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At that
time, the reel tab!e winding
speed and the
torque
needed
in
a wide
variety
of
modes
are
obtained
by shifting
the UP and down
STEP GEAR
positioned
at
the
upper
section
of
pulley.
The
selection
of the STEP GEAR is precision
controlled
by the MODE CAM GEAR via the BRAKE CONTROL
SLIDE. With
the UP and down
STEP GEAR down,
the
clutch
mechanism
is direct
linked,
and
the
transmission
power from the capstan
motor is sent
to the
reel table
via
IDLER GEAR assembly
and
REEL GEAR (S/T).
On the other
hand, FRICTION
MECHANISM acts between
the pulley and the STEP
GEAR when
the UP and down
STEP GEAR are in
the
elevated
state ,
thereby
controlling
the
transmission
torque
for generation
of the take-up
slip. Normally, it is desirable that the take-up torque
of the reel table is higher in the R-SEARCH mode
than
that
in the
PLAY mode. This
is because
in
the forward
tape running
the tape winding
load to
.
the
HEAD DRUM
has
to
be taken
care
of
the
..-'
.,..
capstan
and the pinch
roller.
White, in the
reverse
tape
running
mode the winding
load has to be taken
on the take-up
reel table. In
the
special
playback
cperation,
a mechanism
for
varying
the
take-up
torque
of
the
reei table
is
required to be changed depending
upon the running
direction
of the tape.
But
in this
mechanism,
the
torque
selection
is made by varying
the reduction
speed ratio
up
to
the reel table from
the capstan
motor
on both
the forward
side and the reverse
side of the tape. Also, design simplification
of the
selection
mechanism
is realized by using
a single
friction
mechanism.
In other
words,
the
take-up
torque
necessary
for
forward/reverse
rotation
is
obtained
by controlling
the capstan
motor
speed.
.,..
,.,.,.
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Rotation
speed and torque
needed for each mode
of
operation
are converted
by clutch
mechanism
for
transmission
of
the
drive
power
to the
idler
mechanism. The left and right moving
IDLER GEAR
assembly
is automatically
rotated
to the left
and
the
right
according
to
the
direction
of
capstan
motor
rotation
by using the friction
force. Because
the mechanism
is so designed
as to drive the reel
table of the side on which
the tape is transported
by
the capstan
and pinch
roller, the forward
and
reverse constant
speed drive (the PLAY, REC, F/R
SEARCH modes) is carried out in the state in which
the FRICTION MECHANISM
is being operated
(Fig.
2-12 @) On the
other
hand,
in the condition
in
which
the friction
mechanism
is not in operation,
the
forward/reverse
high
speed
drive (FF/REW
mode) is made possible (Fig. 2-12 @).
Also,
the
reel
drive in all modes
is taken
care of by the single
left and right moving
idler for design simplification.
The
idler
body
employs
gear
drive
to
improve
reliability
with
a view
to
realizing
parts
thinning
while
securing
the transmission
reliability.
Using a
resin
molded
gear
as
material
of
an
idler,
the
efficiency
of the entire
reel drive system
has been
improved
because
there
are no deformation
and
loss,
and
minimized
rotation
moving
torque
necessary
for biting-in
as in the case- of a material
such
as rubber
which
shows
considerable
elastic
deformation,
etc.
Further
in
this
mechanism,
an
intermediate
gear is provided
in between
the reel
side
and
the
idler
to
minimize
the
rotating
and
moving
angle of the left
and right
moving
idlers,
thereby
holding
the reversing
time
to a minimum
when shifting
to the tape running
direction
change
mode. This results in significantly
reduced possibility
of tape looseness.
(a) PLAY, REC, F/R-SEARCH MODE
SUPPLY/TAKE-UP
REEL GEAR (S/T)
STEP IDLER GEAR
IDLER GEAR 2
+
PINCH
ROLLER
FRICTION GEAR
CAPSTAN
MOTOR
ENGAGED
1
REEL PULLEY
REEL DRIVE BELT
STEP GEAR (a)
(b) F-FWD/REW, STOP MODE
FRICTION GEAR
STEP IDLER GEAR
GEAR (b)
+ (direct
linked)
DISENGkGED
~
REEL PULLEY
(a)The clutch mechanism is disengaged, and rota-
tional force is transmitted through the friction
mechanism. (Constant speed rotating mode)
(b) Direct transmission is obtained by disengaging
the friction
mechanism with a clutch mechanism.
(High-speed rotating mode)
"d..
Fig. 2-12 REEL TABLE DRIVE (Si DE VIEW)
–15–
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