Duerkopp Adler 281 Operating instructions

281
Spezialnähmaschine
Serviceanleitung
Service Instructions
Service Instructions
Manufacturer: Dürkopp Adler Manufacturing (Shanghai) Co., Ltd.
1201 Luoshan Road, Pudong New Area, Shanghai 200135, China
Contact: Dürkopp Adler AG, PO Box 17 03 51, D-33703 Bielefeld, Potsdamerstr. 190, D-33719 Bielefeld,
Phone [phone], Fax [phone], www.duerkopp-adler.com
Manufacturer: Dürkopp Adler Manufacturing (Shanghai) Co., Ltd.
1201 Luoshan Road, Pudong New Area, Shanghai 200135, China
Contact: Dürkopp Adler AG, PO Box 17 03 51, D-33703 Bielefeld, Potsdamerstr. 190, D-33719 Bielefeld,
Phone [phone], Fax [phone], www.duerkopp-adler.com
Ausgabe / Edition: Änderungsindex Teile-Nr./Part.-No.:
01/2009 Rev. index: 00.0 PrintedinChina 0791 281641
D
GB
CN

Alle Rechte vorbehalten.
Eigentum der Dürkopp Adler und urheberrechtlich geschützt. Jede, auch auszugsweise Wiederverwendung
dieser Inhalte ist ohne vorheriges schriftliches Einverständnis der Dürkopp Adler verboten.
All rights reserved.
Property of Dürkopp Adler and copyrighted. Reproduction or publication of the content in any manner, even in
extracts, without prior written permission of Dürkopp Adler, is prohibited.
All rights reserved.
Property of Dürkopp Adler and copyrighted. Reproduction or publication of the content in any manner, even in
extracts, without prior written permission of Dürkopp Adler, is prohibited.
Copyright © Dürkopp Adler - 2009

General safety instructions
The non-observance of the following safety instructions can cause
bodily injuries or damages to the machine.
1. The machine must only be commissioned in full knowledge of the
instruction book and operated by persons with appropriate training.
2. Before putting into service also read the safety rules and
instructions of the motor supplier.
3. The machine must be used only for the purpose intended. Use of
the machine without the safety devices is not permitted. Observe all
the relevant safety regulations.
4. When gauge parts are exchanged (e.g. needle, presser foot, needle
plate, feed dog and bobbin) when threading, when the workplace is
left, and during service work, the machine must be disconnected
from the mains by switching off the master switch or disconnecting
the mains plug.
5. Daily servicing work must be carried out only by appropriately
trained persons.
6. Repairs, conversion and special maintenance work must only be
carried out by technicians or persons with appropriate training.
7. For service or repair work on pneumatic systems, disconnect the
machine from the compressed air supply system (max. 7-10 bar).
Before disconnecting, reduce the pressure of the maintenance unit.
Exceptions to this are only adjustments and functions checks made
by appropriately trained technicians.
8. Work on the electrical equipment must be carried out only by
electricians or appropriately trained persons.
9. Work on parts and systems under electric current is not permitted,
except as specified in regulations DIN VDE 0105.
10. Conversion or changes to the machine must be authorized by us
and made only in adherence to all safety regulations.
11. For repairs, only replacement parts approved by us must be used.
12. Commissioning of the sewing head is prohibited until such time as
the entire sewing unit is found to comply with EC directives.
13. The line cord should be equipped with a country-specific mains
plug. This work must be carried out by appropriately trained
technicians (see paragraph 8).
It is absolutely necessary to respect the safety
instructions marked by these signs.
Danger of bodily injuries !
Please note also the general safety instructions.

GB
Contents Page:
Part 3: Service Instructions Class 281
(Edition 01/2009)
1. General
1.1 Tools and Gauges .............................................. 3
1.2 Adjustingaids................................................. 4
2. Feeding and sewing equipment
2.1 Timingofthethrusteccentric ....................................... 5
2.2 Timingoftheliftingcam........................................... 6
2.3 Feeddogheightandinclination...................................... 7
2.4 Feeddogpositionwithinthethroatplate................................. 8
2.5 Stitch length limitation ............................................ 9
2.6 Stitch length symmetry ........................................... 10
3. Sewing foot height and sewing foot lifting
3.1 Pressure-barheight............................................. 11
3.2 Mechanical sewing foot lifting ....................................... 12
3.2.1 Liftingmotionandliftedsewingfootheight ............................... 12
3.3 Electromagnetic sewing foot lifting .................................... 13
3.3.1 Sewing foot lifter solenoid position .................................... 13
3.3.2 Mounting the sewing foot lifting solenoid................................. 14
3.3.3 Replacing the shock absorbing washer of the sewing foot lifter solenoid ............. 16
3.4 Sewingfootpressure ............................................ 18
4. Thread-guiding parts
4.1 Releasing the needle thread tension ................................... 19
4.2 Threadtake-upspring............................................ 20
4.3 Thread regulator ............................................... 21
5. Needle bar height .............................................. 22
6. Hook setting
6.1 Looping stroke and distance between the hook point and needle .................. 23
6.2 Bobbin case holder.............................................. 24
7. Thread trimmer
7.1 Controlcamfortheknifemotion...................................... 25
7.1.1 Controlcamposition............................................. 25
7.1.2 Distancebetweentherollerandthreadtrimmercam ......................... 26
7.2 Hookedknife ................................................. 27
7.3 Settingthecuttingpressure ........................................ 28

Contents Page:
8. Setting the bobbin winder
8.1 Switching off the bobbin winder ...................................... 29
8.2 Winding form of the bobbin ......................................... 30
8.3 Windingtightness .............................................. 30
9. Filling up oil (gear box) .......................................... 31
10. Hook lubrication
10.1 Setting the oil quantity for the hook .................................... 33
11. Maintenance ................................................. 34

GB
1. General
The present service instruction describes the adjustment of the special
sewing machine 281.
ATTENTION!
The operations described in the service instructions must only be
executed by qualified staff or correspondingly instructed persons
respectively!
Caution: Risk of injury !
In case of repair, alteration or maintenance work turn off the main
switch and make sure to protect the machine from powering up
accidentally.
Carry out adjusting operations and functional tests of the running
machine only under observation of all safety measures and with
utmost caution.
The present service instruction describes the adjustment of the sewing
machine in an appropriate sequence. Please observe in this
connection that various setting positions are interdependent. Therefore
it is absolutely necessary to perform the adjustment following the
described order.
For all setting operations of parts involved in the stitch formation use a
new needle without any damage.
Machine covers having to be screwed off and on again for checking
and adjusting operations are not mentioned in the text.
Please note:
The shaft of the special sewing machine 281 is provided with flat spots.
This facilitates the adjustment considerably.
In case of adjustments on flat spots the first screw in rotation direction
is put on such a flat spot.
3

1.1 Tools and Gauges
Art Size Figure
Allen key
5
4
3
2.5
2
1.5
Screw driver
Flat tip 0.7 x 4,5
Flat tip 0.3 x 3
Flat tip 0.7 x 4.5
Cross tip B2 -H
Open-end wrench 10
Gauge Needle bar height
0281 801819 for needle diameter 1.62 mm
Gauge Needle bar height
0281 800300 for needle diameter 2.00 mm
Setting pin For locking the machine at position 1 - 6
9301 022608
Gauge Feed dog height / Needle bar height
0281 800290
4

1.2 Adjusting aids
The sewing machine can be locked in six different setting positions
with the locking pin 1 and the arresting notches 2 on the arm shaft
crank 3.
The crank has six notches which are marked on the handwheel by the
figures 1, 2, 3, 4, 5 and 6. In conjunction with marking 4 the figures
indicate the position of the notches in which the machine can be locked
with locking pin 1.
The figures simplify the finding of the arresting notches. A precise
setting can only be ensured by arresting the machine at the provided
notches.
The following items should be adjusted in the various positions:
Pos. Symb. Description
Loop stroke
Distance between the hook point and needle
Feed dog standstill when stitch-length regulator moves
feed dog height
2nd needle position (thread lever upper dead centre)
Reference position machine head / Control cam for thread trimmer
1st Needle position
Needle in lowest position
5
GB
2
1
3
4

2. Feeding and sewing equipment
2.1 Timing of the thrust eccentric
Caution: Risk of injury !
Turnthemainswitchoff!
Check and set the feed standstill only when the machine is switched
off.
ATTENTION!
The thrust eccentric in the gear box 3 is already optimally set
ex factory.
The setting should preferably not be modified.
Standard checking
With the sewing machine arrested at locking position “2", there should
be no feeding movement if the reverse feed lever 2 is actuated and the
greatest stitch length is selected.
Correction
–Set the greatest stitch length at the setting wheel 1.
–Loosen the screws 5 at the lower toothed belt wheel 4.
–Turn the lower shaft accordingly.
–Fasten the screws 5 at the lower toothed belt wheel 4.
ATTENTION!
Should the lower shaft be misaligned, the following
positions must also be re-adjusted again:
lHook (see chapter 6.1)
lThread trimmer cam (see chapter 7.11)
lLifting cam (see chapter 2.2)
6
13
4
5
2