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EXPLANATION
OF TAPE
RECORDER
MECHANISM
Auto-Stop Mechanism
Fig. 1 shows
the order
of operations
for the auto-stop
mechanism.
1. Main drive-power transmission mechanism
The take-up reel and the AS (Auto-Stop) cam gear are
driven by the motor.
1) The oscillating cam is on the same axis as the reel and
light contact is made with reel by means of the coil
spring.
When
the
reel revolves,
a force
is applied
in the
revolving
direction
to the oscillating cam
and the
cam
slips.
2) The AS gear and the AS cam gear are of the clutch
type as shown in Fig. 3. This clutch prevents the auto-
stop from
operating by stopping the rotation of the
AS cam gear and releasing the engagement of the gears
during the review, cue and pause modes by means of
the
AS operation
plate of the auto-stop
prevention
mechanism.
During
playback,
fast forward
and re-
winding,
the gears
engage
and drive-power
is trans-
mitted and auto-stop
is possible.
3) The
AS cam
gear is provided with a cam to which
drive-power
is transmitted
from
the AS gear and
which oscillates the arm, and the cam which engages
with the AS arm auto-matically stops the mechanism.
2. Tape end detection mechanism
The tape end detection
mechanism
is composed of the
oscillating cam and the oscillating arm as shown in Fig. 5.
Note: Fig. 5 shows the operation of the oscillating cam
and oscillating arm when the AS cam gears revolve
during
playback
and
fast forward,
and
Fig. 6
shows the same during rewinding.
Whichever
the condition,
the oscillating arm re-
peats
the
oscillating
movements
using the arm
installation screw as a fulcrum.
Fig. 7 shows the operation of the oscillating cam
and the oscillating arm when the tape has com-
pleted its winding and the reel is stopped, e.g. the
tape end is detected, during playback, fast forward
or rewinding modes.
The oscillating arm slides in the direction of the
arrow by the rotation of the AS cam gear, with
the convex
section of the oscillating cam as the
fulcrum.
3. Auto-stop prevention mechanism
When the review or cue operation is carried out during
playback,
the
reel
may
stop
because
the
auto-stop
mechanism
operates erroneously. Also, when the pause
operation
is carried out, since the rotation of the reel
stops, this too is automatically stopped.
The
auto-stop
prevention
mechanism
makes
the
AS
operation
plate,
shown
in Fig. 3, slide during these
operations, and it releases the AS gear and AS cam gear
and stops the movement of the AS cam gear.
. Auto-stop mechanism
Respective
button
sliders
for playback,
fast forward,
rewind and recording are locked by the lock plate shown
in Fig. 8.
The lock plate is made to slide by the stop slider or the
AS lever, and the lock is released. The AS lever operates
when the AS arm and the AS cam gear engage, e.g. when
the
tape-end
is detected
by the
tape-end
detection
mechanism.
When the tape-end is not detected.
Since the oscillating arm is in a position as shown in Fig.
5 and 6, the AS arm, shown in Fig. 8, is in a position at
the point shown
in black, and it never engages the AS
cam gear.
When the tape-end is detected
The oscillating arm slides in the direction shown in Fig. 7
by the red arrow. At the same time, the AS arm rotates
to the position shown
in Fig. 8 by the red arrow, and
engages with the cam portion of the AS cam gear.
By this engagement, the AS lever rotates as shown by
the red portion in Fig. 9, it makes the plate slide and
releases the locking of respective button sliders.
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