Pfaff 900/56 User manual

-900/56
-900/61
296-12-14827
Justieranleitungengl.06.95
Service Manual
for 440-R, 1440, 420
and 1420
series machines

2
Adjustment
11Safety ............................................................................................. 34
11.01 General notes on safety..................................................................................... 34
11.02 Safety symbols .................................................................................................. 44
11.03 Important points for the user ............................................................................. 44
11.04 Operating and specialist personnel .................................................................... 44
11.04.01 Operating personnel .......................................................................................... 44
11.04.02 Specialist personnel ........................................................................................... 54
11.05 Warning ............................................................................................................. 54
12Adjustment ...................................................................................... 64
12.01 Tools, gauges and other accessories ................................................................. 64
12.02 Notes on the adjustments ................................................................................. 64
12.03 Abbreviations ..................................................................................................... 64
12.04 Explanation of the symbols................................................................................ 6#
13Tension release trip ........................................................................... 7#
14Solenoid bracket ............................................................................... 81
14.01 Solenoid bracket on -900/56............................................................................... 81
14.02 Solenoid bracket on -900/61............................................................................... 91
15Engaging lever pin ............................................................................ 10
16Eccentric pin of catcher control lever on -900/61 only ............................. 11
17Control cam and locking bracket ......................................................... 12
17.01 Axial position of crank lever ............................................................................... 12
17.02 Radial position of control cam............................................................................ 13
17.03 Locking bracket.................................................................................................. 14
18Engaging solenoid ............................................................................ 15
19Stop lug .......................................................................................... 16
10 Catcher actuating lever ...................................................................... 17
11 Catcher connecting rod (two-needle machines) ..................................... 18
12 Catcher height .................................................................................. 19
13 Thread catcher rest position ............................................................... 20
14 Knife height ..................................................................................... 21
15 Knife pressure .................................................................................. 22
16 Bobbin thread trapper spring .............................................................. 23
17 Needle thread tension release ............................................................ 24
18 Synchronisizer.................................................................................. 25
19 Manual trimming test ........................................................................ 26
Contents

3
Adjustment
1 Safety
1.01 General notes on safety
●This machine may only be operated by adequately trained operators and only after having
completely read and understood the Instruction Manual.
●All Notes on Safety and Instruction Manuals of the motor manufacturer are to be read
before operating the machine!
●Pay attention to all warnings and safety instructions mounted on the machine!
●This machine may only be used for the purpose for which it is intended and may not be
operated without its safety devices. All Safety Regulations relevant to its operation are to
be adhered to.
●When exchanging sewing tools (e.g. needle, presser foot, needle plate, feed dog or
bobbin), when threading the machine, when leaving the machine unattended and during
maintenance work, the machine is to be separated from the power supply by switching
off the On/Off switch or by removing the plug from the mains!
●Everyday maintenance work is only to be carried out by appropriately trained personnel!
●Repairs and special maintenance work may only be carried out by qualified service staff
or appropriately trained personnel.
●When servicing or carrying out repairs on pneumatic devices, the machine is to be
removed from the compressed air supply. The only exceptions to this are adjustments
and function checks carried out by appropriately trained personnel!
●Work on electrical equipment may only be carried out by appropriately trained personnel!
●Work is not permitted on parts and equipment which are connected to the power
supply. Exceptions to this are in accordance with the regulations EN 50110.
●Modifications and alterations to the machine may only be carried out under observance
of all the relevant safety regulations!
●Only spare parts which have been approved by us are to be used for repairs!
We expressly point out that any replacement parts or accessories which are not supplied
by us have not been tested and approved by us. The installation and / or use of any such
products can lead to negative changes in the construction characteristics of the machine.
We shall not be liable for any damage which may be caused by non-original parts.
Safety

4
Adjustment
1.02 Safety symbols
Danger!
Points to be observed.
Danger of injury for operating and specialist personnel!
1.03 Important points for the user
●This Instruction Manual is a component part of the machine and must be available to the
operating personnel at all times.
The Instruction Manual must be read before operating the machine for the first time.
●The operating and specialist personnel is to be instructed as to the safety equipment of
the machine and regarding safe work methods.
●It is the duty of the operator to only operate the machine in perfect running order.
●It is the obligation of the operator to ensure that none of the safety mechanisms are
removed or deactivated.
●It is the obligation of the operator to ensure that only authorised persons operate and
work on the machine.
Further information can be obtained at your PFAFF agent.
1.04 Operating and specialist personnel
1.04.01 Operating personnel
Operating personnel are persons responsible for the equipping, operating and cleaning of the
machine as well as taking care of faults arising in the sewing area.
The operating personnel is obliged to observe the following points and must:
●always observe the Notes on Safety in the Instruction Manual!
●never use any working methods which could limit the level of safety in using the
machine!
●not wear loosely fitting clothing or jewellery such as chains or rings!
●also ensure that only authorised persons have access to the potentially dangerous area
around the machine!
●always immediately report to the person responsible any changes in the machine which
may limit its safety!
Safety

5
Adjustment
1.04.02 Specialist personnel
Specialist personnel are persons with a specialist education in the fields of electrics,
electronics and mechanics. They are responsible for the lubrication, maintenance, repair and
adjustment of the machine.
The specialist personnel is obliged to observe the following points and must:
●always observe the Notes on Safety in the Instruction Manual!
●switch off the On/Off switch before carrying out adjustments or repairs and ensure that
it cannot be switched on again unintentionally!
●never work on parts which are still connected to the power supply. Exceptions are
contained in the regulations EN 50110.
●when servicing or carrying out repairs on pneumatic devices, remove the machine from
the compressed air supply. The only exceptions to this are function checks.
●replace the protective coverings and close the electrical control box after all repairs or
maintenance work!
1.05 Warning
While sewing keep your hands away from the needle area!
Danger of injury by the needle!
When making adjustments do not leave any objects on the tabletop or
in the needle plate area! Objects could become clamped or slung away!
Danger of injury!
To adjust this unit the machine must be tipped to the back!
Use both hands when setting the machine upright! Danger of clamping
between machine and tabletop!
Safety

6
Adjustment
2 Adjustment
Special attention should be payed to the following
This service manual is valid for the subclasses -900/56 and -900/61 for the PFAFF 440-R;
1440; 420 and 1420 series of machines.
The PFAFF 442-R two needle version is illustrated.
The text refers to the single needle version. Notice of additional adjustments for the two
needle machines are marked as such in the corresponding sections. Deviations in the
illustration have no influence on the adjustments.
2.01 Tools, gauges and other accessories
●Screwdrivers with blade width from 2 to 10 mm
●Wrenches from 7 to 14 mm (across flats)
●Hexagon keys, 1.5 to 6 mm
●Metal rule (Part No. 08-880 218-00)
●Continuity tester
●Sewing thread and test material
●Feeler gauge
2.02 Notes on the adjustments
All adjustments in this manual apply to the fully assembled machine. Machine covers which
have to be removed and re-fitted for checks and adjustments are not mentioned in the text.
Screws or nuts in brackets ( ) must be loosened before an adjustment and tightened again
afterwards.
2.03 Abbreviations
t.d.c. = top dead center
b.d.c. = bottom dead center
2.04 Explanation of the symbols
Note, information
Servicing, adjustment

7
Adjustment
3 Tension release trip
6
3
97
2
43
2
1
1 mm
●Remove solenoid bracket1(screws2)
●Loosen screws 3and for more extensive adjustments, also screws4.
●Turn balance wheel until the widest part of trip 5is aligned with tension release trip6.
●Adjust lateral position of stop finger7according to the requirement.
●In this position, make sure that stop finger7is in contact with bracket 8, move bracket 9
of release trip fully to left in elongated hole and tighten both screws 3.
●Check this adjustment according to the requirement.
●If more extensive adjustments are to be made, screws 4should remain loose until the
catcher actuating lever is adjusted.
●For adjusting the solenoid bracket1only lightly tighten screws 2(chap. 4).
5
7
5
8
6
Requirement
When the broadest partof trip 5is aligned with tension trip 6, with the control cam in
resting position and the presser foot lowered, there must be a clearance of roughly 1 mm
between the left side of trip 5and tension release trip 6.

8
Adjustment
4 Solenoid bracket
4.01 Solenoid bracket on -900/56
●Turn balance wheel until tip of trip1is aligned with control pin 2.
●Operate engaging lever3.
●Loosen both screws4.
●Adjust position of solenoid bracket 5according to the requirement
●In this position, tighten screws4.
●Check this adjustment according to the requirement.
●Turn balance wheel opposite feeding direction until control pin 6is retained.
2
7
3
54
7
1
6
Requirement
When the tip of trip 1is aligned with control pin 2and the engaging lever has been
operated, there must be a clearance of roughly 0.5 mm between the left inside of control
cam 7and control pin6.
0.5 mm
2

9
Adjustment
4.02 Solenoid bracket on -900/61
●Turn balance wheel in feeding direction until needle bar is positioned 10 mm before b.d.c.
●Operate engaging lever1.
●Continue turning balance wheel until control pin2is positioned opposite return motion
cam3.
●Loosen screws4.
●Adjust position of solenoid bracket5according to the requirement.
●In this position, tighten screws4.
●Check this adjustment according to the requirement.
●Turn balance wheel opposite feeding direction until control pin 6is retained.
3
2
4
6
2
35
0.5 mm
1
Requirement
With engaging lever 1operated, and control pin 2positioned beside return motion cam3,
there must be a clearance of 0.5 mm between control pin 2and return motion cam3.

10
Adjustment
5 Engaging lever pin
Requirement
When the trimming mechanism is at rest there must be a clearance of 0.1 mm between
the highest point of cam track 1and control pin2.
●Make sure control cam 1is in its starting position. Then turn balance wheel until highest
point of cam track 1is aligned with control pin2.
●Loosen screw3.
●Turn eccentric stud 4according to the requirement.
●In this position, tighten screw3.
●Check this adjustment according to the requirement.
4
1
0.1 mm
1
3
2

11
Adjustment
6 Eccentric pin of catcher control lever on -900/61 only
●Turn balance wheel in feeding direction until needle bar is positioned 10 mm before b.d.c.
●Operate engaging lever1.
●Continue turning balance wheel until control pin 2has moved control cam3to its left
reversal point.
●Retaining this position, loosen screw 5and turn eccentric pin 4according to the
requirement.
●In this position, tighten screw5.
●Check this adjustment according to the requirement and repeat, if necessary.
Requirement
Over the entire cam circumference the roller of eccentric pin 4must be as close to control
cam 3as possible.
1
3
2
4
5
3
x

12
Adjustment
7 Control cam and locking bracket
7.01 Axial position of crank lever
●Turn balance wheel in feeding direction until needle bar is positioned 10 mm before b.d.c.
●Loosen screw 1just sufficiently for crank lever 2to be moved on its shaft against
resistance.
●Operate engaging lever3.
●Continue turning balance wheel until control pin 4has set control cam5at its left point of
reversal.
●Retain this position, then move crank lever 2laterally according to the requirement.
●Turn balance wheel in feeding direction until needle bar is positioned 10 mm before b.d.c.
●Tighten screw 1.
●Make sure control cam 5is just about to snap back to starting position, then push it all
way to left. As you continue turning balance wheel, return motion cam 6must freely pass
stud7.
If required, repeat solenoid bracket adjustments (chap.4).
7
6
5
3
1
2
8
4
0.2 mm
Requirement
Operate engaging lever 3and turn the balance wheel to set control cam 5at its far left
position; there must then be a clearance of0.2 mm between guide finger8and bottom of
the control cam cutout (see below).

13
Adjustment
7.02 Radial position of control cam
3
2
●Adjust guide finger 1(screw 2) according to the requirement without moving it axially.
2
1
Requirement
When the take-up lever is at t.d.c., the trimming action must be completed and control cam
3must spring back to its starting position.

14
Adjustment
7.03 Locking bracket
➤
➤
➤
3
4
2
65
1
4
0.5 mm
●Turn balance wheel in feeding direction until needle bar is positioned 10 mm before b.d.c.
●Operate engaging lever1.
●Continue turning balance wheel in feeding direction until needle bar is positioned at t.d.c.
●Loosen screws 2on locking bracket 3.
●Push control cam 4all way to left by hand.
●Retaining this position, set clearance between control cam 4and locking
bracket 3according to the requirement.
●Tightenscrews2.
●Loosen nut 5and bring screw6into contact with locking bracket3.
●Tightennut5.
●Check this adjustment according to the requirement.
Requirement
With control cam 4guided to the left and pushed to the left by hand and the needle bar at
t.d.c. there must be a clearance of0.5 mm between locking bracket 3and control cam 4.

15
Adjustment
8 Engaging solenoid
Requirement
With the needle bar positioned10 mm before b.d.c. and engaging lever 2operated, core4
of the engaging solenoid must have a play of 1 mm.
●Turn balance wheel in feeding direction until needle bar is positioned 10 mm before
bottom dead centre.
●Loosen screw1.
●Operate engaging lever2.
●Push solenoid housing3upwards until solenoid core 4is fully inside housing.
●In this position, make a mark on solenoid housing3immediately below solenoid bracket 5.
●Push solenoid housing3downwards by 1 mm and tighten screw 1.
●Check this adjustment according to the requirement.
2
4
5
3
1
1 mm

16
Adjustment
9 Stop lug
Requirement
With stud 5positioned at the highest point of disengaging cam 4(take-up lever shortly
before t.d.c.) there must be a clearance of 0.1 mm between stop lug7and the bedplate.
●Turn balance wheel in feeding direction to set needle bar 10 mm before b.d.c.
●Operate engaging lever1.
●Loosen screws 2, then loosen screw 3.
●Turn balance wheel to position highest point of disengaging cam 4under stud 5of
catcher control lever 6(shortly before control cam returns to starting position).
●Maintaining this position, set stop 7according to the requirement.
●Tighten screw 3.
●Check this adjustment according to the requirement.
2 3
6
4
1
5
6
0.1 mm
7

17
Adjustment
➤
10 Catcher actuating lever
●Loosen nut1.
●Set ball-joint connecting link2in centre of elongated hole in crank 3.
●Tightennut1.
●Making sure trimming mechanism is at rest and screws 4are still loose, loosen screws 5.
●Adjust catcher actuating lever 6both axially and radially according to the requirement.
●In this position, tighten screws4.
●Check this adjustment according to the requirement.
●Screws 5are left loose for adjustment of thread catcher.
6
2
7
5
1
4
3
9 mm
Requirement
With the trimming mechanism at rest, ball-joint connecting link 2must be at right angles to
the edge of the bedplate. Also, there must be a clearance of 9 mm between the left edge
of ball-joint connecting link 2and the centre of catcher driving shaft7.
When difficult threads are processed and the catcher does not take up the bobbin
thread reliably, the stroke of the catcher can be increased or decreased through the
elongated hole in crank3.

18
Adjustment
11 Catcher connecting rod (two-needle machines)
Requirement
The left bell-crank lever4must be parallel to the right bell-crank lever 5.
●Make sure control cam 1is in starting position and loosen screws 2.
●Adjust catcher connecting rod 3according to the requirement.
●In this position, tighten screws2.
4
3
1
2
5

19
Adjustment
12 Catcher height
Requirement
Thread catcher 5must pass 0.8 mmabove bobbin case 6.
If during a manual trimming test (chap. 19) the end of the thread catcher pushes
against the bobbin thread, change height setting.
●Making sure that screws 1are still loose, loosen screw 2.
●Loosen screws3in collar4.
●Swing thread catcher5by hand to center it above bobbin case 6, and adjust it according
to the requirement.
●In this position, tighten screw2.
●Center vertical play of catcher driving lever 7, making sure catcher driving joint is not
strained.
●Maintain position and making sure that collar4does not strike other parts, move fully
downwards and tighten screw3.
●Check this adjustment according to the requirement.
●On two-needle machines, make adjustment twice. Screws 1are left loose.
1
7
743
0.8 mm
6
5
143
2
➤
➤
2
5
5
S
re
In CM
sc
CO

20
Adjustment
1
1
2
4
2
4
-900/56 -900/61
0.5 mm 0.5 mm
3
13 Thread catcher rest position
Requirement
When the trimming mechansim is at rest, the triangular cutting tip of catcher2must be
positioned0.5 mm behind the cutting edge of knife 4.
●Make sure trimming mechanism is in starting position and screws1are loose, then
swing thread catcher 2by hand according to the requirement.
●Maintain position while moving crank 3against its stop and tighten screws 1.
●Check this adjustment according to the requirement.
●On two-needle machines, make adjustment twice.
3