Abstract:
A disk playback device provides a space above and below a selected disk held in a disk holder. A turntable and optical pickup reside within the space. The turntable is moved inward in the space from a storage position to chuck, and withdraw, the selected disk from its disk holder to a playback position in which the axis of the turntable is within the outline of disks stored in disk holders. The storage position places the axis of the turntable outside the outline of disks stored in the disk holders. In a single play mode, a disk not stored in a disk holder is moved directly from outside the disk playback device to the playback position where it is chucked and played. On conclusion of single play, the disk is transported out of the disk playback device without being resident in a disk holder.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a changer-type disk playback device capable of selectively playing back a plurality of disks. 
     U.S. Pat. No. 5,138,591, Japanese Laid-open Publication Number 6-36436, and U.S. Pat. No. 5,561,657 disclose changer-type disk playback devices that allow a selected disk to be played back without requiring the disk to be pulled out from its storage position. In order to make the device compact, playback means, comprising an optical pickup, a turntable, and the like, is moved horizontally between a plurality of coaxially disposed disks. 
     These conventional examples comprise a magazine having a plurality of mounting plates. A disk is mounted on each of these mounting plates. The magazine can be attached and removed from the device. When this magazine is outside the device, a lock mechanism locks the mounting plates so that the mounting plates do not separate from each other. When the magazine is stored in the device, the lock mechanism is released by a prescribed lock releasing mechanism in the device. During disk playback, the mounting plates are moved in a direction perpendicular to the disk surfaces, thereby providing more space. Playback mechanisms positioned at recessed positions, such as a turntable and an optical pickup, are moved in the space created by moving the mounting plates to allow disks to be played back without requiring the disks to be pulled out from the magazine. 
     When disks not held in the magazine are to be played back, the magazine is removed from the device, and disks are removed from the magazine. Then, the disk to be played back is mounted in the magazine, and the magazine is remounted in the device. This makes operating the device complex. Thus, there is a need for this type of changer-type disk playback device to be equipped with a loading mechanism for loading a disk inserted from a slit formed on a front panel of the device into the device. The loading mechanism can be either a pinch-roller loading mechanism where the disk surface is interposed between a drive roller and a driven roller, or a belt loading mechanism where the edges of the disk are supported by a continuous drive belt disposed along a disk transfer path. 
     When a disk is to be stored in a storing position using a loading mechanism, a supporting means must be disposed to support the disk at the storing position. The supporting means can take on a variety of different structures. When the recording surface or label surface of disks are mounted on a mounting plate, as in the conventional technology described above, the disk can be damaged by the sliding contact between the disk surface and the mounting surface during the loading operation. In Japanese Laid-open Publication Number 9-17171, filed by the present applicant, an arcuate disk holder that supports the disk edge over approximately 180 degrees can be used. According to this disk supporting means, the sliding contact between the disk and the disk holder takes place only at the edge, where no data is recorded. Thus, even if the disk is scratched, there is no effect on playback. 
     During disk playback, the disk must be moved away from the disk holder so that the disk holder and the disk are out of contact with each other. If the disk holder is disposed close to the front panel of the device, the disk would project from the front panel when the disk is pulled out. Thus, the disk holder needs to be disposed further back in the device so that there is space between the front panel and the disk holder for the disk to be pulled out. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide a playback device which overcomes the drawbacks of the prior art. 
     It is a further object of the invention to provide a playback device which permits playing of a disk while an axis of the disk remains within a perimeter of stored disks. 
     It is a still further object of the invention to provide a disk playback device in which a spacing between disks is sufficient to permit a turntable to move to and chuck a disk stored in a disk storage device, then withdraw the disk to a playback position. 
     It is a still further object of the invention to provide a disk playback device in which a storage position for a turntable and optical pickup is located outside a vertical space about a disk playback position. 
     Briefly stated, the present invention provides a disk playback device in which a space above and below a selected disk held in a disk holder provides room for a turntable and optical pickup to move in and out of positions outside and inside the perimeter of stored disks. The turntable is moved inward in the space from a storage position to chuck, and withdraw, the selected disk from its disk holder to a playback position in which the axis of the turntable is within the outline of disks stored in disk holders. The storage position places the axis of the turntable outside the outline of disks stored in the disk holders. In a single play mode, a disk not stored in a disk holder is moved directly from outside the disk playback device to the playback position where it is chucked and played. On conclusion of single play, the disk is transported out of the disk playback device without being resident in a disk holder. 
     When the disk holder is moved perpendicular to the disk surface in order to play back a disk, playback means needs to be recessed to a position where there is no overlapping with the disk. The space that is needed to provide a recessed position for the playback means acts as a bottleneck in making the device more compact. 
     In order to achieve the object described above, a changer-type disk playback device according to the present invention comprises: a plurality of disk supporting members supporting a plurality of disks so that the disks are coaxial; disk support member transferring means transferring the plurality of disk supporting members in a direction perpendicular to the surface of the disks; disk transferring means transferring a disk between a selected disk supporting member and a disk insertion/removal position; playback means performing playback of a disk comprising at least an optical pickup and a turntable; disk withdrawing means pulling out a disk from a disk supporting member so that the disk and the disk supporting member are out of contact; and a playback means transferring mechanism moving the playback means to a recessed position and a playback position. The recessed position is a position in a flat region formed by the transfer of the disk by the disk transferring means where the turntable does not overlap with the disks held in the plurality of disk support members. The playback position is a position where the turntable overlaps with the disks held in the plurality of the disk support members. 
     When the playback means is at the recessed position, it is positioned between the disk insertion/removal position, which is provided by disk transferring means, and disk supporting means. Thus, there is no need to prepare a space exclusively for the recessed position of playback means. 
     The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic plan view to which reference will be made in describing the operations of the disk playback device over time. 
     FIG. 2 is a schematic plan view to which reference will be made in describing the operations of the disk playback device over time. 
     FIG. 3 is a schematic plan drawing for the purpose of describing the operations of the disk playback device over time. 
     FIG. 4 is a schematic plan drawing for the purpose of describing the operations of the disk playback device over time. 
     FIG. 5 is a schematic plan drawing for the purpose of describing the operations of the disk playback device over time. 
     FIG. 6 is a schematic plan drawing for the purpose of describing the operations of the disk playback device over time. 
     FIG. 7 is a side-view drawing of the cam means. 
     FIG. 8 is a cross-section drawing along the A—A line in FIG. 1 for the purpose of describing the operations of the cam means over time. 
     FIG. 9 is a cross-section drawing along the A—A line in FIG. 1 for the purpose of describing the operations of the cam means over time. 
     FIG. 10 is a cross-section drawing along the A—A line in FIG. 1 for the purpose of describing the operations of the cam means over time. 
     FIG. 11 is a cross-section drawing along the A—A line in FIG. 1 for the purpose of describing the operations of the cam means over time. 
     FIG. 12 is a cross-section drawing along the A—A line in FIG. 1 for the purpose of describing the operations of the cam means over time. 
     FIG. 13 is a cross-section drawing along the A—A line in FIG. 1 for the purpose of describing the operations of the cam means over time. 
     FIG. 14 is a cross-section drawing along the A—A line in FIG. 1 for the purpose of describing the operations of the cam means over time. 
     FIG. 15 is a cross-section drawing along the A—A line in FIG. 1 for the purpose of describing the operations of the cam means over time. 
     FIG. 16 is a cross-section drawing along the A—A line in FIG. 1 for the purpose of describing the operations of the cam means over time. 
     FIG. 17 is a cross-section drawing along the A—A line in FIG. 1 for the purpose of describing the operations of the cam means over time. 
     FIG. 18 is a cross-section drawing along the A—A line in FIG. 1 for the purpose of describing the operations of the cam means over time. 
     FIG. 19 is a cross-section drawing along the A—A line in FIG. 1 for the purpose of describing the operations of the cam means over time. 
     FIG. 20 is a cross-section drawing along the A—A line in FIG. 1 for the purpose of describing the operations of the cam means over time. 
     FIG. 21 is a schematic side-view drawing for the purpose of describing the operations of the disk playback device over time. 
     FIG. 22 is a schematic side-view drawing for the purpose of describing the operations of the disk playback device over time. 
     FIG. 23 is a schematic side-view drawing for the purpose of describing the operations of the disk playback device over time. 
     FIG. 24 is a schematic side-view drawing for the purpose of describing the operations of the disk playback device over time. 
     FIG. 25 is a schematic side-view drawing for the purpose of describing the operations of the disk playback device over time. 
     FIG. 26 is a schematic side-view drawing for the purpose of describing the operations of the disk playback device over time. 
     FIG. 27 is a schematic side-view drawing for the purpose of describing the operations of the disk playback device over time. 
     FIG. 28 is a schematic side-view drawing for the purpose of describing the operations of the disk playback device over time. 
     FIG. 29 is a schematic side-view drawing for the purpose of describing the operations of the disk playback device over time. 
     FIG. 30 is a schematic side-view drawing for the purpose of describing the operations of the disk playback device over time. 
     FIG. 31 is a schematic side-view drawing for the purpose of describing the operations of the disk playback device over time. 
     FIG. 32 is a schematic side-view drawing for the purpose of describing the operations of the disk playback device over time. 
     FIG. 33 is a schematic side-view drawing for the purpose of describing the operations of the disk playback device over time. 
     FIG. 34 is a schematic side-view drawing for the purpose of describing the operations of the disk playback device over time. 
     FIG. 35 is an enlarged drawing of flange  16 . 
     FIG. 36 is a top-view drawing of belt drive mechanism  40 . 
     FIG. 37 is a cross-section drawing along the B—B line of FIG.  36 . 
     FIG. 38 is a top-view drawing of guide mechanism  50 . 
     FIG. 39 is a cross-section drawing along the C—C line in FIG.  38 . 
     FIG. 40 is a block diagram of the control circuit of the disk playback device. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following is a description of the embodiments according to the present invention of a changer-type disk playback device capable of holding five disks. 
     Referring to FIG. 1, there is shown a disk playback device  1 , having a five disk capacity, in which disks are absent. Arcuate disk holders  11 - 15  (only upper disk holder  11  is seen in FIG. 1, the relative positions of the five arcuate disk holders  11 - 15  are shown in FIG.  21 ), for holding up to five disks, are disposed to support the edges of disks along an angular range of approximately 180 degrees. All of disk holders  11 - 15  are identical, therefore only first disk holder  11 , at the uppermost position is described in detail. 
     Four flanges  16  are disposed on disk holder  11 . A round hole  17  is formed on each flange  16 . Referring momentarily also to the enlarged drawing in FIG. 35, an engagement pin  18  projects into round hole  17 . 
     Returning now to FIG. 1, together with FIG. 7, each round hole  17  fits over a disk holder transferring means  30 . Each disk holder transferring means  30  includes a cylindrical part having interconnected cam grooves  33 - 34  in its surface. Engagement pin  18  fits into cam grooves  33 ,  34 . Disk holder transferring means  30 , which is described later, transfers disk holders  11 - 15  in a direction perpendicular to the paper surface of FIG.  1 . 
     Referring now to FIG. 8, a cross-section drawing along the line A—A line in FIG. 1 shows the relationship between disk holders  11 - 15  and disk holder transferring means  30 . Disk holder  11  (as well as the remainder of the disk holders) includes disk supports  23 ,  24  for supporting the edges of the label side and the recording side of a disk. A base  25  is attached integrally with disk supports  23 ,  24 . A flange  16 , attached to base  25 , encircles the cylindrical portion of disk holder transferring means  30 . Engagement pin  18  extends inward into round hole  17  to engage a cam groove  33  in a first cylindrical cam  31 . 
     Disk holder transferring means  30  is a two-piece structure which includes first cylindrical cam  31  and a second cylindrical cam  32  having identical outer diameters. Second cylindrical cam  32  is free to rotate relative to first cylindrical cam  31 . First cylindrical cam  31  is free to rotate on a pin  35  extending upward from a chassis  4 . Cam groove  33  is formed on the outer perimeter of first cylindrical cam  31 . A second cam groove  32  is formed on second cylindrical cam  32 . Engagement pin  18  of upper disk holder  11  rides in cam groove  33 . Engagement pins  18  of disk holders  12 - 15  ride in cam grooves  34  and  33 , as will be explained. Disk holder transferring means  30 , comprising first and second cylindrical cams  31 ,  32 , move disk holders  11 - 15  in the vertical directions. 
     Referring to FIGS. 7 and 8, cam grooves  33 ,  34  have an irregular pitch. Positions P 1 -P 11  indicate positions to which engagement pins  18 , and the disk carried in their related disk holders, are moved by rotation of disk holder transferring means  30 . A pitch LI separates positions P 1 -P 5 . A pitch L 2 , larger than pitch L 1 , separates positions P 5 -P 7 . A pitch L 3 , larger than pitch L 2 , separates positions P 7 -P 8 . Pitch L 1  is also duplicated to separate positions P 8 -P 11 . First cylindrical cam  31  and second cylindrical cam  32  are positioned at rotational positions in which the connecting positions between cam grooves  32  and  33  aligned. Pitch L 1  is set so that adjacent disk holders are in close contact without a separating space. This enhances compactness of the apparatus. 
     A spur wheel  36  is disposed on first cylindrical cam  31 . A second spur wheel  37  is disposed on second cylindrical cam  32 . Spur wheels  36 ,  37  are connected to conventional cylindrical cam driving mechanisms  83 ,  82 , which may be, for example, a motor or the like. Spur wheels  36 ,  37  control the rotational direction and position of first cylindrical cam  31  and second cylindrical cam  32 . Disk holder transferring means  30  are disposed on each of the four flanges  16 . Spur wheels  36 ,  37  are connected to each disk holder transferring means  30  so that all four disk holder transferring means  30  are driven by cylindrical cam drive mechanisms  82 ,  83  in the same direction and the same rotation angle. Rotation of disk transferring means  30  moves disk holders  11 - 15  vertically within disk playback device  1  while maintaining them parallel to each other. 
     Referring also to FIG. 1, a disk inserted through a slit  3  in front panel  2  of device  1  is transferred to disk holders  11 - 15  by a disk transferring means. The disk transferring means is preferably a belt drive mechanism  40  on the left side and a guide mechanism  50  on the right side. Referring to FIG. 36, which shows a topview drawing of belt drive mechanism  40 , and FIG. 37, which shows a crosssection drawing along the B—B line in FIG. 36, a pair of upper and lower guide plates  41 ,  42  support the edge of a disk from above and from below. A continuous drive belt  45  is disposed between guide plates  41 ,  42 . Drive belt  45  passes over a driven pulley  43  and an idler pulley  44 . Driven pulley  43  is driven in a conventional manner by a conventional pulley drive mechanism  84  such as, for example, a motor or the like. A fixing block  46  is disposed within the loop of drive belt  45  to support drive belt  45  against inward flexing. 
     Referring to FIGS. 38 and 39, guide mechanism  50  includes an upper guide plate  51  and a lower guide plate  52  supporting the edge of a disk. A guide wall  53  between upper and lower guide plates  51  and  52  contacts the disk edge. A connecting mechanism (not shown in the drawings) allows belt drive mechanism  40  and guide mechanism  50  to move in the direction of arrows D and E in FIG.  1 . Guide mechanism  50  and belt drive mechanism  40  are connected so that when guide mechanism  50  is moved a transverse distance in the direction of arrow E, drive mechanism  40  is moved the same distance in the opposite direction, in the direction of arrow D. Thus, a center position, equally spaced between guide mechanism  50  and belt drive mechanism  40  remains in the same transverse location, during inward and outward movement of these two elements. A belt/guide driving mechanism  85  includes a motor or the like to move belt drive mechanism  40  and guide mechanism  50  in the D-E direction. 
     With a disk supported between drive belt  45  and guide wall  53 , drive pulley  43  is rotated counter-clockwise by pulley drive mechanism  84 . This rotates the disk clockwise while transferring it in the direction indicated by an arrow F, which is perpendicular to the D-E direction. This transfers the disk, after insertion through slit  3  in front panel  2 , into a storage position in the selected disk holder in device  1 . Also, when drive pulley  43  is rotated clockwise by pulley drive mechanism  84 , the disk is rotated counter-clockwise to transfer it in the direction of an arrow G, which is in the opposite direction from arrow F. This moves the selected disk out from the disk holder to a position where a section of the disk projects from slit  3 , where it can be grasped by a user. 
     Referring to FIGS. 1 and 21, a spindle motor  62  (not shown in FIG.  1 ), which rotates a turntable  61  for mounting disks, is fixed to a chassis  63 . Turntable  61  is known as a self-chucking turntable that does not require a damper for clamping the disk to turntable  61 . A feed screw  65  is rotated by a thread motor  64  disposed on chassis  63 . The rotation of feed screw  65  causes an optical pickup to be moved between an inner perimeter and an outer perimeter of a disk. A playback means includes at least turntable  61  and optical pickup  66  to perform the known operation of beaming a laser from optical pickup  66  to a disk while rotating it using turntable  61 , and then reading the reflected light to playback data recorded on the disk. 
     A guide rail  67  is disposed to guide optical pickup  66  to move parallel to chassis  63 . A shaft  68  is disposed at one end of chassis  63 . Chassis  63  can rotate  45  degrees counter-clockwise from the stowage position shown in FIG. 1 around shaft  68 . From this rotated position, chassis  63  can move straight in the direction of arrow F. The motion of chassis  63  is controlled by a chassis driving mechanism  86  comprising a motor or the like. Thus, shaft  68  and chassis driving mechanism  86  serve as the playback means transferring mechanism, which transfers playback means as described above. 
     Turntable  61  is positioned between front panel  2  and disk holders  11 - 15 . Referring to FIG. 3, when a disk  71  is supported by disk holder  11 , turntable  61  does not overlap disk  71 . Instead, it is positioned in the loading path of disk  71  between front panel  2  and disk  71 . 
     Referring now to FIG. 40, there is shown a block diagram for the circuit in device  1 . Processing of data from disk  71  is performed by a conventional playback circuit  91  on the data read by optical pickup  66 . The results are then output from an output terminal  92 . A control circuit  93 , comprising a microprocessor or the like, controls playback circuit  91  and controls cylindrical cam drive mechanisms  82 ,  83 , pulley drive mechanism  84 , belt/guide drive mechanism  85 , and chassis drive mechanism  86  according to the timings described below. 
     Referring to the following drawings, the operations of this embodiment will be described below, with reference to FIG.  1  through FIG. 6, which show schematic plan views of device  1 ; FIG. 7, which shows a side-view of disk holder transferring means  30 , which controls the vertical transfer of disk holders  11 - 15 , and which shows positions P 1 -P 11  of disk holders  11 - 15 ; FIG.  8 -FIG. 20, which show the rotation of disk holder transferring means  30 ; and FIG.  21 -FIG. 34, which show side-views of device  1  and describe the motion of the disk and disk holders  11 - 15  within device  1 . 
     Referring to FIG. 1, in the initial state for storage of disks, drive belt  45  of belt drive mechanism  40  and guide wall  53  of guide mechanism  50  are moved to positions where their separation is smaller than the diameter of the disk. Referring to FIGS. 7 and 8, in the initial state, engagement pin  18 , on flange  16  of first disk holder  11  is positioned at position P 6  at cam groove  33  of first cylindrical cam  31 . This positions first disk holder  11  at the same height as slit  3  in front panel  2 . Engagement pins  18 , on flanges  16  of second—fifth disk holders  12 - 15  are positioned at positions P 8 -P 11  at cam groove  34  of second cylindrical cam  32 . 
     From this state, disk  71  is inserted into slit  3 . The insertion force causes belt drive mechanism  40  to be moved in the direction of arrow D, and guide mechanism  50  to be moved in the direction of arrow E by the same amount, resulting in the state shown in FIG.  2  and FIG.  21 . This motion triggers pulley drive mechanism  84  to turn belt drive mechanism  40  and drive pulley  43  counterclockwise, and turn drive belt  45  counter-clockwise. Disk  71 , which is supported between drive belt  45  and guide wall  53 , is rotated clockwise and transferred in the direction indicated by arrow F. Belt drive mechanism  40  and guide mechanism  50  are moved away from each other slightly, and disk  71  is moved fully into device  1 . 
     Referring to FIG. 3, FIG. 9, and FIG. 22, the rotation of drive belt  45  moves disk  71  into first disk holder  11 . In this state, disk  71  is stably supported over approximately 180 degrees of its edge by disk supports  23 ,  24  of disk holder  11 . To play back disk  71  after it has been loaded, the belt/guide drive mechanism first moves belt drive mechanism  40  in the direction of arrow D and guide mechanism  50  in the direction of arrow E. This moves belt drive mechanism  40  and guide mechanism  50  away from disk  71 . 
     Then, chassis  63  is rotated 45 degrees counter-clockwise around shaft  68  from the recessed position shown in FIG. 3 to the position shown in FIG.  4 . Chassis  63  is then moved in the direction of arrow F. Chassis drive mechanism  86  transfers chassis  63  to a position shown in FIG.  5  and FIG. 23 so that the center of rotation of turntable  61  is aligned with the center of a center hole  81  in disk  71 . 
     From this position, first cylindrical cam  31  is rotated 180 degrees counter clockwise by cylindrical cam drive mechanism  82  while second cylindrical cam  32  is kept stationary. This moves disk holder  11  from position P 6  to position P 7 , descending by a distance of pitch L 2 . 
     Referring to FIG.  10  and FIG. 24, disk  71  is mounted on turntable  61 . A conventional self-chucking mechanism, not shown in the drawings, chucks disk  71  onto turntable  61 . While disk holder  11  descends, the other disk holders  11 - 15  remain stationary, since they are positioned by second cylindrical cam  32 , which remains stationary at this time. 
     After disk  71  is chucked onto turntable  61 , chassis drive mechanism  86  moves chassis  63  in the direction of arrow G in FIG.  5 . This moves disk  71  out of disk holder  11  so that they are out of contact with each other. This state is shown in FIG. 6, FIG. 11, and FIG.  25 . Thus, the motion of chassis  63  from FIG. 5 to FIG. 6 moves disk  71  out from disk holder  11 . Turntable  61 , chassis  63 , and chassis drive mechanism  86  together serve as disk withdrawing means. 
     From this position with the disk withdrawn, cylindrical cam drive mechanism  82  rotates first cylindrical cam  31  by itself 360 degrees clockwise. Disk holder  11  is raised from position P 7 , shown in FIG. 7, for a distance two times the distance of pitch L 2  to position P 5 . This state is shown in FIG.  12  and FIG.  26 . 
     Referring to FIG. 6, chassis drive mechanism  86  moves chassis  63  in the direction of arrow F. Seen from above, disk  71  is moved to the same position as shown in FIG.  5 . Referring to FIG.  13  and FIG. 27, however, disk holder  11  is moved vertically above the disk surface by a distance twice that of pitch L 2 . Thus, if the surface of disk  71  is shaken or if chassis  63  is suspended, disk  71  is prevented from coming into contact with other members while it rotates, even if chassis  63  is shaken vertically by an external vibration or the like. 
     Referring to FIG.  1 -FIG. 3, when chassis  63  is at the recessed position, turntable  61  is positioned between front panel  2  and the disks supported by disk holders  11 - 15 . As described above, disk  71  of disk holder  11  is pulled out to a withdrawn position for playback. Thus, disk holders  11 - 15  must remain separated from front panel  2 , with a prescribed distance between the disk holders and front panel  2 . 
     However, in this embodiment, chassis  63  is disposed in this space made necessary for other reasons. Turntable  61 , when it is at the recessed position, is disposed in the flat region formed by the transfer of disk  71  from FIG. 2 to FIG. 3 at a position where it does not overlap with the disks in disk holder  11 - 15 . Thus, there is no need for a separate space for the recessed position of turntable  61 . This allows smaller lateral (the D-E direction in FIG. 1) and depth (the F-G direction in FIG. 1) dimensions for device  1 . 
     The following is a description of the procedure for storing another disk  72  in disk holder  12  after the playback of disk  71  described above has been completed. Referring to FIG. 5, FIG. 13, and FIG. 27, after playback of disk  71  is completed, chassis drive mechanism  86  moves chassis  63  in the direction of arrow G in FIG.  5 . 
     Referring to FIG. 6, FIG. 12, and FIG. 26, disk  71  is moved to the withdrawn position. Then, disk holder  11  is lowered from position P 5  to position P 7  shown in FIG.  11  and FIG.  27 . This is achieved by cylindrical cam drive mechanism  82  rotating cylindrical cam  31  360 degrees counter-clockwise while cylindrical cam  32  remains stationary. The rotation of cylindrical cam  31  aligns the height of disk holder  11  with disk  71 . 
     Chassis drive mechanism  86  then moves chassis  63  in the direction of arrow F. Referring to FIG. 5, FIG. 10, and FIG. 24, the edge of disk  71  are inserted in disk holder  11 . Then, cylindrical cam  31  is rotated 180 degrees clockwise, moving disk holder  11  from position P 7  shown in FIG. 7 to position P 6 . Referring to FIG.  9  and FIG. 23, disk  71  is raised up and the chucking between disk  71  and turntable  61  is released. Chassis drive mechanism  86  moves chassis  63  from the playback position shown in FIG. 5 to the position shown in FIG. 4 to a recessed position shown in FIG. 3 where it does not obstruct the vertical motion of the disk. 
     Then, cylindrical cam drive mechanism  82  rotates cylindrical cam  31  180 degrees counter-clockwise. Referring to FIG. 10, disk holder  11  is first brought back to position P 7 . Then, cylindrical cam drive mechanisms  82 ,  83  rotates both cylindrical cam  31  and  32  360 degrees clockwise. This causes disk holder  11  to move from position P 7  to position P 5 , disk holder  12  from position P 8  to position P 7 , disk holder  13  from position P 9  to position P 8 , disk holder  14  from position P 10  to position P 9 , and disk holder  15  from position P 11  to position P 10  (see FIG.  7 ). 
     Referring to FIG. 14, cylindrical cam drive mechanism  82  is used to rotate cylindrical cam  31  180 degrees clockwise without rotating cylindrical cam  32 . This causes disk holder  12  to move from position P 7  to position P 6  (see FIG.  7 ). The height of disk holder  12  is aligned with slit  3  in front panel  2 . This state is shown in FIG.  15  and FIG.  28 . 
     Referring again to FIG. 1, drive belt  45  of belt drive mechanism  40  and guide wall  53  of guide mechanism  50  are moved to a separation distance smaller than the diameter of the disk. Referring to FIG.  16  and FIG. 29, disk  72  is then loaded through slit  2  and moved inward until disk  72  is supported in disk holder  12  in the same manner as described above. 
     Then, when disk  72  is to be played back, chassis  63  is moved (FIG.  30 ), and first cylindrical cam  31  is rotated 180 degrees counter-clockwise without rotating second cylindrical cam  32 . This causes disk  72  to be chucked to turntable  61  (FIG. 17, FIG.  31 ). Then, chassis  63  is moved so that disk  72  is withdrawn from disk holder  12  (FIG. 18, FIG.  32 ). First cylindrical cam  31  is rotated 360 degrees clockwise without rotating second cylindrical cam  32  so that disk holder  12  is moved to position P 5  in FIG.  7  and disk holder  11  is moved to position P 4  (FIG. 19, FIG.  33 ). Then, chassis  63  is moved, resulting in the playback state (FIG. 20, FIG.  34 ). 
     As described above, first cylindrical cam  31  can be rotated without rotating second cylindrical cam  32 . It is also possible to rotate both by the same angle. When a disk is being played back, the disk holder corresponding to the disk to be played is positioned at position P 5  (see FIG.  7 ). In order return the disk after playback to the disk holder, the disk holder is moved to a position P 7 , where its height is aligned with the playback position. During this operation, cylindrical cam  32  is not rotated. Similarly, in order to play back a loaded disk, the disk holder is moved from position P 6 , where its height is aligned with that of the loading surface, to position P 7 , which is aligned with the chucking position. In this case, only first cylindrical cam  31  is rotated counter-clockwise. 
     The following is a description of the sequence that takes place when disks are in all the disk holders, playback of disk  71  mounted in disk holder  11  has completed, and the disk mounted in fourth disk holder  14 , the fourth disk holder from the top, is to be played back. In this case, cylindrical cams  31  and  32  are both rotated clockwise. Disk holder  11  is moved to position P 3 , disk holder  12  to position P 4 , disk holder  13  to position P 5 , disk holder  14  to position P 7 , and disk holder  15  to position P 8  (see FIG.  7 ). Then, cylindrical cam  31  moves disk holder  14  from position P 7  to position P 6 , and then to position P 7  and then to position 
     By separating cylindrical cam  31  and  32 , the disk holder containing the disk to be played back can be moved to position P 7 , where it is aligned with the playback position. Then, the disk holder can be moved to position P 5  without the need to move another disk holder below this disk holder or the disk contained in the lower disk holder. Thus, the disk to be played back can be given adequate clearance below it. 
     In the playback means transferring mechanism of the embodiment described above, turntable  61 , optical pickup  66 , and the like are disposed on chassis  63 , which is rotated  45  degrees counter-clockwise and then moved. This causes turntable  61  to move from the recessed position where it does not overlap the disk to the disk playback position. However, the present invention is not restricted to this, and the playback means transferring mechanism can use different methods to move the playback means. 
     Furthermore, in the embodiment described above, the playback position of the disk is coplanar with the holding position of the disk. However, the present invention is not restricted to this. The playback position can also be the position shown in FIG. 6, FIG. 11, and FIG. 25 where the disk is withdrawn from the disk holder. 
     In the embodiment described above, the disk holder transfer mechanism includes cylindrical cams  31 ,  32 , which engage disk holders  11 - 15 . However, the present invention is not restricted to this, and other mechanisms that can perform similar operations can be used. 
     In the embodiment described above, disk transferring means includes drive belt  45 , which engages with the edge of the disk. However, the present invention is not restricted to this. For example, a pair of rollers that support the recorded surface and the label surface of the disk can also be used. 
     In the embodiment described above, the disk support member includes a disk holder that supports the edge of the disk over a range of approximately 180 degrees. However, other structures can be used, such as a plate on which the disk is mounted. In this case, if the disk is mounted on the plate so that the recorded surface of the disk faces the plate, the plate and the plate below it are lowered after the chucking operation. A first and a second disk support member transfer mechanism must be structured so that during this lowering operation, the plate above the mounted plate does not come near the plate on which the disk is chucked. 
     During disk playback, the disk and the disk support member are moved away from each other by the chassis drive mechanism to move the disk, which is chucked to the turntable. However, it would of course also be possible to use the transferring means that transfers the disk into the device to move the disk to the withdrawn position. 
     As described above, according to the present invention, a playback means is disposed so that a recessed position, where the turntable does not overlap with the disks held inside a plurality of disk supporting members, is positioned inside a space for withdrawing a disk, which is provided to move the disk away from the disk supporting member. Thus, there is no need to provide a separate space for the recessed position of the playback means. 
     As described above, playback includes moving disks between stored positions in disk holders and the playback position. A single-play mode is also possible. Referring to FIG. 34, in single-play mode, even if all disk holders are full, or if storage of a disk to be played is not desired, disk  72  may be moved from slit  3  directly to the play position, where it is chucked and played. At the conclusion of play, disk  72  is moved directly outward through slit  3  without residence time in a disk holder. 
     Having described preferred embodiments of the invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.