Singer 271K - Stop Motion

TIMING MARK (
STOP
CAM
LOOSEN
TO ADJUST
MORE
TENSION
PINION
TURN
ECCENTR C
STUD
CLOCKWISE
STOP NOTCH
INTERLOCKING
ROD
^•^LESS
TENSION
Fig. 41. Interlocking Rod and
"Stop" Position Notch
STOP CAM
GEAR
LOOSEN SET SCREW
TO ADJUST
HIGH POINT OF STUD
AT 6 O'CLOCK
Fig. 42. Stop Cam Gear and Pinion
HIGH POINT
CAM
Fig. 43. High Point of Stop Cam
STOP MOTION
To ensure a positive stop and to minimize
the possibility of breakage of parts, a two-
speed drive mechanism automatically slows
down arm shaft to one-half driving speed as
machine approaches
"stop" position. A stop
cam driven at half speed of arm shaft (now 1/4
of operating speed, to reduce strain as machine
goes into "stop") is now engaged by the stop
motion interlocking rod.
Stop motion interlocking rod, shown In Fig.
41, is designed to aid in retarding speed of
arm shaft before finally stopping machine.
TENSION ON INTERLOCKING ROD should
be only sufficient to prevent rod from jumping
cut of notch, shown in Fig. 41, in stop cam.
When making buttonholes on heavy fabrics
it may become necessary to lighten the tension
on interlocking rod. Light weight fabrics usually
require a heavier tension.
To
adjust, loosen lock nut and turn thumb
screw at lower end of rod as instructed in Fig.
41. Tighten lock nut.
EXCESSIVE PLAY BETWEEN STOP CAM
GEAR AND PINION should be eliminated.
To adjust, loosen set screw shown in Fig.
42 and turn eccentric stud clockwise (facing
rear of machine) as shown, until
minimum play,
without binding between teeth of gears, is
obtained. Turning the stud clockwise will draw
stop cam closer to interlocking rod (rather
than away
from it) making certain that rod will
ride on high point, of stop cam, as shown in
Fig. 43, before dropping into "stop" position
notch, as shown in Fig. 41.
When minimum play between gears is a-
chieved, high point of eccentric stud should be
at bottom (approximately at 6 o'clock position),
as shown in Fig. 42. Never moke this setting
with high point of stud on top, as this may
allow interlocking rod to enter stop cam notch
without first riding on high point of stop cam.
19
From the library of: Superior Sewing Machine & Supply LLC