ENGLISH – 13
3.9 ADJUSTING THE MECHANICAL LIMIT
SWITCHES
To adjust the limit switches, proceed as follows:
1. unlock the gearmotor with the relevant key provided (refer
to the “Manually unlocking and locking the gearmotor”
paragraph)
2. manually move the boom so that it completes a full open-
ing and closing manoeuvre
3. turn the screws of the mechanical stops (A - B) to adjust
the boom’s horizontal position, when it is closed, and its
vertical position, when it is open
A
B
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4. after making the adjustments, tighten the nuts vigorously.
3.10 BOOM BALANCING
The boom balancing operation is used to nd the best balance
between the overall weight of the boom, inclusive of the installed
accessories, and the force opposed by the tension of the bal-
ancing spring.
To verify the spring tension, proceed as explained below.
For models M-BAR (“Figure 28”)
1. unlock the gearmotor with the relevant key provided (refer
to the “Manually unlocking and locking the gearmotor”
paragraph)
2. manually move the boom to about half-way (45°) and
leave it stationary
3. if the boom tends to rise, reduce the tension of the spring
(A) by manually turning the latter clockwise. On the other
hand, if the boom tends to fall, increase the tension by
manually turning the spring anti-clockwise.
Note The imbalance is acceptable when the force required
to move the boom during the opening and closing ma-
noeuvres and in all other positions is less than or equal
to half the nominal value. The force required is therefore
equal to roughly 1.5 kg for M3; 3.5 kg for M5; 4.5 kg for
M7. The force is measured perpendicularly to the boom
at 1 m from the rotation axis.
45°
45°
A
B
28
4. repeat the operation by positioning the boom also at
roughly 20° and 70°. If the boom remains stationary in its
position, it means that it is correctly balanced; a slight im-
balance is allowed, but the boom must never move sub-
stantially
5. loosen the nut (B) to block the balancing spring
6. lock the gearmotor.
For models L-BAR (“Figure 29”)
1. unlock the gearmotor with the relevant key provided (refer
to the “Manually unlocking and locking the gearmotor”
paragraph)
2. manually move the boom to about half-way (45°) and
leave it stationary
3. if the boom tends to rise, reduce the tension of the spring
by turning the nut (C) clockwise. On the other hand, if the
boom tends to fall, increase the spring tension by manual-
ly turning the nut (C) anti-clockwise.
45°
45°
C
29
Note The imbalance is acceptable when the force required
to move the boom during the opening and closing ma-
noeuvres and in all other positions is less than or equal
to half the nominal value. The force required is therefore
equal to roughly 6.5 kg. The force is measured perpen-
dicularly to the boom at 1 m from the rotation axis.
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