Axtone offers complete equipment of passive safety systems in accordance with European standard EN 15227. The system consists of a shock absorber, Crash components and an impact beam. The parameters of all the components are designed to cater for Customer's individual needs and the design of the tram.
The systems can be manufactured both on the basis of defined parameters or it can be Axtone that performs and provides simulations and selection of individual parameters based on the required operating conditions of trams.
Axtone systems are characterized by low weight due to the use of light metals for the production of the impact beam. Axtone offers comprehensive systems as well as provides Crash components according to Customer's specification.
Albert couplers can be used as operational or emergency couplers for trams and light rail vehicles. Operational couplers can be used for daily vehicle service on tram and/or LRV lines, where there is a need for a safe, cost effective and simple connection. Emergency couplers are used for towing a faulty vehicle. They are often used as couplers in working service trams.
In trams coil springs can be used as primary or secondary suspension. Due to space and load requirements regarding the primary springs, linear spring sets are usually used.
Linear coil spring means a cylindrical coil spring with constant diameter and constant wire diameter. The spring ends are either “closed and ground” or “taper rolled, closed and ground”.
Linear spring set means that two linear coil springs with the same length are put together one into the other. Therefore the inner spring has a smaller outer diameter than the inner diameter of the outer spring. The inner spring also has a smaller wire diameter. The two springs of one set must have different coiling directions (one left, one right hand coiled).
If coil springs are also used in the secondary suspension, single coil springs are usually installed. As the lateral deflections are quite high, these springs must have a bigger length than primary springs.
The direction of the lateral displacement under vertical load (“chasse”) is marked on the springs and they have to be mounted into the vehicle according to the correct orientation of this marking.
TKS springs can also be used in trams as secondary suspension, because due to the big load difference between the empty and the fully loaded vehicle (for example in the rush hour), a progressive characteristic has advantages.
A TKS spring is a single spring with a progressive characteristic due to an inconstant inclination of the coils and an inconstant cross section of the wire. The low stiffness at tare load, the smooth and continuous transition of the stiffness with increasing numbers of passengers and a high end stiffness for the maximum loaded vehicle ensure a better ride quality under all those conditions.
As the maximum load in trams is very high, the stress in such coil springs is usually rather high so that the springs for trams require a high material grade and production quality.
Production of rings used for friction springs which meet the requirements of the chart UIC 827-2 takes place in the Czech company owned by the Group. The springs are manufactured in a wide range of various diameters from 80 to 400 mm. The rings are used in friction springs of Ringfeder type applied in buffers, tractive apparatuses, pull rod bars and automatic couplers.
- Hot formed, highest quality materials;
- Various shapes possible;
- Linear characteristic;
- Safe against overloading;
- Big damping due to friction;
- Characteristic independent of the speed;
- Characteristic independent of the temperature;
- Proven in rail applications.
Basic technical dates of friction springs:
|F Spring terminal force|
Se Stroke for 1 element
We Spring work for 1 element
he Height of 1 element
|d1 Inner diameter|
b/2 Half ring width
D2 Guide outer diameter
d2 Guide inner diameter
Example of spring calculation
This spring consists of 4 elements type 19600:
- End force = 600 kN
- Stroke = 4 x 4,4 (Se ) = 17,6 mm
- Spring work (Absorbed energy) = 4 x 1300 (We) = 5200 J
- Spring length = 4 x 23,4 (he) = 93,6 mm
By adding additional elements, we increase the stroke (length of the spring), the absorbed energy (spring work) but the end force will remain the same. End force still 600 kN.
During the operation of the friction spring two thirds of the input energy is dissipated as frictional heat. The recoil force at any point on the diagram is approximately equal 1 / 3 of the relative compressive force F. The capacity of the spring is represented by the total area shown below the load curve.
Friction springs are generally designed to „block”, so it is therefore ensured that the admissible stresses cannot be exceeded and the friction spring will not be damaged.
- Draw gears;
- Draw bars;
- (Semi) automatic couplers