2
3. Head of the sewing machine
3.1 Hook and the hook box
3.1.1 Description
The hook (1) is mounted on the shaft (2) and is driven by the
gear (3) from the shaft (4). The shaft of the hook (2) is mounted
on the top in a sliding bearing and, on the bottom, in a needle
bearing. The hook is provided with a lever (6) which is tilted
when removing the bobbin (7). The protecting sheet (8)
protects against the collision of the needle with the hook point.
The bobbin case opener (9) is driven by the eccentric (10) on
the shaft (2). The lubricating tube (11), on which a lubricating
wick is fastened in the tube (12), feeds oil for lubricating the
sliding bearing (5) of the eccentric (10) and the hook path.
The screws (13) serve for taking up the clearance of the gear.
The screws (14) fasten the hook box to the bedplate.
The lubricating felt (15) is connected by the wick (16) with the
main lubricating system and serves for lubricating the gear (3).
With the machines provided with a thread trimmer, the hook R
821 (17) is used on the lefthand side. It differs from the hook R
820, which is used on the righthand side and from the machines
without thread trimmer, by modified medium part of the hook.
The gap (18) formed by the part (19) serves for stabilizing the
lower thread.
3.1.2 Height setting of the hook
The designated distance A should be 5.3 mm.
Caution! Danger of injury!
Switch off the main switch ! Before starting the
setting operation, wait until the motor stops!
- Remove the slide plate (1).
- Loosen both screws (2).
- By turning the screws (3 and 4), set the required distanceA.
For setting up use the setting gauge (7) as per the repective
figure.
After having set it, tighten carefully the screws.
- By axial shifting of the gear wheel (5), set the axial clearance
in such a way that this clearance is the least possible, but
sufficient for turning easily the hook.
- Tighten carefully the screws (2). Caution ! One of these
screws must bear on the flat of the shaft 6).
3.1.3 Setting the distance of the hook from
the needle
The hook point (1) is set up to the maximum distance of
0.1 mm from the bottom of the needle recess (2). For the
sewing categories 1 and 2, the needle size 100 is set, for the
sewing categories 3 and 4, it is the needle size 160.
Caution! Danger of injury!
Switch off the main switch ! Before starting the
setting operation, wait until the motor stops!
- Shift the plate (3).
- Loosen only one screw (4).
- Loosen the screws (5) and tighten them only slightly.
- Shift the hook box (6) at the determined distance between
the needle and the hook point.
- Tighten the screw (4).
- Tighten duly the screws (5).
- Check up the setting with magnifying glass and proceed to
the eventual correction of setting.
Caution!
When changing substantially the sewing category,
the protecting sheet of the hook (7) should be set up.
1
7
max. 0,1
2
1
3
15
4
5
9
7
8
6
11
12
14
10
16
13
2
14
3
4
6
3
5
4
4
5
5
2
6
A
18
19
7
17
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