Pfaff 3734-2/01 User manual

296-12-18 352/002
Betriebsanleitung engl. 05.2002
Instruction Manual
This instruction manual applies to machines from the
following serial numbers onwards:
# 2207198
3734 -2/01
-2/21

The reprinting, copying or translation of PFAFF Instruction Manuals, whether in whole or in
part, is only permitted with our previous authorisation and with written reference to the
source.
PFAFF Industrie Maschinen AG
Postfach 3020
D-67653 Kaiserslautern
Königstr. 154
D-67655 Kaiserslautern
Redaktion / Illustration
VTD GmbH
D-77901 Lahr

Contents
Contents ............................................................................... Chapter - Page
1Safety ........................................................................................................................ 1 -1
1.01 Directives ...................................................................................................................1- 1
1.02 General notes on safety ............................................................................................. 1 - 1
1.03 Safety symbols .......................................................................................................... 1 - 2
1.04 Important points for the user ..................................................................................... 1 - 2
1.05 Operating and specialist personnel ............................................................................ 1 - 3
1.05.01 Operating personnel ................................................................................................... 1 - 3
1.05.02 Specialist personnel ................................................................................................... 1 - 3
1.06 Danger .......................................................................................................................1- 4
2Proper use................................................................................................................. 2 - 1
3Specifications ........................................................................................................... 3 - 1
3.01 PFAFF 3734-2/01; -2/21 .............................................................................................. 3 - 1
3.02 Model, needles and threads ....................................................................................... 3 - 1
4Disposal of machines ............................................................................................... 4 - 1
5Transport packaging and storage ........................................................................... 5 - 1
5.01 Transport to the customer’s premises ....................................................................... 5 - 1
5.02 Transport within the customer’s premises ................................................................ 5 - 1
5.03 Disposal of the packaging .......................................................................................... 5 - 1
5.04 Storage ......................................................................................................................5 - 1
6Explanation of the symbols ..................................................................................... 6- 1
7Controls .................................................................................................................... 7 - 1
7.01 On/off switch ............................................................................................................. 7 - 1
7.02 Pedal .......................................................................................................................... 7 - 1
7.03 Knee switch ............................................................................................................... 7 - 2
7.04 Lever for lifting the roller presser ............................................................................... 7 - 2
7.05 Control panel .............................................................................................................. 7 -3
7.05.01 Displays on the screen ............................................................................................... 7 - 3
7.05.02 Key functions .............................................................................................................7 - 3
8Mounting and commissioning the machine .......................................................... 8 - 1
8.01 Mounting .................................................................................................................... 8- 1
8.01.01 Adjusting the table-top height .................................................................................... 8 - 1
8.01.02 Fitting the tilt lock....................................................................................................... 8 - 2
8.01.03 Adjusting the V-belt tension ....................................................................................... 8 - 2
8.01.04 Mounting the synchronizer......................................................................................... 8 - 3
8.01.05 Mounting the spool holder ......................................................................................... 8 - 3
8.01.06 Attaching the earthing wire / connecting the plug connections .................................. 8 - 4
8.02 Commissioning .......................................................................................................... 8 - 4
8.03 Switching the machine on/off .................................................................................... 8 - 4

Contents
Contents ............................................................................... Chapter - Page
9Preparation ............................................................................................................... 9 - 1
9.01 Inserting the needle ................................................................................................... 9 - 1
9.02 Winding the bobbin thread, adjusting the thread tension ........................................... 9 - 2
9.03 Removing / Inserting the bobbin case ........................................................................ 9 - 3
9.04 Threading the bobbin case / Adjusting the bobbin thread tension .............................. 9 - 4
9.05 Threading the needle thread / adjusting the needle thread tension ............................ 9 - 5
9.06 Setting the stitch length / fullness .............................................................................. 9 - 6
9.06.01 Entering the standard stitch length / fullness ............................................................. 9 - 6
9.06.02 Entering a second stitch length / fullness ................................................................... 9 - 6
9.06.03 Entering the fullness range for pedal adjustment ....................................................... 9 - 7
9.07 Entering / adjusting the code number. ....................................................................... 9 - 8
10 Sewing .................................................................................................................... 10 - 1
10.01 Applying fullness ...................................................................................................... 10 - 1
11 Care and maintenance ........................................................................................... 11 - 1
11.01 Cleaning ................................................................................................................... 11- 1
11.02 Lubricating the hook ................................................................................................. 11 - 2
11.03 Filling the oil reservoir .............................................................................................. 11 - 2
11.04 Lubricating the bevel gears ...................................................................................... 11 - 3
12 Adjustment ............................................................................................................. 12 - 1
12.01 Notes on adjusting ................................................................................................... 12 - 1
12.02 Tools, gauges and other accessories for adjusting ................................................... 12 - 1
12.03 Abbreviations ........................................................................................................... 12 - 1
12.04 Adjusting the basic machine ................................................................................. 12 - 2
12.04.01 Adjusting the synchronizer ....................................................................................... 12 - 2
12.04.02 Positioning the needle in the direction of sewing ..................................................... 12 - 3
12.04.03 Positioning the needle across the direction of sewing ............................................. 12 - 4
12.04.04 Preadjusting the needle height ................................................................................. 12 - 5
12.04.05 Needle rise, hook-to-needle clearance, needle height and needle guard .................. 12 - 6
12.04.06 Bobbin case opener height ....................................................................................... 12 - 8
12.04.07 Bobbin case opener stroke ...................................................................................... 12 - 9
12.04.08 Feed wheel height ................................................................................................... 12 - 10
12.04.09 Clearance between the roller presser or band feed and the feed wheel .................. 12 - 11
12.04.10 Roller presser ( 3734-2/01 ) ...................................................................................... 12 -12
12.04.11 Band feed ( 3734-2/21) ............................................................................................. 12 - 13
12.04.12 Changing the band ( 3734-4/21)................................................................................ 12 - 14
12.04.13 Automatic presser-foot lifter .................................................................................... 12 - 15
12.04.14 Retainer ................................................................................................................... 12 - 16
12.04.15 Tension release ........................................................................................................ 12 -17
12.04.16 Thread check spring ................................................................................................. 12 - 18
12.04.17 Bobbin winder .......................................................................................................... 12 -19
12.04.18 Roller presser pressure ............................................................................................ 12 - 20
12.04.19 Locking the set-value transmitter ............................................................................. 12 - 21

Contents
Contents ............................................................................... Chapter - Page
12.05 Adjusting the thread trimmer -900/53 ................................................................... 12 - 22
12.05.01 Removing the scissors ............................................................................................. 12 - 22
12.05.02 Control cam to bobbin opener and tripping lever ...................................................... 12 - 23
12.05.03 Radial position of the tripping lever .......................................................................... 12 - 24
12.05.04 Engaging solenoid .................................................................................................... 12 - 25
12.05.05 Scissor drive lever .................................................................................................... 12 -26
12.05.06 Control cams to the bobbin opener and cutter (adjustment with adjustment gauge) ... 12 - 27
12.05.07 Radial position of the control cam to the bobbin opener
( adjustment without adjustment gauge )................................................................. 12 - 28
12.05.08 Scissor tripping-lever in relation to the control cam of the scissor ........................... 12 - 29
12.05.09 Control cam to cutter ( adjustment without adjustment gauge ) .............................. 12 - 30
12.05.10 Scissor return lever .................................................................................................. 12 - 31
12.05.11 Scissor return control ............................................................................................... 12 - 32
12.05.12 Installing the scissor ................................................................................................ 12 - 33
12.05.12 Eccentric sleeve ....................................................................................................... 12 -34
12.05.14 Scissor drive bar ....................................................................................................... 12-35
12.05.15 Scissor function test ................................................................................................ 12 - 36
12.06 Tension unit control ............................................................................................... 12 - 38
12.07 Parameter settings ................................................................................................. 12 - 40
12.08 Error messages ...................................................................................................... 12 - 42
12.09 Carry out cold start ................................................................................................ 12 - 43
13.01 Wearing parts ......................................................................................................... 13 - 1

Safety
1 - 1
1 Safety
1.01 Directives
This machine is constructed in accordance with the European regulations contained in the
conformity and manufacturer’s declarations.
In addition to this Instruction Manual, observe also all generally accepted, statutory and other
regulations and legal requirements and all valid environmental protection regulations!
The regionally valid regulations of the social insurance society for occupational accidents or
other supervisory organisations are to be strictly adhered to!
1.02 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!
●The danger and safety instructions on the machine itself are to be followed!
●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, roller presser, needle plate, 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!
●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 only to be found in 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 structural characteristics of the machine.
We shall not be liable for any damage which may be caused by non-original parts.

Safety
1 - 2
1.03 Safety symbols
Danger!
Points to be observed.
Danger of injury for operating and specialist personnel!
1.04 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 user to only operate the machine in perfect running order.
●It is the obligation of the user to ensure that none of the safety mechanisms are removed
or deactivated.
●It is the obligation of the user to ensure that only authorized persons operate and work on
the machine.
Further information can be obtained at your PFAFF agent.
I
Caution
Do not operate without finger guard and safety devices.
Before threading, changing bobbin and needle, cleaning
etc. switch off main switch.

Safety
1 - 3
1.05 Operating and specialist personnel
1.05.01 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 loose-fitting clothing or jewellery such as chains or rings!
●also ensure that only authorized 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!
1.05.02 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 only in the regulations EN 50110.
●replace the protective coverings and close the electrical control box after all repairs or
maintenance work!

Safety
1 - 4
1.06 Danger
A working area of 1 meter is to be kept free both in front of and behind the
machine while it is in operation so that it is always easily accessible.
Never reach into the sewing area while sewing! Danger of injury by the needle!
Never leave objects on the table or in the needle plate area while adjusting the
machine settings! Objects can become trapped or be slung away! Danger of
injury!
Do not operate the machine without support 1!
Danger due to top-heavy sewing head!
Machine can tip over backwards when tilted!
Do not operate the machine without its take-up-lever guard 2!
Danger of injury due to the motion of the take-up lever!
Do not operate the machine without belt guards 3!
Danger of injury by the moving V-belt!
Do not operate the machine without tilt lock 4!
Danger of crushing between sewing head and table top!
2
3
Fig. 1 - 01
1
4

Proper use
2 Proper use
The PFAFF 3734-2/01 is a high-speed, single needle, postbed sewing machine (post to the
right of the needle) with forwards and reverse feeding feed-wheel
and roller presser.
The PFAFF 3734-2/21 is a high-speed, single needle, postbed sewing machine (post to the
right of the needle) with forwards and reverse feeding feed-wheel
and band feed.
This machine is used for sewing lockstitch seams in the clothing industry.
Any and all uses of this machine which have not been approved of by the
manufacturer are considered to be inappropriate! The manufacturer cannot be
held liable for any damage caused by the inappropriate use of the machine! The
appropriate use of the machine includes the observance of all operational,
adjustment, maintenance and repair measures required by the manufacturer!
2 - 1

Specifications
3 Specifications
3.01 PFAFF 3734-2/01 ▲
PFAFF 3734-2/21 ▲
Stitch type: ................................................................................................ 301 ( lockstitch )
Handwheel eff. dia. .................................................................................................. 65 mm
Roller presser clearance: ............................................................................................ 9 mm
Clearance width: .................................................................................................... 245 mm
Clearance height: ................................................................................................... 115 mm
Post height: ............................................................................................................ 180 mm
Sewing head dimensions:
Length: ...................................................................................................... approx. 615 mm
Width: ....................................................................................................... approx. 240 mm
Height ( above table ): ............................................................................... approx. 500 mm
Bed-plate dimensions: .................................................................................. 518 x 177 mm
Max. speed: ................................................................................................... 2800 s.p.m. ◆
Connection data:
Operating voltage: ...........................................................................230 V ± 10%, 50/60 Hz
Max. power consumption: ...................................................................................... 1,2 kVA
Fuse protection: ............................................................................................ 1 x 16 A, inert
Noise data:
Emission sound level at the workplace at a speed of 2700 spm: ......................... 80 dB(A)■
(Noise measurement in acc. with DIN 45 635-48-A-1, ISO 11204, ISO 3744, ISO 4871)
Net weight of sewing head: ........................................................................... approx. 61 kg
Gross weight of sewing head: ....................................................................... approx. 71 kg
▲Subject to alternation
◆Varies according to material, work process and stitch length
■KpA = 2,5 dB
3.02 Model, needles and threads
Model: ............................................................................................................................... A
Needle system: ..................................................................................................... 134-35 R
Needle size in 1/100 mm:................................................................................................ 80
Max. thread size synthetic *: .................................................................................... 60 - 60
*Or comparable thicknesses of other thread types
3 - 1

Disposal of machines
4 Disposal of machines
●The proper disposal of machines is the responsibility of the customer.
●The materials used in the machines are steel, aluminium, brass and various plastics.
The electrical equipment consists of plastics and copper.
●The machine is to be disposed of in accordance with the locally valid
environmental protection regulations. If necessary, a specialist is to be commissioned.
Special care is to be taken that parts soiled with lubricants are separately
disposed of in accordance with the locally valid pollution control regulations!
4 - 1

Transport packaging and storage
5 Transport packaging and storage
5.01 Transport to the customer’s premises
Within Germany, complete machines (with table and motor) are delivered without
packaging.
Machines without a table (sewing head with motor only) and machines for export are
packaged.
5.02 Transport within the customer’s premises
The manufacturer bears no liability for transport within the customer’s premises or to the
individual locations of use.
Always ensure that the machine is only transported upright.
5.03 Disposal of the packaging
The packaging of these machines consists of paper, cardboard and VCE fibre.
The proper disposal of the packaging is the responsibility of the customer.
5.04 Storage
The machine can be stored for up to 6 months if not in use. During this time it should be
protected from dust and moisture.
For longer storage the individual parts of the machine, especially the moving parts, should
be protected against corrosion, e.g. by a film of oil.
5 - 1

Explanation of the symbols
6 - 1
6 Explanation of the symbols
In the following section of this Instruction Manual, certain tasks or important pieces of
information are accentuated by symbols.
The symbols used have the following meanings:
Note, information
Cleaning, care
Lubrication, greasing
Servicing, repairing, adjustment, maintenance
(only to be carried out by specialist personnel)

Controls
7 - 1
Fig. 7 - 01
7 Controls
7.01 On/off switch
●Turn the machine on/off by turning
On/Off switch 1.
0
1
7.02 Pedal
0= Neutral position
1= Sewing
2= Raise roller presser
3= Trim thread and raise roller
presser
1 + 4 = Variable application of fullness
Fig. 7 - 02
401
32

Controls
7 - 2
7.04 Lever for lifting the roller presser
●The roller presser is raised by turning
lever 1.
7.03 Knee switch
●By operating knee switch 1it is possible
to select 2pre-set values for fullness.
Fig. 7 - 03
1
Fig. 7 - 04
1

Controls
7 - 3
7.05 Control panel
The control panel consists of the display 1 and a row of function keys.
Fig. 7 - 05
7.05.01 Displays on the screen
●In sewing mode ( LED in the Parameter input key is off ) the actual values are shown on
the screen when the corresponding function keys are operated.
●When the left pedal is used for applying variable amounts of fullness, the fullness is
displayed as a bar diagram on the screen.
●When parameters are entered, the selected parameter with its corresponding value is
displayed.
7.05.02 Key functions
The keys described below are used basically to select machine functions for setting-up the
machine, for sewing operation and for entering parameters.
Starttack stitches forwards/in reverse
●In sewing mode the number of forward stitches ( key A ) or reverse stitches ( key B ) for
the starttack can be changed with these keys. The current value is displayed on the
screen when the corresponding key is operated.
Endtack stitches forwards/in reverse
●In sewing mode the number of reverse stitches ( key C ) or forward stitches ( key D ) for
the endtack can be changed with these keys. The current value is displayed on the
screen when the corresponding key is operated.
Stitch length roller presser
●In sewing mode the stitch length ( feed stroke ) of the roller presser can be changed with
this key. The current value is displayed on the screen when the key is operated.
Stitch length feed wheel
●In sewing mode the stitch length ( feed stroke ) of the feed wheel can be changed with
this key. The current value is displayed on the screen when the key is operated.
1

Controls
7 - 4
Starttack on/off
●With this key the starttacks can be switched on or off.
When the LED is on, starttacks are sewn.
Endtack on/off
●With this key the endtacks can be switched on or off.
When the LED is on, endtacks are sewn.
Backtack suppression
●Press the key once: starttacks are not sewn.
●Press the key twice: start- and endtacks are not sewn
Program key
●When this key is activated (LED is on), a ”program” (stitch length values) can be entered
and selected with the knee switch.
Parameter input
●After this function has been activated (LED is on) you are in the parameter input function.
After the function has been switched off, you return to sewing mode.
Keys F1 – F5
●These keys have no function in sewing mode.
●When the code number is entered, these keys correspond to the numbers 1 – 5.
Needle position
●The needle position can be selected with this key.
When the function is switched on (LED on): The needle positions at t.d.c. when sewing stops.
When the function is switched off (LED off): The needle positions at b.d.c. when sewing stops.
●When the code number is entered, this key corresponds to number 6.
Presser foot position when sewing stops
●The position of the presser foot when sewing stops can be selected with this key.
When the function is switched on (LED on): The presser foot is raised when sewing stops.
When the function is switched off (LED off): The presser foot is lowered when sewing stops.
●When the code number is entered, this key corresponds to number 7.
Presser foot position after thread trimming
●The position of the presser foot after thread trimming can be selected with this key.
When the function is switched on (LED on): The presser foot is raised after thread trimming.
When the function is switched off (LED off): The presser foot is lowered after thread trimming.
●When the code number is entered, this key corresponds to number 8.
Thread trimmer on/off
●With this key the thread trimmer can be switched on or off.
When the LED is on, the thread can be trimmed with the pedal function.
●When the code number is entered, this key corresponds to number 9.
Enter key
●This key has no function in sewing mode.
●When the code number is entered, the number sequence is taken over by pressing this key
( enter function ).
to

Mounting and commissioning the machine
8 - 1
8 Mounting and commissioning the machine
The machine must only be mounted and commissioned by qualified personnel!
All relevant safety regulations are to be observed!
If the machine is delivered without a table, it must be ensured that the frame
and the table top which you intend to use can hold the weight of the machine
and the motor, even while sewing.
8.01 Mounting
The necessary electricity supply must be available at the machine’s location.
There must be a stable and horizontal surface and adequate lighting at the
machine’s location.
Due to reasons of packaging, the table top is lowered for transport.
The following is a description of how to adjust the height of the table top.
8.01.01 Adjusting the table-top height
●Loosen screws 1and 2and set the desired table-top height
●Tighten screws 1well.
●Adjust the position of the pedal so that you can operate it comfortably and
tighten screw 2.
Fig. 8 - 01
1
2
2
1

Mounting and commissioning the machine
8 - 2
47.002
Fig. 8 - 03
8.01.03 Mounting the upper V-belt guard
●Screw position stop 1onto the right half
of V-belt guard 2.
●Slide the slots of lower belt guard 3
behind the heads of mounting screws 4
and fasten with screws 5. Then tighten
screws 4through the holes.
●Mount the right and left halves of belt
guard with screws 6 and 7.
1
2
4
4
6
6
7
7
5
3
Fig. 8 - 02
8.01.02 Fitting the tilt lock
●Screw on tilt lock parts 1and 2, provided
in the accessories, using screws 3 and 4.
Do not operate the machine
without tilt lock 1!
Danger of crushing between
sewing head and table top!
1
2
3
4