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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 connection of the belt wheel (1) with the hub
is enabled by the pins (5) which fit with their conic ends into the
holes of the belt wheel. The pins are pushed by 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 moment of 8 to 9 Nm is correctly set, when the screwed in
adjusting screws (3) come to lie 0.5 to 1.5 mm under the face
of the hub (2). When the clutch disengages during a normal
run, the screws are to be turned by one thread to the right and
a test is to be done during the running. In an opposite case,
when the hook is blocked, but the clutch does not disengage,
the disengaging moment of the clutch is to be reduced in
turning the screws to the left.
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 screws (3) 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.
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