GASPARDO NINA Empleo Y Mantenimiento página 36

ENGLISH
3.3 STABILITY OF PLANTING UNIT AND TRACTOR
DURING TRANSPORT
When a planting unit is coupled to a tractor, so becoming an integral
part of it for the purposes of road travel, the stability of the planting
unit-tractor complex may change and cause driving or operating
diffi culties (rearing up or side-slipping of the tractor). The condition
of equilibrium can be restored by placing a suffi cient number of
ballasts on the front of the tractor so that the weights on the two
tractor axles are distributed suffi ciently evenly.
To work in safety the instructions given in the highway code should
be followed; these prescribe that at least 20% of the weight of
the tractor alone should be borne by the front axle and that the
weight on the arms of the hoist should not be more than 30% of
the weight of the tractor itself. These factors are summarized in
the following formulas:
Z > [M x (s1+s2)]-(0.2 x T x i)
The symbols have the following meanings (please see Fig. 9 for
reference):
M (Kg) Mass weighing on arms off hoist with full load (weight +
mass, see cap. 1.4 Identifi cation).
T (Kg) Mass of tractor.
Z (Kg) Total mass of ballast.
i (m) Tractor wheelbase, that is, the horizontal distance between
the tractor axles.
d (m) Horizontal distance between the centre of gravity of the
ballast and the front axle of the tractor.
s1 (m) Horizontal distance between the inferior point of attach-
ment of the equipment and the posterior axle of the tractor
(equipment supported to the ground).
s2 (m) Horizontal distance between the barycentre of the
equipment and the inferior point of attachment of the
equipment (equipment supported to the ground).
The amount of ballast that should be applied according to the
formula is the minimum required for circulation on the road. If for
reasons of tractor performance or to improve the set-up of the
planting unit during operation it is thought necessary to raise these
values, please refer to the registration document of the tractor to
check its limits.
When the formula for calculating the ballast gives a negative result
it will not be necessary to add any weight. In any case, as long as
the limits of the tractor are respected, a suitable quantity of weights
may be applied in order to ensure greater stability during travel.
Check that the tractor tyres are suitable for the load.
3.4 PREPARATIONS FOR SOWING
To obtain the most correct investment of the seeds per hectare (kg/
Ha) the distribution parts must be adjusted properly: the gear-box,
the feelers, rollers and sliding doors. Use the sowing table to fi nd
the relevant instructions (refer to the sowing test chapter 3.11.5).
To proceed, the values to follow are: the type of seed (wheat,
barley, etc.), the amount in kg to be distributed per hectare and
the distance between the rows to be sowed.
3.4.1 SPEED CHANGE GEAR
The gear shift is located on the right side of the seeder and receives
motion from the drive wheel. The gear shift is used to change speed
to the seed distribution units through the adjustment lever which is
calibrated on a continuous scale of 1 to 55 (Fig. 10).
Loosen the knob, move the lever to bottom of scale «0» (zero) and
then set it to the value indicated. Lock it by tightening the knob.
36
USE AND MAINTENANCE
(d+i)

fi g. 9
fi g. 10
1
S2 = 380 mm
55
cod. G19502553