Adjusting The Thread Trimming Cam - JUKI LH-3500A Series Instruction Manual

6-3. Adjusting the thread trimming cam

❶ ❼
❷

❸
❺
❹
Surface B
❻

❻
❽
❾
A
– 36 –
(1) Position of the thread trimming cam and
the thread trimming timing
1) Align engraved marker dot ❶ on the arm with
engraved marker dot ❷ (red) on the handwheel.
2) When thread trimmer driving arm stopper ❸
comes in contact with knife driving arm ❹ , press
cam roller ❺ into the groove in thread trimming
cam ❻ .
3) Keeping the aforementioned state, turn thread
trimming cam ❻ until the location as indicated
in the sketch on the left is reached. When the
thread trimming cam is brought to the location as
indicated in the sketch (the intermediate point of
the section where the shape of groove in thread
trimming cam ❻ changes from linear shape to
diagonal shape), tighten two clamping screws of
thread trimming cam ❻ .
[Checking the timing of the thread trimming cam]
1) Press cam roller ❺ into the groove in the cam
until it securely fits in there.
2) Turn handwheel ❼ in the opposite direction of
the rotating direction of the sewing machine until
its smooth move is hindered. At this time, check
to be sure that engraved marker dot ❶ on the
arm is aligned with engraved marker dot ❷ (red)
on the handwheel.
(2) Clearance between the thread trimming
cam and thread tension release arm
1) Depress thread tension release arm ❽ .
2) At this time, adjust so that clearance A of 0.5 mm
is provided between surface B of the right end
face of thread trimming cam ❻ and roller section
❾ of thread tension release arm ❽ .
3) To adjust, loosen two setscrews  , adjust the
position of thread tension release driving arm
stopper  so that it is spaced 0.5 mm from sur-
face B, and tighten two setscrews  .
* In the case the clearance is larger than 0.5 mm:
The space pin mechanism does not rise enough,
resulting in a thread trimming failure.
* In the case the clearance is smaller than 0.5
mm:
Roller section ❾ comes in contact with thread
trimming cam ❻ to disable the thread trimmer
operation.