Duerkopp Adler 4260-6 Troubleshooting guide

Instructions for service
4260 - 6
Minerva Boskovice, a.s., Sokolská 60, CZ - 680 17 Boskovice
Tel.: [phone], 453433, 494111 Fax: [phone] http://www.minerva-boskovice.com
Edition: 05/2002 Printed in Czech Republic 735 342 000 499

CONTENTS:
1. General safety instructions ............................................................................................................................................................. 1
2. Introduction ........................................................................................................................................................................................... 1
3. Head of the sewing machine ........................................................................................................................................................... 2
3. 1 Hook and the hook post ........................................................................................................................................................ 2
3.1.1 Description
3.1.2 Height setting of the hook
3.1.3 Setting of the distance of the hook from the needle
3.1.4 Angular setting of the hook (timing)
3.1.5 Protection of the needle and of the hook point
3.1.6 Setting of the bobbin case opener
3.1.7 Setting the regulation of the hook lubrication
3.1.8 Replacement of the hook
3.1.9 Setting the gear
3.1.10 Dismantling of the hook post
3.2 Needle and thread mechanism .............................................................................................................................................. 5
3.2.1 Description
3.2.2 To check the handwheel angular adjustment
3.2.3 Height setting of the needle bar
3.2.4 Angular setting of the pin of the thread mechanism
3.2.5 Side setting of the needle bar holder
3.3 Throat plate and its post ...................................................................................................................................................... 7
3.3.1 Description
3.3.2 Side setting of the throat plate post and setting of the needle bed shifting
3.3.3 Setting the needle (the needle bar holder) in the direction of sewing (fine setting)
3.4 Front and rear guides of needles ......................................................................................................................................... 7
3.4.1 Description
3.4.2 Setting the front guide
3.4.3 Setting the rear guide
3.4.4 Setting the guide of the needles (stitch widths with needles, side by side)
3.5 Thread tensioners and limiter ............................................................................................................................................. 9
3.5.1 Description
3.5.2 Setting the tension of the main and auxiliary tensioners
3.5.3 Setting the tensioning mechanism of the main tensioners
3.5.4 Setting the adapting spring
3.5.5 Setting the thread limiter
3.6 Feeding mechanism of the lower feed wheel .................................................................................................................. 11
3.6.1 Description
3.6.2 Stitch length mechanism
3.6.2.1 Setting the upper eccentric
3.6.2.2 Setting the prop
3.6.2.3 a Forward and rearward stitch length distribution (rough)
3.6.2.3 b Forward and rearward stitch length distribution (fine)
3.6.2.4 Setting the control knob (including the stitch length limitation)
3.6.3 Lower feed wheel
3.6.3.1 Feeding clutches
3.6.3.1.1 Description
3.6.3.1.2 Setting the lever of the second step of feeding(angle, position)
3.6.3.1.3 Setting of the lower eccentric
3.6.3.1.4 Setting the engagement and disengagement of the clutches
3.6.3.2 Wheel feeder and its post
3.6.3.2.1 Height setting of the feeder and tensioning of the chain
3.6.3.2.2 Replacement of the feeder
3.6.4 Setting the top roller (pressing force, height)
3.7 Feeding mechanism of the top roller ............................................................................................................................... 16
3.7.1 Description
3.7.2 Side setting of the indented lower pulley
3.7.3 Side setting of the indented upper pulley
3.7.4 Setting the tensioning roller
3.7.5 Replacement the indented belt

3.7.6 Setting the feeding difference
3.7.7 Replacement of friction wheels of the drive conversion unit
3.7.8 Top roller
3.7.8.1 Selection of the top roller diameter
3.7.8.2 Forward, rearward and side setting
3.7.8.3 Setting the gear clearance and in the mounting of the top roller
3.7.8.4 Replacement of the top roller
3.8 Setting the top roller lift ..................................................................................................................................................... 20
3.9 Bobbin winder ..................................................................................................................................................................... 21
3.9.1 Description
3.9.2 Setting the bobbin winder stop
3.9.3 Setting the friction gear
3.10 Safety clutch ......................................................................................................................................................................... 22
3.10.1 Description
3.10.2 Setting the disengaging moment
3.11 Indented belt transmission ............................................................................................................................................... 22
3.11.1 Setting the tensioning roller of the indented belt
3.11.2 Replacing the indented belt
3.12 V-belt, motor - head ............................................................................................................................................................ 23
3.12.1 Tensioning
3.12.2 Replacing the V-Belt
3.13 Driving toothed belt.............................................................................................................................................................. 23
3.13.1 To exchange the driving toothed belt
3.14 Lubrication ............................................................................................................................................................................. 24
3.14.1 Description
3.14.2 Refilling oil
3.14.3 Multiple oil use
4. Thread trimming ............................................................................................................................................................................... 25
4.1 Description of the trimming mechanism
4.2 Setting the pickup roller
4.3 Setting the cam
4.4 Setting the fork
4.5 Setting the moving knife
4.6 Setting the fixed knife
4.7 Setting the retaining spring of the hook thread
4.8 Setting the switching of the electromagnets
5. Lifting the top roller by electromagnet ...................................................................................................................................... 27
5.1 Description
5.2 Setting the electromagnet pin
5.3 Setting the electromagnet current
5.4 Assembly of the top roller lifting electromagnet
6. Backtacking using electromagnet ................................................................................................................................................ 28
6.1 Description
6.2 Electromagnet height setting
6.3 Setting the position of push-buttons
6.4 Change of the function push-buttons
7. Connecting the electric elements on the machine head ....................................................................................................... 29
8. Drive, control panel, position sensor ....................................................................................................................................... 29
9. Lighting ............................................................................................................................................................................................ 29
9.1 Mounting on the machine head
9.2 Lamp replacement
10. Maintenance (table of operations) ............................................................................................................................................. 30
11. Setting the machine according to the sewing category .......................................................................................................... 30
11.1 Introduction
11.2 Table of setting the machine according to the sewing category
11.3 Table of possible stitch widths of needles according to the sewing category

1
1. 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 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, top roller, needle plate, feed dog and bobbin) when treading, 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 the machine must be disconnected from the compressed air supply system.
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.
It is absolutely necessary to respect the safety instructions marked by these signs.
Danger of bodily injuries !
Please note also the general safety instructions.
IMPORTANT WARNING
In spite of all safety measures made on the machines, inappropriate actions of the operator may lead to dangerous situations. In industrial
sewing machines Minerva, attention should be paid to the following still remaining possible sources of injury:
1. Moving sewing needle
- risk of injury when sewing with raised pressure foot or top roller, because the finger guard is then positioned too high.
2. Moving thread take-up lever
- risk of injury when inadvertently or intentionally inserting the finger(s) between the thread take-up lever and its guard.
3. Moving pressure member
- risk of injury when holding sewn work in immediate vicinity of the pressure member and beginning to insert under the pressure
member a considerably thicker sewn work portion,
- risk of injury when sinking the pressure member.
4. When switched off, the clutch motor slows down by inertia but would be reactivated by an accidental treading down of the
motor treadle. To avoid such risk, it is advised to hold the handwheel by hand and slightly to depress the motor treadle.
2. Introduction
This service book contains instruction for regulating the mechanisms of the sewing machine head.
The instructions for use and for putting the machine into operation and for the control of the stopmotor are not included in this service
book, but they are supplied as separate publications.
This service book is universal for all subclasses of the machine - it contains setting procedures for all elements which may be placed on
the machine of the given class. When the supplied subclass of this machine does not include some element, then it is possible to leave out
the respective parts of the instructions. The optional equipments of the machine and the respective configurations of the subclasses of
the machine are given in the operating instructions.
This sewing machine disposes of a large extent of its use. The machine should be set with respect to the parameters of the sewn material,
the sewing thread etc. The setting for the individual categories is given in the chapter 11.2.
For setting the machine, simple setting aids are used which are included in the accessory of the machine. Besides these aids, universal
measuring devices are used, such as slide calliper, feeler gauges and dynamometer for measuring the thread tension.

2
3. Head of the sewing machine
3.1 Hook and the hook post
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 post 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).
3.1.2 Height setting of the hook
The designated distance A should be 6.1 mm.
Caution! Danger of injury!
Switch off the main switch ! Before starting the setting
operation, wait until the motor stops!
- Loosen both screws (2).
- By turning the screws (3 and 4), set the required distanceA.
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 90 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 post (6) at the determined distance between the
needle and the hook point.
- Tighten carefully the screw (4) (be sure not to damage the
threads!)
- Tighten duly the screws (5).
- Check up the setting using a narrow strip of thin paper and
proceed to the eventual correction of setting.
Caution!
When changing substantially the sewing catego-
ry, the protecting sheet of the hook (7) should be
set up.
1
2
3
4
67
8
9
10
11
12
5
13
14
15
16
6
4
5
5
3
1
7
max. 0,1
2
4
5
A
3
4
2
6
A

3
3.1.4 Angular setting of the hook (timing)
The hook is to be angularly set in such a way that the hook
point (1) is opposite the needle at the moment, when the
needle shifts by 2.5 mm from its bottom dead center. This
corresponds to the 2O5°on the scale of the handwheel (3).
Caution! Danger of injury!
Switch off the main switch! Before starting the setting
operation, wait until the motor stops!
- Remove the throat plate.
- Turn the handwheel (3) to the 2O5°and fix it with the screw
(4) which is component part ot the accessory of the machine
(tighten it carefully).
- Loosen the screws (5).
- Turn the hook into the required position.
- Set up the distance of about 0,5 mm between the gear wheel
(6) and the pin (7).
- Tighten to the maximum the screws (5).
3.1.5 Protection of the needle and of the hook point
The protecting sheet (1) is to be set up in such a way that the
clearance between the protecting sheet and the needle (2) is the
least possible.
Caution ! Danger of injury!
Switch off the main switch! Before starting the setting
operation, wait until the motor stops!
- Remove the throat plate and the movable trimming knife.
- Unscrew the screw (3).
- Put the screwdriver into the hole of the screw (3) and, using the
regulating screw, set up the required clearance between the
needle (2) and the protecting sheet (1). When turning to the
right, the protecting sheet shifts out from the groowe and
inversely.
- Check up the protecting effect in pushing against the needle in
the sense of the arrow (5). The hook point must not catch the
needle. If so, set up the protecting effect, correct eventually the
setting of the distance of the hook point from the needle accord-
ing to the paragraph 3.1.3.
- Screw in the screw (3).
3.1.6 Setting of the bobbin case opener
The bobbin case opener (1) is to be set in such a way that, at the
moment when the opener is in its dead centre, there would be a
clearance A between the opener (1) and the projection (2),
whereas the finger (3) bears on the projection (4), A = 0.7 mm
for the sewing category 1 and 2, A = 0.3 mm for the sewing
category 3 and 4.
Caution ! Danger of injury!
Switch off the main switch! Before starting the setting
operation, wait until the motor stops!
- Remove the sheet guard of the hook post.
- On the handwheel (5), set the angle of 295°(the hook is in
its dead centre).
- Loosen the screw (6).
- Turn the eccentric (7) in such a way that the required clearance
between the elements (1) and (2) is attained.
- Set the height of the eccentric (7) in such a way that it is in its
highest position in retaining the minimum clearance between
the slide (8) and the fork (9).
- Tighten duly the screw (6).
1
2
3
4
205o
57
6~ 0,5
1
2
5
3
1
1
A
2
3
4
6
5
A
295o
7
8
6
9

4
3.1.7 Setting the regulation of the hook lubrication
By turning the lubricating tube (1) in the sense of the arrow
(2), the size of the contacting surface between the wick (3)
and the felt insert (4) is regulated. In this way, the speed of the
capillary lift of oil into the felt insert (5) is influenced, from
which oil is wiped on the surface (6) and is driven by centrifugal
force into the hook path (7).
Setting of full lubrication
- Turn the screw (8) into the position (9).
Setting of limited lubrication
- Turn the screw (8) into the position (10).
After having ended the regulation, set the height of the lubricating
tube (1) at 0.4 mm from the eccentric (11).
3.1.8 Replacement of the hook
Caution! Danger of injury!
Switch off the main switch ! Before starting the setting
operation, weit until the motor stops!
- Remove the throat plate and the trimming knife.
- Unscrew the screws (1) and remove the gib (2).
- After having suitably turned a bit the hook, remove the bobbin
case (3).
- Unscrew thorougly the screw (4).
- Remove the body of the hook (5) upwards.
- When mounting, the procedure is inverse.
3.1.9 Setting the gear
The mutual angular orientation of the gear wheel (1) relative
to the gear wheel (2) should ensure the accessibility of the
screw (5) at the moment when the hook point comes to lie
opposite the needle (4). The wheel (2) is to be set with its gear
rim symmetrically to the centre of the gear wheel (1). The
clearance between the gear wheels is to be the least possible.
Caution ! Danger of injury!
Switch off the main switch! Before starting the setting
operation, wait until the motor stops!
- Set the angle of 2O5°on the handwheel (6) and lock it with the
screw (7).
- On the removed post of the hook (8), according to the pa-
ragraph 3.1.10, the hook point (3) is to be turned a bit
according to the illustration.
- Turn the gear wheel (2) into the suitable position and insert the
post of the hook into the machine according to the respective
arrows. Check up, whether the screw (5) is accessible and,
if not, repeat the procedure.
- Set the the distance of the hook from the needle according to
the paragraph 3.1.3.
- Set the precise angular displacement of the hook according to
the paragraph 3.1.4.
- Loosen the screw (10) and tighten them slightly.
- Set the clearence in the gear in turning the screws (9). Check
up, whether the gear has a clearance during the whole revolution
of the hook. Turn the handwheel step by step by 15°and, with
each step, grasp the hook and try, if there is an angular dead
travel. Tighten carefully the screws (9).
- Tighten duly the screws (10) and try anew the clearance of the
gear.
1
2
3
4
5
4
3
6
205o
7
10
9
8
10
9
1
5
2
~ 0,5
1
5
2
~ 0,5
1
2
1
3
4
5
6 7
11
0,4
8
10
9
15
o

5
3.1.10 Dismantling of the hook post
When dismantling the post (1), the supplies of lubricating oil
are to be disconnected first, the fastening screws unscrewed
and, thereafter, the post is removed.
Caution ! Danger of injury!
Switch off the main switch! Before starting the setting
operation, wait until the motor stops!
- Unscrew the screw (2).
- Push the lubricating tube (3) downwards into the post.
- Disconnect the hose with the wick.
- Loosen only one screw (5).
- Unscrew the screws (6).
- Shift the post in the sense of the arrows and remove it out from
the machine.
- When mounting it, proceed inversely. Make sure that the
wicks in the tubes are in contact with the other wicks leading
oil into the box (7).
3.2 Needle and thread mechanism
3.2.1 Description
The take-up lever (1) is mounted in ball bearings, both at the spot
of its suspending on the connecting rod (2) and in the mounting
on the loop (12). The take-up lever is of aluminum and is provided
with a stuck-in eye for two threads. The connecting rod (2) is
mounted on the pin (3). The needle bar holder (4) is mounted
through the pin (5) in a rotating way in the arm (6). In its upper
part, the holder is fastened with the screw (7).
The connecting rod (10) of the needle bar (11) on the loop
(12) is mounted in a ball bearing and it is slidingly mounted
on the needle bar carrier. The mechanism is lubricated by means
of a central-wick lubricating system.
3.2.2 To check the handwheel angular adjustment
The handwheel (5) must be situated in its precise position
relative to the needle and thread mechanism. This position is
given by a pin (2), which locks the connecting rod of the
needle rod (1) through a hole in the arm (3). In this position,
the indicator (6) of the handwheel must show O. The position
is fixed by the handwheel screw (4) contacting a small flat
surface provided on the upper shaft.
The correct adjustment of the angular position has been car-
ried out at the producers.
Caution ! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
1
2
3
4
5
6
0o
1
5
6
6
3
2
1
7
11
4
5
10
3
1
2
7
12
6

6
3.2.3 Height setting of the needle bar
At the moment, when the hook point passes around the needle,
the upper edge of the needle eye must be about 1 mm below
the hook point. In an opposite case, it is necessary to set the
height of the needle bar as follows:
Caution ! Danger of injury!
Switch off the main switch! Before starting the setting
operation, wait until the motor stops!
- Remove the front guard.
- Loosen the screw (1) of the needle bar carrier.
- Set the correct height of the needle bar and tighten anew the
screw (1).
Caution !
An incorrect setting of the needle bar height may
cause the striking of the hook point against the needle.
3.2.4 Angular setting the pin of the thread
mechanism
The hinged pin (2) of the connecting rod (3) can be set in
three positions (the pin has got 3 flats ground for the screw):
- for the hook of small diameter (value A  minimum)
- for the hook of large diameter , sewing category 100 and
200 (value A = medium)
- for the hook of large diameter, sewing category 300 and
400 (value A  maximum)
The value A is to be measured in the bottom position of the
take-up lever. Set the pin of the connecting rod as follows:
Caution! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
-Remove the front guard.
- Set the lowest (bottom) position of the take-up lever.
- Loosen the screw (1) of the pin (2) of the connecting rod (3).
- The position of the take-up lever is changed when turning
the pin (2).
- Set the pin (2)into the corresponding position and tighten
anew the screw (1).
The correct position is given by the flat on the pin (2), on
which the screw (1) is to be tightened.
3.2.5 Side setting of the needle bar holder
The correct position of this holder is in such case, when the needle
bar is lined up with the presser-foot bar. The needle bar holder
can be set as follows:
Caution! Danger of injury!
Switch off the main switch! Before starting the setting
operation, wait until the motor stops!
- Loosen the screw (1) of the pin (2).
- Loosen the screw (3) of the pin (4).
- In shifting the pin (2) set the needle bar holder on the measure
A = 7.5 mm (distance of the front faces of the arm and of
the needle bar holder) /at the same time the pin (4) shifts/.
- The guide pin (4) is to be set in such a way that the needle
bar holder moves easily.
- Tighten the screws (1 and 3).
1
2
3
A
1
A
2
34
1
1

7
3.3 Throat plate and its post
3.3.1 Description
The throat plate (1) is always for the given stitch width of
needles and universal for all respective categories of sewing
(see Tab. sewing equipments - Spare parts list).
In the throat plate there is mounted an exchangeable throat
plate insert (2). For each stitch width of needles, it is possible
to supply several throat plate inserts differing one from
another by the width of the piercing hole.
3.3.2 Side setting of the throat plate post and
setting of the needle bed shifting
The throat plate post (1) and the needle holder (2) are to be
mutually positioned in such a way, so that, with the given
stitch width A, both needles pass through the centres of the
needle penetration holes.
Caution! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Loosen the screw (3) of the needle bar carrier.
- Shift the needle bed (2) in such a way, so that the required
stitch width of needles A" is attained.
- Tighten up the screw (3) and check up the setting.
- Loosen the screws (4) /from the rear side of the post too/.
- Shift the post (1) in the right direction in such a way, so that
both needles pass through the centres of the needle pene-
tration holes.
- Tighten up the screws (4) and check up the correctness of
setting.
3.3.3 Setting the needle (the needle bar holder) in
the direction of sewing (fine setting)
Caution! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Loosen the screw (5).
-In turning the needle bar holder (7), set the needle against
the centres of the needle penetration holes.
- Tighten up the screw (5) and check up the setting.
Caution!
A faulty setting may cause bending or breaking of
needles against the throat plate insert.
3.4 Front and rear guides of needles
3.4.1 Description
The front guide (1) and the rear guide (2) are used together
for stitch widths of a tandem arrangement. For stitch widths
with needles side by side, the rear guide (3) is used only. All
guides serve for holding the sewn material against the throat
plate. In addition to this, they contribute to a as well and
protect the needles in guiding them into the piercing holes.
1
2
1
2
4
3
6
5
A
1
2
3