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3.9 Safety clutch
3.9.1 Description
The machine is provided with a safety clutch which enables
the turning through of the lower belt wheel (1) on the hub of
the lower shaft (2), when the hook is blocked. This blocking
occurs due to the penetration of thread into the hook path.
With current running, this clutch should not disengage during
the normal running.
The mutual coupling of the belt wheel (1)
and the hub (2) is effected by means of the bills (3) which are
firmly connected with the belt wheel (1). The bills fit in the
conic holes of the hub (2) and are pushed therein by means of
the springs (4).
Putting the clutch in its working position, eventual checking
its correct position are to be done in blocking the hook using
a screwdriver and in turning a bit the handwheel.
3.9.2 Setting the disengaging moment
Caution! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
The correct value of the tensioning moment (8 Nm) has been
set up by the manufacturer. when this value is lower, in a
current running, the clutch may disengage. In an opposite
case (the moment is higher), the clutch will not disengage. In
both cases it is necessary to proceed to a correction of the
moment. In turning the nut (5) to the right, the moment will
increase and on the contrary. The value of the tensioning
moment is very sensible to the turning of the nut (5). When
setting it, it is necessary to proceed very carefully, set it up
only in emergency cases! Check the moment using a torque-
limiting wrench.
Caution!
The clutch guarantees only one mutual position
of the hub of the lower shaft (2) and that of the
belt wheel (1). No checking according to the gauge
marks is needed. Putting the clutch out of operation by
excessive tightening of the nut (5) can cause, when blocking
the hook, the destruction of the gear within the drive of the
hook.
3.10 Indented belt transmission
3.10.1 Setting the tensioning roller of the
indented belt
The optimum tension of the indented belt (1) is attained in
setting the tensioning roller (2) in such position, when the
roller applies the pressure of F = 20 N against the belt. The
roller must be side set in such a way that the edge of the
indented belt does not overlap over the edge of the roller.
Caution! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Remove the handwheel and the belt guard, remove the V-
belt.
- Unlock the fastening of the loop, on which the roller (2)
is mounted in such a way that the loop turns freely.
- Lift the roller (2) upwards and, thereafter, using the dynamo-
meter (4), pull horizontally the roller in applying the force of
2O N. In this position, tighten the fastening screw (3).
- Check the side shifting of the roller.
3
2
1
4
5
1
4
3
2
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