MLS MMLS3, Operator'S Manual

Page: 18 / 48

MLS Test Systems Pty Ltd
Revised: April 2013
16
Refer to fig. 5 below. It shows a side view of the bogie
suspension system. In the machine the system can only be seen
from the top.
The large spring at the bottom pushes the rubber wheel
downwards to create the load of the wheel onto the pavement.
When the machine is lifted off the pavement the wheels moves
downwards so that the gap closes until the rubber stoppers make
contact with the metal frame of the bogie. The stoppers then
bear the force of the spring and the wheel cannot move further
downwards.
When the machine is lowered so that the wheel makes contact
with the pavement, the pavement starts to push the wheel
upwards and the stoppers move away from the metal frame.
The pavement now counteracts the force of the spring and the
set wheel load is applied to the pavement.
To be sure that the correct load is applied to the pavement the
stoppers should not make contact with the metal frame of the
bogie. To allow for unevenness of the pavement as the wheel
travels down the pavement test section, the initial gap should be
set large enough. The required initial gap is about 10mm. (See
Adjusting the wheel load under 3.1 above).
The 10mm suspension gap can be measured with the supplied
tool, as indicated in fig. 5. You can also feel the gap with your
finger.
To make the gap larger the machine has to be adjusted lower
onto the pavement by turning the handles on top in an anti-
clockwise direction. In the same way, to make the gap smaller,
the machine must be raised from the pavement by turning the
handles in a clockwise direction.