English - Nooteboom Giants on the Road Magazine English - Nr. 6 - 2019 - Page 55
ADBAN drawbar trailer was pulled by a Scania 140 6x4 tractor.
Hydraulic suspension for pendle axles is known at Nooteboom under
the abbreviation HP.
Raising and lowering the trailer is different than it is on a trailer with
air suspension, where one simply releases and pumps up air. There are
two options: a built-in pump or the oil can be drained or replenished
from outside. To lift the axles there are two options as well. The first
one can only be used if the trailer is equipped with a pump. In that
case the procedure is as follows: first lower the trailer completely. Then
the suspension of one or more axles is shut with a valve. The axle is
then locked with a chain, turnbuckle or locking pin. When the trailer
is pumped up and put at ride height again the lift axles will remain
suspended above the ground. Another – more modern – option is to
use double-acting cylinders. By adding oil at the bottom of the cylinder
the axle is lifted. This system is known under the name “power-up”.
In the engineering department of Nooteboom they have been working
for a while on the next generation of trailers with hydraulic suspension.
They will not be for sale soon. Why not?
At Nooteboom the suspension is first of all overloaded for a long
time in a test setup. This is followed by tests in practice by carefully
selected customers for at least a year. Going to so much trouble for a
part of the trailer that you cannot even see? Yes, because these invisible
components are the basis for a next generation of Nooteboom trailers
with even better specifications and even lower maintenance costs. ■
SIGNALLING AXLE PRESSURE AND RIDE HEIGHT
Transports travelling across Europe often have to comply with different
regulations for axle pressures on parts of their journey. If pressure
gauges are fitted the driver can pretty well work out the pressure on
the axles. This prevents unnecessary fines and road wear but it is also
benefits the lifespan and repair costs of the trailer. Another useful option
is the indicator light that operates via sensors. Even in the dark the
driver can see when the normal ride height is reached.
■ RB suspension(rigid axle)
■ RB suspension(rigid axle)
■ HR suspension(rigid axle)
Nooteboom has been delivering trailers with hydraulic suspension since
1975. Since those days the quality of the components has increased
dramatically. But heavy transport operators are conservative. Sometimes
an old hand in the profession will grumble: ‘A cylinder underneath the
trailer is never going to work, what about dirt and stone chippings?’
Whoever believes this has not paid attention in the last few years. The
maintenance costs of hydraulic suspension are anno 2018 exceptionally
low. Due to the beneficial axle pressure compensation the tyres and
brake lining enjoy a long lifespan. Shock absorbers are not fitted, so they
don’t need replacing either. And the progressive suspension ensures the
mechanical parts, such as the parabolic springs and silent-blocs are not
HYDRAULIC SUSPENSION, STEERING AND GOOSENECK
Hydraulic steering and suspension are two separate systems that
are not connected. This is different for a gooseneck with hydraulic
compensation. For trailers up to five axles a fixed neck is sufficient.
But for a long trailer with many axles a neck that can increase
the compensation while driving is preferable. This is achieved by
hydraulically connecting the front axles with the gooseneck. An addition
here is a differentiator which, by turning one single lever, makes the
hydraulic gooseneck suitable for the maximum permissible fifth wheel
pressure of a 6x4 or 8x4 tractor. At the beginning of this story – in 1975
– the detachable gooseneck had just been invented. The steering of the
axles was done mechanically with rods and the suspension? Leaf spring
suspension was the standard. Older mechanics can still recall how they
had to replace a broken leaf spring bolt or a leaf in a spring assembly
nearly every week. We quickly forget, but the hydraulic suspension of
today is infinitely more reliable and maintenance-friendly.