Duerkopp Adler 4280i-6 Troubleshooting guide

Instructions for service
4280i - 6
Minerva Boskovice, a.s., Sokolská 60, CZ - 680 17 Boskovice
Tel.: [phone], 453433, 494111 Fax: [phone] http://www.minerva-boskovice.com
Edition: 09/ 004 Printed in Czech Republic S735 000626

CONTENTS:
1. General safety instructions ............................................................................................................................................... 1
2. Introduction .......................................................................................................................................................................... 1
3. Head of the sewing machine .............................................................................................................................................. 2
3. 1 Hook and hook post ................................................................................................................................................................ 2
.. 3.1.1 Description
3.1.2 Height setting of the hook
3.1.3 Setting 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
3.2.6 Setting the needle (the needle bar holder) in the direction of sewing
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
3.4 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 main and auxiliary tensioners
3.5.3 Setting the tensioning mechanisms of the main tensioners
3.5.4 Setting the adapting spring
3.5.5 Setting the thread limiter
3.6 Feeding mechanism of the needle feed and 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 of 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 of the indented belt
3.7.6 Top roller
3.7.6.1 Selection of the top roller diameter
3.7.6.2 Forward, rearward and side setting
3.7.6.3 Setting the gear clearance and in the mounting of the top roller
3.7.6.4 Replacement of the top roller
3.8 Setting the presser foot 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 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 of push-buttons
7. Connecting the electric elements on the machine head .......................................................................................................... 29
8. Drive, control panel, position sensor ......................................................................................................................................... 29
9. Maintenance (table of operations) ............................................................................................................................................... 30
10. Setting the machine according to the sewing category ............................................................................................................ 30
10.1 Introduction
10.2 Table of setting the machine according to the sewing category
10.3 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 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.
. 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 function 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. Conversions 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.
IMPORTA T WAR I G
In spite of all safety measures made on the machines, inappropriate actions of the operator may lead to dangerous situations. In
industrial sewing machines, 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,
- risk of injury when inadvertently threading down of the motor threadle.
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.
. 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 slidably mounted on the top, in
post and, on the bottom, in a needle bearing.
The hook is provided with a lever (5) which is tilted when
removing the bobbin (6). The protecting sheet (7) protects
against the collision of the needle with the hook point. The
bobbin case opener (8) is driven by the eccentric (9) on the
shaft (2).
The oil tank (10) contains oil supply for the hook lubrication.
Superfluous oil is taken by the felt piece (11) used to lubricate
sliding mounting hook shafts. The wick connected to the felt
piece (11) lubricates the gearing (3).
The screws (12) serve for taking up the clearance of the gear.
The screws (13) fasten the post to the bedplate.
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!
- Loosen both screws (1).
- By axial shifting of the bushing (2) set the axial clearance of
the wheel (3) to the least value still ensuring easy rotation
of the shaft (4) with the fixed wheel (3).
- Tighten both screws (1).
- Loosen both screws (5).
- Shift axially the shaft (4) with the hook (6) so as to obtain
the required distance “A”. For setting up use the setting
gauge (7) as per the repective figure.
- Carefully retighten the screws (5) after the adjustment.
Caution! One of these screws must bear on the flat of the
shaft (4).
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!
- 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
7
max. 0,1
2
A6
7
3
1
5
24
2
34
9
10
11
13
12
16
7
8
5
6
4
5
54

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.
- Pass the locating pin (7) contained in the machine acces-
sories through the hole in the hook post bed (8) and insert
it into the groove of the gear wheel (6). In this way, the wheel
is axially set.
- Tighten to the maximum the screws (5) and take the locating
pin (7) out.
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 even-
tually the setting of the distance of the hook point from the
needle according 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!
- On the handwheel (5), set the angle of 308°(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.
- By turning the screw (10), 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).
3
4
205o
1
2
5
31
7
6
5
8
1
2
3
4
A
5
308o
7
86 910
1
2

4
3.1.7 Setting the regulation of the hook lubrication
Oil is wiped from the lubrication wick by the surface of the
hook eccentric and is then supplied by centrifugal force into
the hook path (7). The intensity of oil supply is regulated by
turning the screw (3).
Caution! Danger of injury!
witch off the main switch ! Before starting the
setting operation, weit until the motor stops!
- To reduce the oil supply, turn the screw (3) to the right.
- To increase the oil supply, turn the screw (3) to the left.
- After the adjustment, loosen the screw (4) and set the height
of the oil tank so as toensure reliable contact between the
surface of the eccentric and the lubrication wick.
Caution!
The quantity of the fed oil has been set up in the
manufacturing factory. This setting is to be done
only in emergency events. A bad setting of the quantity of the
fed oil or of the height of the lubrifying tube may cause a
rapid wear or a seizure of the hook.
3.1.8 Replacement of the hook
Caution! Danger of injury!
witch off the main switch ! Before starting the
setting operation, weit until the motor stops!
- Remove the throat plate and the trimming knife together
with its holder.
- Unscrew the screws (1) and remove the splice (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. 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!
witch off the main switch! Before starting the
setting operation, wait until the motor stops!
- et 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 acces-
sible and, if not, repeat the procedure.
- et the the distance of the hook from the needle according
to the paragraph 3.1.3.
- et the precise angular displacement of the hook according
to the paragraph 3.1.4.
- Loosen the screw (10) and tighten them slightly.
- et 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.
5
2
1
3
4
1
2
3
4
5
7
6
205o
8
10
10
9
51
3
4

5
3.1.10 Dismantling of the hook post
Caution ! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Loosen only one screw (5).
- Unscrew the screws (6).
- Shift the post(1) in the sense of the arrows and remove it
out from the machine.
- When mounting it, proceed inversely.
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 eccentric pin (3), by
means of which the thread mechanism is adjusted according
to the category of stitching. The needle rod holder (4) is
mounted through the pivot (5) in a rotating way in the arm (6).
In its top part, the holder is guided by the guide pin (7). The
movement for the needle feed is given to it by the connecting
rod (8) driven by the feeding shaft (9). The connecting rod (8)
is mounted by pin (13) with needle bar holder (4).
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!
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.
0o
5
6
6
15
2
1
12
3
4
56
7
8
9
13
10
11
1
2
34
5
6
1
1

6
3.2.4 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 guide pin (4).
- In shifting the pin (2) set the needle bar holder on the
measure „A“ = 8 mm (distance between the front face of the
arm and the front face of the safety bolt (5) 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).
3.2.5 Setting the needle (the needle bar holder)
in the direction of sewing
In the lower dead point of the needle bar (needle), the distances
„A“ between the needle and the walls of the needle aperture in
the throat plate insert must be alike.
Caution ! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Set the needle bar to its lower dead point /corresponding to
the anle of 180°on the hand wheel (1)/.
- Fix the position by tightening screw (2).
- Loosen the screw (4) of the lever (5).
- By turning the needle bar holder (6) on the pin (7) set the
same distance “A”.
- Tighten up the screw (4) and check up the setting.
Caution!
A faulty setting may cause bending or breaking of
needles against the throat plate insert.
3
4
2
5
4
5
6
7
1
2
180o
A
1
AA

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 post of the throat plate (1) and the needle bed (2) are
to be set up one to the other in such a way, so that with the
given stitch width „A" there are the same distances „B" between
the edges of the piercing holes and the needles. The inserts
of the throat plates have got the distance of the axes „C" of
the piercing holes by 0.2 mm larger than the stitch width
of needles „A". The space „B" then will always be smaller than
the space „D".
Caution! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Loosen the screws (4) /from the rear side of the post too/.
- Shift the post (1) in the right direction in such a way that the
distances „B" are equal with both needles.
- Tighten up the screws (4) and check up the correctness of
setting.
- 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.
1
2
A
BB
C
DD
1
3
2
4

8
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. With the sewing
categories 300 and 400, it is possible to replace these guides
by one guide (4) /the rear guide and the side guide in one
guide/.
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.
3.4.2 Setting the front guide
The front guide is universal for tandem stitch widths and for
all categories of sewing. It should be set in such a way that,
from the point of view of the operator, it protects the right
needle from the left-hand side. In the that, when backward
stitching, it could not negatively influence the stitch locking.
Its correct height is set up according to the sewn material
1-2 mm above the bottom edge of the feeding wheel. For
harder materials, it is set a bit lower and inversely.
Caution! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Loosen the screw (4) and set the correct height of the guide
(1). Tighten then the screw.
- Loosen the screw (5) and set the guide (1) in the direction
of sewing in front of the left needle at the moment, when
the needle starts piercing the material and set, at the same
time, the side clearance between the guide and the right-
hand needle, tighten then the screw.
- Check up the influence of the setting on the stitch locking.
3.4.3 Setting the rear guide
For different stitch widths of needles there is always used, for
all sewing categories, the respective guide (in each sewing
set there is supplied a corresponding guide). The rear guide
protects the left needle from the right-hand side. It is to be set
in such a way in the direction of sewing that it favourably
influences the stitch locking even when sewing the radii. Its
correct height is set 1-2 mm above the bottom edge of the
feeding wheel, namely according to the hardness of the sewn
material.
Caution! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Loosen the screw (6) and set the guide (2) in the direction
of sewing behind the right needle at the moment when the
needle leaves the sewn material, tighten up the screw.
- Loosen the screws (7) and set the guide in its correct height
and, at the same time, set the side clearance between the
guide and the left needle, tighten up the screw.
- Check up the influence of setting on the stitch locking.
1
4
5
6
2
7
1
2
3
4

9
%
$
!
3.4.4 Setting of the rear and side guides
With the sewing categories 300 and 400, it is possible to
replace the front and the rear guides by one guide. This is a
variant, where the use of the front and of the rear guides does
not enable attaining a satisfactory stitch locking. This guide
is to be set in height -2 mm above the lower edge of the
feeding wheel in accordance with the hardness of the sewn
material. In the sewing direction and with regard to the
clearance against the needle, the setting is to be done in such
a way, so that the guide should not have any influence on the
quality of the stitch locking.
Caution! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Loosen the screws ( ) and set the guide (2) in height, set
the clearance between the needle and the guide, tighten the
screws ( ).
- Loosen the screw (3) and set the guide in the sewing
direction, tighten the screw.
- Check the influence of the setting on the stitch locking.
3.4.5 Setting the guide of the needles (stitch
widths with needles, side by side
The side setting of the guide is to be done starting from the
axis of the stitch width of the needles, that is to say that the
clearances between both needles and the guide must be the
same. The correct height of the guide is set up according to
the sewn material, -2 mm above the bottom edge of the
feeding wheel. In the sense of sewing, the guide is to be set in
such a way that the contact of the guide with the material is at
the same spot as the contact of the feeding wheel with the
material.
Caution! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Loosen the screws (7) and set the guide (3) into the axis of
the stitch width of the needles and set the guide in its
correct height, tighten the screws.
- Loosen the screw (6) and set the guide in the direction of
sewing according to the feeding wheel, tighten the screw.
- Check up the influence of setting on the stitch locking.
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3.5 Thread tensioners and limiter
3.5.1 Description
The main tensioners (1) serve for producing the thread tension
when tightening stitches. The auxiliary tensioners (2) prevent
the pulling out of the thread after having ended the thread
trimming when removing the sewn material, when the threads
are being passed through this material and when the main
tensioners are relieved. The main tensioners are relieved by
means of a mechanism which is controlled by the presser foot
lifting shaft (3), on which the lever (4) with a pulley is attached.
The motion is then transmitted by the lever (5) and the tie rod
(6) on the thread tensioner plate (7) whose displacement
(motion) relieves the thread tensioner springs (8). In machines
provided with a thread trimming device, the main tensioners
(1) are relieved as well upon the switching on of the electro-
magnet (10) whose electromagnetic field will attract the thread
tensioner plate (7). The mechanism of the adapting spring
(12) maintains the upper thread in its tensioned state when
passing through the hook and when entering the needle into
the sewn material. The thread limiter (13) limits the length of
the thread fed by the take-up lever when moving from the
upper to the bottom dead centre to get a controlled passing
of the thread through the hook. The auxiliary guide (14)
maintains the upper thread in front of the needle in a tensioned
condition and helps against pulling the thread from the needle
after thread trimming.
3.5.2 Setting the tension of the main and auxiliary
tensioners
The tension of the main tensioners of both threads is regulated
by the nuts (1) and by the nut (2) of the common tensioner.
The force of tensioning the thread is measured by the
dynamometer (3) as it is shown on the illustration. The size of
this force differs according to the category, and its orientation
value is indicated in the par. 11.2.
The tension of the auxiliary tensioners is regulated by the
nuts (4). It must be the least possible, but sufficient for getting
out the threads from the sewn material under the pressing
element after having ended the trimming operation, without
leaving the tensioners.
3.5.3 Setting the tensioning mechanisms
of the main tensioners
In the rest position of the tensioners, when pushing the plate
of the tensioners on the spot “A” 3.5.1, this plate must have
the socalled dead travel of about 0,5 mm. At this lifting, the
tension discs of the tensioners must not be relieved. This can
be attained by a suitable shaping of the relieving disc of the
tensioners - this has been set up in the manufacturing factory.
In the maximum opened position of the tensioners, the plate
of the tensioners, when pushing it at the spot “A” 3.5.1, must
still have the minimum lifting. This can be attained when axially
shifting the lever (3) with the roller (5) on the shaft (4).
The disengagement of the main tensioners must be
coordinated with the top roller lift. To achieve this, turn the
lever (3) with the roller (5) on the shaft (4). The movement of
the roller (5) on the slanting surface (6) of the lever (7)
disengages the tensioners. In this way, also a lag of the upper
thread tension disengagement after the top roller lift can be
obtained.
Caution ! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Remove the rear cover with the top roller lift magnet.
- Loosen the screws (1) and (2) of the lever (3).
3
4
5
610
A
7
2
1
13
12
14
8
3
4
1
4 1 7
3 2 5
8
0,1
6
9
2

11
- In the rest state of the machine (with not relieved tensioner
discs) set the lever (3) in turning it slightly on theshaft (4)
to a position in which the roller (5) of the lever (3) is in
contact with theslanting surface ( ) of the lever (7) and is
about 0.1 mm distant from the flat surface (8) of thelever.
- At the maximum lift of the top roller, the roller (5) moves on
the flat surface (9) of the lever (7); in this condition, there
must be a minimal play at the tensioner plate lift (when
pushing qat the spot A (3.5.1), the plate must still have a
minimum lifting - between the roller (5) and the surface (9)
there is a minimum clearance). Retighten the screws (1) and
(2), check the play, and correct it in case of need.
3.5.4 Setting the adapting spring
The mechanism of the adapting spring is in the machine arm
set by the pin (1) and fixed by the screw (2). The axial
adjustment shall ensure that the surfaces of the parts (3) and
(4) are aligned (the threaded thread must in no place break on
edges). The initial position of the adapting spring (5) shall
ensure that B = 1 to 1.5 mm (see the Figure).
Caution! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
-Loosen the screw (2) and take the mechanism out of the
machine arm.
- Turning the body ( ) relative to the pin (1), set the required
initial position of the adapting spring /the screw (7) has
been set at the producer´s so as to permit the turning
movement of the body ( ) the screw must not be fully
tightened/.
- During the installation of the mechanism into the machine
arm take care of the axial adjustment of the mechanism.
- Retighten the screw (2) and check the adjustment.
- Loosen the nut (8) of the mechanism, insert a screwdriver
into the notch of the screw (9) and set the required value of
the adapting spring. By turning the screw clockwise you
increase the spring force, and vice versa.
- Retighten the nut (8) and check the function of the adapting
spring.
3.5.5 Setting the thread limiter
The thread limiter is to be set in such a way that, when sewing
and passing the thread through the most distant point of the
hook, the spring (2) shifts by about 1/4 to 1/2 length of its
total length. This means that the thicker will be the sewn
material and the longer will be the stitch length, the more will
be the limiter shifted in the sense of the arrow and inversely.
Caution! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Tighten the screw (3).
-Set the thread limiter (1) so as to ensure a minimum motion
of the adapting spring (2) when the thread passes around
the bottom of the hook.
- Tighten the screw (3).
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3.6 Feeding mechanism of the needle feed
and of the lower feed wheel
3.6.1 Description
The feeding mechanism is formed by the leverage (1) which is driven
from the main shaft through the eccentric with connection rod (2). The
feeding motion is transmitted by the shaft (3) on the clutch of the
bottom feed (7).
The engaging and the disengaging function of the clutch (7) is
controlled from the lower shaft (8) through the eccentric with
the connecting rod (9) and through the wedge coupling (10).
The feeding movement is transmitted by the shaft (11) through the
chain transmission (12) onto the wheel feeder (13).
The stitch length is set by the knob (14) through the leverage (15) to
the feeding mechanism (1).
3.6.2 Stitch length mechanism
3.6.2.1 Setting the upper eccentric
The eccentric (1) must be set in its angular position in such a way that
the horizontal component of the needle motion is in a phase delay from
the vertical component of this movement. This refers to the angle of
90°on the handwheel (2), when the setting stick (3) is engaged into
the eccentric (1) and leans from above against the feeding shaft (4).
Caution! Danger of injury!
Switch off the main switch! Before starting the setting
operation, wait until the motor stops!
- Set the angle 90°on the handwheel (2) and fix it with the screw (5)
which is component part of the accessory of the machine (tighten it
with care).
- Loosen the gripping joints of the levers (6) and (7).
- Turn the feeding shaft (4) in such a way, so that the recesses (flats)
point towards the bedplate (owing to the unambi-guous setting of
the eccentric by means of the setting bar).
- Insert the setting bar (3) into the hole in the eccentric (1) and prop
it from above against the feeding shaft (4).
- Shift axially the eccentric (1) on the shaft into its extreme positions
and place it in the middle.
- Tighten the screws of the eccentric (1) to the maximum (one screw
first and, after having turned slightly the hand-wheel, the second
screw as well).
- Turn the feeding shaft (4) back into the position for setting the
leverage in such a way, so that the levers (10) of the mechanism pass
in the spots of the recesses.
- Tighten the gripping joints of the levers (6) and (7).
- Test the sufficient clearance in the recesses of the feeding shaft (4)
and, using the levers (10) with the maximum stitch length forward
and rearward – push against the reverse stitching lever.
- Correct eventually the position of the feeding shaft.
3.6.2.2 Setting the prop
In this machine with a wheel feed, the prop (1) is mounted in the pits
(A and C) as per the drawing.
3.6.2.3aForward and rearward stitch length
distribution (rough)
The cam (1) is to be set at the respective angle in such a way that the
stirrup (6) is oriented in such a position, so that the connecting rods (7
and 8) are in a line with a thoroughly screwed in knob (9) and with
turning the handwheel at 0°. This setting can be done only after having
set the top eccentric according to the paragraph 3.6.2.1.
Caution! Danger of injury!
Switch off the main switch! Before starting the setting
operation, wait until the motor stops!
- Set the zero stitch /screw in the knob (9) to the bottom of the cam (1).
- Set the angle 0°on the handwheel and lock it with the screw (4).
- Turn the screw (3) in the respective sense in such a way that the
connecting rods (7 and 8) are in a line and tighten the screw (2).
C
D
A
B
1
4
0o
678
19
3
2
5
2
90o
6
10 1
4
3
7
15
4
5
13
12
14
11 10
6
8
7
2
1
9
3

13
3.6.2.3bForward and rearward stitch length
distribution (fine)
When setting the maximum length of the stitch, the forward
and the rearward stitch length must be equal with the
maximum error of ± 5 %. This setting can be done only after
having set the needle bar holder in the direction of sewing
(par. 3.2.6) and the wheel feed (par. 3.6.3.1.2).
Caution! Danger of injury!
switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Set the maximum stitch length .
- Place a suitable material under the presser foot and mark
therein the forward and the rearward stitch length.
- With an unequal length of the stitch, proceed to the
correction
of setting by turning the screws (2 and 3). When tightening
the screw (3), the forward length of the stitch is shortened
and inversely. When tightening the screw (2), the forward
stitch length is lenghtened.
- Each time first loosen one screw and then retighten the
other one.
3.6.2.4 Setting the control knob
(including the stitch length limitation)
The control knob (1) is to be set up in such a way that, when
turning it in counterclockwise sense up to the stop, the
maximum stitch length valid for the given sewing category is
attained (cat. 1: 3 mm, cat 2: 5 mm, cat. 3 and 4: 7 mm). The
scale of the control knob is to be oriented in such a position,
so that the scale end corresponds to the maximum stitch
length, excepting the first sewing category, where the stitch
length of the indicator is 3 mm.
Caution! Danger of injury
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Screw in the screw of the control knob in such a way, that
the spherical surface of the screw (3) bears on the seat of
the cam (4).
- Loosen the screw (5) and turn the control knob in the
clockwise direction, until the pin (6) of the knob (1) bears
on the pin (7). Tighten firmly the screws (5).
- Turn the knob in the counterclockwise direction up to the
stop, when the pin (6) of the knob (1) bears on the pin (7).
- In a sewing test check up the length of the stitch, if this
corresponds to the maximum stitch length valid for the given
sewing category.
- If the stitch is longer, loosen then the screws (5) and turn
the knob in the clockwise direction and inversely. Tighten
firmly the screws (5).
- Insert a screwdriver into the hole (8) of the scale (2) and
adjust the scale in such a way that the maximum length on
the scale is against the marking of the stitch length on the
machine arm.
- For the sewing category 1, set the control knob (1) on the
stitch length of 3 mm and check it by a sewing test.
- Loosen the screws (5) and turn the control knob (1) in the
counterclockwise direction, until the pin (6) of the knob (1)
bears on the pin (7). Tighten firmly the screws (5).
- Put a screwdriver into the hole (8) of the scale (2) and adjust
the scale in such a way that the value of the stitch length on
the scale against the marking on the arm is 3 mm.
3
2
1
2
5
3
4
6
7
5
1
28

14
3.6.3 Lower feed wheel
3.6.3.1 Feeding clutches
3.6.3.1.1 Description
The feeding clutch is formed by the clutch cover (1) driven
from the connecting bar (2), by the clutch star (4) driven from
the connecting rod (3) and by the carrier plate (5) firmly
connected with the shaft (6). Of the clutch give the connecting
rods (2 and 3) an opposite direction swinging movement. The
clutch is coupled by means of the wedge (7) on the connecting
rod (8) through the eccentric (9) which is placed on the lower
shaft (10).
In the position, when the wedge is disengaged, the star (4)
is shifted out from the frictioning engagement with the lining
of the carrier plate (5) by means of the spring washer (11). The
plate (5) lining is then pushed by means of a flat profiled
spring (12) against the cover of the clutch (1).
In the position, when the wedge is disengaged, the star (4)
is pushed against the plate (5) lining and, at the same time,
the friction connection with the cover of the clutch (1) is
disconnected. Within a short instant, when engaging and
disengaging with the carrier plate (5), there are in a friction
engagement both the cover (1) and also the star (4), namely in
the dead centre of the connecting rods (2 and 3). The setting
of the change-over of clutches is done by tightening or by
loosening the nut (13).
3.6.3.1.2 Setting the lever of the second step of
feeding (angle, position)
The lever of the second step (1) must be set in such a way
that, in the bottom dead centre of the needle, the axis of the
spider part (2) lies in the screw axis (3). The pin screw (4) can
be mounted into the position (4.1 - corresponds to the
maximum stitch length of 5 mm) or into the position (4.2 -
corresponds to the stitch length of 7 mm). The position of the
pin screw is given by the sewing category (see par. 11.2).
Caution! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
Lever (1) displacement.
- Loosen the screw (6).
- Set the maximum stitch length.
- Set the angle 180°on the handwheel.
- Unscrew the screw (5) and put the needle shank in its hole.
- Turn the lever (1) until the needle drops into the clutch disk (2).
- Side set the lever (1) to the measure „A“= 0.5 to 1 mm.
- Tighten the screw (6).
- Screw in the screw (5) and seal it with the Loctite cement.
Change of the position of the pin screw (4).
- Remove the retaining ring (7).
- Unscrew the screw (4) and screw it into the new position
and tighten it duly. Mount the connecting rod (8) and the
retaining ring (7).
3
9
1
13
7
412
5
11
6
10
8
2
2
5
78 14
A
32
5
8
6
4.2
4
1
4.1

15
3.6.3.1.3 Setting of the lower eccentric
The rotation of the eccentric (3) must be delayed in phase by
1/4 revolution against the rotation of the eccentric of the stitch
length. This corresponds to the angle of 244°on the handwheel
(1), when the setting pin (4) is put into the eccentric (3) which
is in contact with the indented belt (5).
Caution! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Set 244°on the handwheel (1) and lock it with the screw
(2), which is included in the accessory of the machine
(tighten it carefully).
- Put the setting stick (4) into the hole in the eccentric (3) and
prop it from below against the indented belt (5).
- Set eccentric (3) axially.
- Tighten it the utmost the screws of the eccentric (6).
- By means of the handwheel, turn the eccentric (3) into the
marked position and check in this position the clearance
„A“ = 0.05, proceed eventually to its correction by a new
side setting of the eccentric.
3.6.3.1.4 Setting the engagement and
disengagement of the clutches
The nut (7) is to be side set in such a way that the shifting of
the clutches is done at the moment when the clutch disks (3)
do not move, which means, when they are at the dead center
of their oscillating movement. This corresponds to the angle
90°on the handwheel.
Caution! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Loosen the screws of the indented pulley of feeding and
shift it to the left.
- Set the maximum stitch length.
- Set the angle 90°on the handwheel (1) and lock it with the
screw (2). which is included in the accessory of the machine
(tighten it carefully).
- Loosen three screws (6) in the nut (7) and unscrew it by
2 mm to the left.
- Tighten slowly the nut (7), until it strikes against the axial
bearing (9). (At this moment, the tightening moment
increases in jumps) and tighten the screws (6).
- Set the the handwheel on 85°and push the backtacking
lever, the feeder is to turn against the movement of the
needle. Set then the handwheel on 95°, the feeder is to be
turned in the sense of the needle movement. If not being
so, correct the side setting of the nut (7). When the clutches
shift too soon, turn a bit the nut (7) to the right and inversely.
- Tighten the screws (6).
- Return the indented pulley in its original place according to
the paragraph 3.7.2.
244o
2
1
3
6
45
A
1
2
90o
6
793

16
3.6.4.2 Wheel feeder and its post
3.6.4.2.1 Height setting of the feeder and tension-
ing of the chain
The wheel feeder (1) is to be set in such a way that the points
of its teeth overtop the insert of the throat plate by X= 0 3 to
0 7 mm When sewing soft and thick materials, it is necessary
to increase the value X, until a good quality of feeding is
attained, but only to the measure of not deteriorating the
beginning of sewing after the carried out thread trimming
Set the height of the feed dog using a setting gauge
With every correction of the teeth height, the tension of the
chain (2) is to be corrected
Caution! Dangere of injur !
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Loosen the screw (3)
- Loosen the screw (4)
- Loosen or tighten the screw (5) and push simultaneously
with finger the feeder (1) downwards, until the required
height of the teeth X of the wheel feeder is attained
- Tighten then still the screw (5) by 45° (1/8 revolution)
- Tension the tensioner (6) up to the stop Be careful in side
shifting it to the centre of the chain Tighten the screw (3)
- Loosen the screw (5) by 45° (1/8 revolution), into its original
position In this way, the optimal clearance of the chain
transmission is attained
- Tighten the screw (4)
- Correct the set height of the top roller according to the
par 3 6 5
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3.6.3.2.2 Replacement of the feeder
For the replacement of the wheel feeder (change of the wheel
feeder according to the machine setting - see par. 11.2 - setting
of the machine - feeder - pitch of the teeth).
Caution! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Unscrew the screws (1) and remove the throat plate (2).
- Dismantle the hook of the left-hand post (see .1.8).
- In pulling upwards (securing by a spring), pull out the feeder
( ) with the guide (4).
- Replace the feeder ( ).
- Insert the feeder with the guide into the groove of the holder
(5).
- Mount the hook of the left-hand post (see .1.8).
- Mount the throat plate (2) and tighten up the screws (1).
- Check up, if the spring (6) pushes the guide (4) with the
feeder ( ) against the wheel (8).
- In the opposite case, loosen the screws (9), tense up the
spring (6) in such a way,so that the guide (4) with the feeder
( ) is pushed against the wheel (8) and tighten the screws
(9).
3.6.4Setting the top roller (pressing force, height)
When lowering the top roller (1), set the clearance A between
the feeder (5) and the top roller to the maximum of 0.2 mm.
Set the pressing force of the top roller (1) so as to avoid the
slippage of the sewn material when feeding it.
Method of setting the height of the top roller:
- Lower by hand the presser bar ( ) with the top roller (1)
above the wheel feeder (5).
- Loosen the screw (4) and set the required value A (0.2
mm).
- Tighten the screw (4).
Setting the force of the top roller (1).
- In screwing in the screw (2),the force of the top roller is
increased and inversely.
3.7Feeding mechanism of the top roller
3.7.1 Description
The starting movement for the drive of the top roller feeder is
the bottom feeding shaft. From this shaft, the movement is
transmitted by the indented belt (1) onto the top feeding shaft
(2). A component part of the transmission by indented belt is
the pulley ( ), the tensioning roller (4), the roller (5) and the
pulley (6). Starting from the shaft (2), the movement is further
transmitted through the wheels (7 and 8) ontothe articulated
shaft (9). From this articulated shaft, the movement is
transmitted by a cone transmission, situated in the holder
(10), onto the feeder wheel (11). The shaft of the wheel (8) is
mounted in the screw (12) on bearings. The articulated shaft
(9) contains two joints (15) and a telescopic part (16). Both
these elements secure the lifting and the tilting of the top
roller.
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