DURKOPP ADLER 838 Operating instructions

838
Spezialnähmaschine
Serviceanleitung
Service Instructions
Postfach 17 03 51, D-33703 Bielefeld • Potsdamer Straße 190, D-33719 Bielefeld
Telefon +49 (0) 521 / 9 25-00 • Telefax +49 (0) 521 / 9 25 24 35 • www.duerkopp-adler.com
Ausgabe / Edition: Änderungsindex Teile-Nr./Part.-No.:
06/2008 Rev. index: 00.0 Printed in Federal Republic of Germany 0791 838641
D
GB

Alle Rechte vorbehalten.
Eigentum der Dürkopp Adler AG und urheberrechtlich geschützt. Jede, auch auszugsweise Wiederverwendung
dieser Inhalte ist ohne vorheriges schriftliches Einverständnis der Dürkopp Adler AG verboten.
All rights reserved.
Property of Dürkopp Adler AG and copyrighted. Reproduction or publication of the content in any manner, even
in extracts, without prior written permission of Dürkopp Adler AG, is prohibited.
Copyright © Dürkopp Adler AG - 2008

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.

Contents Page:
Service Instructions for the Class 838
(Edition 06/2008)
1. General
1.1 Setting gauges ................................................ 3
1.2 Adjusting the handwheel .......................................... 4
2. Bottom feed
2.1 Base setting for stitch adjustment and stitch length limit ....................... 5
2.2 Stitchuniformityforforwardsandreversestitching.......................... 6
2.3 Adjustingtheleversontherearfeedshaft................................ 7
2.4 Position of the eccentric tappet for the feed movement ........................ 8
2.5 Position of the eccentric tappet and the feed dog stroke ....................... 9
2.6 Switchingoverthefeedclutch....................................... 10
2.7 Position of the eccentric tappet for the switch over of the feed clutch ............... 11
2.8 Checkingtheswitchoverofthefeedclutch............................... 12
2.9 Feeddog.................................................... 13
3. Top feed
3.1 Positioning the needle holder for single-needle sewing machines ................. 14
3.2 The needle feed ............................................... 16
3.3 Toproller.................................................... 18
3.4 Liftingthetoproller ............................................. 19
3.5 Press pad for the double-needle sewing machine ........................... 20
4. Adjusting the needle bar and the hook
4.1 Hookheight.................................................. 21
4.2 Needle bar height, play of needle to hook tip, loop stroke ...................... 22
4.3 Protection for the hook tip and loop former ............................... 23
4.4 Bobbin housing lift .............................................. 24
4.5 Hooklubrication ............................................... 25
5. Adjusting the thread
5.1 Thread regulator, thread take-up lever, bolt for the thread lever mechanism ........... 26
5.2 Bobbin Winder ................................................ 27
6. Thread trimmer
6.1 Height of the thread trimming blade. Position of the counter-knife ................. 28
6.2 Startingpositionforthethreadtake-upknife.............................. 29
6.3 Controlcam.................................................. 30
6.4 Bobbin thread clamp............................................. 31
7. Electronic control and machine drive – positioning drive .................... 32

3
GB
1. General
These service instructions describe the adjustments that can be made
to the Class 838 special sewing machine.
CAUTION!
The operations described in these service instructions may only be
carried out by qualified staff or other appropriately trained persons!
Caution: Risk of Injury!
Turn the main switch off for repair, conversion and maintenance work
and separate the machine from the pneumatic supply line.
Any adjustment work and functional testing with the machine running
should be conducted only under observance of all safety measures
and with the greatest possible caution.
These service instructions describe the adjustment of the sewing
machine in a logical order. Please observe that various setting
positions are dependent on each other. Thus it is essential that the
settings be conducted while keeping to the order described.
For all adjustments of parts involved in the stitch formation, a new
undamaged needle must be inserted.
This text does not specifically mention any machine covers or panels
which must be removed or re-mounted in order to conduct inspections
or adjustments.
Note
Some shafts on the special 838 machine are provided with flat
eccentric surfaces. This significantly simplifies machine adjustments.
For all adjustments on flat surfaces, the first screw screwed in the
direction of the eccentric surface.
1.1 Setting gauges
The retention pin required for adjusting the machine in included with all
units. It is located with the machine accessories and can be attached
so that it is easily accessible below the oil tray.

1.2 Adjusting the handwheel
Rule:
The handwheel (4) is labelled with degree numbers.
Certain adjustments are made with these marked handwheel positions.
–Turn the handwheel until the degree value specified in the
instructions is aligned with the pointer (3).
–Proceed with the adjustment described.
When the needle bar is at top dead centre, the pointer (3) should be
aligned with“0” degrees.
–Loosen the handwheel screws with a 3-mm hexagon socket
wrench (1).
–Position the needle bar in the top dead centre position. Use the
retention pin (3 mm diameter) to peg the position (2).
–Turn the handwheel so that the pointer (3) points to 0 degrees on
the rotary scale.
–Tighten the first screw with the wrench (1). Turn the handwheel
to 50° and tighten the second screw with the wrench (1).
4
1
3
2
4

2. Lower (bottom) feed
2.1 Base setting for stitch adjustment and stitch length limit
Rules:
1. When setting the stitch length at “0”, the stitch regulator gear should
have as little play (clearance) as possible when you press down on
the bartacking lever.
2. The maximum stitch length is limited to 8 mm.
–Loosen screw (1) and take off the settings dial (2).
–Turn the screw (3) as far as needed to the right using a 10-mm
spanner wrench. Verify that the stitch regulator gear is without
motion by pressing down on the bartacking lever. This fulfils rule 1.
–Set the scaling ring (4) with stitch length 0 to align with the circular
mark (5).
–Limit the stitch length according to rule 2. For this, screw the
retention pin (6) into the proper hole. The holes are marked with
numbers which indicate the maximum stitch length.
–If a maximum stitch length of 7 mm is required, unscrew the screw
(6) for 2.5 mm. Another end stop is available for this length.
–Put the settings dial (2) back on and tighten the screw (1).
Caution: Risk of Injury!
Turnthemainswitchoff.
Only carry out this stitch adjustment when the machine is turned off.
ATTENTION: Danger of breakage!
If the set stitch length is larger than allowed by the sewing equipment
in use, then the needle will hit against the throat plate insert.
5
GB
12
536 4

2.2 Stitch uniformity for forwards and reverse stitching
Rules:
1. When making a rough-scale adjustment to the stitch regulator gear,
the machine should not feed when the stitch length is set to 0.
2. When making a fine-scale adjustment to the stitch regulator gear,
the forwards and reverse stitch lengths should only deviate in value by
a half stitch.
–Set the stitch length to “0”.
–Loosen screw (1) and turn the grooved (3) eccentric tappet (2)
according to the illustration. Fasten with screw (1).
–Loosen screw (4) on the clamping lever. Turn the settings frame (5)
so that the shackles (6) are parallel. Tighten screw (4). This then
fulfils rule 1.
–The next step is to match up the forwards and reverse stitch
lengths. Sew ten stitches forwards. Press the bartacking lever and
then sew ten stitches backwards. Rotate the eccentric tappet (2) so
that rule 2 is met.
–Clockwise = enlarge forward stitch, decrease reverse stitch.
–Counter-clockwise = decrease forward stitch, enlarge reverse stitch.
6
32 56
1 4

2.3 Adjusting the levers on the rear feed shaft
Rule:
When setting the stitch length" 0“, the feed clutch should be in the
middle range of the work limit settings.
–Set the stitch length to “0”.
–Loosen screw (1).
–Set the lower feed dog in the middle between the dead centre
points of its motion in the throat plate.
–Tighten screw (1).
–Loosen screws (2).
–Screw out the screw on the feed clutch (4). Push the needle (3) into
this opening. Turn the clutch (4) with your hand until the needle (3)
is 5mminto the hole. The rule is then fulfilled.
–Tighten screw (1).
Caution: Risk of Injury!
Turnthemainswitchoff.
Only carry out this lever adjustment when the machine is turned off.
ATTENTION: Danger of breakage!
With large stitch lengths, it is possible that parts within the clutch will
collide if the middle working range of the clutch is not maintained.
7
GB
1
34
2

2.4 Position of the eccentric tappet for the feed movement
Rule:
When the handwheel pointer indicates 355 degrees, the feed lever (1)
should not move when the bartacking lever is pressed down.
–Turn the handwheel so that the pointer indicates “355”.
–Loosen screws (2). To make the rough-scale adjustment, turn the
eccentric tappet (3) so that it is approximately in the position shown
in the illustration. Now make the fine-scale adjustment to the
eccentric tappet. Continue until you have found the position where
the feed lever (1) no longer moves when the bartacking lever is
pressed down.
–Tighten screws at eccentric tappet (3).
Caution: Risk of Injury!
Turnthemainswitchoff.
Only carry out this eccentric adjustment when the machine is turned
off.
ATTENTION: Danger of breakage!
Imprecise settings can shorten the lifespan of the machine.
8
132

2.5 Position of the eccentric tappet and the feed dog stroke
Rule:
When the handwheel pointer indicates “239” on the scale, a settings
pin inserted into the eccentric tappet should be flush with the ridge on
the crankshaft (4).
–Turn the handwheel so that the pointer indicates “239”. Loosen
screws (1).
–Insert a settings pin (2) into the eccentric tappet (3). Position it so
that it is flush with the crankshaft ridge.
–Tighten screws (1).
9
GB
3
1
24

2.6 Switching over the feed clutch
Rule:
The clutch should be switched over when it is motionless (i.e., when it
is in the dead centre point of its pendulum motion).
–Loosen the screws (1) on the eccentric tappet (2).
–Turn the eccentric tappet so that the dash (2) is aligned with the
other dash (3).
–Loosen the three screws (4). Loosen the adjusting nut (5).
–Tighten the adjusting nut (5) until you feel it strike (the tightening
increases in jumps).
Push the clutch (6) to the right until the end stop is reached.
Tighten the screws (4).
–Verify the adjustment. Turn the eccentric tappet with your hand in
the other direction. The resistance during the rotation of the
eccentric tappet should increase significantly when the two dashes
are lined up.
Caution: Risk of Injury!
Turnthemainswitchoff.
Only carry out this adjustment when the machine is turned off.
ATTENTION: Danger of breakage!
Imprecise settings can shorten the lifespan of the machine.
10
45
2
13
6

2.7 Position of the eccentric tappet for the switch over of the feed clutch
Rule:
When the handwheel pointer indicates “305” on the scale, the dash (1)
on the eccentric tappet should be lined up with the lower dash (2) on
the V-shaped push rod.
–Loosen screws (3).
–Turn the handwheel to position “305”.
–Turn the eccentric tappet in the direction of arrow so that dash (1)
is lined up with dash (2).
–Turn back the eccentric tappet about 2° and move axially on the
shaft until the middle is between the limit settings.
–Align the two dashes (1) and (2) again. Tighten the screws (3).
Caution: Risk of Injury!
Turnthemainswitchoff.
Only carry out this adjustment when the machine is turned off.
11
GB
321

2.8 Checking the switch over of the feed clutch
Rule:
The feed clutch should be switched over when it is motionless (i.e.,
when it is in the dead centre point of its pendulum motion). This can be
detected from the rotational direction of the belt pulley (1) in front of
and behind the dead centre point.
1234
A 270° 276° 88° 93°
B0 0
–Set the maximum stitch length.
–Turn the handwheel (A) so that it is positioned at “270” degrees (refer
to Table / A). Push the bartacking lever down. Check if the rotational
direction (B) of the belt pulley (1) corresponds to the direction
specified in the table. Do the same for “276” degrees.
–If the rotational directions do not correspond to those specified in the
table, correct the necessary settings. If the clutch switches over too
soon (on a smaller angle), tentatively loosen the adjusting nut (5) (see
chapter 2.6) and repeat the check. Continue loosening until you locate
the correct position for the nut. If the clutch switches over too late,
tighten the controlling nut (5).
Caution: Risk of Injury!
Turnthemainswitchoff.
Only carry out this adjustment when the machine is turned off.
CAUTION!
Imprecise settings can shorten the lifespan of the machine.
12
B1

2.9 Feed dog
Rules:
1. The height (A) that the feed dog (1) is above the throat plate must
be appropriate for the thickness and toughness of the material.
2. In its highest position (A), the feed dog should be 1 mm over the
throat plate insert.
–Loosen screw 1.
–According to the above rule, lower or raise the feed dog.
Then re-tighten screw (1).
13
GB
A
12

3. Top feed
3.1 Positioning the needle holder for single-needle sewing machines
Rule:
The needle holder positioning is carried out according to the following
table and depends on the thickness of the needle.
Angularity
of the needle holder
Needle width, Nm 120 - 160 180 - 200
–Loosen screw (1). Turn the needle bar with the right grooved
edge (2) on the needle-bar axis (in the sewing direction).
Tighten screw (1).
–Move the needle bar into the top dead centre point. Use the
2.5 mm hexagon socket wrench (4) to loosen the needle-holder
screw in the hole (3).
–Turn the needle holder (5) according to the rule above. Tighten the
screw (1).
14
2
5
3
4
5
1

For your notes:
15
GB

3.2 The needle feed
Rules:
1. The needle bar should be adjusted so that it is flush with the presser
foot bar.
2. The post bed feed should be:
2.1: for the single-needle machine, it should be set so that the axis
of the needle is moved (A) = 0.1mm to the left to the middle of
the stitch hole.
2.2: for the double-needle machine, it should be set so the needle
stands symmetric to the middle of the stitch hole.
3. The transport motion of the needle should be set as follows: at the
maximum stitch length the needle leaves the throat plate very near
the back edge of the stitch hole.
–Loosen screws (1) and adjust the needle bar to the dimension
(B) = 31mm as show in the illustration. Rule 1 has been fulfilled.
16
B
1
A