Stitch Length - Singer Curvy 8763 Service Manual

Original issue
Service Manual
Dec.2007
Page 34/47
Model

18. Stitch length

COSMO-II series
(A) Checking meshing position of gears
This procedure is needed only when disassembling and re-assembling cams.
Rotate motor gear clockwise to touch it with stopper pin and mesh these gears so that
feed regulator gear may be positioned with full two gears below line from feed regulator to
motor gear
Stopper pin
Full two gears below line
（B）Origin point positioning of stitch length
*Full-step version of stitch length mechanism
Step motor rotates 7.5 degrees with one pulse as in the half-step version, but ratio of
motor gear vs. feed regulator gear is 1:5. This amount of rotation makes feed regulator
rotate 1.5 degree. This amount of rotation makes stitch length vary by 0.25 mm. 0.25 mm
stitch pitch moves at each of 7.5 degree exciting position, but amount of rotation increases
two times in comparison to the half-step version for maximum stitch length. This is the
details of Full-step version.
Shape of stitch length mechanism is different from the half-step version due to the
difference of ratio of gears. Check which is the machine serviced according to the shape of
motor gear.