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26. Setting of the starting position of the movable
thread cutter (Fig. 24, 25)
Caution! Danger of injury!
Switch off the main switch! Before starting the setting
operation, wait until the motor stops!
The cutting knife (1) should be set in its starting position in such a way,
so that there is between the outer knife edge and the outer edge of the
plate (2) the distance of 0,5 - 1 mm (the outer edge of the plate (2) is
idential with the outer edge of the bedplate). The plate must be fastened
with two screws (3) to the bedplate of the machine in such position, that
there is no gap between this plate and the throat plate. The position of the
cutting knife is to be set after loosening the lock nuts (5) in turning the
connecting draw bar (6). In turning the driving draw bar, its necessary
length is to be set for securing the correct position of the thread wiper,
then tighten anew the lock nuts (5).
27. Setting of the stationary knife pressure (Fig. 25)
Caution! Danger of injury!
Switch off the main switch! Before starting the setting
operation, wait until the motor stops!
For ensuring the correct function of the thread cutting, it is necessary to regulate the
pressure of the stationary cutting knife. In screwing the screw (4) in the plate (2), the
pressure is increased, in screwing it out, it is reduced. Be careful in having this
pressure the least possible when the knife still cuts the thread in a reliable way. In the
opposite case there occurs an excessive wear of the stationary and of the movable
knife (and that of the thread wiper). When even after having set up no reliable trimming
occurs, it is necessary to check up the state of the cutting edge of the stationary knife,
to restore this cutting edge or to replace the knife.
28. Setting of the stop in the top position of the needle
Caution! Danger of injury!
Switch off the main switch! Before starting the setting operation, wait
until the motor stops!
The proper principle of the top position setting is described in detail in the instructions for setting the driving unit. The machine is being delivered
from the manufacturing factory after having been tested and after having proceeded to a running-in sewing with the adjusted values, i.e. the machine
stops in the top position which varies between 5
29. Making an upper thread reserve
Caution! Danger of injury!
Switch off the main switch! Before starting the setting operation, wait until the motor stops!
The reserve of the upper thread may be influenced by several methods:
a) Correct tension of the ausiliary tensioner - the greater is the tension of the auxiliary tensioner, the lesser is the reserve of the upper thread and
inversely.
b) Correctly set the top position of the thread lever - in stopping before the top dead centre of the thread lever the reserve of the upper thread is
reduced, behind the top dead centre it is increased.
30. Dismounting and mounting of the plate (Fig. 25)
Caution! Danger of injury!
Switch off the main switch! Before starting the setting operation, wait until the motor stops!
When it is necessary to dismount the plate (2), loosen two screws (3) which secure the firm connection of the plate with the bedplate of the machine,
and take out the plate. When remounting it, proced in the inverse way.
31. Dismounting and mounting of the movable cutting knife (Fig. 24)
Caution! Danger of injury!
Switch off the main switch! Before starting the setting operation, wait until the motor stops!
Proceed to the dismounting of the plate (2) according to the point 30 and then take out the knife (1) from the guide in the direction of the arrow "S".
When remounting it, proced in the inverse way.
0,5 - 1
o
o
- 10
behind the top position of the thread lever.
9
2
1
S
5
6
3
2
4
5
Fig. 24
Fig. 25
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