The Momentary Start-Stop Feature - TANDBERG 12 Service Manual

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4.8 THE SPEED CHANGE MECHANISM
T h e s p e e d c h a n g e m e c h a n i s m i s d e s i g n e d a s s h o w n
i n f i g . 3 4 .
T h e s p e e d t r a n s f e r w h e e l ( 5 3 . 1 ) i s e n g a g e d w i t h t h e
l o w e s t t r a c k o n f h e m o t o r p u l l e y ( 6 2 . 1 ) , a n d t h e
m o u n t i n g a r m f o r t h e s p e e d t r a n s f e r w h e e l ( 5 3 . 3 ) i s
pressed against the lowest level (level a) on the cam
d i s c ( 5 9 . 1 . l ) i n t h e 1 ? / s i . p . s . p o s i r i o n .
T h e s p e e d t r a n s f e r w h e e l ( 5 3 . 1 ) w i l l b e d i s e n g a g e d
f r o m t h e m o t o r p u l l e y ( 6 2 . 1 ) , a n d m o v e d o u t h o r i -
z o n t a l l y a p p r o x . 1 " , w h e n t h e s p e e d s e l e c t o r k n o b
(53.4) is turned towards Ihe 33/t i.p.s. position. This
h o r i z o n t a l m o v e m e n t i s a c c o m p l i s h e d b y t h e c a m d i s c
a r m ( 5 9 . 1 2 ) , w h i c h r o l l e r r e s t s a g a i n s t t h e c u r v a t u r e
o f t h e c a m d i s c ( 5 9 . 1 l ) . T h e c a m d i s c a r m ( 5 9 . 1 2 )
presses against the mounting arm for the speed trans-
f e r w h e e l ( 5 3 . 3 ) i n p o i n t D .
F i g . 3 5 . T h e m o m e n t o r y s t q r f - s t o p m e c h o n i s m .
i s a d i u s t e d b y b e n d i n g t h e n o s e o f t h e c a m d i s c a r m
( 5 9 . 1 2 ) . R e m o v e t h e m o t o r p u l l e y ( 6 2 . j ) t o m a k e t h i s
a l i g n m e n t .
4.9 THE MOMENTARY START.STOP FEATURE
The momentary start-stop mechanism (33.4) is de-
s i g n e d a s s h o w n i n f i g . 3 5 .
T h e d e l r i n b u s h i n g ( 3 3 . 9 ) w i l l p r e s s a g a i n s t t h e p r e s -
sure wheel lever (5 1.5) in point B when the start-stop
l e v e r ( 3 3 . 1 1 ) i s m o v e d t o s t o p p o s i t i o n . T h e p r e s s u r e
w h e e l l e v e r ( 5 1 . 5 ) m o v e s t h e p r e s s u r e w h e e l s h a f t
( 5 . l . 2 ) w i t h t h e p r e s s u r e w h e e l i S t . l ) a w a y f r o m t h e
c a p s t a n ( 6 6 . 2 ) a n d a c t i v a t e s t h e t a p e b r a k e ( 5 1 . 9 ) .
Adiustments
Move the operating lever to normal forward drive
position and set the momentary start-stop lever in
ttr
The vertical lifting of the mounting arm for the speed
lransfer wheel (53.3) is accomplished by the slope of
t h e c a m d i s c ( 5 9 . 1 1 ) b e t w e e n t h e l e v e l s a a n d b . T h e
slope presses the mounting arm for the speed trans-
f e r w h e e l ( 5 3 . 3 ) u p w a r d s f r o m t h e l e v e l a ( l z , / 6 i . p . s .
p o s i t i o n ) t o t h e I e v e l b ( 3 , / o i . p . s . p o s i t i o n ) d u r i n g t h e
rotation of the speed selector knob (53.4).
Adiustments
The spacing at point D between the cam disc arm
(59.12) and the mounting arm for ihe speed transfer
w h e e l ( 5 3 . 3 ) s h o u l d b e 0 . 5 m m ( . 0 2 ' , ) w i i h t h e o p e r a r -
i n g l e v e r ( 5 4 . . l ) i n n o r m a l f o r w a r d d r i v e . T h e s p a c i n g
< S T O P > > p o s i t i o n . A d i u s t t h e p r e s s u r e w h e e l l e v e r
( 5 - 1 . 5 ) b y b e n d i n g t h e f l a t p a r t B t o o b t a i n a s p a c i n g
o f a p p r o x . 0 . 5 m m ( . 0 2 " ) b e t w e e n i h e p r e s s u r e w h e e l
( 5 1 . 1 ) a n d t h e c a p s t a n ( 6 6 . 2 ) . A s c e r t a i n a p l a y o f
a p p r o x . 0 . 2 m m ( . O 1 2 " ) b e t w e e n t h e p r e s s u r e w h e e l
l e v e r ( 5 i . 5 ) a n d t h e t r a n s f e r b r a c k e t ( 5 9 . 2 4 ) .
Start the mechanism by moving the start-stop lever to
the left posifion. Adiust lhe pressure wheel lever
( 5 1 . 5 ) b y b e n d i n g t h e t o n g u e C t o o b t a i n a s p a c i n g o f
approx. I mm (.04") between the pressuie wheel
s h a f t ( S t . 2 ) a n d t h e p r e s s u r e w h e e l l e v e r ( 5 i . 5 ) a t
point D. Make sure that the space between the pres-
s u r e w h e e l l e v e r ( 5 I . 5 ) a n d f h e s t a r t - s t o p l e v e r ( 3 3 . 1 I )
i s a p p r o x . 0 . 5 m m ( . O 2 " ) .
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