Parabolic and trapezoidal springs:
Flexible and adaptable
Trapezoidal springs and the modern parabolic springs, made by Langen & Sondermann, are well proven spring elements for goods waggons all over Europe and beyond - in many dimensions and special designs!
If you should ever get the impression that there is nothing in our extensive range that meets your special needs, we will react - as flexible as our springs - with acustomised solution, made to measure for your vehicle.
The parabolic spring is the modern variant of the leaf spring, which has many advantages compared with the usual trapezoidal springs:
- longer lifetime due to defined residual stresses (shot peening, presetting)
- better structural design possibilities (spring center, spring eyes)
- lower weight due to better material utilisation
- constant friction conditions, therefore defined damping behaviour over the whole lifetime
- constant elasticity rate (spring rate) over the lifetime
- improved corrosion protection due to the possibility to apply an effective anti-corrosion coat (gap between the leaves)
Due to the special design the parabolic spring consists of only a few, relatively thick leaves with the same length but which thickness is reduced from the center to the ends according a quadratic parabola. Thats why the spring has its name! Therefore every leaf by itself is a bending beam with constant strength with optimal matrial utilisation resulting in a low weight and a reduction of unsprung mass. In the main springing areas there is a gap between the leaves so that the spring has a constant good spring and damping characteristics which is independent from the runtime and makes the spring maintenance-free and wear-free.
This gap between the leaves gives also the possibility of an effective and durable surface treatment by shot peening (under prestress), presetting and painting (corrosion protection). This allows a higher strain of the material and therefore increases the lifetime and on the other hand makes a further weight reduction possible.
As all leaves have the same length a two-stage spring can be realized very easy by adding a parallel working helper spring which is arraged below the main spring. Due to this arrangement there are no additional supports necessary and an optimal suspension regarding comfort and safety against derailment can be reached.
The parabolic spring has got its name by the shape of of the spring leaves. This parabolic shape results from the requirement of an optimal material utilisation which is given when a constant bending stress over the length of a spring is achieved.
Out of this requirement results with constant leaf width the leaf thickness between spring center and spring ends changes according to the function of a quadratic parabola which has its vertex at the spring eye and has its maximum thickness at the center.
Particularly it is an advantage that the thickness of the spring eyes can be adjusted very well to the requirements as it is not directly depending from the leaf thickness as it is the case at trapezoidal springs.
Langen & Sondermann offers you a variation of different parabolic springs for all kind of freight wagons (see parabolic springs catalog).If you nevertheless find anything fitting for your application we will be glad to develop an adapted solution for you. Because also here is valid
Flexibiliy is our business.
