Note: Descriptions are shown in the official language in which they were submitted.
~3S~
1 -1- RCA 72,598
VIDEO DISC PLAYER HAVING UNITARY
RECORD HANDLING PLATFORM CONSTRUCTION
This invention generally relates to record players,
and more particularly, it relates to players suitable for
use with a record caddy.
In certain video disc systems, information is
stored on a disc record in the form of geometric variations
in the bottom of a continuous spiral groove disposed on the
record surface. The variations ln capacitance between an
electrode incorporated in a groove-riding stylus and a con-
ductive coating disposed on the record surface are sensed
16 to reproduce the stored information. A capacitance-type
video disc system is illustratively disclosed in U.S.
Patent No. 3,842,194 (Clemens).
In such systems, it is advantageous to mount a
groove-riding pickup stylus in a demountable cartridge. The
player is provided with rails for guiding a carriage, having
a compartment for receiving the pickup cartridge, along a
path. The carriage is driven during playback along the
carriage guiding rails in correlation with the motion of the
groove-riding stylusO U.S. Patent No. 3,870,320
2~ (Torrington), discloses a type of carriage translating
system.
It i9 beneficial to enclose a record n a thin
plastic caddy. For record loading, an occupied caddy is
inserted into an input slot provided in the player. The
player is equipped with another set of rails for guiding
caddy insertion along a further path. A record extracting
mechanism disposed in the player removes the record from
the caddy during subsequent caddy withdrawal, whereby the
record is retained in the player. The player is equipped
with a platform for supporting the retained record when it
is disposed in an elevated position. The retained record
is transferred to the turntable for playback during motion
of the platform to a depressed position. For subsequent
record retrieval, the platform, with the retained record ;~
~0 ,; ", .
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-
,
.
~3~
1 -2- RCA 72,598
resting thereon, is raised, and an empty caddy is inserted
into the player, thereby returning the record back into
the caddy. Withdrawal of the caddy, effects record removal
from the player. U.S. Patent No. 4,098,511 (Leedom), U.S.
Patent 4,124,866, issued Nov. 7, 1978 (Coleman) and U.S.
Patent 4,133,540 (Torrington) issued January 19, 1979,
illustrate systems suitable for use with a record caddy.
In such systems, the carriage is typically
mounted for side-to-side motion and the direction of caddy
insertion is from front-to-back, a direction which is
orthogonal to the carriage path. Such configuration imposes
several constraints on player design and constxuction:
for example, lt is necessary that the starting position of
the carriage is beyond the record periphery, one of the
caddy guiding rails is mounted on the carriage to prevent
interference thereof with the motion of the carriage toward
the record center; a separate mechanism is needed to return
the carriage to the starting position subse~uent to play-
back; and a stylus landing adjustment mechanism is necessary
to insure that the stylus is lowered precisely over the
beginning of the recorded band during travel of the carriage
from an off-record starting position toward a position over-
lying the record.
In a U.S. Patent 4,196,906, issued April 8, 1980,
~. A. Torrington~ entitled "VIDEO DISC PLAYER", a novel
video disc player construction, which overcomes the herein-
before mentioned constraints, is disclosed. In the therein
disclosed system, the carriage is translated along a path
disposed parallel to the path of caddy insertion. Pursuant
to a further feature of the Torrington invention, the
direction of translation of the carriage during playback
is opposite to the directlon of the caddy insertion. The
location of the caddy path relative to the carriage path is
such that the caddy engages the carriage, when the carriage
is at a position other than at a starting position, during
~3.~
1 -3- RCA 72,598
a caddy insertion to reset the carriage at the starting
position.
In accordance with the principles of the present
invention, both the caddy guiding rails and the parallel
carriage guiding rails are integrally mounted on the record
retaining platform. Such an arrangement provides a precise
~10 alignment of the record caddy relative to the carriage and
the carriage relative to the turntable throughout the opera-
ting range.
IN THE DRAWINGS:
.
FIGURE 1 is a plan view of a video record player
incorporating the principles of the present invention;
FIGURE 2 is a perspective end view of the player
of FIGURE 1, with a depressible platform being shown in the
raised position;
FIGURE 3 is a perspective end view of the player
of FIGURES 1 and 2, with the depressible platform being
shown in the lowered position;
FIGURES 4 and 5 depict a ~ecord caddy, comprising
a jacket and a record retaining member, suitable for use
with the player of FIGURES 1-3;
FIGURE 6 illustrates a record extracting mechanism
disposed in the player of FIGURES 1-3;
FIGURES 7 and 8 show the operation of the record
extracting mechanism of FIGURE 6;
FIGURES 9 and 10 demonstrate the sequence
involved in transferring a record, resting on the depress-
ible platform of FIGURES 1-3, to the player tu.rntable;
FIGURES 11-13 illustrate a mechanical toggle
switch suitable for use with a pickup carriage translating
mechanism provided in the player of FIGURES 1-3;
FIGUR~ 14 shows an arrangement suitable for opera-
ting the toggle switch of FIGURES 11-13 by means of controls
provided at the input end of the player;
FIGURE 15 depicts an alternate carriage translat-
ing mechanism suitable for use with the player of FIGURES
~35~
1 -4- RCA 72,598
1-3; and
FIGURE 16 illustrates a stylus lifting/lowering
apparatus suitable for use with the player of FIGURES 1-3.
In FIGURES 1, ~ and 3, a video disc p]ayer 20
includes a housing 22 which is provided with an input slot
24 at the front end thereof, through which a record caddy
is inserted for loading an enclosed record into the player.
A turntable 26 includes a record centering spindle 28, and a
soft annular pad 30 for supporting the record. The turn-
table diameter is made less than the record diameter, and
the soft annular pad supports the record in the grooved
area.
1~ The turntable 26 is driven by a motor 32 (FIGURE
1) to rotate at a predetermined speed within preset limits
(e.g., 450 rpm + 0.01%). U.S. Patent No. 3,912,283
(Hammond, et al.), discloses an alternate form of a turn-
table drive system.
ao A platform 34, mounted on a shaft 36 which is
located at the non-input end of the housing 22, is subject
to motion between an elevated posit:ion (FIGURE 2) and a
depressed position (FIGURE 3). A pair of rails 3~ and 40
are disposed on the platform 3~. The rails have grooves
42 and 44 for guiding insertion of a caddy into the housing
along a path. The front ends of the caddy guiding grooves
are aligned with the input slot 24 when the platform is
occupying the elevated position for permitting insertion of
a caddy into the player.
~s shown in FIGURES 4 and 5, the record caddy 50
comprises an outer jacket 52 and a record retaining member
54 removably located within the jacket. The retaining
member comprises (1) an annular portion 56, and encircles
the enclosed record 5~, and (2) a spine portion 60, which
serves as a closure to keep dust and debris from entering
the record enclosing cavity. The spine has an opening 62
into which the latch arms 70 and 72 of a record extracting
mechanism 74 (FIGURE 1) protrude during arrival of a record
caddy at a fully inserted position in the player to effect
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.
~L~35~
1 -5- RCA 72,598
record removal during subsequent caddy withdrawal.
The record extracting mechanism 74 is mounted on
the platform 34. In the manner shown in FIGURE 6, the
extracting mechanism 74 includes latch arms 70 and 72
pivotally secured to a platform-mounted bracket 76. The
latch arms are alternated between an open condition (FIGURES
6 and 7) and a closed condition (FIGURE 8)l in response to
each caddy arrival at the fully inserted position in the
player. The arrangement for rendering the extracting
mechanism caddy responsive includes a pivotally-mounted
actuating arm 78 disposed in the caddy path. The actuating
arm advances a ratchet 80, carrying a square-shaped cam 82,
through 45 degrees each time a cover arrives at a fully
inserted position in the player. Each advancement of the
square-shaped cam changes the condition of latch arms from
the condition they occupied prior to cover insertion to the
other condition thereof. Springs (not shown) are provided
for returning the actuating arm to the rest posiiton there-
of, and to bias the latch arms into engagement with the
square-shaped cam 82. A pawl (not shown) is provided to
prevent the ratchet from rotating irl the reverse direction
when the actuating arm is returned t:o its rest position.
U.S. Patent No. 4,109,919 (Elliott, et al.), discloses a
suitable caddy-actuated record extracting mechanism.
To load a record into the player, the latch arms
70 and 72 are disposed in the closed condition (FIGURE 8),
the platform 34 is disposed in the elevated position
(FIGURE 2) and an occupied caddy is inserted through the
input slot 24 along the caddy guiding grooves 42 and 44.
The latch arms enter the opening 62 in the spine 60 as the
caddy reaches the fully inserted position in the player.
The engagement of the caddy with the actuating arm 78
indexes the latch arms into the spread apart condition
(FIGURE 7), whereby the retaining member and the associated
record are locked to the platform. Subsequent withdrawal
of the caddy removes the record therefrom, thereby retaining
the record in the player resting on the raised platform
~35~
1 -6- RCA 72,598
(FIGURE 9). To transfer the retained record to the turn-
table, the platform is lowered to the depressed position
(FIGURE 10).
For record retrieval, the above sequence is
reversed. The platform, with the record resting thereon,
is raised (FI~URE 9). The inner diameter of an opening 90
in the platform 34 is sufficiently less than the record
diameter to positively insure lifting of the retained record
during upward motion of the platform. The platform is
provided with a set of depressible lifting pads 92, 93, 94,
95 and 96 (FIGURE 1) to align the record resting thereon
with the caddy guiding grooves 42 and 44 to cause return
of the record into an empty caddy during insertion thereof
into the player. As a caddy is loaded into the player, the
leading edge thereof depresses the lifting pads to allow
forward motion of the caddy. The engagement of the caddy
with the actuating arm 78 reindexes the latch arms to the
closed condition (FIGURE 8), thereby freeing the record
from the player. Subsequent caddy withdrawal removes the
enclosed record therewith.
The rails 38 and ~0 are further provided with a
second set of grooves 100 and 102 (~'IGURES 2 and 3) for
guiding a carriage 104 along a second path parallel to the
caddy path (front-and-back). The carriage is provided with
a pair of projections (not shown), which are respectively
received in the carriage guiding grooves.
A pickup cartridge 106, carrying a groove-riding
stylus 107 at the end of a stylus arm 108, is installed in
a compartment provided in the carriage 104 (FIGURE 1). The
carriage is translated during playback along the rails
toward the turntable center (a direction opposite to the
direction of caddy insertion) in correlation with the speed
of rotation of the turntable in the manner hereinafter des-
cribed. An armstretcher apparatus 109 oscillates the pickup
stylus back-and-forth along the groove so as to offset
cyclical errors in stylus/record relative velocity. U.S.
Patent No. 4,030,124 (Allen), discloses a pickup cartridge
~3~
1 ~7~ RCA 72,598
suitable for use with the player described herein. A suit-
able armstretcher apparatus is shown in U.S. Patent
No. 3,9~3,318 (Miller, et al.).
A pair of racks 110 and 112 are respectively
secured to the platform rails 38 and 40. A shaft 11~,
caxrying a set of pinions 116 and 118, is rotatably secured
to the carriage 104 (FIGURE 1). A respective one of the
pinions engage a respective one of the racks to ensure that
the carriage path lies radially of a turntable-supported
record throughout the operating range thereof.
Prior to playback, the carriage is restored to a
starting position. The resetting of the carriage to the
starting position is done automatically when a caddy is
inserted, for example, to retrieve a record, resting on the
platform while it is disposed in the raised position,
from the player. The location of the caddy path relative
to the carriage path is such that a caddy engages the
carriage during insertion thereof into the player. The
player is dimensioned such that the arrival of the carriage-
engaging caddy at the fully inserted position in the player
coincides with the arrival of the engaged carriage at the
starting position.
For playback, the platform, with a retained record
resting thereon, is depressed to trans~er the record to the
turntable. The carriage is translated during playback along
the rails in a direction opposite to the direction o~ caddy
insertion in correlation with the speed of rotation of the
turntable. In addition to normal correlated translation of
the carriage during playback, the carriage is translatable
in either direction at a speed independent of the speed o~
rotation of the turntable during active search.
The carriage drive mechanism includes an endless
play belt 130, an endless search belt 132 and a carriage-
mounted, mechanical toggle switch 134 (FIGURE 1~. The
toggle switch selectively connects one of the two belts to
the carriage to effect carriage translation by a selected
one of the belts. The play belt is driven in correlation
~35~
1 -~~ RCA 72,59~
with the turntable rotational speed, and in a dir~oction
causing carriage translation toward the record center. The
search belt is driven independent of the turntable rotational
speed, and in either direction. The belts are driven in the
manner described hereinafter. The plav belt is disposed
about a pair of pulleys 136 and 138, and the search belt
is disposed about an additional set of pulleys 140 and 142.
Pulleys 136 and 1~0 are loosely mounted on the platform
shaft 36 for motion independent thereof. The other pulleys
138 and 142, serving as idling members, are freely mounted
for rotation about a pin 144 secured to the platform 34,
and extending parallel to the platform shaft 36. The res-
pective locations of the pulleys are such that the belts liealong a path parallel to the carriage path.
The mechanisms for driving the two belts will now
be described. As shown in FIGURE 1, a turntable-driven
pulley 150 and a thumbwheel-driven pulley 152 are also
~0 loosely mounted on the platform sha:Et 36 for motion inde-
pendent thereof. The play belt driving pulley 136 and the
search belt driving pulley 140 are respectively secured to
the turntable-driven pulley 150 and the thumbwheel-driven
pulley 152 for rotation therewith.
The turntable-driven pulley 150 is coupled to a
pulley 1~4 which, in turn, is driven by the turntable drive
motor 32 via a drive chain 156. The selection of proper
gear ratios permits carriage translation in correlation
with the radial motion of the groove-riding stylus during
playback.
A serrated thumbwheel 160 is rotatably mounted in
the housing 22, and has a portion, which is accessible to
the user of the player through a slot in the front instru-
ment panel 230 of the player. A pulley 162 is mounted co-
axially with the thumbwheel for rotation therewith. Thecoaxially mounted pulley drives the thumbwheel-driven
pulley 152 by means of endless belts 164 and 166 via an
intermediate pulley 168. It will be seen that the speed of
the bidirectional search belt is continuously variable over
~35~
1 -9- RCA 72,598
a range of speeds in either direction by utilizing the
manually-actuated thumbwheel. All of the endless belts
and the pulleys herein used are equipped with teeth to
provide nonslip coupling.
An apparatus 170 (FIGURES 1 and 16) for causing
motion of the pickup stylus between a lowered position,
permitting engagement between the stylus and a turntable-
supported record, and a raised position, precluding stylus/record engagement, is mounted in the carriage 104. The
pickup stylus is lowered for engagement with a turntable-
supported record during playback and active search. The
pickup stylus is raised when the player is in a pause mode
and when the carriage reaches an end-of-play position.
Essentially, as shown in FIGURE 16, the stylus
lifting/lowering apparatus 170 includes a stylus arm rest
172 mounted for motion between an elevated position and a
depressed position. The stylus arm rest in the elevated
position supports the stylus arm 108 (FIGURE 1) in a manner
precluding stylus/record contact. The stylus arm rest in
the depressed ~osition permits the stylus arm to occupy a
lowered position. The lowered posit:ion of the stylus arm
is such that the stylus/record contact is established when
the carriage is in the over-record play position. An
electromagnet 174 is energized to repel a permanent magnet
176 secured to the stylus arm rest to dispose the stylus
arm rest in the depressed position. A leaf spring 178
secured to the stylus arm rest lifts the stylus 107 off the
record when the electromagnet is de-energized. A selec
tively actuated plunger 179 depresses the stylus arm rest
when actuated. U.S. Patent No. 4,053,161 (Bleazey, et al.),
discloses such stylus lifting/lowering apparatus.
Disposed in the--carriage are pickup circuits
coupled to the output of the groove-riding stylus ~or
developing a signal representative of the information
stored on the turntable-supported record. Signal processing
circuits, coupled to the output of the pickup circuits, are
located in the housing for developing a signal suitable for
1 -10- RCA 72,598
application to a television receiver for audio/visual
presentation of the inform~tion stored on the record~
U.S. Patent No. 4,080,625 (Kawamoto, et al.), discloses
suitable pickup circuits. U.S. Patent, No. 4,097,899 (Yu),
illustratively describes signal processing circuits.
To obtain various special effects, the mechanical
toggle switch 134 is thrown into an active search mode to
connect the carriage to the variable speed, bidirectional
search belt 132 to the exclusion of the constant speed,
unidirectional play belt 130. It will be noted that in the
active search mode, as well as in the play mode, the stylus
lifting/lowering apparatus permits stylus/record engagement.
To realize, for example, fast forward motion, the carriage
is translated at a rapid rate in the foward direction by
rotating the thumbwheel 160 at appropriate speed in the
required direction, while the stylus is allowed to ride on
the record. The reverse motion can be obtained by translat-
ing the carriage in the reverse direction (i.e., away from
the turntable center or toward the starting position). To
obtain stop motion effect, the carriage is allowed to remain
stationary, thereby causing the groove-riding stylus to
repetitively trace a selected set of groove convolutions.
The mechanical toggle switch 134 for selectively
coupling the carriage to one of the two belts to effect
carriage translation by a chosen one of the belts will now
be described. FIGURES 11, 12 and 13, respectively, illus-
trate (1) the pause mode, wherein the carriage-mounted
toggle switch is disconnected from both belts, (2) the play
mode, wherein the toggle switch is secured to the play belt
130, and (3) the search mode, wherein the toggle switch is
connected to the search belt 132.
The toggle switch includes a block 180 secured to
the platform-mounted carriage for translation therewith.
The block has a pair of surfaces 182 and 184 defining a
slot 186 through which the upper runs of the play and the
search belts pass. The block is equipped with a recQss 188
in communication with the top surface 182. A bifurcated
,
~3.5~
1 -11- RCA 72,598
plate 190 is mounted in the recess for arcuate motion about
a pin 192 to selec-tively occupy the above-mentioned three
positions. In the play mode, the upper run of the play
belt 130 is squeezed between the toggle plate and the bottom
surface 184 (FIGURE 12). In the search mode, the upper run
of the search belt 132 is held between the toggle plate and
the bottom surface 184 (FIGURE 13). In the pause mode,
the carriage is freed from both belts (FIGURE 11).
The switch actuating mechanism includes a pin 194
rotatably secured to the carriage-mounted block. An
eccentric protrusion 196 is disposed at one end of the pin
194 for reception in a cutout 198 provided in the toggle
15 plate 190. The position and orientation of the pin 194
relative to the toggle plate is such that the rotation of
the pin effects pivotal motion of the toggle plate. A mode
select lever 200 is secured to the pin 194 to selectively
dispose the toggle plate in a selected one of the modes.
It is advantageous to be able to operate the
toggle switch by means of controls provided at the input
end of the player. One such arrangement 210 is illustrated
in FIGURE 14. As shown therein, the mode selection lever
200 is curled upward at the free end thereof to provide an
25 offset tab 212. A flap 214 is swingably mounted on the
platform for arcuate motion about an axis lying parallel
to the carriage path. A torsional spring 216 is provided
to bias the mode selection lever to occupy an extreme posi-
tion adjacent to the flap, whereby the carriage 104 is
connected to play belt 130. The flap is rotated to a first
extent (corresponding to the midway position of the toggle
plate 190) and a second extent (corresponding to the other
extreme position of the toggle plate) in anti-clockwise
direction (when viewed from the input end) to, respectively,
set the toggle switch in the pause mode, wherein the carri-
age is released from both belts, and the search mode,
wherein the carriage is under the influence of the search
belt 132.
An extension 220 is disposed on the flap 214 at
~3~
1 -12- RCA 72,598
the non-input end of the player for cooperation with struts
222 and 224. The struts 222 and 224 are actuated, respec-
tively, by a pause button 226 and a search button 228(FIGURE 1) to cause the flap to, respectively, rotate to
the first and the second extent. Thus, operation of the
pause button and the search button indexes the toggle
switch, respectively, into the pause mode and the search
mode- The mode selection buttons are disposed on the front
instrument panel, and are of push-on/push-off variety.
The flap 214 is additionally equipped with a
second extension 232 at the input end of the player for
cooperation with a stationary overhanging member 234. The
relative location of the stationary member is such that,
when the platform 34 is raised to the elevated position, the
stationary member depresses the second extension 232 to an
extent that disposes the toggle switch into the pause mode,
thereby freeing the carriage from both belts. Thus, the
action of the stationary member on the flap when the plat-
form is raised allows restoration of the carriage to the
starting position, with freedom from interference by the
carriage translating mechanism, during inse.rtion of an
empty caddy into the player for record retrieval.
2~ The platform lifting/lowering mechanism will now
be described in conjunction with FIGURES 1-3. A function
selection lever 250 secured to a rotatably mounted wheel
252, extends through a slot provided in the front instrument
panel of the player. The function selection lever is moved
to the positions shown in FIGURES 2 and 3, respectively, to
raise and lower the platform. In the raised position of
the platform, the front ends o~ the caddy guiding grooves
42 and 44 are aligned with the input slot to permit caddy
insertion and extraction.~ The depression of the platform,
with a retained record resting thereon, effects transfer
of the retained record to the turntable for playback. The
function selection lever may also serve to shut off power to
the player, for example, when it is shifted to a position
beyond the caddy in/out position (FIGURE 2).
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~L~3~r~
1 -13- RCA 72,598
The function selection wheel is provided with
peripheral, axial notches 254 and 256 corresponding to the
raised and lowered position oE the platform. A detent 258,
secured to a pivotally mounted lever 260, is received in
one of the notches to releasably hold the function selec-
tion wheel in a selected one of the positions thereof.
A spring 262 urges engagement between the detent and the
periphery of the function selection wheel 252.
The linkage between the function selection lever
and the platform includes a pair of spaced levers 264 and
266 secured to a rotatably mounted shaft 268. A set of
platform-engaging rollers 270 and 272 are respectively
disposed at the free ends of the spaced levers. As shown
in FIGURE 1, an endless toothed belt 274 is disposed about
a toothed pulley 276, securely mounted on the shaft 268,
and another toothed pulley 278, mounted coaxially with the
function selection wheel for rotation therewith. The
20 relative angular location of the spaced levers 264 and 266
is such that the motion of the function selection lever
between the two positions causes corresponding motion of
the platform between the elevated and the depressed position.
A rotatably-mounted dial 290 (FIGURE 1), bearing
an indicia indicative of the respective playing times
associated with distance traveled by the carriage from a
starting position, is visible through a readout window pro-
vided in the front instrument panel of the player. A cord
292 extends between the carriage 104 and the indicia bear-
ing dial such that the displacement of the carriage alongthe guiding rails effects synchronized rotation of the dial.
A torsion spring 294 is disposed about the axis of rotation
of the dial such that it gets coiled during translation
of the carriage away from the starting position, whereby
energy is stored in the torsion spring. The coiled spring
applies a force to the carriage in a sense urging carriage
travel toward the starting position. The applied force
aids resetting of the carriage to the starting position,
when it is at a position other than the starting position,
~3~
1 -14- RCA 72,598
during a caddy insertion. The cord 292 is passed over a
grooved pulley 296 and another grooved pulley 298. The
pulley 2~8 is coaxially mounted on the platform shaft. One
end of the cord is fastened to the carriage-mounted block
180, and a portion at the other end thereof is wrapped
around the stem portion of the dial. The stiffness of the
torsion spring is selected to give the desired feel to the
user of the player as he inserts a caddy into the player to
restore the carriage to the starting position.
An alternate carriage translating mechanism is
shown in FIGURE 15. As shown therein, a spiral groove 310
is disposed on the periphery of a shaft 312 rotatably
secured to the carriage 314. A cord 316 has a portion
wrapped around the carriage shaft along the spiral groove
therein. The cord, moreover, has further portions respec-
tively passing over a grooved, turntable-driven pulley 318
and an idler pulley 320. A pair of pinions 322 and 324 are
secured to the respective ends of the CarriaCJe shaft for
engagement with platform-mounted racks 326 and 328. A
drive chain 330 rotates the turntable-driven pulley at a
speed such that the carriage is translated in synchronism
with a pickup stylus riding in an information bearing track
disposed on a turntable-supported record. For playing back
variable pitch records, the diameter of the peripheral
groove in the carriage sha~t is varied in correspondence
with the variation in the record pitch, thereby providing
precise carriage translation throughout the operating range.
The input slot is covered with a flap for keeping
dust and debris from entering the record chamber in the
player. When the player is disposed in the caddy in/out
mode (FIGURE 2) by means of the function selection lever,
the flap uncovers the input slot to allow caddy insertion
and extraction. In other modes of the player, the flap
remains closed.
It will be noted that both the caddy guiding
grooves and the carriage guiding grooves are integrally
molded with the platform to provide a single-main-frame
` !
~35~
1 -15- RCA 72,598
construction. This permits a precise positioning of the
caddy relative to the carriage and the carriage relative to
the turntable throughout the operating range.
The mounting of the play belt driving pulley 136,
the search belt driving pulley 140, the turntable-driven
pulley 150, the thumbwheel-driven pulley 152 ~nd the grooved
pulley 298 on the platform shaft 36 permits the platform
motion without disturbing the rest of the player system.
3~
