Disc player

A disc player including a fixed chassis provided with a disc transport tray reciprocatingly movably, and a movable chassis liftably supported by the fixed chassis. The movable chassis has mounted thereon a disc rotating turntable and a signal reproduction pickup reciprocatingly movable along a radial line of a disc on the turntable. The tray and the movable chassis are driven by a loading motor serving as a common power source. First and second power transmission routes from the motor to the tray and movable chassis are changed over to each other by an intermediate gear mechanism provided between the tray and the movable chassis.

FIELD OF THE INVENTION 
The present invention relates to disc players for reproducing recorded 
signals, such as audio or video signals, from optical discs by an optical 
pickup, and more particularly to mechanisms and signal reproduction 
systems for use in disc players of the front loading type wherein the 
front panel of the player body is provided with a retractable tray having 
one or a plurality of disc support portions. 
BACKGROUND OF THE INVENTION 
For use in compact disc players for reproducing digital audio signals from 
compact discs wherein the signals are optically recorded, Examined 
Japanese Patent Publication SHO 60-80159, for example, discloses a loading 
device for transporting the disc to a signal reproducing position inside 
the player. The disclosed loading device comprises a tray having a disc 
support portion, retractably provided at the front panel of the player 
body and horizontally reciprocatingly movable by the power of a motor. The 
tray has a lifter for slightly lifting the disc during the transport 
thereof, while disc clamper is provided inside the player above a 
turntable for holding the disc in pressing contact with the turntable. 
After the disc supported on the tray by the lifter has been transported 
into the player, the disc clamper lowers with the retraction of the lifter 
into the tray, and the disc on the tray is lowered onto the turntable and 
held in pressing contact with the turntable. 
The disc player described above requires, in addition to a mechanism for 
reciprocatingly driving the tray, a mechanism for driving the disc clamper 
upward and downward and a mechanism for operating the lifter. The player 
therefore has the problem of being large-sized and necessitates an 
increased number of parts. 
On the other hand, Unexamined Japanese Patent Publication SHO 61-145758 
discloses a disc player which comprises, as seen in FIG. 26, a subchassis 
161 pivotally movably supported by a shaft 162 on a main chassis 160 and 
having mounted thereon a turntable 163, pickup 164, pickup transport 
mechanism 165, etc. A disc clamper 166 is mounted on the main chassis 160 
rotatably but immovably upward or downward. When a tray 168 is pushed into 
the body of the player, the subchassis 161 is moved upward by the 
operation of a chassis drive mechanism 167. With this movement, the 
turntable 163 on the sub-chassis 161 lifts a disc off the tray 168 and 
presses the disc against the clamper 164, whereby the disc is completely 
loaded. Accordingly, the disc can be lifted and lowered and the turntable 
is caused to effect a clamping action by a mechanism which is merely 
adapted to pivotally move the subchassis. 
However, the disc player is cumbersome to use since the tray 168 must be 
reciprocatingly moved manually. The tray may be made automatically movable 
by providing a known tray drive mechanism which is operable by a motor, 
whereas the motor, if additionally provided, makes the player larger and 
heavier and needs a motor control circuit, which makes the circuit of the 
player complex in construction. 
With disc players, an optical pickup is moved along a radial line of the 
disc which is rotating at a hight speed for the pickup to trace tracks 
formed on the signal bearing surface thereof in the form of concentric 
circles or a spiral track thereon and thereby read signals. Unexamined 
Japanese Patent Publication SHO 62-62485, for example, discloses a 
mechanism for transporting the pickup. 
The disclosed transport mechanism comprises a guide shaft for guiding the 
pickup for a linear motion thereof, a rack secured to the pickup immovably 
relative thereto, a pinion in mesh with the rack, and a feed motor for 
driving the pinion. The pickup is reciprocatingly movable by the operation 
of the feed motor. 
With the above pickup transport mechanism, the pickup is mounted on the 
guide shaft without any backlash so as to be movable straight accurately, 
with the rack secured to the pickup immovably relative thereto, so that 
the pitch line of the rack must be parallel to the direction of movement 
of the pickup with high precision. .If the parallelism is low, the 
distance between the rack and the pinion varies with the travel of the 
pickup, impairing the proper meshing engagement therebetween and giving 
rise to the problem that the power of the motor will not be transmitted to 
the pickup smoothly, for example, owing to objectionable meshing of the 
rack with the pinion. 
With disc players adapted for a multiplicity of functions in recent years, 
disc players have been proposed wherein two discs can be loaded at the 
same time for a single pickup to read signals therefrom in a desired order 
(as disclosed, for example, in Unexamined Japanese Patent Publication SHO 
57-195368). With this player, two discs are arranged side by side on a 
plane within the player, and the pickup is reciprocatingly transported 
along a path extending over the two discs. 
In the case where the foregoing drive mechanism comprising a rack and a 
pinion is employed for transportion the pickup of such a disc player, the 
above-mentioned problem arising from the poor parallelism between the rack 
and the direction of pickup movement becomes more pronounced because the 
distance of movement of the pickup is more than twice the corresponding 
distance in conventional common disc players, necessitating a rack with 
more than twice the conventional length. 
Although the disc player disclosed in the Publication SHO 57-195368 is 
adapted to reproduce signals successively from the two discs loaded 
therein, the player is not of the front loading type and therefore has the 
drawback that discs are not loadable conveniently. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a disc player which 
comprises a tray reciprocatingly movable through a front panel inwardly 
and outwardly thereof, and a movable chassis mounted on a fixed chassis 
upwardly and downwardly movably and having a turntable, a pickup, etc. 
mounted thereon and in which the reciprocating movement of the tray and 
the upward-downward movement of the movable chassis can be effected 
continuously by a loading motor serving as a common power source therefor. 
Another object of the present invention is to provide a disc player of the 
type stated above which has a first power transmission route from the 
loading motor to the tray, a second power transmission route from the 
loading motor to the movable chassis, and an intermediate gear mechanism 
adapted to change over the two routes to each other with the loading motor 
held in rotation in the same direction. 
Another object of the present invention is to provide a disc player 
comprising a pickup supported on a chassis reciprocatingly movably and a 
pickup transport mechanism wherein a pinion drivingly rotatably by a feed 
motor is in mesh with a rack coupled to the pickup, the pickup tranport 
mechanism being adapted to smoothly transmit power from the feed motor to 
the pickup and to transport the pickup accurately on a straight line even 
if the parallelism between the direction of pickup movement and the pitch 
line of the rack is somewhat impaired. 
Another object of the present invention is to provide a disc player of the 
front loading type which comprises a tray loadable with two discs at the 
same time, and a pickup transportable along a path over the two discs on 
the tray so as reproduce signals from the desired disc. 
Still another object of the present invention is to provide disc player 
which is adapted for the playback of a plurality of discs in succession 
and in which a pickup is adapted to read contents data from the discs in 
an optimum order in the course of disc loading and thereafter wait for 
signal reproduction at the contents data recorded position of the disc to 
be driven first for playback so as to be operable for signal reproduction 
promptly. 
The present invention provides a disc player which comprises a fixed 
chassis having a disc transport tray mounted thereon reciprocatingly 
movably along a path, and a movable chassis liftably supported by the 
fixed chassis, the movable chassis being provided with a disc rotating 
turntable and a signal reproduction pickup reciprocatingly movable along a 
radial line of the disc to be placed on the turntable. 
The tray and the movable chassis are driven by means which comprises a 
drive gear drivingly rotatable by a loading motor, a tray drive mechanism 
having a rack meshable with the drive gear, a movable chassis drive 
mechanism having a rack portion meshable with the drive gear, and an 
intermediate gear mechanism for effecting a change-over between a first 
power transmission route wherein the tray drive mechanism is in operation 
and a second power transmission route wherein the chassis drive mechanism 
in operation. The intermediate gear mechanism receives power from one of 
the power transmission routes in operation to forcibly bring the other 
route into operation. 
Accordingly, the reciprocating movement of the tray and the upward-downward 
movement of the movable chassis can be effected continuously by the 
loading motor serving as a common power source. 
The chassis drive mechanism comprises a drive member slidably mounted on 
the fixed chassis, and a cam mechanism interposed between the drive member 
and the movable chassis. The rack portion is integral with the drive 
member. With the movement of the drive member in a tray withdrawal 
direction, the cam mechanism operates to drive the movable chassis upward. 
Consequently, the drive gear, when moving the tray toward the disc loading 
side, rotates in the same direction as when lifting the movable chassis, 
with the result that a disc loading operation including tray transport 
through disc clamping can be effected with the loading motor held in 
rotation in the same direction. 
The pickup is transported by a mechanism which comprises guide means for 
guiding straight movement of the pickup, rack means reciprocatingly 
movable in parallel to the direction of movement of the pickup, a pinion 
meshing with the toothed portion of the rack means at all times and 
drivingly rotatable by a feed motor, and connecting means for 
interconnecting the rack means and the pickup so that the rack means and 
the pickup are not movable relative to each other along the direction of 
pickup movement but are movable relative to each other in a direction 
perpendicular to the direction of pickup movement. 
Accordingly, even if the parallelism between the direction of pickup 
movement and the rack means is somewhat impaired, variations in the 
distance between the pickup and the rack means are absorbed by the 
relative movement therebetween to ensure smooth and accurate transport of 
the pickup. 
The present invention further provides a disc player which comprises a pair 
of turntables, a pickup reciprocatingly movable on a straight line through 
the centers of rotation of the turntables, and a reciprocatingly movable 
tray. The tray is formed on its upper side with a pair of recessed disc 
support portions arranged in a direction perpendicular to the direction of 
movement of the tray. The tray further has a cutout across both the disc 
support portions for the pair of turntables and the pickup to advance 
thereinto. When the tray is set in the disc loading end of path of its 
movement, two discs on the tray are positioned above the respective 
turntables. The discs are thereafter clamped on the turntables. 
Accordingly, the pickup is reciprocatingly movable through the cutout in 
the tray to reproduce signals from both the discs. 
The tray is marked on its front side with a pair of identification symbols 
in corresponding relation with the pair of disc support portions, 
respectively. 
In the course of disc loading, the pickup moves toward the loading 
completed position of the disc corresponding to the identification symbol 
later in order than the other symbol. 
On completion of disc loading, the pickup moves from this disc toward the 
other disc and reads the contents data on the discs during this movement. 
Eventually, the pickup waits for signal reproduction at the contents data 
recorded position of the other disc corresponding to the other 
identification symbol earlier in order. 
Accordingly, when a disc playback signal is subsequently given, the pickup 
can be promptly brought into operation for signal reproduction.

DETAILED DESCRIPTION OF EMBODIMENT 
The present invention will be described below with reference to the 
drawings showing an embodiment thereof, i.e., a disc player adapted for 
the playback of two compact discs in succession. 
Overall Construction and Disc Loading Operation 
As shown in FIG. 1, the disc player has a flat cabinet 1 having housed 
therein the mechanisms and electric circuit to be described later. A tray 
2 having support portions for two compact discs 10 is movable into and out 
of an opening 16 of the cabinet provided with a front panel 11. 
A fixed chassis 12 provided with a loading motor 71, etc. is attached to 
the cabinet 1 inside thereof. A movable chassis 3 is liftably supported on 
the fixed chassis 12 and has mounted thereon a pair of turntables 4, 4, 
pickup 5, pickup transport mechanism 51, etc. 
The horizontal movement of the tray 2 and the upward-downward movement of 
the movable chassis 3 are effected, as will be described later, by the 
loading motor 71 which serves as a common power source therefor. 
With reference to FIG. 2A, a clamp member 62 is positioned above each 
turntable 4 and rotatably supported by a support arm 61. The support arm 
61 is provided with a plate spring 64 for biasing the clamp member 62 
downward. 
Prior to a detailed description of the constructions of various mechanisms, 
a disc loading operation will be described generally with reference to 
FIGS. 2A, 2B and 2C. 
With the tray 2 withdrawn through the front 20 panel 11 as seen in FIG. 2A, 
discs 10 are placed on the tray 2, and a loading start button (not shown) 
on the front panel 11 is depressed, whereupon the loading motor 71 is 
started to operate the tray drive mechanism to be described later, whereby 
the tray 2 carrying the discs 10 is transported into the cabinet 1. 
On completion of transport of the tray 2 as shown in FIG. 2B, the center of 
each disc 10 on the tray 2 is positioned above and in coincidence with the 
spindle of the turntable 4 on the movable chassis 3. In this state, the 
rotation of the loading motor 71 is transmitted to the chassis drive 
mechanism to be described later to drive the movable chassis 3 upward. 
With this movement, the turntable 4 rises. During the rise, the turntable 4 
lifts the disc 10 off the tray 2 first and further presses the disc 10 
into contact with the clamp member 62. Consequently, under the action of 
the plate spring 64, the disc 10 is held between the turntable 4 and the 
clamp member 62, whereby the disc is completely loaded in place as seen in 
FIG. 3C. 
When an unloading start button (not shown) on the front panel 11 is 
depressed after the reproduction of signals, the loading motor 71 rotates 
in a direction opposite to the above to perform a disc unloading operation 
in the order of FIG. 2C, FIG. 2B and FIG. 2A. 
Tray 2 
With reference to FIGS. 3 and 4, the upper side of the tray 2 is recessed 
to provide a pair of first disc accommodating portions 22, 22 of a large 
diameter. Each of these portions 22 is further recessed centrally thereof 
to provide a second disc accommodating portion 23 of a small diameter. A 
compact disc, 12 cm in diameter, is to be accommodated in the first 
portion 22, and a compact disc, 8 cm in diameter, in the second portion 
23. 
The tray 2 is centrally formed with a cutout 24 extending laterally across 
the central portions of the pair of second disc accommodating portions 23, 
23. With the rise of the movable chassis 3, the pair of turntables 4, 4 
and the pickup 5 shown in FIG. 5 advance into the cutout 24. 
Further as seen in FIGS. 3 and 4, each of the second disc accommodating 
portions 23 is formed with a hole 27 for the light of a disc detecting 
photocoupler to pass therethrough. 
The upper side of the tray 2 is also recessed to a greater depth than the 
second portion 23 to provide a stepped portion 26 positioned closer to the 
tray front end than the cutout 24 and extending along the cutout 24. The 
tray upper side is further recessed at its front portion to a greater 
depth than the second disc accommodating portion 23 to provide a pair of 
cavities 25, 25 each positioned on a radial line extending from the center 
of the portion 23 at an angle of 45 degrees with the direction of movement 
of the tray outwardly thereof. The stepped portion 26 and the cavity 25 
are so positioned as to overlap the first disc accommodating portion 22 
and the second disc accommodating portion 23. 
Accordingly, the user can easily hold the disc when removing the disc from 
the first or second portion 22 or 23 by engaging the index finger with the 
inner periphery of the disc and the thumb with the outer peripheral edge 
thereof utilizing the cavity 25 or the stepped portion 26. 
As seen in FIG. 3, the front end face of the tray 2 is marked with the 
symbols "A" and "B" in corresponding relation with the pair of disc 
support portions, respectively, for identifying these portions. 
Tray Drive Mechanism 21 
The tray 2 is formed on the respective opposite sides thereof with a pair 
of ridges 28, 28 extending along the direction of movement of the tray. 
These ridges 28 are slidably in engagement with four L-shaped retainers 18 
mounted on the fixed chassis 12 at opposite side portions thereof, two 
retainers 18 on each side portion, whereby the tray 2 is guided for 
reciprocating movement in the directions of arrows A, A' as seen in FIG. 
5. 
A plurality of ball bearings 20, each comprising a ball socket 20b and a 
ball 30a rollably fitted therein as shown in FIG. 7, are arranged on the 
surface of the fixed chassis 12 slidingly supporting the tray thereon. 
This renders the tray 2 smoothly movable in reciprocation. 
As seen in FIG. 6, the tray 2 is provided on the rear side thereof with a 
pair of opposed racks 29, 29 extending along the direction of tray 
movement. 
As shown in FIG. 5, a connecting shaft 75 extending laterally is rotatably 
supported on the fixed chassis 12. The shaft 75 fixedly carries at its 
opposite ends a pair of drive gears 74, 74 meshable with the respective 
racks 29, 29 on the tray 2. The loading motor 71 is fixed to the rear side 
of the fixed chassis 12 as seen in FIG. 7. The output shaft of the motor 
71 is coupled to reduction gear means 73 via pulley means 72. The gear 
means 73 includes a terminal gear 73a projecting upward through a hole 14 
in the fixed chassis 12 and meshing with one of the drive gears 74 at all 
times. 
Thus, the power of the loading motor 71 is transmitted to the racks 29, 29 
on the tray 2 via the above transmission mechanism 7 while the racks 29 
are in mesh with the respective drive gears 74 on the fixed chassis 12, 
whereby the tray 2 is driven reciprocatingly. 
When the tray has been drived to a position immediately adjacent to the 
disc loading end of path of movement thereof, the drive gear 74 is in mesh 
with the rack 29 at the terminal end thereof. Upon the tray 2 reaching the 
loading end, the rack 29 is brought out of meshing engagement with the 
drive gear 74. 
Movable Chassis 3 and Chassis Drive Mechanism 9 
With reference to FIG. 5, the movable chassis 3 is liftably disposed in a 
rectangular opening 13 formed in the fixed chassis 12 centrally thereof. 
As shown in FIG. 15, two pins 30 project outward from each side of the 
movable chassis 3. As shown in FIGS. 9 and 10, these pins 30 slidably fit 
in respective vertical guide grooves 17 formed in the fixed chassis 12 to 
guide the upward and downward movement of the movable chassis 3 in a 
horizontal position. 
To drive the movable chassis 3 upward and downward along the guide grooves 
17, a pair of opposed drive members 91, 91 movable forward and rearward 
along the fixed chassis 12 are arranged at the respective sides of the 
opening 13 in the fixed chassis 12. 
With reference to FIG. 8, each drive member 91 comprises a horizontal plate 
91a and a vertical plate 91b. The horizontal plate 91a is formed with a 
slot 92 extending in the front-to-rear direction, while the vertical plate 
91b is formed with a pair of cam slots 93, 93 each extending in the form 
of a stair in this direction. Each cam slot 93 comprises two horizontal 
portions 94, 95 at different levels, and a slanting portion 96 
interconnecting the two portions. A rack portion 98 meshable with the 
drive gear 74 is formed on the upper surface of the horizontal plate 91a. 
As shown in FIG. 5, the pair of drive members 91, 91 are mounted on the 
fixed chassis 12 forwardly and rearwardly movably. A screw 92a extends 
through the slot 92 in each drive member 91 and is driven into the fixed 
chassis 12. The screw 92a guides the linear movement of the drive member 
91. 
With reference to FIG. 9, the two pins 30 projecting from each side of the 
movable chassis 3 extend through the respective cam slots 93 in the drive 
member 91 and are fitted in the guide grooves 17 in the fixed chassis 12. 
Accordingly, with the drive gear 74 in mesh with the rack portion 98 of the 
drive member 91, the power of the loading motor 71 is transmitted to the 
rack portion 98, whereby the drive member 91 is driven forward and 
rearward reciprocatingly. 
FIG. 9 shows the movable chassis 3 as located in its lowered position, with 
the drive member 91 in a rearwardly (rightwardly, in the illustration) 
moved limit position. When the drive member 91 moves forward from this 
position as indicated by an arrow, the pins 30 are forced upward by the 
slanting slotted portions 96 defining the cam slots 93 with the movement 
of the slots 93, whereby the movable chassis 3 is lifted along the guide 
grooves 17. Upon the drive member 91 reaching a forwardly moved limit 
position, the pins 30 are positioned in the horizontal portions 95 of the 
cam slots 93, holding the movable chassis 3 in its raised position. 
The drive member 91 and the fixed chassis 12 respectively have hooks 97, 19 
projecting downward therefrom and spaced apart from each other in the 
direction of movement of the member 91, with a spring 90 connected between 
these hooks 97, 19. This diminishes the load involved in the lift of the 
movable chassis 3 by the drive member 91. 
The chassis drive mechanisms 9, 9 provided at the opposite sides of the 
movable chassis 3 are identical with respect to the construction described 
above. 
The drive member 91 drives the movable chassis 3 downward by an operation 
reverse to that for lifting the chassis 3. When the drive member 91 moves 
from the position of FIG. 10 rearward as indicated by an arrow, the pins 
30 are forced down by the cam-defining slanting slotted portions 96, 
whereby the movable chassis 3 is lowered eventually to the position shown 
in FIG. 9. 
Intermediate Gear Mechanism 100 
Next, a description will be given of an intermediate gear mechanism 100 for 
smoothly transmitting the power of transmission 7 shown in FIG. 7 to the 
chassis drive mechanism 9 as changed-over from the tray drive mechanism 
21. 
With reference to FIG. 5, a pair of opposed intermediate gears 101, 101 
having a rotary shaft in parallel to the connecting shaft 75 are rotatably 
supported on the fixed chassis 12 respectively at opposite sides of the 
movable chassis 3. As shown in FIGS. 11 and 12, each intermediate gear 101 
has a pair of main gear portions 102, 102 positioned at its periphery in 
back-to-back relationship to each other and each composed of three teeth, 
first and second toothless portions 103, 104 formed between the main gear 
portions, a trigger gear portion 105 in the form of a single tooth and 
formed on the first toothless portion 103 at one side thereof closer to 
the movable chassis (at the left in FIG. 11), a first circular-arc portion 
106 formed over the second toothless portion 104 at one side thereof 
closer to the movable chassis, and a second circular-arc portion 107 
diametrically larger than the first circular-arc portion 106 and formed at 
one side of the portion 106 closer to the movable chassis. The 
intermediate gear 101 has a bore 108 extending centrally therethrough for 
a shaft to fit in. 
With reference to FIG. 6 and FIG. 6A, formed on the rear side of the tray 2 
are a first gear portion 120 in the form of two teeth and positioned 
inwardly of the terminal end of each rack 29, and a ridge 116 extending 
along the rack 29 from a position a specified distance away from the first 
gear portion 120. Further formed on the tray rear side inwardly of the 
first gear portion 120 are a second gear portion 121 in the form of three 
teeth, a toothless portion 123 extending along the first gear portion 120 
and having a predetermined length, and a third gear portion 122 in the 
form of a single tooth. These portions 121 to 123 are arranged in a row. 
Further formed inwardly of the second and third gear portions 121, 122 are 
a first projection 124 and a second projection 125 which are spaced apart 
by a predetermined distance. 
With reference to FIG. 8, formed on the upper face of the horizontal plate 
91a of the drive member 91 inwardly of the rack portion 98 are a first 
gear portion 110 in the form of two teeth, and a ridge 99 extending 
longitudinally of the member 91 from a position a specified distance away 
from the first gear portion 110. Further formed inwardly of the first gear 
portion 110 are a second gear portion 111 in the form of three teeth, a 
toothless portion 113 extending along the first gear portion 110 and 
having a predetermined length, and a third gear portion 112 in the form of 
a single tooth. These portions 111 to 113 are arranged in a row. Further 
formed inwardly of the second and third gear portions 111, 112 are a first 
porjection 114 and a second projection 115 which are spaced apart by a 
predetermined distance. 
When the tray 2 has been assembled on the fixed chassis 12, the first gear 
portion 120 of the tray 2 and the first gear portion 110 of the drive 
member 91 are positioned within the same vertical plane as the main gear 
portions 102 of the intermediate gear 101. The second and third gear 
portions 121, 122 of the tray 2 and the second and third gear portions 
111, 112 of the drive member 91 are positioned on the same vertical plane 
as the main gear portions 102 and the trigger gear portion 105 of the 
intermediate gear 101. Further the first and second projections 124, 125 
of the tray 2 and the first and second projections 114, 115 of the drive 
member 91 are positioned on the same vertical plane as the second 
circular-arc portion 107 of the gear 101. 
The operation of the intermediate gear mechanism 100 will be described 
below with reference to FIGS. 13A to 13E. 
FIG. 13A shows the drive gear 74 in clockwise rotation in mesh with the 
rack 29 on the tray 2, driving the tray 2 toward the disc loading 
direction (the direction of arrow shown). In this state, the first and 
second circular-arc portions 106 and 107 are respectively in engagement 
with the toothless portion 113 and the portion between the projections 
114, 115 of the drive member 91, and the first toothless portion 103 of 
the gear 101 is in engagement with the ridge 116 of the tray 2, whereby 
the intermediate gear 101 is restrained from rotation, but the tray 2 is 
allows to move. The drive member 91 is prevented from moving by the first 
and second circular-arc portions 106, 107 of the intermediate gear 101. 
Consequently, the movable chassis 3 is held locked in its lowered 
position. 
When the tray 2 is moved toward the loading completed position after it has 
been brought to a position a short distance to the front of the completed 
position by the rotation of the drive gear 74, the end of the second gear 
portion 121 of the tray first comes into contact with the trigger gear 
portion 105 of the intermediate gear 101 as seen in FIG. 13B, further 
pushing the gear portion 105 to rotate the gear 101 clockwise. 
When the tray 2 further moves, the end of the first main gear portion 102 
of the intermediate gear 101 pushes the end of the first gear portion 110 
of the drive member 91 as shown in FIG. 13C to move the drive member 91 
leftward in the drawing, with the result that the first main gear portion 
102 meshes with the second gear portion 111 of the drive member 91. At the 
same time, the second main gear portion 102 of the intermediate gear 101 
meshes with the second gear portion 121 of the tray 2. In this state, the 
drive gear 74 has completed engagement with the rack 29 on the tray 2 and 
is about to come into meshing engagement with the rack portions 98 on the 
drive member 91. 
Accordingly, with continued clockwise rotation of the drive gear 74 from 
the state of FIG. 13C, the drive member 91 is driven leftward in the 
drawing. With this movement, the drive member second gear portion 111 
moves leftward, which in turn rotates the intermediate gear 101 clockwise. 
At this time, the second main gear portion 102 of the intermediate gear 101 
is in mesh with the second gear portion 121 of the tray 2, so that the 
rotation of the gear 101 further drives the tray rightward. 
Immediately thereafter, the drive gear 74 is released from the meshing 
engagement with the rack 29 on the tray 2 as shown in FIG. 13D. 
When the drive member 91 moves further leftward, the first and second 
circular-arc portions 106 and 107 of the intermediate gear 101 come into 
engagement with the toothless portion 123 of the tray 2 and with the 
portion between the projections 124, 125 thereof, respectively, and the 
first toothless portion 103 of the intermediate gear 101 engages with the 
ridge 99 of the drive member as seen in FIG. 13E. Consequently, the tray 2 
is locked in the loading completed position shown in FIG. 13E. 
The drive member 91 is driven leftward by the drive gear 74 also 
thereafter, whereby the movable chassis 3 is lifted as already described. 
In the meantime, the first toothless portion 103 of the intermediate gear 
101 remains in engagement with the ridge 99 on the drive member 91, 
whereby the gear 101 is restrained from rotation to hold the tray 2 
locked. 
The operation of the intermediate gear mechanism 100 to lower the movable 
chassis 3 from its raised position and to withdraw the tray 2 for disc 
unloading is reverse to the above operation thereof for disc loading and 
proceeds from the state of FIG. 13E to the states of FIGS. 13D, 13C, 13B 
and finally back to the state of FIG. 13A. 
More specifically, the drive gear 74 rotates counterclockwise to move the 
drive member 91 rightward in FIG. 13E, whereupon the end of the second 
gear portion 111 of the drive member 91 first pushes the trigger gear 
portion 105 of the intermediate gear 101, rotating the gear 101 
counterclockwise as shown in FIG. 13D. 
As the drive gear 74 further rotates, the main gear portions 102, 102 of 
the intermediate gear 101 come into meshing engagement with the drive 
member second gear portion 111 and the tray second gear portion 121, 
respectively, as in FIG. 13C, whereby the power of the drive gear 74 is 
transmitted to the tray 2 via the drive member 91 and the intermediate 
gear 101 to drive the tray 2 leftward. 
When the drive gear 74 meshes with the tray rack 29, the power of the gear 
74 is now delivered to the drive member 91 via the tray rack 29 and the 
intermediate gear 101. The drive member 91 is driven further righward as 
in FIG. 13B, whereby the movable chassis 3 is driven to its lowered 
position. 
With continued counterclockwise rotation of the drive gear 74, the first 
and second circular-arc portions 106, 107 of the intermediate gear 101 
come into meshing engagement with the toothless portion 113 of the drive 
member 91 and with the portion between the projections 114, 115 thereof, 
respectively, as in FIG. 13A, whereby the movable chassis 3 is locked in 
its lowered position. 
In this state, the drive gear 74 operates to deliver the tray 2 outward. 
Disc Clamp Mechanism 6 
With reference to FIGS. 5A and 14, a disc clamp mechanism 6 comprises a 
support arm 61 mounted on the fixed chassis 12, and a pair of clamp 
members 62, 62 rotatably supported by the arm 61. 
Each clamp member 62 comprises a plurality of circular-arc upright pieces 
62a arranged in a circular form on its upper side, a plurality of elastic 
claws 62b arranged between the pieces 62a, and an upward projection 66 
having a ball-shaped upper end and provided centrally of the member 62. 
The support arm 61 is formed with a pair of cicular holes 63, 63 
positionable above the respective turntables 4, 4 coaxially therewith and 
provided for the clamp members 62, 62, respectively, for the upright 
pieces 62 and the claws 62b to engage in. In the vicinity of each hole 63, 
two lanced lugs 68, 69 are provided for attaching a plate spring 64 
thereto. 
The plate spring 64 is formed with apertures 64a, 64b for the lugs 68, 69 
to engage in. When the spring 64 is attached to the support arm 61 with 
the lugs 68, 69 engaged in the apertures 64a, 64b, the spring 64 is warped 
and bears on the upper end of the projection 66 of the clamp member 62. 
The spring presses the clamp member 62 downward with the elasticity 
afforded by the warp. 
FIG. 2C shows that the disc 10 on the tray 2 is pressed against the clamp 
member 62 by the turntable 4 in its raised position. In this state, the 
clamp member 62 is slightly raised above its lowered position against the 
plate spring 64. The disc 10 is held between the clamp member 62 and the 
turntable 4 by the elastic force of the spring 64. Accordingly, when the 
turntable 4 rotates, the clamp member 62 rotates with the disc 10 and the 
turntable 4, as supported by the projection 66. 
Pickup Transport Mechanism 
With reference to FIGS. 15 and 16, an opening 31 formed in the movable 
chassis 3 centrally thereof is provided with a pair of guide shafts 53, 53 
in parallel to each other and also in parallel to a line through the 
centers of rotation of the two turntables 4, 4. Each shaft 53 is clamped 
at each end thereof between a spring plate 34 and a lug 35 and is thereby 
secured to the movable chassis 3. 
The guide shafts 53, 53 slidably extend through bores 54, 55 formed in the 
body of the pickup 5 in intimate contact therewith to guide the pickup 5 
for an accurate linear movement. In this state, the optical center of an 
objective lens 50 of the pickup 5 is positioned on the line through the 
centers of rotation of the turntables 4, 4 and moves on this line. 
A pickup transport assembly 61 reciprocatingly drives a rack assembly 8 
mounted on the movable chassis 3 with the power of a feed motor 52 
attached to the lower side of the movable chassis 3, whereby the pickup 5 
coupled to the rack assembly 8 is transported from a position close to one 
of the turntables 4 to a position close to the other turntable along the 
guide shafts 53. 
A drive gear 56 is fixed to the output shaft of the feed motor 52. The 
rotation of the drive gear 56 is subjected to a speed reduction by a first 
driven gear 57 and a second driven gear 58 on the movable chassis 3. A 
pinion 59 attached to the second driven gear 58 is in mesh with the gear 
portion of the rack assembly 8 at all times. 
Disposed on the movable chassis 3 is a sensor switch 144 which is actuated 
when the pickup 5 is brought to the middle position in the range of its 
movement by the rack assembly 8. 
As seen in FIG. 15, the rack assembly 8 comprises a first rack 81 and a 
second rack 82 superposed thereon and connected thereto by a spring (not 
shown) as will be described later. 
With reference to FIG. 18, the first rack 81 has a gear portion 81a formed 
on the upper half of its one side face, and a ridge 81b formed on the 
lower half of the side face and having approximately the same height as 
the teeth of the gear portion 81a. The gear portion 81a and the ridge 81b 
extend over the entire length of the rack 81. The first rack 81 has a pair 
of holders 83, 83 spaced apart by a specified distance and projecting 
forward from the other side face thereof. Pieces 83a, 83a project downward 
from the holders 83, 83, respectively. Between these holders 83, 83, the 
first rack 81 has a pair of pieces 84, 85 spaced apart by a specified 
distance and projecting forward therefrom. The projecting pieces 84, 85 
are formed on their inner faces a pair of protrusions 84a, 85a opposed to 
each other. 
The first rack 81 has an opening 86b centrally thereof. One side portion of 
the rack plate defining 20 this opening extends upward to provide a 
projection 86 and is formed with an inward protrusion 86a. A T-shaped 
apertures 87 is formed in each of opposite end portions of the first rack 
81. 
A guide groove 81c extending along the ridge 81b is formed in the rear side 
of the first rack 81. 
FIG. 19 shows the second rack 82 as turned upside down. The second rack 82 
has on one side face thereof a gear portion 82a extending over its entire 
length and on the other side face a forward projection 82b at the 
midportion thereof. 
With reference to FIG. 19, the second rack 82 has an opening 88b centrally 
thereof. One side portion of the rack plate defining the opening 88b 
extends upward to provide a projection 88, which has on its inner surface 
an inward protrusion 88a. A pair of engaging pieces 89, 89 each having an 
enlarged end are formed on the upper side of the second rack 82 at the 
respective end portions. 
To assemble the first and second racks 81, 82, the second rack 82 as shown 
in FIG. 19 is turned upside down longitudinally thereof, and the engaging 
pieces 89, 89 of the second rack 82 are inserted into the enlarged 
portions of the respective apertures 87, 87 in the first rack 81 from 
above the first rack 81. Consequently, the projection 88 of the second 
rack 82 is inserted into the opening 86b of the first rack 81, and the 
protrusions 86a and 88a of the two racks are opposed to each other within 
the opening 86b. The two racks 81, 82 are thereafter slidingly moved 
relative to each other so as to position the engaging pieces 89, 89 in the 
constricted portions of the apertures 87, 87, whereby the two racks are 
unremovably engaged with each other while being allowed to move relative 
to each other longitudinally within a given range. 
A first spring 154 is then placed as compressed between the protrusions 
86a, 88a of the first and second racks to bias the two racks 81, 82 away 
from each other. As a result, the pitch lines of the two racks are aligned 
with each other as shown in FIG. 16 with their gear portions out of phase. 
As shown in FIG. 17, three pins 36, 36, 36 projecting upward from the 
movable chassis 3 are arranged at a given spacing along a straight line 
extending in the direction of movement of the pickup 5 along the opening 
31. The rack assembly 8 fabricated as stated above has its guide grooved 
portion 81c engaged with the pins 36 with slight play and is thereby 
slidably mounted on the movable chassis 3. Except when the rack assembly 8 
is positioned centrally of the range of its movement, the assembly 8 is 
guided for movement by two of the three pins 36. 
As seen in FIG. 17, the movable chassis 3 has around the opening 31 mount 
portions 37, 37 for the spindle motors 41, 41, a mount portion 39 for the 
feed motor 52, and shafts 32, 33 for the driven gears 57, 58. 
With the rack assembly 8 mounted on the movable chassis 3, the gear 
portions 81a, 82a of the two racks 81, 82 mesh with the pinion 59 at the 
same time as shown in FIG. 21. At this time, the two racks 81, 82 are 
biased by the spring 154 away from each other, so that when one tooth of 
the pinion 59 is in engagement with two teeth of the racks 81, 82 which 
teeth are positioned at opposite sides of the one tooth, the pinion tooth 
is clamped between the two teeth. This eliminates the backlash between the 
rack assembly 8 and the pinion 59. Consequently, the pinion is changeable 
in the direction of its rotation without producing play in the movement of 
the rack assembly 8. 
The rack assembly 8 is prevented from slipping off the movable chassis 3 
upward by the contact of the ridge 81b of the first rack 81 with the end 
of the pinion 59 shown in FIG. 15. 
The pickup 5 is coupled to the rack assembly 8 by the following 
arrangement. 
As shown in FIG. 20, the pickup 5 is formed with a recessed portion 5a in 
its rear side. The projections 84, 85 of the first rack 81 are fitted in 
the recessed portion 5a in intimate contact with the opposed faces 
thereof, and a second spring 155 is provided as compressed between these 
projections 84, 85. As a result, the two projections 84, 85 are biased 
away from each other by the second spring 155 into pressing contact with 
the pickup recessed portion 5a. Furthermore, the pickup 5 is held between 
the pair of holders 83, 83 of the first rack 81. 
When the feed motor 52 operates to move the rack assembly 8 along the pins 
36, 36, 36, the pickup 5 moves along the guide shafts 53, 53 with this 
movement. If the parallelism between the direction of movement of the rack 
assembly and the guide shaft 53 is low owing to variations in the degree 
of precision with which the pickup transport mechanism 51 is assembled, 
the distance between the pickup 5 and the rack assembly 8 varies with the 
transport of the pickup 5. Nevertheless, the pickup 5 is restrained only 
with respect to the direction of movement of the rack assembly by the 
holders 83, 83 and the projections 84, 85 of the assembly 8 as already 
described but is movable relative to the assembly 8 in a direction 
perpendicular to the direction of assembly movement. The relative movement 
therefore absorbs the variation in the distance. 
Accordingly, the rack assembly 8 can be driven smoothly by the operation of 
the pinion 59 and exerts no objectionable force on the pickup 5, 
permitting the pickup to move straight along the guide shafts 53 
accurately. 
Control of Transport of Pickup 
As is well known, the compact disc has recorded on the innermost peripheral 
portion of its signal bearing surface "table of contents" (hereinafter 
referred to as "TOC") which is the data as to the titles of pieces of 
music recorded in the program area of the signal bearing surface. For 
signal reproduction, the TOP of the disc intended for playback must be 
read out first and stored. 
With disc players such as the one described above which are adapted for the 
playback of two discs in succession, there is a need to read TOC from the 
two discs with a signle pickup, so that a series of operations from 
reading of TOC through the reproduction of signals from the program area 
must be conducted as promptly as possible. For this purpose, the operation 
of the pickup should not involve any idle movement. 
According, the following signal reproduction system is employed for the 
present disc player. 
FIG. 22 shows a circuit for controlling the operation of the tray 2 and the 
pickup 5. The control system includes a system controller 130 comprising a 
microcomputer and adapted to control the starting, stopping and direction 
of rotation of the loading motor 71 and the feed motor 52. 
The front panel of the cabinet has an open switch 136 and a close switch 
137 for giving a command to open or close the tray. The command signals 
from these switches are fed to the system controller 130. Accordingly, the 
controller 130 produces a control signal for starting the loading motor 71 
in the disc unloading direction when the open switch 136 is actuated, or a 
control signal for starting the motor 71 in the disc loading direction 
when the close switch 137 is actuated. 
The time when the pickup 5 has reached a first end position of its movement 
where it is opposed to the innermost peripheral portion of one of the 
discs, and the time when the pickup has reached a second end position of 
its movement as opposed to the innermost peripheral portion of the other 
disc are detected respectively by a first limit switch 134 and a second 
limit switch 135 which are arranged at opposite ends of the range of 
movement of the pickup 5 as shown in FIG. 15, in corresponding relation to 
the respective projecting pieces 83a, 83a of the pickup 5. The detection 
signals from these switches are fed to the system controller 130. 
The time when the tray has reached the limit position of its movement 
toward the disc discharge side is detected by a third limit switch 138 
mounted on the fixed chassis 12 in opposed relation with the end of the 
tray 2 as shown in FIG. 5. 
The presence or absence of the disc on the tray 2 upon the completion of 
charging of the tray 2 is detected by photocouplers comprising a pair of 
laser diodes 132, 132 attached to the support arm 61 of of the disc clamp 
mechanism 6 as shown in FIG. 14, and a pair of photosensors 131, 131 
provided on the movable chassis 3 and opposed to the respective laser 
diodes 132 as seen in FIG. 5. 
When the tray 2 has been completely placed in, each laser diode 132 is 
turned on, and whether or not the photosensor 131 receives the laser beam 
is detected. With the disc 10 set on the turntable 4 as seen in FIG. 2C, 
the beam of the laser diode 132 is blocked by the disc 10 without 
impinging on the photosensor 131, whereas if the disc 10 is absent, the 
beam from the diode 132 passes through the hole 27 in the tray 2 and 
reaches the photosensor 131 and is detected. The detection signal from the 
photosensor 131 is fed to the system controller 130 shown in FIG. 22. 
The arrival of the movable chassis 3 at its raised position, i.e., the 
completion of disc loading operation, is detected by a fourth limit switch 
139 which is disposed on the fixed chassis 12, as opposed to the end of 
the drive member 91 as shown in FIG. 5. 
The feature of the signal reproduction system for the disc player of the 
present invention is that in response to a command signal from the open 
switch 136 or the close switch 137, the system controller 130 feeds a 
control signal to the feed motor 52 to move the pickup 5 toward the disc 
accommodating portion marked with the identification symbol "B" and 
position the pickup 5 at the innermost peripheral portion of the disc 
(hereinafter referred to as the "disc B") in the accommodating portion for 
the pickup to read TOC from the disc B first. The pickup 5 is then 
transported to the innermost peripheral portion of the disc (disc A) in 
the accommodating portion marked with the identification symbol "A" for 
the pickup to read TOC from the disc A and is thereafter allowed to wait 
at this position for the reproduction of signals. 
Thus, the pickup 5 is eventually positioned at the innermost peripheral 
portion of the disc A for the following reason. Generally, the user 
determines in his mind a preferential order of playback according to the 
order of identification symbols, and it is thought that the disc A is to 
be followed by the disc B when signals are to be reproduced. It is 
therefore likely that the disc intended for playback first will be set in 
the disc accommodating portion marked with "A" which is earlier in the 
order of identification symbols. 
The operation of the control circuit will be described in greater detail 
with reference to the flow charts of FIGS. 23 to 25. 
FIG. 23 is a flow chart showing a tray discharge operation. When the open 
switch 136 is manipulated with the tray placed in, the loading motor 71 is 
started in response to the command, starting to discharge the tray 2 (step 
1). Simultaneously with this, the feed motor 52 is started to transport 
the pickup 5 toward the position of the innermost periphery of the disc B 
(step 2). 
Next, a signal from the third limit switch 138 indicates completion of 
discharge of the tray 2 (step 3). If the inquiry of this step is answered 
in the negative, step 4 inquires whether the pickup 5 has reached the 
position of the innermost periphery of the disc B with reference to a 
signal from the first limit switch 134. When the answer is affirmative, 
the pickup 5 is stopped (step 5), whereupon the sequence returns to step 
3. 
According to steps 3 to 5, if the pickup has reached the end position of 
its movement prior to the completion of tray discharge, the pickup is 
immediately stopped. For example, if the open switch is manipulated when 
the pickup is at the outermost peripheral position of the disc A, the 
pickup is close to the portion where the disc B is accommodated, and the 
distance the pickup is to be moved is small, so that the transport of the 
pickup is completed earlier than the completion of tray discharge. In this 
case, the answer to the inquirey of step 4 is affirmative, followed by 
step 5 to discontinue the transport of the pickup. 
When the answer to step 3 is affirmative, step 6 follows to discontinue the 
discharge of the tray. Step 7 inquires whether the pickup has been 
completely transported. If the answer is negative, pickup transport is 
continued, but if it is affirmative, pickup transport is discontinued 
(step 8) to complete the tray discharge operation. 
The above process executed brings the pickup to the innermost peripheral 
position of the disc B. 
FIG. 24 is a flow chart showing a tray forwarding or charging operation. If 
the operation of FIG. 23 has been entirely completed when the tray 
charging operation is to be initiated, the pickup is already at the 
innermost peripheral position of the disc B, so that it is no longer 
necessary to transpor the pickup. However, in the case where a tray charge 
command is given as an interrupt command while the pickup is still in 
continued movement after the tray has been discharged (for example when 
step 7 in FIG. 23 is answered in the negative), a tray charge operation is 
initiated during the transport of the pickup. In this case, transport of 
the pickup needs to be continued. The process of FIG. 24 is therefore 
executed. 
Upon the manipulation of the close switch 29, an operation to charge the 
tray 2 is started (step 1). At the same time, the pickup 5 is transported 
toward the innermost peripheral position of the disc B (step 2). 
Step 3 then inquires whether the tray 2 has been completely charged. If the 
answer is negative, a further inquiry is made as to whether the pickup has 
been completely transported (step 4). When the inquiry is answered in the 
negative, the sequence returns to step 3. If otherwise, the pickup is 
stopped (step 5), followed by step 3. 
When transport of the pickup is started in step 2 of FIG. 24 in the case 
where pickup transport has been completed with the tray discharge 
operation of FIG. 23 as already stated, step 4 is answered in the 
affirmative at the same time, followed by step 5 to discontinue pickup 
transport, with the result that the pickup remains in the initial position 
almost without any movement. In the case where the pickup is in movement, 
on the other hand, an inquiry is made in step 4 as to whether the pickup 
has reached the innermost peripheral position of the disc B. When the 
answer is negative, step 3 follows, whereas if otherwise, the pickup is 
stopped in step 5, whereupon the sequence returns to step 3. 
When the inquiry of step 3 is answered in the affirmative because the tray 
has been placed in, the tray is halted (step 6). If the pickup is in 
travel at this time, pickup transport is forcibly discontinued (step 7), 
whereby the tray charge operation is completed. 
The above procedure is so adapted that if the pickup is brought to the 
innermost peripheral position of the disc B bedore the completion of tray 
charge, the pickup is allowed to wait at the peripheral position, and that 
if the tray is completely charged during the transport of the pickup, the 
pickup is immediately halted. 
The operation to read TOC will be described with reference to the flow 
chart of FIG. 25. 
On completion of the tray charge operation as described above, the 
procedure of FIG. 25 is started immediately. First, step 1 inquires 
whether the disc B is present according to whether the photosensor 
receives laser beam from the laser diode. When the answer is affirmative, 
the pickup 5 is transported to the innermost peripheral position of the 
disc B (step 2), followed by step 3 to read out TOC from the disc B. The 
TOC is stored in a RAM within the system controller 130. 
The pickup is transported in step 2 only in the case where the transport 
has been discontinued before the pickup reaches the end position of its 
movement in the tray charge operation of FIG. 24. In this case, the pickup 
has been brought close to the innermost peripheral position of the disc B 
by the tray discharge and charge operations of FIGS. 23 and 24, so that 
the the pickup 5 can be transported to the innermost peripheral position 
within a very short period of time. 
In the case where the disc B is present on the tray 2, the TOC is thus read 
out promptly by the pickup 5. 
On completion of reading of the TOC from the disc B, an inquiry is made as 
to whether the disc A is present with reference to a signal from the 
photosensor concerned (step 4). When the answer is affirmative, the pickup 
is transported to the innermost peripheral position of disk A (step 5) and 
reads TOC from the disc A (step 6). The TOC is stored in the RAM within 
the system controller 130. 
In the case where both the disc A and the disc B are present, the pickup 
reads TOC first from the disc B and then from the disc A, with the result 
that on completion of TOC reading, the pickup is located at the innermost 
peripheral position of the disc A. Accordingly, when signals are to be 
reproduced from the disc A immediately thereafter, the pickup can be 
promptly initiated into the reproducing operation. 
In the case where the disc A only is present and the disc B is absent, the 
absence of the disc B is detected in step 1, followed by step 4 to detect 
the presence of the disc A and by step 5 to transport the pickup toward 
the innermost peripheral position of disc A. 
While the pickup is often located in the innermost peripheral position of 
the disc B when to be transported toward the disc A, it is likely that the 
pickup will be positioned closer to the disc A than the disc B innermost 
peripheral position. This occurs in the case of the foregoing tray charge 
operation when the tray has been charged in place before the completion of 
pickup transport. In such a case, the distance the pickup is to be 
transported is shorter than the entire distance of transport to 
correspondingly shorten the time required for transporting the pickup. 
When the disc B only is present and the disc A is absent, TOC is read from 
the disc B in steps 1 to 3 of FIG. 25, and the absence of the disc A is 
detected in step 4, whereby the TOC reading operation is completed. 
When no disc is present on the tray, the inquires of steps 1 and 4 are both 
answered in the negative, whereby the TOC reading operation is completed. 
When the procedures of FIGS. 23 to 25 are resorted to for the discharge and 
charge of the tray, the pickup is first set in the innermost peripheral 
position of the disc B or in the vicinity of this position, so that the 
TOC on the disc B can be immediately read out, followed by the reading of 
the TOC on the disc A, whereupon the pickup can be initiated into a 
playback operation for the disc A promptly. 
The construction of the disc player of the present invention is not limited 
to that of the foregoing embodiment but can be modified variously by one 
skilled in the art without departing from the scope of the invention as 
defined in the appended claims.