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Service Manual 

Buttonhole machine 

 

ZOJE  

ZJ781-BD 

 

 

 

Summary of Contents for ZJ781-BD

Page 1: ...Service Manual Buttonhole machine ZOJE ZJ781 BD ...

Page 2: ......

Page 3: ...15 Left and right position of the upper knife 16 Height of the upper scissors 17 The position of the roll into the upper thread at the start of sewing 18 The time when the scissors are opened 19 Adjustment of the limit plate 20 Safety crank adjustment 21 Upper scissors spring pressure 22 Fixed knife position 23 Height of the presser plate 24 Low speed bump position 25 Starting lever and starting r...

Page 4: ...ws to adjust Note the needle should fall in the center of the needle plate The phenomenon when the adjustment value changes When sewing elastic fabric the needle bar is lowered a little more than the standard value and the effect is better 2 The cooperation of the needle and the hook Adjustment requirements When the needle bar is lifted by 2 3mm from the lowest point the center of the hook tip and...

Page 5: ... the baseline adjustment handle adjusting the parallel gap between the cutter and the left and right amplitudes Adjustment requirements 1 Position of the parallel portion on the left side The lower end of the left baseline adjustment screw is 10 mm from the upper plane of the baseline adjustment handle and the lower plane of the baseline adjustment handle is exposed to be about 1 mm 2 Position of ...

Page 6: ...sed toward either side and the stitches adjacent to the parallel portion of the cutter may be biased to the inner side When the amplitude is increased the left parallel portion is individually biased to the left 4 The needle bar cooperation Adjustment requirements 1 When the needle is at the top center the engraved line of the pinion gear should be aligned with the center of the lower shaft 2 If t...

Page 7: ...oint on the paper that is to ensure that the swing of the needle before the needle bar is lowered to the front of the puncturing cloth should end The phenomenon when the adjustment value changes When the reticle is missed it will cause the needle to flow the needle to break and the needle to jump 5 The adjustment of the needle drop for the needle board Adjustment requirements When sewing the paral...

Page 8: ... needle bar swing fork is about 5 mm Adjustment method When the machine is in the parking position the needle is in the left needle position loosen the fastening screw on the baseline adjustment handle push down the needle bar swing fork so that the large arc of the needle swing cam is convex to the top of the needle bar swing fork About 5mm adjust the shank to the baseline adjustment shank and th...

Page 9: ...er foot does not move back and forth the position of the crank under the feed is correct When the crank body does not move tighten the fastening screw of the lower crank The phenomenon when the adjustment value changes If the position is wrong whenever the sewing size is changed the action of the scissors will fail and the position of the presser foot will also change causing a broken needle or th...

Page 10: ...completely decelerated it will fall 2 3 before the stop 1 2 3 pin is the reference Adjustment method Move the cutter action bump position and adjust the cutter fall time to 2 3 stitches before the sewing machine stops Moving in the direction of the mark the cutter falls early Note When the number of stitches is adjusted to 93 or less adjust the low speed bumps The phenomenon when the adjustment va...

Page 11: ...does not return or continuously falls check the gap between the cutter drive lever and the cutter action hook or change the cutter drive lever tension spring 2 The cutter often does not fall down and it is not possible to drop the knife at a low speed It may be that the tension spring of the cutter driving claw is insufficient replace the tension spring 12 Adjustment of the stop device Adjustment ...

Page 12: ... the stop sub block A and the stop lever block B is too small and there is no stopping 2 When the hex nut loosens and the sewing machine stops the height of the needle changes 13 Start the position of the security hook Adjustment requirements When parking the distance between the start safety hook and the lifter lever is 0 5 0 8mm Adjustment method Adjust with the rotating eccentric shaft screw Th...

Page 13: ...ssively adjusted the protruding portion of the scissor swing frame will slide out from the groove of the presser roller frame Once it is slipped out the presser foot cannot be lifted and the feeding becomes heavy 15 Left and right position of the upper knife Adjustment requirements 1 The upper scissors is aligned with the center of the needle when it advances to the foremost end and the front end ...

Page 14: ...erlap between the upper knife and the lower knife The phenomenon when the adjustment value changes 1 When the front back and left and right positions are not good when the presser foot is raised the scissors swing frame is caught and cannot move smoothly 2 The position of the scissors action board A is too far forward to produce the upper line cut continuously scissors are not close together 3 Whe...

Page 15: ...method after adjustment Place a gasket with a thickness of about 4 mm under the presser foot When moving the presser foot lever up and down the presser foot and the scissors should not touch each other The phenomenon when the adjustment value changes The position of the scissors is too high and sometimes the thread will remain on the knot 17 The position of the roll into the upper thread at the st...

Page 16: ...titch On the contrary the upper line will be beyond the left side of the stitch 18 The time when the scissors are opened Adjustment requirements Adjustment method 1 Loosen the wire head control plate fixing screw and move the control board back and forth to adjust 2 The time to move the control board forward to clamp the upper line is longer and on the contrary it is shortened Confirmation method ...

Page 17: ...speed start state there should be no gap in the long hole at the safety pusher shaft screw 2 There should be a gap between the safety lever and the limit plate when parking and upper scissors moving The phenomenon when the adjustment value changes Note After an emergency stop the presser foot should be raised at the needle up position 20 Safety crank adjustment Adjustment method After the upper sc...

Page 18: ...n be clamped regardless of where the scissors cut the thread 2 When the upper scissors edge is not sharp the scissors can be replaced 22 Fixed knife position Adjustment requirements The fixed knife edge is 0 3 0 5mm away from the needle plate hole Adjustment method 1 Loosen the fixed knife fixing screw for the fixed knife adjustment 2 When changing the fixed knife take out the hook finger to repla...

Page 19: ...ess the presser foot lifting pedal and press the presser foot clamp and the presser foot roller frame then tighten the presser foot fixing screw Confirmation after adjustment After adjustment it must be confirmed that the presser foot can work normally 24 Low speed bump position Adjustment method Adjust the size of A according to the number of stitches used to loosen the fixing screws of the low s...

Page 20: ...the adjustment value changes If the gap at the starting ram is too large it cannot be rotated at a high speed If it is small it will cause an inaccurate stop 26 Belt adjustment Head start fork position Adjustment method When idling the belt is exposed from the runner by about 0 5 1mm which is adjusted by the long hole of the starting fork on the nose At low speed the belt should completely cover t...

Page 21: ...vement of the fork is 14mm Adjust the pad with the shift fork to adjust When you spin it out the stroke is reduced Note If the fork is swung too far at low speed and parking the fork cam is not properly installed Therefore the fork cam should be installed parallel to the processing surface of the fork cam holder The phenomenon when the adjustment value changes When the speed adjustment mechanism f...

Page 22: ...left baseline moves to the right but even if the amplitude is changed the left baseline A hardly needs to be adjusted 2 Screw in the screw 2 the right baseline will move to the left and when it is rotated it will move to the right Adjustment of horizontal width and reinforcement width 1 Rotate the adjustment screw 3 the width of the course will increase and the rotation will decrease 2 Screw in th...

Page 23: ...ne phenomenon when starting the seam When the thread is removed the amount of the thread will increase When adjusting do not touch the first tension and through the hole 4 Adjustment of thread adjustment hook The amount of thread supply is adjusted according to the thickness of the sewn product so that the stitches to be sewn will become better the amount of thread adjustment hooks will increase t...

Page 24: ... bobbin pressure bar device The bobbin presser device is in synchronous connection with the bottom thread trimming device When the lower thread is plucked the bobbin pressure bar presses the bobbin on the back to prevent idling and at the same time the upper thread remaining on the cloth is pulled down to the cloth and a certain amount of lower thread is ensured to prevent the needle from jumping ...

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