Pfaff 900/51, Service Manual, Page: 19 / 24

Adjustment
2
.17
Tension release of needle thread
Requirements
1. When the thread trimming unit is in resting position, trip
5
should be engaged and at
a distance of
0.5 mm
from the release cone
1.
2. When trip
5
is positioned at the highest point of the release cone
1
, the tension disks
should be spaced at a mimimum of
0.5 mm
from each other.
2 - 14
●
Turn release cone
1
(nut
2
) in accordance with
requirement 1
.
●
Lower the presser foot onto the needle plate.
●
Pull out the thread from between the tension disks.
●
Pull down linkage
3
(screw
4
) until you feel it stop.
●
Position the needle bar at b.d.c and activate the engaging lever manually.
●
Turn the hand wheel until trip
5
is positioned at the highest point of release cone
1
.
●
The tension disks now have to be spaced at a minimum of
0.5 mm
from each other.
●
Bring the rock shaft back to its starting position by turning the hand wheel.
●
Trip
5
now must be engaged, the needle thread must be under full tension.
●
Grease release cone
1
slightly.
Fig. 2 - 13
2-14
24V = 4% ED
0.5 mm
0.5 mm
2
1
5
4
3