USE AND MAINTENANCE
42
-
cod. G19503220
ENGLISH
3.1.2 UNHITCHING THE PLANTING UNIT FROM THE TRACTOR
PERICOLO
Unhooking the seed drill from the tractor is a very dangerous
operation. This operation should be carried out with the tractor
engine switched off, the parking brake on and the equipment
resting on the ground. Great caution must be used and the
whole operation must be carried out following the instructions.
For a correct unhooking operation of the seed drill it is necessary
to proceed on a horizontal level.
1) Lower the supporting base elements (B, Fig. 9).
2) Slowly lower the seed drill until it rests completely on the ground.
3) Loosen and unhook the third point, following the fi rst and second
(1, Fig. 6).
3.2 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)
(d+i)
The symbols have the following meanings (please see Fig. 10 for
reference):
M
(Kg) Mass weighing on arms off hoist with full load (
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.
0,2 T
Z
T
i
s1
s2
d
M
s2 = 700 mm
fi g. 10
Summary of Contents for S MARIA 250
Page 31: ...31 Notes cod G19503220 ...
Page 59: ...59 Notes cod G19503220 ...
Page 87: ...87 Notes cod G19503220 ...
Page 115: ...115 Notes cod G19503220 ...
Page 143: ...143 Notes cod G19503220 ...
