gas spring keeps its position. Under external force it is rigid in pull direction, and it moves flexibly in compression directionas the gas is compressible. When the valve is open it acts as a compression gas spring.

Parts of rigid blockable in extension gas spring:
1, release pin 2, piston rod 3, guding element 4, seal 5, oil 6, piston with valve 7, floating piston 8, gas and lubrication 9, cylinder 10, end fitting


In the medical technology, beds, chairs, tables and adjustable sanitary ware, as well as a reliable accesory to the cosmetics industry.


The Fedbaer gas springs can be ordered with the following appearances and materials

Fedbaer Basic series

Standard version, black rod and tube

Fedbaer Silver series

Chrome plated rod, silver metallic tube

Fedbaer Inox series

Stainless steel rod and tube



Accessories for Fedbaer gas springs

End fittings

List of optional fittings

Release systems

Tools for operation

Protective cover

Protect the rod from damage


Operating temperature

The Fedbar gas springs can be ordered for the following temperature conditions:

Coldproof gas spring

max.: +80 °C
min.: -45 °C

Recommended below -20 °C

max.: +80 °C
min.: -30 °C

Recommended for normal use

max.: +200 °C
min.: -30 °C

Recommended above +80 °C