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A.
5-4: LOWER LOOP SETTER SYSTEM
Descriptign
Torn or damaged sprccket holes in a film will
cause the lawer loop to be shortened- lilhen
this occurs, the fl[m pull dow* wi]l be out of
sequence with the shutter causing e iitter or
iumping picture. litlhen tltis occurr the automatic
loop setter will resct the lower loop again
bringing the film under conrrcl of the pull
down rnechanisrn.
Fis. 45
LOWER LOOF SETTER ROLLER
'?:3{l O'GLOCK" P0SITiOFI
Fis' #zo
The automatic loop settcr consist! of the sctter
roller {6}, the hub assembly (li and the gear
and shaft assembly (11)- When the lower loop
is shortened one complete frame or more, the
filrn applies pr€ssure on the setter roller (5)
which in turn causes the cccentric gear {11} to
engage, rotating fhe s€tter roller one complete
revolution, pulling down on the film thus re-
estahlishing the correct lower loop. Additianal
rotations may indicate severely damagrd film
or incorrect loop scttcr adiustments.
B. Adiustments
In the normal operate position with good film the
loop setter roller should rcst at approximately
7:30 o'clocf {Fig. #75}, v;36 the flat side of the
gear {11) parallel to the main drive belt with ap-
proximately 0.5 to 1mm of clearance. The belt
must ride flat with respsct to rhe gear. lf nor, the
tension gear and arm assembly is not aligned
correctly. To correct thir condition it may be
necessary to reform the tension gear arm. With the
belt and gear parallel the loop setter roller is
adiusted to the 7:30 position by loosening the arm
position screw (10). While holding the gear in
place, adjust t}re arm position and secure the screw.
Operate the proiector withour fitm. lf the loop
setter rotatet ffiore than once with a smali arnount
of upward pres$ure, the spring (12) tension is too
loose. Remove the spring and slightly stretch or
replace it- Re-ad just and test again.
C. Loop Setter Timing:
Corffiiffi[iliied
for prawr operation of
the loop-setter. Set the projector to self-thread.
Turn on the proiector and insert a 2 - 3 meter
strip of good film. When threaded, release the
threading mechanism. Observe the loop setter
slrould only
rotate once- Continucd rourion
indicates too small a lor*er loop. Too large a loop
will not reset the loop when missing or damaged
sprocket holes are present. The size of the fower
loop is determined by the relationship between the
claw and the #2 sprocket drive-
#Z SPBOCKET
COVEB SCFEW
7' ---------r
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