3734 -2/01 -2/21 Instruction Manual This instruction manual applies to machines from the following serial numbers onwards: # 2207198 296-12-18 352/002 Betriebsanleitung engl. 05.2002...
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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...
Feed wheel height ....................12 - 10 .04.09 Clearance between the roller presser or band feed and the feed wheel ....12 - 11 .04.10 Roller presser ( 3734-2/01 ) ..................12 -12 .04.11 Band feed ( 3734-2/21) ..................... 12 - 13 .04.12 Changing the band ( 3734-4/21)................
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Contents Contents ................Chapter - Page Adjusting the thread trimmer -900/53 ..............12 - 22 .05.01 Removing the scissors ..................... 12 - 22 .05.02 Control cam to bobbin opener and tripping lever ............12 - 23 .05.03 Radial position of the tripping lever ................12 - 24 .05.04 Engaging solenoid ....................
Safety Safety 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! General notes on safety...
● 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. 1 - 2...
Safety Operating and specialist personnel Operating personnel .05.01 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: ●...
Safety 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!
Proper use 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.
Disposal of machines 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. ●...
Transport packaging and storage Transport packaging and storage 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. 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.
Explanation of the symbols 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) 6 - 1...
Controls Knee switch ● By operating knee switch 1 it is possible to select 2 pre-set values for fullness. Fig. 7 - 03 Lever for lifting the roller presser ● The roller presser is raised by turning lever 1. Fig. 7 - 04 7 - 2...
Controls Control panel The control panel consists of the display 1 and a row of function keys. Fig. 7 - 05 Displays on the screen .05.01 ● 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.
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Controls 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 ●...
Mounting and commissioning the machine 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.
Mounting and commissioning the machine Fitting the tilt lock .01.02 ● Screw on tilt lock parts 1 and 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! Fig.
Mounting and commissioning the machine Mounting the synchronizer .01.04 ● Slide synchronizer 1 onto the shaft. ● Tighten screws 2 slightly. ● Plug the synchronizer plug into the electrical socket of the control box. ● Adjust the synchronizer ( see chapter 12.04.01 Adjusting the synchronizer ).
Mounting and commissioning the machine Attaching the earthing wire / connecting the plug connections .01.06 Fig. 8 - 06 Fig. 8 - 07 ● Screw the earthing wires from the sewing head, the main switch and the control box to the stand.
Preparation Preparation All regulations and instructions in this Instruction Manual are to be observed! Special attention is to be paid to the safety regulations! All preparation work is only to be carried out by appropriately trained personnel. Before all preparation work, the machine is to be separated from the electricity supply by removing the plug from the mains or switching off the On/Off switch! Inserting the needle...
Preparation Winding the bobbin thread, adjusting the thread tension Fig. 9 - 02 ● Place an empty bobbin 1 onto bobbin winder spindle 2. ● Thread the bobbin in accordance with Fig. 9 - 02 and wind it clockwise around bobbin 1 a few times.
Preparation Removing / Inserting the bobbin case Turn the machine off! Removing the bobbin case: ● Open the post cap. ● Raise latch 1 and remove bobbin case 2. Inserting the bobbin case: ● Insert bobbin case 2. ● Close the latch and close the post cap. Fig.
Preparation Threading the bobbin case / Adjusting the bobbin thread tension ● Insert the bobbin into the bobbin case 1. ● Pass the thread through the slot under spring 2. ● Pass the thread through the notch. ● Adjust the thread tension by turning screw 3.
Preparation Threading the needle thread / adjusting the needle thread tension Fig. 9 - 05 Switch off the machine! ● Thread needle thread as shown in Fig. 9-05. ● Adjust the needle thread tension by turning knurled screws 1 and 2. 9 - 5...
Preparation Setting the stitch length / fullness The stitch length is determined by setting the feed strokes of the roller presser and feed wheel. To apply fullness the feed stroke of the roller presser must be larger than that of the feed wheel.
Preparation Entering the fullness range for pedal adjustment .06.03 It is possible to pre-set the fullness range which can be selected using the left pedal. ● Switch on the machine ● Press the Parameter input key ( LED on ). ●...
Preparation Entering / adjusting the code number. ● Switch on the machine. ● Press the Parameter input key ( LED on ). ● Select the required parameter by pressing the plus/minus key. ● Enter the code number ( factory code setting is ”1493 ). CODE When entering the code number these keys...
Sewing Sewing Applying fullness The machine must be installed and connected in accordance with Chapter 8 Installation and Commissioning. ● Set up the machine, see Chapter 9 Setting up. ● Switch on the machine, see Chapter 7.01 On / off switch. ●...
Care and maintenance Care and maintenance Cleaning .............. daily, several times if in continuous use Checking the oil level ( lubricating the head parts ) ........daily before use Lubricating the hook................. daily before use Lubricating the bevel gears ................once a year Cleaning the air filter ..................
Fig. 11 - 03 Use only oil with a mean viscosity of 22.0 mm /s at 40°C and a density of 0.865 g/cm at 15°C. We recommend PFAFF sewing machine oil Part no. 280-1-120 144. 11 - 2...
Use both hands to return the machine to an upright position. Danger of crushing between machine head and table top. We recommend PFAFF hard soap grease with a drop point of approx. 150°C. Part no. 280-1-120 243. 11 - 3...
Adjustment Adjustment Notes on adjustment All following adjustments are based on a fully assembled machine and may only be carried out by expert staff trained for this purpose. Machine covers, which have to be removed and replaced to carry out checks and adjustments, are not mentioned in the text.
Adjustment Adjusting the basic machine Adjusting the synchronizer .04.01 Requirement When, in the direction of sewing, the descending needle point is at the top edge of the needle plate, the machine must position. Fig. 12 - 01 ● Switch on the machine and sew a few stitches. ●...
Adjustment Positioning the needle in the direction of sewing .04.02 Requirement The needle must penetrate the middle of the needle hole as viewed in the direction of sewing. Fig. 12 - 02 ● Move the needle bar frame 1 ( screws 2 and 4 and nut 3 ) in accordance with the requirement.
Adjustment Positioning the needle across the direction of sewing 04.03 Requirement The needle must penetrate the middle of the needle hole as viewed across the direction of sewing. Fig. 12 - 03 ● Move the feed wheel post 1 ( screws 2, 3 and 4 ) in accordance with the requirement. Screws 4 remain loosened for the following adjustments.
Adjustment Preadjusting the needle height 04.04 Requirement With the needle bar at TDC there must be approx. 22 mm between the point of the needle and the needle plate. 22 mm Fig. 12 - 04 ● Move the needle bar 1 ( screw 2 ) in accordance with the requirement without turning it. 12 - 5...
Adjustment Needle rise, hook-to-needle clearance, needle height and needle guard 04.05 Requirement When the needle bar is positioned at 1.8 mm after b.d.c. 1. The point of the hook must be pointing to the centre of the needle and have a clearance of 0.05 –...
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Adjustment Fig. 12 - 05 ● Taking the play of the bevel gear into account, tighten screws 2. ● Remove the adjustment pin from hole 5. ● Install the retaining collar 6 on bevel gear 7 and tighten screws 1 and 3. ●...
Adjustment Bobbin case opener height 04.06 Requirement The top edges of the bobbin case opener 1 and the bobbin case base 3 must be at the same height. Fig. 12 - 06 ● Move the bobbin case base 1 ( screws 2 ) in accordance with the requirement. 12 - 8...
Adjustment Bobbin case opener stroke 04.07 Requirement When the bobbin case opener presses the bobbin case to the furthest extent, the projection of the bobbin case must protrude 0.3 - 0.5 mm from the rear edge of the needle plate recess. 0,3 - 0,5 mm Fig.
Adjustment Feed wheel height 04.08 Requirement On the 3734-2/01 the feed wheel should project approx. 0.8 mm from the needle plate and 0.4 mm on the 3734-2/21. Fig. 12 - 08 ● Swing out the roller presser. ● Loosen screw 1.
Adjustment Clearance between the roller presser or band feed and the feed wheel 04.09 Requirement When lever 1 is raised, there should be a clearance of 7 mm between the roller presser and the feed wheel or the band feed. Fig.
Adjustment Roller presser ( 3734-2/01 ) 04.10 Requirements When the roller presser 1 is resting on the feed wheel 5 it must 1. be parallel to the feed wheel 5 when viewed in the direction of sewing, 2. be in the middle of the needle when viewed in the direction of sewing and 3.
Adjustment Band feed ( 3734-2/21) 04.11 Requirement Band feed 5 should be set so that 1. The centre of roller 6 is approx. 2.5 mm from the centre of feed wheel 7 2. The band feed 5, seen in the direction of sewing, is parallel to feed wheel 7 and the seam runs directly below O-ring 8.
Adjustment Changing the band ( 3734-2/21) 04.12 Fig. 12 - 10b ● Turn eccentric 1 (screw 2) towards the inside. ● Fit feed band 3 and tighten with eccentric 1. ● Tighten screw 2. Part no. Feed band 91-189 210-95 0-ring 15-120 723-05 12 - 14...
Adjustment Automatic presser-foot lifter 04.13 Requirement When solenoid 1 is activated, lever 3 for the roller presser must drop automatically. Fig. 12 - 11 ● Move solenoid 1 ( screws 2 ) in accordance with the requirement. ● Turn the machine on and check the requirement. ●...
Adjustment Retainer .04.14 Requirement The retainer 3 should just rest on the material, so that the material does not start fluttering during sewing. Fig. 12 - 12 ● Adjust pin 1( screw 2 ) according to the requirement. 12 - 16...
Adjustment Tension release 04.15 Requirement With lever 1 raised or the automatic presser foot lifter activated, both tension discs 6 must be at least 0.5 mm apart. 0.5 mm Fig. 12 - 13 ● Raise the roller presser using lever 1. ●...
Adjustment Thread check spring 04.16 Requirements 1. The motion of the thread check spring 7 must be finished when needle point enters the material ( spring stroke approx. 7 mm ). 2. When the thread loop is at its largest when going around the hook, the thread check spring must raise slightly from the workpiece rack 1.
Adjustment Bobbin winder 04.17 Requirements 1. With the bobbin winder on, the bobbin winder spindle must engage reliably. With the bobbin winder off, the friction wheel 5 must not engage the drive wheel 1. 2. The bobbin winder must turn off automatically when the thread level is approx. 1 mm from the edge of the bobbin.
Adjustment Roller presser pressure 04.18 Requirement The material must be fed reliably. There must not be any pressure marks on the material. Fig. 12 - 16 ● Adjust the roller presser pressure with screw 1 in accordance with the requirement. Screw 1 is underneath a cover.
Adjustment Locking the set-value transmitter 04.19 Requirement The pedal for selecting the fullness should be held reliably in every position without binding too much. Fig. 12 - 17 ● Adjust screw 1 according to the requirement. 12 - 21...
Adjustment Adjusting the thread trimmer -900/53 Removing the scissors 05.01 Fig. 12 - 18 ● Open post cover 1 and unscrew post cover plate 2 ( screws 3 ). ● Loosen screw 4. ● Swing out bobbin case base 5 by hand and hold it in this position. ●...
Adjustment Control cam to bobbin opener and tripping lever 05.02 Requirements 1. Control cam 2 must be touching bearing collar 3. 2. The roller of tripping lever 6 must fall slightly into the path of control cam 2. Fig. 12 - 19 ●...
Adjustment Radial position of the tripping lever 05.03 Requirement With the tripping lever 3 in resting position, there must be a clearance of 0.3 mm between its roller and the circumference of the control cam 4. Fig. 12 - 20 ●...
Adjustment Engaging solenoid 05.04 Requirement With the trimming device swichted on, the field core must still be 1 mm before its lower stop. Fig. 12 - 21 ● Bring the needle bar to BDC and activate the tripping lever by hand. ●...
Adjustment Scissor drive lever 05.05 Requirement The top edge of screw 1 must protrude approx. 9 mm from the recess on the housing. Fig. 12 - 22 ● Turn screw 1 ( nut 2 ) in accordance with the requirement. 12 - 26...
Adjustment Control cams to the bobbin opener and cutter 05.06 ( adjustment with adjustment gauge ) Requirements With the needle bar at BDC, both control cams must be positioned in such a way that 1. adjustment gauge 5 can be slid into the grooves of both control cams, 2.
Adjustment Radial position of the control cam to the bobbin opener 05.07 ( adjustment without adjustment gauge ) Requirement The retracting motion of the bobbin opener must begin when the needle bar is 4 mm after BDC. Fig. 12 - 24 ●...
Adjustment Scissor tripping-lever in relation to the control cam of the scissor 05.08 Requirements At the left point of reversal of the rock shaft 3 1. the roller of tripping lever 4 and the roller of back-racking lever 5 must be in the middle of control cam 6 and 2.
Adjustment Control cam to cutter 05.09 ( adjustment without adjustment gauge ) Requirements 1. The cutting motion must begin when the needle bar is 0.6 mm after TDC. 2. There must be a clearance of 9 mm between control cams 2 and 4. 9 mm Fig.
Adjustment Scissor return lever 05.10 Requirement When the roller of tripping lever 3 is exactly at the point of the trip of control cam 2 the maximum distance between the roller of return lever 4 and control cam 2 must be 0.2 mm.
Adjustment Scissor return control 05.11 Requirements When the point of the trip of control cam 1 is exactly at the roller of tripping lever 2 and trip 3 is touching the beginning of the angular edge of guide plate 5 ( see arrow ) there must be a clearance of approx.
Adjustment Installing the scissor 05.12 Requirements 1. The pin of bolt 4 must protrude into the cam tracks of the scissor halves. 2. The scissor must work with as little lateral play as possible. Fig. 12 - 29 ● Swing out drive bar 1. ●...
Adjustment Eccentric sleeve 05.13 Requirements 1. In its starting position the scissor must be flush with the contour of the needle plate. 2. The scissor must lightly touch the needle plate and the eccentric sleeve 2. Fig. 12 - 30 ●...
Adjustment Scissor drive bar 05.14 Requirements 1. In its starting position the scissor must be flush with the needle plate contour. 2. At the TDC of the drive bar 2 there must be a safety clearance of at least 0.3 mm between pin 5 and the top end of the cam guide.
Adjustment Scissor function test 05.15 Requirements 1. The threads must be cut neatly. 2. After being trimmed, the bobbin thread must be held securely by the thread trapper. Fig. 12 - 32 ● Turn the machine on. ● Sew a few stitches and turn the on/off switch off. ●...
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Adjustment ● As the process continues, both the bobbin thread and the part of the thread loop closest to the scissor which is held by the catching lug must be cut reliably. ● If the threads are not cut or not cut cleanly check chapter 12.05.14 Scissor drive bar again.
Adjustment Tension unit control Requirement When the roller presser touches the material 1. For materials up to 2 mm one tension unit should be active ( magnet activated ) 2. For materials over 2 mm the second tension unit should be connected ( magnet drops out ) 0.5 mm Fig.
Adjustment Parameter settings Group Parameter Meaning Setting Standard value Pedal-controlled starttacks (I = OFF, II = ON) Reverse (I = OFF, II = ON) Max. stitch length of fullness pedal 0.8 – 6.5 mm 4.0mm Display software version Machine class 1: 1493M 2: 3734 Roller presser drop speed...
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Adjustment Group Parameter Meaning Setting Standard value Move stepping motor roller presser and feed wheel Display inputs 0123456789ABCDEF 0: Not assigned 1: Knee switch 2: Sewing motor reference position 3: Material thickness 4: Not assigned (E12) 5: Not assigned (E11) 6: Not assigned (E10) 7: Not assigned (E9) 8: Not assigned (E8)
Adjustment Group Parameter Meaning Setting Standard value Brake ramp 1 – 50 Reference position 0 – 191 Time-out 0 – 255 Starting current motor 3 – 10 Antivibration filter 1 – 10 Rotation direction allocation 0 – 1 Reference position correction 0 –...
Adjustment Carry out cold start ● Switch on the machine. ● Press Parameter input key ( LED on ). ● Select the required parameter by pressing the plus/minus key. ● Enter the code number ( factory code setting is ”1493” ) CODE ●...
Wearing parts Wearing parts This list indicates the most important wearing parts. You can request a detailed parts list for the complete machine under parts number 296-12-17 816. 3734-2/01 91-164 711-91 91-176 329-05 3734-2/21 15-120 723-05 11-108 093-15 91-173 664-15...