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22. Time setting of the control cam of the thread cutter (Fig. 22)
Caution! Danger of injury!
Switch off the main switch! Before starting the setting
operation, wait until the motor stops!
For a safe and correct thread catching under the throat plate it is neces-sary
to set the correct position of the control cam which is placed on the bottom
shaft. From this cam, the movement of the thread wiper derived for catching
the upper and bottom thread including its cutting, and the mechanisme of
the tensioner. With the machine switched off, tilt the machine head and,
using the hand wheel, set the take-up lever into its top position. Loosen two
screws (1) of the cam (2) and set the loosened cam in such a way, so that
we set the gauge mark on the cam (marked with colour) into the axis of the
pin (3) and secure the cam anew by the screws (1). This position is to be
taken as a basic setting of the cam and it is necessary to eventually reset it
according to the thread or sewn material type. The start of the thread wiper
movement is to be set in slight turning of the cam on the bottom shaft.
Push the lever (4), in this way the pin (3) is put into the straight course of
the groove. In turning the hand wheel in the direction towards the sewer
(in counter-clockwise direction) check the start of the movement of the
thread wiper from the starting into the rear position.
Check the correct position of the thread wiper as follows:
At the moment when the loop of the upper thread and the bottom thread
will leave the knocking-over slide of the hook and form so a characteristic triangle, the point of the thread wiper should be in its close vicinity. When
further turning the hand wheel, the point of the thread wiper must pass through the triangle (one branch of the upper thread loop, bottom thread
on one side of the thread wiper and the other upper thread loop branch on the other side of the thread wiper). The thread lying on the side of the wiper
provided with a cutout, must fit into this cutout.
After having loosened two screws (1) on the cam (2) set the start of the thread wiper movement. In turning the cam in the direction of the bottom
shaft rotation the start of the thread wiper is accelerated and, inversely, it is delayed. After having set up the cam, check whether the pin (3), after
pushing on the lever (4), fits easily onto the straight part of the cam (2) groove. Push the carrier ring (5) to the cam set up in this way and tighten
it up with the screws (6) on the bottom shaft.
23. Setting of the movable cutting knife lifting (Fig. 22)
Caution! Danger of injury!
Switch off the main switch! Before starting the setting operation, wait until the motor stops!
After having engaged the pin (3) into the cam (2), turn the hand wheel towards ourselves, until the bottom thread and one branch of the loop enter
into the cutout on the side of the cutting knife. When this does not occur, loosen the nut (7) on the tilting lever (8) and shift the draw bar (9) in the
groove of the lever (8). To increase the movement, the lever arm is to be lenghtened. Secure the position in tightening up the nut (7).
24. Setting of the upper thread tensioner releasing (Fig. 22)
Caution! Danger of injury!
Switch off the main switch! Before starting the setting operation, wait until the motor stops!
The cutting mechanism needs that, within its course, the upper thread is released i.e. that the main thread tensioner is to be released. It is
automatically released within the necessary cutting cycle through the cable (13) and the lever system when starting the cutting operation. If there no
release thereof occurs, it is necessary to set the tension of the cable (13). This is done when loosening the screw (11) on the lever (12) or in turning
slightly the whole lever (12) after having loosened the screw (10).
25. Setting of the adjusting spring function (Fig. 23)
Caution! Danger of injury!
Switch off the main switch! Before starting the setting operation, wait
until the motor stops!
After having loosened the screw (1) remove the complete upper thread tensioner from
the machine arm. The size of the elasticity of the adjusting spring (2) is to be set after
having loosened the screw (3) on the sleeve (4) in turning slightly the pin (5) using a
screwdriver. In turning the pin to the left, the size of the spring elasticity is being
reduced, in turning it to the right, it is increased. In the same way, the lesser or the
greater swing of the spring arm is to be set. The correct setting of the adjusting spring
is to be checked after having sewn some stitches. Tilt the machine head and check the
correct passing of the thread over the hook. The thread passing over the biggest hook
diameter should slightly move the adjusting spring without tensioning it.
6
5
8
9
8
1
2
3
1
3
4
2
5
7
12
13
11
10
4
Fig. 22
Fig. 23
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