Patent Publication Number: US-6212139-B1

Title: Disk changer apparatus for multiple closely held disks

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a division of U.S. application Ser. No. 08/713,688, filed on Sep. 17, 1996, Pat. No. 5,978,823 currently pending. 
    
    
     FIELD OF THE INVENTION AND RELATED ART STATEMENT 
     1. Field of the Invention 
     The present invention relates to a disk changer apparatus for holding a plurality of disks and reproducing selected disks sequentially and continuously. 
     2. Description of the Related Art 
     In recent years, a disk changer apparatus capable of selectively reproducing a given one of a plurality of disks held in the apparatus has been spread widely with the spread of use of disks such as the compact disk. 
     Especially, a disk changer apparatus is under development, in which a plurality of disks are arranged upright or horizontally in layers at predetermined spatial intervals. In this way, at least 50 disks can be held in an apparatus of about the same size as the conventional cassette deck. Such a disk changer apparatus has such a superior holding capacity and operability that the use thereof has extended widely and rapidly among general users. 
     An example of such a conventional disk changer apparatus is disclosed in the gazette of the Japanese examined patent application hei 6-34290 (Tokko hei 6-34290). 
     This conventional disk changer apparatus comprises a holding tray unit for holding a plurality of disks removably on the front thereof. Also, a disk drive unit having a reproduction unit for reproducing the disks is arranged backward of the holding tray unit (in the depth of the apparatus) and is movable along the direction in which the disks are arranged. 
     In this conventional disk changer apparatus, when a disk is held or a held disk is exchanged, the holding tray unit is removed entirely from the apparatus proper beforehand. 
     In the conventional disk changer apparatus described above, even in the case that only one of the disks held therein is exchanged, the whole of the holding tray unit is required to be removed from the apparatus and therefore the operation for exchanging the disks is very burdensome. 
     Another problem of the above-mentioned conventional disk changer apparatus is that in the case where a specific disk is to be taken out from the holding tray unit holding a substantially maximum number of disks, it is not easy to confirm the position of the disk to be taken out. 
     Further, even when the position of the disk to be taken out can be confirmed, it is very difficult to pick up only the desired one of the disks held in the apparatus because of the close spatial relation with adjacent disks. Especially in the case where a small disk of 8 cm in outer diameter is held between large disks 12 cm in outer diameter like ordinary compact disks, it is very difficult to take out the small disk. This problem has yet to be solved in this particular field. 
     OBJECT AND SUMMARY OF THE INVENTION 
     A disk changer apparatus of the present invention has been developed in order to solve the above-mentioned problems, and the object thereof is to provide a small disk changer apparatus with a simple construction, in which the disks held therein can be easily exchanged and a disk of any shape can be easily taken out from a multiplicity of disks closely held with each other. 
     In order to achieve the above-mentioned object, according to one aspect of the invention, there is provided a disk changer apparatus comprising: a stocker tray including a plurality of partitioning plates arranged substantially in parallel at predetermined spatial intervals and a plurality of couplers each having an opening at least in a part of the bottom thereof for coupling the partitioning plates, the stocker tray holding disks one each between every adjacent partitioning plates; and a disk delivery unit including a push-up lever and an operating means for driving the push-up lever, the push-up lever being adapted to advance into a partition between every adjacent partitioning plates from the opening formed in the coupler of the stocker tray and take a disk from the stocker tray to outside the apparatus, the disk delivery unit being movable along the direction in which the disks are arranged. 
     According to another aspect of the invention, there is provided a disk changer apparatus comprising: a stocker tray including a plurality of partitioning plates arranged substantially in parallel at predetermined spatial intervals and a plurality of couplers each having an opening in at least a part of the bottom thereof for coupling the partitioning plates, the stocker tray holding a plurality of disks each between adjacent ones of the partitioning plates; a reproduction (playback) unit movable along the direction of disk arrangement in the stock tray for selectively reproducing a plurality of disks held in the stocker tray; and a disk delivery unit including a push-up lever adapted to advance into a partition between every adjacent partitioning plates from the opening formed in the coupler of the stocker tray and taking a given disk from the stocker tray to outside the apparatus and an eject lever for taking out a given disk from the stocker tray by rotating the push-up lever and retaining the disk thus taken out, the disk delivery unit being movable along the direction in which the disks are arranged in the stocker tray. 
     According to still another aspect of the invention, there is provided a disk changer apparatus so configured that the disk delivery unit is moved to the position of the desired disk held in the stocker tray and the operating unit is pushed. This simple operation permits the disk push-up lever to advance into a partition between adjacent partitioning plates and positively pick up the desired disk alone. For this reason, in the case where a plurality of disks are closely held in the stocker tray or in the case where it is desired to take out a small disk from between large disks, the desired disk can be easily and accurately taken out or exchanged without touching the remaining disks. 
     According to a further aspect of the invention, there is provided a disk changer apparatus small in size and simple in construction comprising a disk delivery unit arranged on the front of a disk holding unit and movable along the direction of disk arrangement for taking out a given disk from the disk holding unit. Thus the disks held in the disk holding unit can be easily taken out or exchanged. Even in the case where a multiplicity of disks are held or especially in the case where a small disk held between large disks is to be taken out, the desired disk can be easily and accurately taken out. 
     While the novel features of the invention are set forth particularly in the appended claims, the invention, both as to organization and content, will be better understood and appreciated, along with other objects and features thereof, from the following detailed description taken in conjunction with the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view showing the external appearance of a disk changer apparatus of a first embodiment in accordance with the present invention; 
     FIG. 2 is a perspective view showing the disk changer apparatus of FIG. 1 with the front panel thereof open; 
     FIG. 3 is a perspective view showing the disk changer apparatus of FIG. 1 with the exterior case thereof removed; 
     FIG. 4 is a side view showing a stocker tray, etc. of the first embodiment; 
     FIG. 5 is a front view showing grooves used for the positioning mechanism of the disk delivery unit of the first embodiment; 
     FIG. 6 is a plan view showing a number indication plate of the stocker tray of the first embodiment; 
     FIG. 7 is a perspective view showing the disk delivery unit of the first embodiment; 
     FIG. 8 is a plan view showing the position indicator of the disk delivery unit of the first embodiment; 
     FIG. 9 is a side view showing the internal mechanism of the disk delivery unit of the first embodiment; 
     FIG. 10 is a side view showing the arrangement of the disk delivery unit and the disk reproduction unit of the first embodiment; 
     FIG. 11 is a side view for explaining the operation of the disk reproduction unit when a disk is held therein of the first embodiment; 
     FIG. 12 is a side view for explaining the operation of the disk reproduction unit in the course of mounting a disk therein of the first embodiment; 
     FIG. 13 is another side view for explaining the operation of the disk reproduction unit in the course of mounting a disk therein of the first embodiment; 
     FIG. 14 is a side view for explaining the operation of the disk delivery unit with a disk held therein; 
     FIG. 15 is a side view for explaining the disk delivery unit in the course of taking out a disk of the first embodiment; 
     FIG. 16 is a side view for explaining the operation of the disk delivery unit with the front panel closed of the first embodiment; 
     FIG. 17 is a side sectional view showing the disk delivery unit of the first embodiment; 
     FIG. 18 is a side sectional view showing the disk delivery unit of a disk changer apparatus of a second embodiment in accordance with the present invention; 
     FIG. 19 is a partially enlarged plan view showing the disk delivery unit of the second embodiment; 
     FIG. 20 is a schematic diagram showing the positioning mechanism of the disk delivery unit of the second embodiment; and 
     FIG. 21 is a side sectional view showing the disk delivery unit with a disk delivered out of the second embodiment. 
     It will be recognized that some or all of the Figures are schematic representations for purposes of illustration and do not necessarily depict the actual relative sizes or locations of the elements shown. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A disk changer apparatus of the first and second embodiments in accordance with the present invention will be described below with reference to the accompanying drawings. 
     First Embodiment 
     FIG. 1 is a perspective view showing the external appearance of a disk changer apparatus of the first embodiment. FIG. 2 is a perspective view showing the disk changer apparatus of which a front panel  6  thereof is open. FIG. 3 is a perspective view showing the internal mechanism of the disk changer apparatus of which an exterior case  10  constituting the external appearance is removed. 
     As shown in FIGS. 1 and 2, the disk changer apparatus of the first embodiment is configured to hold a plurality of large disks  7  (12 cm in diameter) and small disks  8  (8 cm in diameter) arranged in upright positions in predetermined spatial relation with each other in the vicinity of the front of the exterior case  10 . In the first embodiment, the large disk  7  and the small disk  8  are collectively called the disk(s)  7 ,  8 . 
     The exterior case  10  is mounted on a chassis  9  of which the front is open. The front panel  6  is arranged on the front surface of the chassis  9 . The front panel  6  is mounted rotatably about a fulcrum  6   a . The disks  7 ,  8  are taken out or exchanged by opening and closing the front panel  6 . 
     As shown in FIGS. 1 and 2, the front panel  6  of the disk changer apparatus of the first embodiment has a transparent window  6   b . Even when the front panel  6  is closed, the presence or absence of the disks  7 ,  8  held in the apparatus can be checked visually through the transparent window  6   b . Also, as shown in FIG. 1, a plurality of operating switches  6 c are provided on the front of the front panel  6  for driving the disk changer apparatus of the first embodiment. 
     FIG. 3 shows the internal mechanism arranged in the chassis  9 . As shown in FIG. 3, the disk changer apparatus of the first embodiment comprises a frame unit  40  including a lower rack plate  1 , a left side plate  2   a , a right side plate  2   b , an upper rack plate  3  and a rear reinforcing plate  11 . This frame unit  40  is a substantially box-shaped of which the front is open. The upper rack plate  3  is formed with a first rack  3   a  and a second rack  3   b  in parallel to the direction in which the disks  7 ,  8  are arranged (along the direction of arrows A and B in FIG.  3 ). The lower rack plate  1 , on the other hand, is formed to have a third rack  1   a  in parallel to the first rack  3   a  and the second rack  3   b  of the upper rack plate  3 . 
     The rear reinforcing plate  11  is fixed on the chassis  9  thereby to secure the whole of the frame unit  40  on the chassis  9 . 
     The teeth of the first rack  3   a  and the second rack  3   b  of the upper rack plate  3 , and the third rack  1   a  of the lower rack plate  1  have the same pitches and the same shape in the same vertical plane. 
     As shown in FIG. 3, the disk changer apparatus of the first embodiment comprises a disk holding unit  100  arranged along the front surface of the apparatus for holding a plurality of disks  7 ,  8 , a disk delivery unit  200  movable in parallel to the direction of arrangement of the disks  7 ,  8  on the front of the disk holding unit  100 , and a disk reproduction unit  300  movable in parallel to the direction of arrangement of the disks  7 ,  8  in the depth of the disk holding unit  100 . 
     Next, the configuration of the disk holding unit  100 , the disk delivery unit  200  and the disk reproduction unit  300  will be explained. 
     [Disk Holding Unit  100 ] 
     As shown in FIG. 3, the disk holding unit  100  includes rests  4   a ,  4   b  hung between the protruded front portions of the left side plate  2   a  and the right side plate  2   b , and a stocker tray  5  fixed on the rests  4   a ,  4   b . The stocker tray  5  is held by the rests  4   a ,  4   b  fixed on the left side plate  2   a  and the right side plate  2   b  by screws  12 . The stocker tray  5  has a plurality of partitioning plates  5   a  having a thickness of 1.5 mm positioned upright therein at spatial intervals of 3 mm, so that the disks  7 ,  8  are adapted to be held respectively in holding slots  5   b  formed between the partitioning plates  5   a.    
     FIG. 4 is a side sectional view showing the stocker tray  5 , the rests  4   a ,  4   b , etc. In FIG. 4, couplers  5   c  for coupling the partitioning plates  5   a  are formed on the lower front and rear parts of the stocker tray  5 . Also, an opening  5   d  is formed in the lower central part of the stocker tray  5 . 
     Several hooks  5   e  are provided on the lower side of the couplers  5   c  of the stocker tray  5  and engage the holes formed in the rests  4   a ,  4   b . As a result, the stocker tray  5  is fixed securely to the rests  4   a ,  4   b . Also, slits  5   f  for positioning the disk reproduction unit  300  are formed in the couplers  5   c  in the rear part of the stocker tray  5 . Positioning slits  4   c  are formed in the rest  4   b  at the same positions as the slit  5   f  of the coupler  5   c . These positioning slits  4   c ,  5   f  are formed at 3-mm intervals in the direction in which the disks  7 ,  8  are arranged, and to correspond to the intervals of the disk holding slots  5   b  of the stocker tray  5 . 
     A plurality of triangular grooves  5   g  are formed in the lower front part of the stocker tray  5  for setting the disk delivery unit  200  exactly in position. FIG. 5 is a partially enlarged front view of the stocker tray  5 . As shown in FIG. 5, the triangular grooves  5   g  are formed in the lower front part of the stocker tray  5  at regular spatial intervals with each other. The centers of the respective triangular grooves  5   g  agree with the centers of the disk holding slits  5   b  of the stocker tray  5 , respectively. A click ball  210  described later of the disk delivery unit  200  engages with one of the triangular grooves  5   g  of the stocker tray  5 . 
     The click ball  210  engaging the triangular groove  5   g  of the stocker tray  5  is provided for positioning the disk delivery unit  200  with precision. The click ball  210  is a steel ball 4 mm in diameter, and is kept urged in pressure contact with the triangular groove  5   g  by a click spring  211  (made of phosphor bronze 0.15 mm thick). 
     FIG. 6 is a partially enlarged plan view showing a number indication plate  5   h  of the stocker tray  5 . As shown in FIG. 6, the number indication plate  5   h  is arranged on the front of the stocker tray  5 . The number indication plate  5   h  has serial numbers attached at each position thereon corresponding to the slots  5   b  for holding the disks  7 ,  8 . The numbers on the number indication plate  5   h  are divided into two groups of single digit and double digits classified by colors such as red and blue, respectively. These numbers are used for indicating the disk positions in the disk delivery unit  200  on the one hand, and as an aid for the user when the disk  7 ,  8  is directly mounted in the stocker tray  5  on the other. 
     As shown in FIG. 4, the front end of the number indication plate  5   h  is bent upward, and forms a supporting edge  5   i  for supporting the disk  7 ,  8  taken out from the stocker tray  5 . This supporting edge  5   i  is formed to have recesses at each position corresponding to the holding slots  5   b  of the stocker tray  5 . The edge of the disk  7 ,  8  taken out is supported by the recess, and the disks  7 ,  8  are thus prevented from being displaced. 
     [Disk reproduction unit  300 ] 
     As shown in FIG. 3, the disk reproduction unit  300  includes a loading unit  50  disposed in the depth of the disk holding unit  100  and movable parallel along the direction in which the disks  7 ,  8  are arranged. The loading unit  50  includes a loading unit drive mechanism for transporting the loading unit  50  laterally of the apparatus (along the direction of arrow A or arrow B in FIG.  3 ), a reproduction unit for reproducing (playing back) the disks  7 ,  8 , a reproduction unit drive mechanism for driving the reproduction unit to a playback position from a playback wait position, and a disk transfer mechanism for transferring the disks  7 ,  8  between the stocker tray  5  and the reproduction unit. 
     The loading unit  50  is arranged at the extreme left of the upper rack plate  3  and the lower rack plate  1  in the initial state (where the disk  7 ,  8  is not reproduced or the disk changer apparatus of the first embodiment is during transport). 
     Relocation gears  51  are arranged on the upper and lower surfaces of the loading unit  50 . The relocation gears  51  are in mesh with the first rack  3   a , the second rack  3   b  and the third rack  1   a . The loading unit  50  of the first embodiment is moved along the direction of arrow A or arrow B by the rotation of the relocation gears  51 . 
     A screen belt  60  for preventing the disks  7 ,  8  in the stocker tray  5  from advancing into the apparatus is hung on the front of the left side plate  2   a  and the right side plate  2   b . The left end of the screen belt  60  is fixed on the left side plate  2   a , and the right end thereof is suspended on the right side plate  2   b  through a spring. The screen belt  60  is arranged slidably around the loading unit  50 . 
     As shown in FIG. 3, a flexible signal wire  80  is connected between the loading unit  50  and a circuit board  70  fixed on the frame unit  40 . The disk reproduction unit  300  of the first embodiment is adapted to follow the movement of the loading unit  50  along the direction of arrow A or B. 
     [Disk Delivery Unit  200 ] 
     The disk delivery unit  200  is a mechanism for taking out a designated disk  7 ,  8  accurately from the disks  7 ,  8  held in the stocker tray  5 . 
     FIG. 7 is a perspective view showing the external appearance of the disk delivery unit  200  arranged on the front of the stocker tray  5 . 
     In FIG. 7, the disk delivery unit  200  includes an eject base  201  which is in slidable mesh with the rest  4   a  for supporting the stocker tray  5 . As a result, the disk delivery unit  200  is capable of moving slidably on the front of the stocker tray  5  along the direction of arrow A or B in which the disks  7 ,  8  are arranged. 
     An eject lever  202  providing as a disk receiving unit is projected from the eject base  201 , and rotatably held on the eject base  201 . The eject lever  202  has a groove  202   a  extending in the direction of projection at the central part thereof. A disk receiving lever  203  arranged in a groove  202   a  of the eject lever  202  is rotatably held on the eject lever  202 . The disk receiving lever  203  is for holding the disk  7 ,  8  taken out from the stocker tray  5  in a delivery position. 
     Since the disk receiving lever  203  is arranged in the vicinity of the forward end of the eject lever  202 , the disk  7 ,  8  held by the disk receiving lever  203  in a delivery position is projected at a position where the user can grasp the disk  7 ,  8  by the central portion thereof. 
     An eject button  206  for taking out the disk  7 ,  8  held in the stocker tray  5  is supported by the eject base  201  to be vertically slid. 
     A supporter  204  is fixed in the vicinity of the forward end of the eject lever  202  and comes into contact with the back side of the front panel  6  so as to protect the front panel  6  and reduce the contact noise generated at the time of opening or closing the front panel  6 . 
     The eject lever  202  has a pair of disk protectors  205  for guiding while protecting the disk  7 ,  8  being taken out. The disk protectors  205  are fixed on the opposite internal surfaces of the groove  202   a  of the eject lever  202 . When the disk  7 ,  8  to be taken out passes along the groove  202   a  of the eject lever  202 , the disk protector  205  prevents the disk  7 ,  8  from being damaged by contacting the wall surface of the groove  202   a . For this purpose, the disk protectors  205  are made of such a soft material as to form a smooth convex surface continuous with the wall of the groove  202   a  of the eject lever  202 . 
     Apart from the above-mentioned first embodiment, wherein the soft resin is used as a soft material, a modified embodiment may be such that felt is used as a material of the disk protectors  205 . 
     FIG. 8 shows a position indicator  500  formed on the disk delivery unit  200 . The position indicator  500  is configured of a forked portion formed on the back of the eject base  201 . As shown in FIG. 8, the position indicator  500  is arranged in the vicinity of the upper part of the number indication plate  5   h  of the stocker tray  5  described above. The position of the disk delivery unit  200  is indicated with number by such a function of the position indicator  500  formed on the back of the eject base  201 . The position indicator  500  is accurately positioned by the positioning mechanism including the triangular grooves  5   g  of the stocker tray  5  and the click ball  210  shown in FIG.  5 . 
     FIG. 9 is a side view showing the internal mechanism of the disk delivery unit  200 . In FIG. 9, the eject button  206  of the disk delivery unit  200  is provided to move down along the wall surface of the eject base  201  by being hand pressed. An engaging groove  206   a  formed on the eject button  206  is in mesh with a first pin  207   a  of an intermediate lever  207 . The intermediate lever  207  is constructed to rotate about the axis  207   c  thereof. As a consequence, the downward movement (along the direction of arrow H in FIG. 9) of the eject button  206  causes the intermediate lever  207  to rotate along the direction of arrow G. Also, the intermediate lever  207  is formed to have a second pin  207   b , and an eject slide plate  208  shown hatched in FIG. 9 is formed to have an engaging groove  208   b . The engaging groove  208   b  of the eject slide plate  208  is in mesh with the second pin  207   b  of the intermediate lever  207 . As a result, by the rotation of the intermediate lever  207  along the direction of arrow G, the eject slide plate  208  moves rearward of the apparatus (along the direction of arrow M in FIG.  9 ). The eject slide plate  208  is formed to have a rack  208   a  at the rear end thereof. The rack  208   a  is in mesh with the gear teeth  209   a  formed on the front end of a push-up lever  209 . (In FIG. 9, the eject slide plate  208  is hatched to facilitate the understanding of the engagement between the intermediate lever  207 , the eject slide plate  208  and the gear teeth  209   a ). When the eject slide plate  208  moves along the direction of arrow M, the push-up lever  209  is rotated in the direction shown with arrow V. 
     The eject slide plate  208  is kept urged along the direction of arrow N by a slide return spring (SUS torsion spring) not shown. As a result, the eject button  206  is normally arranged at an upper position when the push-up lever  209  is located under the stocker tray  5 . 
     The push-up lever  209  is made of stainless steel SUS301 CSP specified in JIS and has a thickness of 0.8 mm. The upper rear end of the push-up lever  209  is chamfered to facilitate insertion into the holding slot  5   b.    
     The eject lever  202  shown in FIG. 9 is kept urged to rotate in the direction of arrow X by an eject lever spring (stainless steel torsion spring) wound on the rotational shaft of the eject lever  202 . 
     FIG. 10 is a side view showing an arrangement of the disk delivery unit  200  and the disk reproduction unit  300  when the front panel  6  is open. 
     [Transfer Operation of Disk Reproduction Unit  300 ] 
     Now, explanation will be made about the operation of transferring the disk reproduction unit  300  for mounting and returning the disk in the disk changer apparatus of the first embodiment. 
     After the reproduction unit  300  is transported to the position where the designated disk  7 ,  8  is held in the stocker tray  5  by the loading unit drive mechanism described above, the disk reproduction unit  300  transfers and mounts the designated disk  7 ,  8  from the stocker tray  5  to the reproduction unit. Further, after the reproduction is completed, the disk  7 ,  8  is returned to the stocker tray  1 . This disk transfer operation will be explained with reference to FIGS. 11 to  13 . 
     FIG. 11 is a side view showing an arrangement of the disk transfer mechanism, etc. when a disk is held in the holding slot of the stocker tray  5 . FIGS. 12 and 13 are side views showing the disk transfer operation of the disk transfer mechanism, etc. for mounting the disk. In these drawings, the disk  7 ,  8  is shown only as a large disk  7 . A similar operation is performed on the small disk  8 . Therefore, the operation will be explained with reference to the disk  7 ,  8 . 
     The disk transfer mechanism includes a forward feed lever  301  for lifting the disk  7 ,  8  from the stocker tray  5  and transferring it rearward of the apparatus. Also, the disk transfer mechanism includes a rearward feed lever  303  for transferring the disk  7 ,  8  further rearward of the apparatus from the position where the disk  7 ,  8  is transferred by the forward feed lever  301 . And further, the disk transfer mechanism has a size detection lever  305  for detecting the size of the large and small disks  7 ,  8  arranged in the rear part of the apparatus, and a return lever  304  for returning the disk  7 ,  8  to the stocker tray  5 . 
     As shown in FIG. 11, the push-up lever  209  of the disk delivery unit  200  and the forward feed lever  301  of the disk reproduction unit  300  are arranged out of contact with each other in different vertical positions under the stocker tray  5 . This configuration makes it possible for the disk delivery unit  200  and the disk reproduction unit  300  to move to an arbitrary position along the directions (shown with arrow A or B in FIG. 3) of disk arrangement without mutual interference. The disk delivery unit  200 , on the other hand, is capable of taking out or exchanging a given disk other than that in reproduction. 
     The disk reproduction unit  300  includes a reproduction unit drive mechanism having a coupling lever  306 , a lower slide plate  307  and an upper slide plate  308 . The reproduction unit drive mechanism has the function of driving the reproduction unit from playback wait position to playback position. The lower slide plate  307  is in mesh-with a slide plate drive gear  350  rotated by a slide plate drive motor (not shown). The lower slide plate  307  drives the reproduction unit from the playback wait position distant from the recording surface of the disk  7 ,  8  to the playback position in proximity to the recording surface in operatively interlocked relation with the upper slide plate  308  connected through the coupling lever  306 . 
     The coupling lever  306  is rotatably supported on the base frame of the disk reproduction unit  300  in the central hole  306   a  thereof. As a result, the turning force of the slide plate drive gear  350  is imparted through the gear train  307   a  to the lower slide plate  307  and the upper slide plate  308 , so that the lower slide plate  307  and the upper slide plate  308  slide in opposite directions. 
     As a result of this movement of the lower slide plate  307  forward of the apparatus (along the direction of arrow N in FIG.  11 ), a feed assisting lever  302  is rotated along the direction of arrow C. This rotation of the feed assisting lever  302  is generated by sliding a rear end of the feed assisting lever  302  along a cam slit  307   b  formed in the forward side of the lower slide plate  307 . As a consequence, the feed assisting lever  302  rotates the forward feed lever  301  upward (along the direction of arrow F in FIG. 11) by means of the teeth formed at the forward end thereof. The forward feed lever  301  thus rotated advances into the holding slot  5   b  holding the designated disk  7 ,  8  from the opening  5   d  formed in the bottom of the stocker tray  5 . As a result, the edge of the disk  7 ,  8  is pushed up by the forward end of the forward feed lever  301 , and the disk  7 ,  8  in the holding slot  5   b  is transferred toward the reproduction unit, that is, rearward of the apparatus as shown in FIG.  12 . 
     Further, since the lower slide plate  307  moves along the direction of arrow N, as shown in FIG. 12, the rearward feed lever  303  in mesh with the cam slit  307   c  of the lower slide plate  307  rotates along the direction of arrow D thereby to transfer the disk  7 ,  8  further rearward of the apparatus. In this transfer operation, the coupling lever  306  moves the upper slide plate  308  rearward of the apparatus (along the direction of arrow M in FIG.  12 ), and the upper slide plate  308  rotates the return lever  304  along the direction of arrow E. As a result of this rotation, the return lever  304  moves to a position not affecting the mounting operation of the disk  7 ,  8 . 
     As described above, the transferred disk  7 ,  8 , as shown in FIG. 13, is retained in clamping position (playback position) by being held between the edges of the rearward feed lever  303 , the return lever  304  and the size detection lever  305 . After that, the lower slide plate  307  and upper slide plate  308  further move (along the directions of arrows N and M in FIG. 13) thereby to drive the rearward feed lever  303 , the return lever  304  and the size detection lever  305  to be slightly away from the outer edge of the disk  7 ,  8 . As a result, the disk  7 ,  8  is now held only by a rotatable clamp (not shown) and a turn table  600  of the reproduction unit. 
     As shown in FIG. 13, when a the 12-cm CD (compact disc) as the large disk  7  is mounted on the reproduction unit, the size detection lever  305  is rotated since the size detection lever  305  is pressed by the edge of the large disk  7 . When an 8-cm CD as the small disk  8  is mounted on the reproduction unit, on the other hand, the size detection lever  305  does not touch the edge of the small disk  8 . The size detection lever  305 , therefore, is not rotated but remains in an initial position. In this operation, the disk changer apparatus of the first embodiment arranges the large and small disks  7 ,  8  to be reproduced in a proper clamping position (playback position) according to their respective sizes. 
     The disk  7 ,  8  transferred to the clamping position (playback position) is reproduced while being held only by the turn table of the reproduction unit and a rotatable clamper (not shown). The disk  7 ,  8 , after complete reproduction, is returned to a predetermined position in the stocker tray  5  by the returning operation which is reverse to the above-mentioned mounting operation. 
     [Delivery Operation of Disk Delivery Unit  200 ] 
     Next, the operation of delivering the disk  7 ,  8  held in the stocker tray  5  will be explained with reference to FIGS. 14 to  16 . FIGS. 14 to  16  are side views schematically showing a configuration of the disk delivery unit  200 . In FIGS. 14 to  16 , the disk reproduction unit  300  is not shown. FIGS. 14 and 15 show the apparatus in which the front panel  6  rotatably mounted on the front of the apparatus is open, and FIG. 16 shows the apparatus with the front panel  6  closed. 
     When the user presses down the eject button  206 , the eject button  206  moves down along the wall surface of the eject base  201 . As a result of this movement, as described above, the intermediate lever  207  rotates so that the eject slide plate  208  moves rearward of the apparatus (along the direction of arrow M in FIG.  14 ). As shown in FIG. 14, the eject slide plate  208  is formed to have the rack  208   a  which is in mesh with a gear teeth  209   a  formed at the front end of the push-up lever  209 . By the movement of the eject slide plate  208 , the push-up lever  209  rotates along the direction of arrow V due to the engagement between the rack  208   a  and the gear teeth  209   a . As a result, the push-up lever  209  advances into the holding slot  5   b  holding the disk  7 ,  8  from the opening  5   d  formed in the central portion of the coupler  5   c  of the stocker tray  5 . By the advancement of the push-up lever  209  into the holding slot  5   b , the forward end of the push-up lever  209  presses the edge of the disk  7 ,  8  and thus transfers the disk  7 ,  8  forward of the apparatus (along the direction of arrow N in FIG.  14 ). 
     As shown in FIG. 15, the disk  7 ,  8  transferred forward of the apparatus passes through the groove  202   a  formed in the central portion of the eject lever  202 . And the disk  7 ,  8  comes to stop as the edge thereof comes into contact with a support member  203   c  of the disk receiving lever  203 . In this operation, the edge of the disk  7 ,  8  is supported on the support edge  5   i  formed at the front end of the number indication plate  5   h  and the support member  203   c . As a result, the disk receiving lever  203  holds the disk  7 ,  8  at a position capable of grasping it by the central portion thereof, as described above. Also, since the forward end of the disk receiving lever  203  is set at a high position, the disk  7 ,  8  (especially, the small disk, i.e., the 8-cm CD) is prevented from jumping out when the eject button  206  is pressed strongly. The eject lever  202  is kept urged along the direction of arrow X by an eject lever spring (not shown) wound on the rotative shaft of the eject lever  202 . 
     When the front panel  6  is opened or closed, the reverse side (the surface located within the apparatus) of the front panel  6  comes into contact with the supporter  204  arranged in the vicinity of the forward end of the eject lever  202 . In the movements of the front panel  6 , the front panel  6  presses the supporter  204  and rotates the eject lever  202  against the driving force of the eject lever spring. As a result, when the front panel  6  is opened, as shown in FIGS. 14 and 15, the eject lever  202  projects forward of the apparatus. When the front panel  6  is closed, on the other hand, as shown in FIG. 16, the eject lever  202  is substantially in upright position and is accommodated within the apparatus. 
     According to the first embodiment having the above-mentioned configuration, when the disk  7 ,  8  is taken out by opening the front panel  6 , no special operation is required for taking out the eject lever  202 , thereby facilitating the operation of taking out the disk  7 ,  8 . 
     Further, according to the disk changer apparatus of the first embodiment, there is no need of providing a place in the front panel or the like so as to receive the disk  7 ,  8  taken out on the front of the apparatus, thereby reducing the size of the apparatus. 
     As described above, every time the front panel  6  is opened or closed, the front panel  6  and the eject lever  202  come into contact with each other. In order to prevent the front panel  6  from being damaged, therefore, the contact portion of the eject lever  202  is provided with a supporter  204  superior in slidability. Although resin is used as the material of this supporter  204  according to the first embodiment, a soft material such as felt may be used with equal effect without departing from the spirit of the present invention. 
     FIG. 17 is a side sectional view showing the disk receiving lever  203  and the like arranged in the groove  202   a  of the eject lever  202 . In FIG. 17, the above-mentioned disk reproduction unit  300  is not shown. As shown in FIG. 17, the eject lever  202  is provided with a resin spring  203   a  (hatched in FIG.  17 ). When the disk receiving lever  203  rotates about the shaft  203   b  by the delivery pressure of the disk  7 ,  8 , the disk receiving lever  203  moves to have elastic property. Therefore, when the disk  7 ,  8  comes into contact with the disk receiving lever  203  for delivery operation, the shock by the disk  7 ,  8  is relaxed, so that the disk  7 ,  8  is securely held by the disk receiving lever  203 . The disk changer apparatus of the first embodiment thus has the function of preventing the disk  7 ,  8  from jumping out. 
     As described above, according to the first embodiment, a guide member for guiding the movement of the disk delivery unit  200  serves as the rests  4   a ,  4   b  of the stocker tray  5 . Even in the case where a disk changer apparatus is configured of a plurality of stocker trays  5  in combination, therefore, it is not necessary to change the configuration of the disk delivery unit  200  or to provide a guide member anew. The disk changer apparatus of the first embodiment, therefore, can readily accommodate a specification change. 
     Also, the forward feed lever  301  for transferring the disk  7 ,  8  to the reproduction unit and the push-up lever  209  of the disk delivery unit  200  are arranged at different vertical positions in order for the levers  301  and  209  not to come into contact with each other. Therefore, in the disk changer apparatus of the first embodiment, any disks  7 ,  8  other than the disk in reproduction can be taken out or exchanged. 
     Also, the disk receiving lever  203  is provided on the disk delivery unit  200  for receiving and holding the disk  7 ,  8  taken out. As a result, the disk  7 ,  8  taken out can be held accurately under any movements of the disk delivery unit  200 . Consequently, there is no need of providing a mechanism for receiving and holding the disk  7 ,  8  in the front panel  6  or the frame unit. The disk changer apparatus of the first embodiment, therefore, is simple in structure and small in size. 
     Further, according to the first embodiment, elasticity is attached to the disk receiving lever  203  providing as a disk receiving means by using a spring or the like, thereby positively preventing the disk  7 ,  8  from jumping out. 
     Furthermore, according to the first embodiment, the front panel  6  is operatively interlocked with the disk receiving means. It is therefore not necessary to rotate the disk receiving means each time the front panel  6  is opened, thereby simplifying the disk delivery operation. 
     Further, since the disk changer apparatus of the first embodiment has the aforementioned positioning mechanism shown in FIG. 5 on the disk delivery unit  200 , the disk changer apparatus makes accurate and facilitates the positioning of the disk delivery unit  200  when the disk delivery unit  200  is moved along the direction of disk arrangement. Also, this configuration makes possible accurate delivery and exchange of the disk  7 ,  8 . 
     The disk changer apparatus of the first embodiment is configured to. indicate the disk holding position of the stocker tray  5  by numeral and the position of the disk delivery unit  200  by using the numeral representing the disk holding position. Therefore, the position of the disks  7 ,  8  and the position of the disk delivery unit  200  can be easily and accurately known. Also, according to the disk changer apparatus of the first embodiment, the disk  7 ,  8  can be easily taken out or exchanged by checking the numeral indicated. 
     Furthermore, in the disk changer apparatus of the first embodiment, the disk receiving lever  203  is arranged at a minimum projected position for holding the disk  7 ,  8 , which is taken out by the disk delivery unit  200 . Therefore, the disk changer apparatus reduces the minimum space required for operating the apparatus. 
     Apart from the disk changer apparatus of the first embodiment wherein the resin spring  203   a  as a part of the eject lever  202  is provided for securing the restitutive power of the disk receiving lever  203 , a modified embodiment may be such that a torsion spring having an elasticity is used instead of the resin spring with equal effect. 
     Second Embodiment 
     A disk changer apparatus of a second embodiment in accordance with the present invention will be described below with reference to the drawings. The component parts of the second embodiment having the same configuration and effect as the corresponding parts of the first embodiment are designated by the same reference numerals respectively and will not be described again. 
     FIG. 18 is a side sectional view showing the configuration of the disk delivery unit  214  of the disk changer apparatus of the second embodiment. FIG. 19 is a plan view showing a part of the disk delivery unit  214  of FIG.  18 . The disk changer apparatus of the second embodiment comprises the disk reproduction unit  300  described with reference to the first embodiment. The disk reproduction unit  300 , however, is not shown in FIGS. 18 and 21. 
     Although the first embodiment is such that the disk- 7 ,  8  is taken out by pressing the eject button  206 , the disk changer apparatus of the second embodiment is so configured that the disk  7 ,  8  is taken out by rotating an eject lever  216 . 
     Also, the disk delivery unit  214  of the second embodiment includes a position indication counter mechanism of rotary type for indicating the position of the disk delivery unit  214 . 
     [Disk Delivery Unit  214 ] 
     FIG. 18 is a side sectional view showing the disk delivery unit  214  arranged on the front of the apparatus. The disk delivery unit  214  shown in FIG. 18 has a front panel  61  thereof open. In FIG. 18, a stocker tray  700  for holding the disks  7 ,  8  is fixedly held by rests  41   a ,  41   b . The eject lever  216 , which is rotatably held on the eject base  215 , is normally held upright by the operation of a spring (not shown) regardless of whether the front panel  6  is opened or closed, as shown in FIG.  18 . An eject slide plate  217  shadowed with broken lines in FIG. 18 is provided to move by a predetermined distance along the direction of arrow N or M. A pin  216   c  formed at an end of the eject slide plate  217  is in mesh with an engaging groove  217   b  formed in the eject slide plate  217 . As a result, by the rotation of the eject lever  216  along the direction of arrow X, the eject slide plate  217  moves along the direction of arrow M. A push-up lever  218  (made by SUS, 0.8 mm thick) arranged behind the eject slide plate  217  is held rotatably about a shaft  218   b  on an eject base  215 . An inclined surface  217   a  formed at the rear end of the eject slide plate  217  is in mesh with the pin  218   a  arranged on the push-up lever  218 . Consequently, the push-up lever  218  rotates along the direction of arrow T by the movement of the eject slide plate  217  along the direction of arrow M. 
     Also, when the eject lever  216  rotates along the direction of arrow Y under the driving force of a spring (not shown), the eject slide plate  217  moves along the direction of arrow N, so that the push-up lever  218  rotates along the direction of arrow U. The push-up lever  218  is kept urged along the direction of arrow U by a spring  218   c . When the eject lever  216  is positioned upright, therefore, the push-up lever  218  is located under the stocker tray  700 . 
     As shown in FIG. 19, a counter  219  indicating the position of the disk delivery unit  214  is juxtaposed with the eject lever  216 . The counter  219  has a cylindrical form with a vertical axis, and is held on the eject base  215  rotatably about the same axis. 
     As shown in FIG. 18, the disk delivery unit  214  is held by engaging between the eject base  215  and the bent portion of the forward rest  41   a . And the disk delivery unit  214  is provided to move laterally of the apparatus (in the direction of disk arrangement) to an arbitrary position while being held on the rest  41   a . In order to set the disk delivery unit  215  in an appropriate position on the stocker tray  700 , the portion of the eject base  215  engaging with the stocker tray  700  is formed with a triangular protrusion  215   a  having the elasticity of resin. 
     FIG. 20 is a schematic diagram showing the triangular protrusion  215   a  of the eject base  215  in mesh with one of triangular grooves  700   a  formed in the stocker tray  700  in FIG.  18 . As shown in FIG. 20, the center of each of the triangular grooves  700   a  formed on the stocker tray  700  coincides with the center of the corresponding one of the slots for holding the disks  7 ,  8 . The itriangular grooves  700   a  are formed equidistantly. Also, the protrusion  215   a  of the eject base  215  is kept pressed against the triangular grooves  700   a  of the stocker tray  700  by the elastic force of resin. When the disk delivery unit  214  moves along the direction of disk arrangement, the protrusion  215   a  of the eject base  215  engages with the triangular grooves  700   a  sequentially and therefore the disk delivery unit  214  is accurately set (corrected) in position with respect to each slot holding the disk  7 ,  8 . 
     As shown in FIGS. 18 and 19, a groove  216   a  for supporting the disk  7 ,  8  delivered from the stocker tray  700  is formed at the central portion of the eject lever  216  along the longitudinal direction of the eject lever  216 . The bottom of the groove  216   a  is formed with another two V-shaped grooves  216   b  (FIG. 18) thereby supporting accurately the disk  7 ,  8  delivered. 
     As shown in FIG. 19, a rack  701  is formed along the direction of disk arrangement on the front of the stocker tray  700 . Also, gear teeth  219   a  adapted to engage with the rack  701  are formed on the counter  219 . The gear arrangements of the second embodiment are so configured that the counter  219  makes one rotation when the disk delivery unit  214  moves along the direction of disk arrangement and has passed through  21  disk holding slots of the stocker tray  700 . In the stocker tray  700  of the second embodiment, one out of every  20  holding slots is not in use, and therefore each  21  disk holding slots can hold  20  disks. 
     As shown in FIG. 19, two continuous strings of numerals  0  to  9  are marked along the circumference on the upper surface of the counter  219 . The counter  219  rotates by an angle equivalent to one numeral each time the disk delivery unit  214  moves to cover one holding slot of the stocker tray  700 . Also, the stocker tray  700  is provided with a tall partitioning plate  700   b  at intervals of ten holding slots on the stocker tray  700  in order to help the user readily recognize the number and position of the disks  7 ,  8  held in the holding slots. 
     Further, the eject base  215  is provided with an indicator  215   b . The indicator  215   b  is configured to indicate one numeral representing the position of the disk delivery unit  214  corresponding to the stocker tray  700  among a plurality of the numerals marked on the upper surface of the counter  219 . According to the second embodiment, the user can easily and accurately recognize the position of the disk delivery unit  214  in motion by using the numerals indicated on the indicator  215   a  and the tall partitioning plates  700   b  for each ten holding slots of the stocker tray  700 . 
     Furthermore, the operating unit of the counter  219  is arranged on the eject base  215  on the front of the apparatus, and therefore the user can easily manipulate it. The user can adjust the position of the disk delivery unit  214  by rotating the counter  219 . 
     [Delivery Operation of Disk Delivery Unit  214 ] 
     Next, explanation will be made about the operation of delivering the disk  7 ,  8  in the disk changer apparatus of the second embodiment. 
     In FIG. 18, the eject lever  216  positioned upright is tilted by rotation forward of the apparatus (along the direction of arrow X in FIG.  18 ), so that the eject slide plate  217  moves rearward of the apparatus (along the direction of arrow M in FIG.  18 ). By the movement of the eject slide plate  217  along the direction of arrow M, the inclined surface  217   a  formed on the upper rear end surface of the eject slide plate  217  pushes up the pin  218   a  of the push-up lever  218 . As a result, the push-up lever  218  rotates along the direction of arrow T. The push-up lever  218  thus rotated in the direction of arrow T advances into a slot holding the disk  7 ,  8  through the opening formed in the central portion of the coupler of the stocker tray  700 . Consequently, the forward end of the push-up lever  218  pushes the edge of the disk  7 ,  8  to transfer the disk  7 ,  8  forward of the apparatus (along the direction of arrow N in FIG.  18 ). The disk  7 ,  8  thus sent forward of the apparatus stops as it is retained in the groove  216   a  formed in the central portion of the eject lever  216 . This state is shown in FIG. 21, which is a side sectional view showing the disk delivery unit  214  in the disk delivering operation of the disk  7 ,  8 . 
     Although the second embodiment uses the rotatable eject lever  216  as the disk receiving means, the disk changer apparatus in accordance with the present invention may alternatively be configured in such a manner that the eject lever  216  is not adapted to rotate but slide to move the disk  7 ,  8  to the delivery point. 
     Also, instead of a separate elastic material used to provide elasticity to the eject lever  216  in the second embodiment, the eject lever itself may be formed of an elastic material to receive a disk. 
     Since the disk changer apparatus of the second embodiment is configured as described above, a specific disk  7 ,  8  alone can be taken out or exchanged both easily and accurately by moving the disk delivery unit  214  along the direction in which the disks are arranged. 
     Especially, even in the case where the disks  7 ,  8  are closely held in the stocker tray  700  or even in the case where a small disk  8  is sandwiched between large disks  7 , the disk changer apparatus of the second embodiment allows the small disk  8  to be taken out or exchanged easily. 
     According to the second embodiment, the push-up lever is driven by rotating the eject lever  216  as a disk receiving unit, and therefore no independent operating means is required for manipulating the push-up lever, thereby simplifying the apparatus. 
     Also, according to the second embodiment, the counter  219  having numerals for indicating the disk position is provided on the disk delivery unit  214 , so that the current position of the disk delivery unit  214  can be easily recognized. 
     Although the present invention has been described in terms of the presently preferred embodiments, it is to be understood that such disclosure is not to be interpreted as limiting. Various alterations and modifications will no doubt become apparent to those skilled in the art to which the present invention pertains, after having read the above disclosure. Accordingly, it is intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention.