 |
Description  |
|
|
BACKGROUND OF THE INVENTION
(1) Field of the Invention:
The present invention relates to a front loading disc player.
(2) Description of the Prior Art:
Front loading disc players have a disc transfer mechanism for transferring
a disc to be played back from a position outside of a player housing into
a playback position, i.e., onto a turntable, and then positioning the disc
on the turntable. Thereafter, the turntable is rotated about its own axis
and a pickup means is moved radially over the disc along an
information-recorded disc surface to reproduce the recorded information.
Some conventional front loading disc players only house one disc at a time
and play back one side of the disc housed in the disc player. For playing
back both sides of a disc or a number of discs successively in such a
front loading disc player, it has been necessary to eject and load the
disc or discs for turning the disc upside down or replacing the disc with
another disc. The user of the disc player has been troubled by such a disc
handling process.
There has been proposed a front loading disc player having two pickup means
that are positioned so as to sandwich a disc placed on a turntable. In
this proposed front loading disc player, both sides of the disc can be
played back without ejecting and reloading the disc. However, the front
loading disc player of this type is expensive to manufacture since the two
costly pickup means must be employed.
SUMMARY OF THE INVENTION
In view of the aforesaid problems of the conventional front loading disc
players, it is an object of the present invention to provide a front
loading disc player that is inexpensive to manufacture which is capable of
playing back both sides of a disc or a plurality of discs successively
without ejecting the disc or discs.
Another object of the present invention is to provide a front loading disc
player which is small in size and can load a disc or discs reliably and
highly accurately.
According to the present invention, there is provided a front loading disc
player comprising a player housing, playback means disposed in the player
housing and having a turntable and pickup means, a disc transfer mechanism
for carrying a disc to be played back and transferring the disc into a
playback position, and a playback means moving mechanism for moving the
playback means between a first position corresponding to one side of the
disc having reached the playback position and a second position
corresponding to the other side of the disc.
The playback means moving mechanism has a support member supporting the
playback means, a pivotal support mechanism for pivotally supporting the
support member to allow the playback means to rotate between the first and
second positions, and driving means for rotating the support member.
The support member has a pivot axis parallel to the direction in which the
pickup means moves.
The support member has a pivot axis substantially normal to the direction
in which the disc is transferred.
The distance between a disc carrier surface of the turntable when the
playback means is in the first position and the disc carrier surface of
the turntable when the playback means is in the second position is equal
to the thickness of the disc, and a median plane of the thickness of the
disc placed on the turntable and the center of rotation of the turntable
intersect at a point where a pivot axis of the support member passes.
The disc transfer mechanism has a carrier movable in a first direction with
respect to the player housing, a tray for carrying a disc, which is
disposed on the carrier and movable in the first direction and a second
direction, and tray driving means for moving the tray with respect to the
carrier.
The carrier is single in number, and a plurality of trays are disposed on
the carrier.
The front loading disc player also includes control means for controlling
the playback means and the disc transfer mechanism, the playback means
including a disc clamping mechanism, the arrangement being such that when
the playback means is in the second position, the control means moves the
tray closely to the turntable and thereafter actuates the disc clamp
mechanism to clamp the disc.
A plurality of trays are juxtaposed with each other on the carrier in the
second direction, the distance between disc carrier surfaces of adjacent
ones of the trays is equal to a unit distance through which each of the
trays is movable in the second direction.
According to the present invention, there is further provided a front
loading disc player comprising a player housing, playback means disposed
in the player housing and having a turntable and pickup means, a disc
transfer mechanism for carrying a disc to be played back and transferring
the disc into a playback position, a plurality of carriers arranged side
by side in a first direction and movable in a second direction with
respect to the player housing, a plurality of trays disposed on the
carrier respectively, for carrying respective discs and movable in the
second direction, carrier driving means for moving the carrier tray
driving means for moving the trays with respect to the carrier first
playback means moving mechanism for moving the playback means between a
first position corresponding to one side of a disc having reached the
playback position and a second position corresponding to the other side of
the disc, and second playback means moving mechanism for carrying and
moving the playback means and the first playback means moving mechanism in
the first direction.
The above and other objects, features and advantages of the present
invention will become more apparent from the following description when
taken in conjunction with the accompanying drawings in which preferred
embodiments of the present invention are shown by way of illustrative
example.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a front loading disc player according to a
first embodiment of the present invention;
FIG. 2 is an exploded perspective view of an internal structure of the
front loading disc player shown in FIG. 1;
FIG. 3 is an view of the internal structure of the front loading disc
player shown in FIG. 1;
FIG. 4 is a plan view, partly in cross section, of the internal structure
illustrated in FIG. 3;
FIG. 5 is a cross-sectional view taken along line V--V of FIG. 4;
FIG. 6 is a cross-sectional view taken along line VI--VI of FIG. 4;
FIG. 7 is a cross-sectional view taken along line VII--VII of FIG. 4;
FIGS. 8(a)-8(c), 9(a)-9(c) 10(a)-10(c), and 11 are views showing the
internal structure of FIG. 3 in detail;
FIG. 12 is a cross-sectional view taken along line XII--XII of FIG. 4;
FIG. 13 is a block digram of a drive control system for the disc player
shown in FIG. 1;
FIGS. 14 through 16 are views explanatory of operation of the disc player
shown in FIGS. 1 through 15;
FIGS. 17(a) through 17(k) are flowcharts of operation of the disc layer
shown in FIG. 1;
FIG. 18 is a perspective view of a front loading disc player according to a
second embodiment of the present invention;
FIG. 19 is an exploded perspective view of main components of an internal
structure of the front loading disc player illustrated in FIG. 18;
FIG. 20 is a plan view of the internal structure of the front loading disc
player illustrated in FIG. 18;
FIG. 21 is a plan view, partly in cross section, of the internal structure
of FIG. 20;
FIG. 22 is a side elevational view of the internal structure of FIG. 20;
FIGS. 23(a)-23(c), 24, and 25 are views showing the internal structure of
FIG. 20 in detail;
FIGS. 26 and 27 are views explaining operation of the front loading disc
player illustrated in FIGS. 18 through 25.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A front loading disc player according to a first embodiment will now be
described with reference to FIGS. 1 through 17.
As shown in FIG. 1, the front loading disc player, generally designated by
the reference numeral 1, has a player housing 2 including a front panel 3
with a laterally elongate rectangular slot 3a defined therein through
which a carrier 4 can project out of the player housing 2. More
specifically, the rectangular slot 3a is elongate laterally in the
direction of the arrow X (leftward direction) and the direction opposite
thereto (rightward direction), both across the direction of the arrow Y
(forward direction) in which the front panel 3 faces. The direction of the
arrow Z is an upward direction normal to the directions of the arrows X,
Y. A keyboard 5 for controlling operation of the disc player is disposed
on the front panel 3 on the lefthand side of the slot 3a.
As shown in FIG. 2, the carrier 4 is formed into a hollow rectangular
parallelepiped with its upper and rear sides open. As indicated by the
solid lines and the two-dot-and-dash lines in FIG. 3, the carrier 4 is
movable in a first or fore-and-aft direction (the direction of the arrow Y
and the direction opposite thereto) between a stored position in the
player housing 2 and a projected position out of the player housing 2.
More specifically, as shown in FIGS. 4 through 6, the carrier 4 has two
pairs of parallel longitudinal ridges or guide rails 4a extending in the
fore-and-aft direction on opposite outer lateral sides thereof. Guide
rollers 6 rollingly ride between the ridges 4a in each pair, as shown in
FIG. 5. As illustrated in FIGS. 5 and 6, a groove 4b is defined in a
lefthand portion of the lower surface of the carrier 4, the groove 4b
extending the entire length of the carrier 4 in the direction in which the
carrier 4 is movable. A cylindrical guide member 7 is fixed to the player
housing 2 and positioned in the groove 4b in slidable engagment with the
surfaces defining the groove 4b. Therefore, the carrier 4 can be guided
for back-and-forth movement without wobbling in the lateral direction (the
direction of the arrow X and the direction opposite thereto).
The upper one of the ridges 4a in the pair on the lefthand side of the
carrier 4 has a rack 4c disposed on and extending over the entire upper
surface thereof. As shown in FIGS. 4 through 6, the rack 4c is held in
mesh with a gear 9a which is a final gear of a speed reducer gear
mechanism 9. The carrier 4 is moved by a motor 11 through the speed
reducer gear mechanism 9, toothed pulleys 10a, 10b, and a toothed belt 10c
trained around the tooled pulleys 10a, 10b. The speed reducer gear
mechanism 9, the toothed pulleys 10a, 10b, the toothed belt 10c, and the
motor 11 jointly serve as a carrier driving means for moving the carrier
4.
As shown in FIGS. 1 and 2, a movable chassis 13 is disposed in the carrier
4. The movable chassis 13 comprises a flat portion 13a extending in the
fore-and-aft direction (the direction of the arrow Y and the direction
opposite thereto) and in the lateral direction (the direction of the arrow
X and the direction opposite thereto), and a pair of laterally spaced
upright portions 13b, 13c extending upwardly (in the direction of the
arrow Z) contiguously from the lateral side edges of the flat portion 13a.
As shown in FIGS. 2, 4 through 7, a pair of movable members 14, 15
extending in the fore-and-aft direction (the direction of the arrow Y and
the direction opposite thereto) is disposed outside of the lateral upright
portions 13b, 13c of the movable chassis 13, the movable members 14, 15
being movable reciprocably in the fore-and-aft direction. The movable
members 14, 15 are shown in detail in FIGS. 8(a) through 8(c) and 9(a)
through 9(c).
In FIGS. 2, 4 through 7, four pins 13d are mounted on the upright portions
13b, 13c (two pins on each upright portion). As shown in FIGS. 2, 5
through 7, the pins 13d are slidably fitted in respective guide grooves 4e
defined in lateral inner wall surfaces of the carrier 4 and extending in
the vertical direction (the direction of the arrow Z and the direction
opposite thereto) for guiding vertical movement of the movable chassis 13.
The pins 13d on the upright portions 13b, 13c of the movable chassis 13
also slidably engage in pairs of cam slots 14a, 15a defined in the movable
members 14, 15, respectively. The cam slots 14a defined in the movable
member 14 positioned leftwardly of the movable chassis 13 are generally
inclined downwardly (in the direction opposite to the direction of the
arrow Z) in the forward direction (the direction of the arrow Y). The cam
slots 15a defined in the other movable member 15 are generally inclined
upwardly in the forward direction. The cam slots 14a, 15a are thus shaped
such that the movable chassis 13 is vertically moved when the movable
members 14, 15 are moved relatively to each other.
The cam slots 14a, 15a comprise three short straight portions 14b, 14c,
14d; 15b, 15c, l5d, respectively, extending in the direction (fore-and-aft
direction) in which the movable members 14, 15 are movable, and two
slanted portions 14e, 14f; 15e, 15f, respectively, contiguous to and
inclined with respect to the short straight portions 14b, 14c, 14d; 15b,
15c, 15d. Therefore, the cam slots 14a, 15b are generally staircase-shaped
as a whole. Consequently, the movable chassis 13 is moved intermittently
in two steps when the movable members 14, 15 are moved.
As shown in FIGS. 2, 4, 5, 8(a), and 8(c), the movable member 14 on the
lefthand side of the movable chassis 13 has a rack 14g extending in the
direction in which the movable member 14 is movable. As illustrated in
FIGS. 4 and 5, the rack 14g is held in mesh with a final gear 17a of a
speed reducer gear mechanism 17 mounted on the carrier 4. The movable
member 14 is driven by a driving force imparting means comprising the
speed reducer gear mechanism 17, toothed pulleys 18a, 18b, a toothed belt
18c trained therearound, and a motor 19.
As shown in FIG. 4, between the movable members 14, 15, there is disposed a
swing lever 20 centrally mounted angularly movably on the carrier 4 by a
support shaft or pin 20a extending vertically (in the direction of the
arrow Z and the direction opposite thereto). The swing lever 20 supports
on its opposite ends two pins 20b, 20c, respectively, projecting parallel
to the support shaft 20a and smoothly engaging in respective recesses 14h,
15h defined respectively in the movable members 14, 15.
Two trays 23, 24 each for carrying a disc 22 (FIG. 1) are disposed, one
over the other, on the movable chassis 13, with a prescribed gap provided
between the trays 23, 24 in a second or vertical direction (the direction
of the arrow Z and the direction opposite thereto). The movable chassis
13, the movable members 14, 15, the swing lever 20, the driving force
imparting means including the motor 19 and other members for imparting a
driving force to the movable member 14, and related minor members jointly
constitute a second tray driving means for moving the trays 23, 24 in the
second direction with respect to the carrier 4.
FIGS. 10(a) through 10(c) and 11 show the tray 23 in detail, FIG. 11 being
a cross-sectional view taken along line XI--XI of FIG. 10(a). The other
tray 24 will not be described in detail as it is identical to the tray 23.
The tray 23 has a first disc carrier surface 23a having a diameter D1 for
carrying a disc 22 (FIG. 1) of a diameter of about 30 cm, and a second
disc carrier surface 23b having a diameter D2 for carrying a disc (not
shown) of a diameter of about 20 cm, the first and second disc carrier
surfaces 23a, 23b being concentric with each other. As is clear from FIG.
11, the second disc carrier surface 23b is defined as a recess with
respect to the first disc carrier surface 23a, the second disc carrier
surface 23b having a depth greater than the thickness of the disc to be
carried on the second disc carrier surface 23b. The tray 23 has a recess
23c defined in a front end thereof for inserting a finger therethrough
below the disc carried on the first or second disc carrier surface 23a or
23b to remove the disc. The recess 23c has a depth from the first disc
carrier surface 23a, the depth being larger than the depth of the second
disc carrier surface 23b.
The trays 23, 24 are movable with respect to the movable chassis 13 on
which they are carried, and hence with respect to the carrier 4, in the
first or fore-and-aft direction (the direction of the arrow Y and the
direction opposite thereto). As shown in FIGS. 4, 5, and 7, righthand ends
of the trays 23, 24 slidably engage two guide shafts 25, 26, respectively,
disposed on a righthand portion of the movable chassis 13 and extending in
the fore-and-aft direction. As illustrated in FIG. 5, lefthand ends of the
trays 23, 24 are slidably held against guide members 28 and guide plates
29 disposed on the movable chassis 13. The trays 23, 24 are therefore
smoothly guided for movement in the fore-and-aft direction by these guide
shafts 25, 26, the guide member 28, and the guide plate 29. As illustrated
in FIGS. 10(a) through 10(c), the tray 23 has a block 23d slidably fitted
over the guide shaft 25, and steel balls 23e and hemispherical projections
23f which are slidably held against the guide members 28 and the guide
plates 29. Likewise, the tray 24 has a block, steel balls, and
hemispherical projections.
As shown in FIGS. 4, 5, and 7, a pair of pulleys 31b, 31c with a wire 31a
trained therearound is mounted on the righthand end of the movable chassis
13, the wire 31a being coupled to the tray 23. The pulley 31b is rotatable
by a motor 32 through a speed reducer gear mechanism 31d, toothed pulleys
31e, 31f, and a toothed belt 31g trained therearound. When the motor 32 is
rotated in one direction (normal direction) and then the other direction
(reverse direction), the tray 23 is reciprocably moved in the fore-and-aft
direction. As illustrated in FIGS. 4 and 5, the tray 24 is reciprocably
movable by a wire 33a, pulleys 33b, 33c, a speed reducer gear mechanism
33d, toothed pulleys 33e, 33f, a toothed belt 33g, and a motor 34.
The wires 31a, 33a, the pulleys 31b, 31c, 33b, 33c, the speed reducer gear
mechanisms 31d, 33d, the toothed pulleys 31e, 31f, 33e, 33f, the toothed
belts 31g, 33g, and the motors 32, 34 jointly constitute a first tray
driving means for moving the trays 23, 24 in the first or fore-and-aft
direction with respect to the carrier 4. As shown in FIG. 3, the trays 23,
24 are movable between a first position directly above the carrier 4 and a
second position rearward of the carrier 4.
The first tray driving means, the second tray driving means, the trays 23,
24, and the carrier 4 jointly constitute a disc transfer mechanism for
carrying a disc 22 (FIG. 1) to be played and transferring the disc 22 into
a playback position in the player housing 2.
As described above, the carrier 4 is movable between the projected and
stored positions in the fore-and-aft direction with respect to the player
housing 2, and the trays 23, 24 disposed on the carrier 4 are movable
between the first and second positions in the fore-and-aft direction with
respect to the carrier 4. Therefore, as shown in FIG. 3, each of the trays
can assume the projected position out of the player housing 2, the stored
position in the player housing 2, and also the playback position at a
deepest position in the player housing 2.
As shown in FIGS. 2 through 3, 6, 7, and 12, a turntable 37 is disposed way
back in the housing 2 and supported by a support member 38 extending
laterally in the player housing 2. The support member 38 has a pair of
support shafts 39 extending laterally from the opposite ends thereof and
rotatably supported by a pair of respective bearings 40, 41 fixedly
mounted in the player housing 2. As shown in FIGS. 4 and 12, a carriage 43
supporting an optical pickup means is mounted on the support member 38
through a guide shaft 44 so as to be movable in the lateral direction (the
direction of the arrow X and the direction opposite thereto) along a plane
parallel to a disc carrier surface of the turntable 37. The carriage 43 is
movable by a carriage driving means comprising a worm 45 meshing with a
half nut 43a mounted on the carriage 43, a worm wheel 46a for rotating the
worm 45 about its own axis, a worm 46b meshing with the worm wheel 46a,
and a motor 47 having an output shaft coupled to the worm 46b. As shown in
FIG. 12, the carriage 43, the guide shaft 44, the worm 45, and the motor
47 are mounted on a swingable plate 48 swingably disposed on the support
member 38 by means of a pin 48a. The swingable plate 48 swings in a plane
normal to the disc carrier surface of the turntable 37. There is a drive
source for swinging the swingable plate 48 through a tilt-servo means.
As illustrated in FIG. 12, a longitudinal bracket 50 is attached to the
support member 38 parallel thereto. To the bracket 50, there is swingably
attached an arm 51 through a pin 51a. A disc-shaped presser 52 is
rotatably mounted on the free end of the arm 51 for pressing a disc in the
playback position against the turntable 37 thereby to clamp the disc in
place on the turntable 37. A cam member 53 having a spiral cam surface 53a
is rotatably mounted on the longitudinal bracket 50 and held in engagement
with the arm 51. In response to rotation of the cam member 53, the arm 51
is caused to swing to move the presser 52 toward or away from the
turntable 37. The cam member 53 is rotatable by a motor 55 through a speed
reducer gear mechanism 54 including a worm 54a. The arm 51 is normally
urged by a spring 56 in a direction to displace the presser 52 toward the
turntable 37.
The arm 51, the presser 52, the cam member 53, the speed reducer gear
mechanism 54, the motor 55, and the spring 56 jointly serve as a disc
clamping mechanism. The disc clamping mechanism, the turntable 37, the
optical pickup means, and the tilt-servo means jointly constitute a
playback means for playing back discs.
The entire playback means is mounted on the support member 38. As described
above, the support member 38 is pivotally supported by a pivotal support
mechanism which comprises the support shafts 39 and the bearings 40, 41.
Therefore, the playback means can be angularly moved between a position
corresponding to the lower surface of a disc 22 which has been transferred
into the playback position by the disc transfer mechanism and a position
corresponding to the upper surface of the disc.
As shown in FIGS. 4 and 12, the support member 38 has a pivot axis 38a
parallel to the direction in which the carriage 43 carrying the optical
pickup means moves. With this arrangement, the space in the player housing
2 is effectively utilized while minimizing any dead space therein, and
hence the disc player is of a reduced overall size. The pivot axis 38a is
perpendicular to the fore-and-aft direction (the direction of the arrow Y
and the direction opposite thereto) in which a disc can be transferred.
This arrangement is also effective in reducing the overall size of the
disc player, particularly its transverse size.
A drive means for rotating the support member 38 which supports the
playback means including the turntable 37 will hereinafter be described.
As shown in FIGS. 4, 6, and 12, a disc-shaped member 61 is fitted over the
support shaft 39 on the lefthand end of the support member 38 for rotation
with the support member 38. A gear 62 is rotatably mounted on the support
shaft 39 on the lefthand side of disc-shaped member 61. As best shown in
FIG. 6, pins 61a, 61b are mounted on the disc-shaped member 61, and pins
62a, 62b are mounted on the gear 62, with a coil spring 61c being
connected between the pins 61a, 62a and a coil spring 61d between the pins
61b, 62b. When the gear 62 is rotated in a normal direction or a reverse
direction, the disc-shaped member 61 and the support member 38 are rotated
through the coil springs 61c, 61d. The gear 62 is rotated by a motor 64
through a double gear 63, a worm 63b, toothed pulleys 63c, 63d, and a
toothed belt 63e.
An engaging pin 38b projects from the lefthand end of the support member
38. The support member 38 can be positioned selectively in two limit
positions (hereinafter referred to as normal and inverted positions)
reached thereby when rotated in the normal and reverse directions, when
the engaging pin 38b engages selectively a pair of stoppers 67a, 67b fixed
to the player housing 2.
The disc-shaped member 61, the coil springs 61c, 61d. the gear 62, the
double gear 63a, the worm 63b, the toothed pulleys 63c, 63d, the toothed
belt 63e, the motor 64, the stoppers 67a, 67b, and related minor
components jointly constitute a driving means for rotating the support
member 38 on which the playback means including the turntable 37 is
supported. The driving means, the support member 38, and the pivotal
support mechanism including the bearings 40, 41 and pivotally supporting
the support member 38 jointly serve as a playback means moving mechanism
for angularly moving the playback means between the first position
corresponding to the lower surface of a disc having reached the playback
position and the second position corresponding to the upper surface of the
disc.
The disc carrier surface of the turntable 37 when the playback means is in
the first position, i.e., when the support member 38 is in the normal
position, and the disc carrier surface of the turntable 37 when the
playback means is in the second position, i.e., when the support member 38
is in the inverted position are spaced from each other by a distance which
is equal to the thickness t of the disc 22 (see FIGS. 1 and 12). As shown
in FIGS. 4 and 12, a median plane of the thickness of the disc 22 placed
on the turntable 37 and the center of rotation of the turntable 37
intersect at a point through which the pivot axis 38a of the support
member 38 passes. This arrangement allows the disc on the turntable 37 to
be in the same position when the playback means is in the first and second
positions.
As shown in FIG. 6, the disc carrier surfaces of the trays 23, 24
juxtaposed with each other on the carrier 4 are spaced from each other by
a distance a. As is apparent from FIGS. 8(b) and 9(b), the
staircase-shaped cam slots 14a, 15a defined respectively in the movable
members 14, 15 for intermittently moving the trays 23, 24 with the movable
chassis 13 in the vertical direction are profiled such that the amount of
downward movement of the movable chassis 13 in a first step is a which is
equal to the distance between the disc carrier surfaces of the trays 23,
24, and the amount of downward movement of the movable chassis 13 in a
second step is b. With this structure, the vertical positions (in the
direction of the arrow Z and the direction opposite thereto) to be assumed
by two discs 22 successively transferred onto the turntable 37 by the disc
transfer mechanism can easily equalized.
Various detector switches disposed in various locations in the disc player
will now be described below.
As shown in FIGS. 4 and 5, detector switches 71, 72 are disposed at a front
lefthand position in the player housing 2 and engageable by a portion of
the carrier 4 for detecting whether the carrier is in the projected
position out of the player housing 2 or in the stored position in the
player housing 2.
As illustrated in FIG. 4, four detector switches 73, 74, 75, 76 are
disposed on a lefthand rear portion of the carrier 4 for engagement with
the movable member 14. When the movable member 14 reciprocably moves in
the fore-and-aft direction (the direction of the arrow Y and the direction
opposite thereto), the movable chassis 13 carrying the trays 23, 24 is
reciprocably moved intermittently in two steps in the vertical direction.
The detector switch 76 serves to detect when the movable chassis 13 is in
a lower position. The detector switch 74 serves to detect when the movable
chassis 13 is in a middle position. The detector switch 74 serves to
detect when the movable chassis 13 is positioned intermediate between the
lower and middle positions. A detector switch 77 is positioned on a
righthand rear portion of the carrier 4 for engaging the other movable
member 15. The detector switch 77 serves to detect when the movable
chassis 13 reaches an upper position. The detector switch 73 serves to
detect when the movable chassis 13 is positioned intermediate between the
middle and upper positions. As shown in FIGS. 4 and 5, a detector switch
79 is mounted on the front end of the movable chassis 13 and engageable
with an engaging member 78 (FIG. 5) fixed to the player housing 2 for
supplementarily detecting when the movable chassis 13 reaches the upper
position.
Two detector switches 81, 82 are disposed on a righthand front portion of
the movable chassis 13 and engageable with respective portions of the
trays 23, 24 for detecting when these trays are positioned at the center
of the movable chassis 13 and hence the carrier 4. Two detector switches
83, 84 are disposed on a righthand rear portion of the movable chassis 13
and engageable with respective portions of the trays 23, 24 for detecting
when these trays reach the projected position rearward of the carrier 4,
i.e., the playback position. Another detector switch 85 is disposed on the
righthand rear portion of the movable chassis 13 near the detector
switches 83, 84. The detector switch 85 is triggered by engagement with
the upper tray 23 when the tray 23 projects rearwardly from the carrier 4
beyond the position where the portion of the tray 23 engages the detector
switch 83.
As illustrated in FIG. 4, the support member 38 supporting the playback
means supports a detector switch 87 for detecting when the carriage 43
comes near the radially innermost edge of an information recording area on
a disc 22, and also supports a photosensor 88 for detecting when a
transferred disc 22 is placed on the turntable 37.
As shown in FIG. 6, the motor 64 is supported on a bracket 90 disposed on
the lefthand side of the support member 38. Two detector switches 91, 92
are mounted on the bracket 90 for engagement with a projection 61f on the
disc-shaped member 61 (FIG. 12) fixed to the lefthand end of the support
member 38. The detector switches 91, 92 serve to detect whether the
support member 38 is in the normal position or the inverted position,
i.e., whether the playback means supported on the support member 38 is in
the first position corresponding to the lower surface of the disc or in
the second position corresponding to the upper surface of the disc.
Detected signals issued by the aforesaid various detector switches are
applied to a control circuit 95 shown in FIG. 13 which operates the motors
and the pickup means according to the timing described later in response
to these applied signals.
A playback process of the front loading disc player thus constructed will
be described with reference to FIGS. 14 through 17(f). The operation
starts from the condition in which the carrier 4 projects from the player
housing 2, as shown in FIG. 1. In this condition, the upper tray 23 is in
a position most projected rearwardly (in the direction opposite to the
direction of the arrow Y) from the carrier 4.
As shown in FIG. 1, discs 22 to be played back are placed respectively on
the trays 23, 24 projecting from the player housing 2, and then the
keyboard 5 is operated upon to start playing back the discs.
As shown in FIGS. 17(a) through (f), when a disc playback starting command
is given, a step S3 confirms whether the playback means including the
turntable 37 is in the normal position or not. Then, the motor 11 is
rotated in the normal direction in a step S6 to store the carrier 4 with
the trays 23, 24 positioned above back into the player housing 2.
Immediately before the carrier 4 reaches the stored position, the motor 32
is rotated in the reverse direction in a step S9 to move the upper tray 23
forwardly a prescribed distance from the above position so that the upper
tray 23 is positioned in the playback position directly above the
turntable 37. The lower trays 24 is positioned centrally in the carrier 4,
i.e., in the stored position. Thereafter, the motor 19 is rotated in the
normal direction in a step S12 to lower the trays 23, 24 together with the
movable chassis 13 carrying them from the upper position to the lower
position thus placing the disc 22 from the upper tray 23 onto the
turntable 37. The motor 55 is rotated in the normal direction in a step
S16 to clamp the disc 22, and then the motor 47 is rotated in a step S19
to start moving the carriage 43 carrying the optical pickup mean for
playing back the lower side of the disc 22. After the lower side of the
disc 22 has been played back, the disc 22 is unclamped in a step S27, and
the motor 19 is rotated in the reverse direction in a step S29 to move the
movable chassis 13 to the middle position. The disc 22 is now transferred
from the turntable 37 to the upper tray 23. The upper tray 23 carrying the
disc 22 again is returned to the position directly above the carrier 4 by
reversing the motor 32 in a step S32. Then, the upper side of the disc 22
on the upper tray 23 starts being played back in the following manner:
The motor 64 is rotated in the normal direction in a step S35 to rotate the
playback means including the turntable 37 into the inverted position as
shown in FIG. 14. At the same time, the motor 19 is rotated in the normal
direction in a step S38 to lower the movable chassis 13 into the lower
position. Thereafter, the motor 32 is rotated in the normal direction in a
step S4l to move the upper tray 23 into the playback position to position
the disc 22 on the upper tray 23 directly below the turntable 37. Then,
the motor 19 is reversed in a step S44 to elevate the movable chassis 13
to a position intermediate between the lower and middle positions, after
which the motor 55 is rotated in the normal direction in a step S47 to
clamp the disc 22. Therefore, when the playback means is in the inverted
position for playing back the upper side of the disc 22, the tray 23
together with the movable chassis 13 carrying the same is moved closely to
the turntable 37, and thereafter the disc 22 is clamped. After completion
of the clamping of the disc 22, the upper side of the disc 22 is played
back.
After the upper side of the disc 22 has been played back, the motor 55 is
reversed in a step S58 to unclamp the disc 22. In response to the disc
unclamping operation, the disc 22 which has been pressed against the
turntable 37 is transferred onto the upper tray 23. Thereafter, the motor
32 is reversed to return the upper tray 23 directly above the carrier 4.
Then, the lower side of the disc placed on the lower trays 24 is played
back as follows:
A step S64 confirms whether the playback means is returned to the normal
position as shown in FIG. 15 or not. Then, the motor 19 is reversed in a
step S70 to lift the movable chassis 13 into the upper position. The motor
34 is rotated in the normal direction in a step S73 to move the lower tray
24 into the playback position directly above the turntable 37.
Subsequently, the motor 19 is rotated in the normal direction in a step
S76 to lower the movable chassis 13 into the middle position for thereby
placing the disc 22 from the lower tray 24 onto the turntable 37. The
motor 55 is rotated in the normal direction in a step 83 to clamp the disc
22, and the motor 47 is also rotated in the normal direction in a step S87
to start moving the carriage 43 to play back the lower side of the disc
22. After the lower side of the second disc 22 has been played back, the
disc 22 is unclamped, and the motor 19 is reversed in a step S97 to move
the movable chassis 13 upwardly into the upper position in a step S98. The
upward movement of the movable chassis 13 transfers the disc 22 from the
turntable 37 onto the lower tray 24. The motor 34 is reversed in a step
S100 to return the lower tray 24 carrying the disc 22 again to the
position directly above the carrier 4.
Then, the upper side of the disc 22 on the lower tray 24 is played back in
the manner described below.
The motor 64 is rotated in the normal direction in a step S103 to turn the
playback means including the turntable 37 into the inverted position as
shown in FIG. 16, and the motor 19 is simultaneously rotated in the normal
direction in a step S106 to lower the movable chassis 13 into the middle
position. Then, the motor 34 is rotated in the normal direction in a step
S109 to move the lower tray 24 directly above the turntable 37.
Thereafter, the motor 19 is reversed in a step S112 to elevate the movable
chassis 13 to the position intermediate between the upper and middle
positions. The motor 55 is rotated in the normal direction in a step S115
to clamp the disc 22, and the spindle motor is rotated in a step S118 and
the motor 47 is rotated in a step S119 to move the carriage 43 for thereby
playing back the upper side of the disc 22.
Upon completion of the playback of the upper side of the second disc 22,
the motor 55 is reversed in a step S126 to unclamp the disc 22. The disc
22 which has been held against the turntable 37 is returned back onto the
lower tray 24. The motor 34 is thereafter reversed to move the lower tray
24 directly above the carrier 4.
After both sides of the two discs have been played back, the motor 19 is
reversed in a step S132 to move the movable chassis 13 which carries the
trays 23, 24 to the upper position. Thereafter, the motor 11 is reversed
in a step S135 to cause the carrier 4 together with the movable chassis 13
and the trays 23, 24 to project out of the player housing 2. The motor 32
is then rotated in the normal direction in a step S138 to move only the
upper tray 23 rearwardly, so that the components of | | |
