– 11 –
If the main shaft eccentric cam
is not fixed, this adjustment should be
carried out after defining its position and fixing it.
1. Loosen the two set screws
of the crank balancer
.
2. Using the four set screws
, remove the crank rod cover
.
3. Turn the main shaft in the direction of forward rotation
A
so that the
needle bar
lowers and the clearance between the needle bar con-
necting
and the needle bar bushing, lower
is 4.6mm.
4. In the state that the two set screws
of the crank balancer
as-
sume the horizontal condition and they are moved in the direction of
the arrow mark
B
, keep the close contact with the main shaft eccen-
tric cam
and tighten the two set screws
. When tightening these
two set screws
, the screws should be tightened reciprocally.
Adjustment Procedures
Results of Improper Adjustment
o If the angle for fixing the crank
balancer
is inadequate,
vibration of sewing machine
operation will be intensified.
o If the sewing machine is used for
a long time while the fixing posi-
tion is inadequate, the operational
life of the main shaft bearing may
be shortened.
o If the crank balancer
is not
moved in the direction of the ar-
row mark
B
, there may be inter-
ference with the sewing machine
frame.
1. Lower shaft backlash
1) Loosen the two set screws
.
2) Turn the lower shaft rear metal
in the direction of the arrow and adjust
the backlash, keeping the metal to contact closely with Face A.
Size of backlash is 0.1mm at the tip of the driver
. The shaft is
required to rotate smoothly.
3) Tighten the two set screws
.
(Caution) When eliminate the backlash, the direction of rotation
should always be kept in the direction of the arrow.
2. Lower shaft connection/disconnection
1) Loosen the two set screws
.
2) The lower shaft
can be taken out if it is pulled in the direction
C
of the arrow.
3) When mounting the lower shaft
, insert it in the lower shaft rear
metal
and the lower shaft gear
. Apply one of the set screws
to the flat section
of the lower shaft
and tighten it approxi-
mately in the center. Tighten the remaining set screw
.
* Connection and disconnection of the lower shaft
become easy if
the above-mentioned backlash has been relieved in advance. In this
case, backlash adjustment must be done after the lower shaft
has
been installed.
Adjustment Procedures
Results of Improper Adjustment
o If the backlash is excessive, the
hook noise will be increased.
o If backlash is too small, the lower
shaft gear
or the oscillator
will give rise to frictional wear. In
addition, this can be a cause of
crank rod lock-up.
o If the front or rear position of the
lower shaft rear metal
is dis-
placed at the time of backlash
adjustment, this can also be a
cause of the lock-up of oscilator
or the crank rod.
Summary of Contents for LK-1900A
Page 20: ... 16 10 Hook adjustment Standard Adjustment 0mm 0mm 7 5mm 0 05 0 1mm For DPX5 For DPX17 ...
Page 90: ... 86 Grease Grease Grease Grease Grease 8 Needle thread clamp mechanism area ...
Page 91: ... 87 Grease Grease A Grease Grease Grease Grease 9 LK 1901A relations ...
Page 92: ... 88 10 LK 1903A relations Grease Grease ...
Page 114: ... 111 12 Circuit diagrams 1 Block diagram A ...
Page 115: ... 112 2 Power supply circuit diagram A ...
Page 116: ... 113 3 Power supply circuit diagram B ...
Page 117: ... 114 4 Power supply circuit diagram C ...
Page 118: ... 115 5 Servo motor circuit diagram ...
Page 119: ... 116 6 Sensor pedal VR circuit diagram ...
Page 120: ... 117 7 MAIN PANEL board circuit diagram ...
Page 121: ... 118 8 Motor solenoid circuit diagram Thread trimmer Lifting the work clamp foot motor ...