Patent Publication Number: US-6215757-B1

Title: Reproduction/recording apparatus having a divisible housing for disc-shaped recording carriers and a reproduction/recording head mounting rack

Description:
This is a Continuation of Ser. No. 08/874,490, filed Jun. 13, 1997 now U.S. Pat. No. 6,052,356. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a reproduction/recording apparatus for disk-shaped recording carriers, which holds a plurality of disk-shaped recording carriers or media such as compact disks (hereinafter abbreviated as “CDs”), including a disk autochanger permitting selective reproduction of any arbitrary one of such disk-shaped carriers. 
     2. Description of the Related Art 
     An audio apparatus or a navigation apparatus having an autochanger function for reading out musical information recorded in a CD or geographic information recorded in a CD-ROM by housing a plurality of CDs in a magazine and housing the magazine containing the CDs in a reproduction/recording apparatus has been widely in use for mounting on an automobile. An auto-mobile-mounting reproduction/recording apparatus cannot house many CDs because of the limited size of an installable equipment for attaching operably within the automobile compartment. The mechanism for housing and replacing CDs is installed at a position far from the compartment such as the trunk room, and it is a common idea to arrange only minimum portions necessary for operation within the compartment. When arranging an autochanger apparatus outside the compartment of automobile, however, it is impossible to conduct any replacement of housed CDs during travel of the vehicle. 
     Prior art automobile autochanger apparatuses capable of housing a plurality of CDs within the compartment are disclosed, for example in Japanese Unexamined Patent Publications JP-A 3-235249(1991), JP-A 620425(1994), and JP-A 6-231526(1994), an outline of which is illustrated in FIG.  66 . FIG.  66 ( a ) is a schematic front sectional view, and FIG.  66 ( b ) is a schematic plan sectional view. CDs can be inserted into and ejected from an enclosure  2  of an autochanger apparatus  1  through an opening provided on the front side of a magazine  3 . The magazine  3  is capable of housing a plurality of CDs  4 , and optical reproduction of the recorded information is accomplished while rotation-driving one of these CDs  4  by means of a pickup (hereinafter referred to as “PU”) unit  5 . The PU unit  5  is mounted on a rack  6 , and can move forward to, and back from, the position of the CD  4  selected in the magazine  3 . The rack  6  is arranged on one side of the enclosure  2  so as not to hinder insertion and ejection of the magazine  3  into and from the front opening of the enclosure  2 . In the automotive autochanger apparatus  1 , a floating mechanism  7  for instantaneously achieving a floating state is provided so as to prevent transmission of external vibration to the rack  6 . 
     In order to select the CD  4  housed in the magazine  3  to attach the CD  4  to the PU unit  5 , there should be provided a space permitting insertion of the PU unit  5  on at least one surface side of the housed CDs. For the selection of the CD  4  to be reproduced by inserting the PU unit  5  in the magazine  3 , it is necessary to cause a lifting displacement of the magazine  3  as a whole so as to align the height of the selected CD  4  with that of the PU unit  5 . When the space for allowing insertion of the PU unit  5  to any of the plurality of CDs  4  housed in the magazine  3  and the magazine  3  has a limited thickness, the number of CDs  4  capable of being housed is reduced. The magazine  3  can therefore be divided into upper and lower parts, and a space can be formed only on one side of the CD  4  to be reproduced by the PU unit  5 . A lifting/dividing mechanism  8  is provided for the purpose of conducting such lifting displacement and division of the magazine  3 . The lifting/dividing mechanism  8  is provided on a side of the enclosure  2 . An electronic circuit board  9  for processing of the information reproduced by the PU unit  5  and for control of the mechanisms of the autochanger apparatus  1  is arranged behind the enclosure  2 . 
     Japanese Unexamined Patent Publications JP-A 6176472(1994) and JP-A 7-272383(1995) disclose prior art devices in which a stocker capable of housing a plurality of CDs or the like is provided in an enclosure thereby enabling insertion and ejection of a CD one by one. In Japanese Unexamined Patent Publication JP-A 6-176472(1994), a drive unit for recording and reproducing optomagnetic disks housed in a cartridge is provided between an inlet and a stocker. In Japanese Unexamined Patent Publication JP-A 7272383(1995), insertion and reproduction are carried out with a CD being placed on a disk-shaped carriage. 
     In a magazine-type autochanger apparatus  1  as shown in FIG. 66, it is necessary to accomplish insertion into, and ejection from, the enclosure  2  by the use of the magazine  3  which is capable of housing a plurality of CDs  4 . Even when only one CD  4  is replaced, therefore, it is necessary to take out the magazine  3  from the autochanger apparatus  1 , replace the CD  4  in the magazine  3 , and reinsert the magazine  3  into the enclosure  2 , thus requiring much labor. Since the magazine  3  is taken out from the enclosure  2 , a high stiffness is required in the taken-out or removed state, and in the inserted state into the enclosure  2 , the magazine  3  must be divisible at an arbitrary CD housing position. A magazine  3  satisfying these requirements will have a very complicated structure with a large weight. In addition, a mechanism for securely holding a CD  4  housed in the magazine  3  taken out from the enclosure  2  must be incorporated. The gap between CDs  4  to be housed cannot therefore be largely reduced. Furthermore, it is necessary to form a space for inserting the PU unit  5  by causing the lifting/dividing mechanism  8  to move up or down in accordance with the position of the PU unit  5  for selecting the CD  4  and to divide the magazine  3  with the position of the selected CD  4  as the boundary. The magazine  3  should therefore have a height largely reduced as compared with the height of the enclosure  2 . As a result, in the automotive autochanger apparatus  1 , the magazine  3 , which is capable of housing CDs in the enclosure  2 , is subject to a height limit due to the necessity of attachment in a console box in the compartment and thus it can house only a small number of CDs  4  on the order of about three. 
     Japanese Unexamined Patent Publication JP-A 6176472(1994), which handles disks in a placed state in a case, requires a large space as compared with the case where a disk is handled in the form of a single disk. In Japanese Unexamined Patent Publication JP-A 7-272383(1995), CDs are handled on a carriage, thus requiring a complicated inserting and ejecting operation into and from the stocker. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide a reproduction/recording apparatus for disk-shaped recording carriers, which permits individual insertion and ejection of disk-shaped recording carriers and is capable of housing a plurality of such carriers in a compact size. 
     The present invention provides a reproduction/recording apparatus for disk-shaped recording carriers comprising: 
     an enclosure provided with an opening through which the disk-shaped recording carriers are individually inserted into or ejected from the enclosure; 
     divisible housing means for housing a plurality of recording carriers; 
     transfer means for transferring the recording carrier between the opening and the housing means; and 
     reproduction/recording means for performing reproduction/recording of the recording carriers, the reproduction/recording means being capable of advancing into and retreating from a space expandable by dividing the housing means. 
     According to the invention, the disk-shaped recording carriers are individually inserted and ejected via an opening of an enclosure. The plurality of recording carriers are housed in the housing means. A transfer means transfers the recording carriers between the opening and the housing means. The housing means is divisible and the reproduction/recording means can advance into, or retreat from, the space expandable by the division. Since the space can be expanded for advance/retreat of the reproduction/recording means, the space for only housing the recording carriers can be small in size, thus permitting downsizing of the housing means. 
     Further, the invention provides a reproduction/recording apparatus for disk-shaped recording carriers comprising: 
     an enclosure provided with an opening through which the disk-shaped recording carriers are individually inserted into or ejected from the enclosure; 
     divisible housing means for housing a plurality of recording carriers; 
     transfer means for transferring the recording carrier between the opening and the housing means; and 
     reproduction/recording means for performing reproduction/recording of the recording carriers, the reproduction/recording means being disposed above or below the transfer means and capable of advancing into and retreating from a space expandable by dividing the housing means. 
     According to the invention, the disk-shaped recording carriers are individually inserted and ejected via the opening of the enclosure. The plurality of recording carriers are housed in the housing means. The transfer means transfers the recording carriers between the opening and the housing means. The housing means is divisible and the reproduction/recording means can advance into, or retreat from, the space expandable by the division. Since the space can be expanded for advance/retreat of the reproduction/recording means, the space for only housing the recording carriers can be small in size. Because the reproduction/recording means is arranged above or below the transfer means, the inner space of the enclosure can be effectively utilized, thereby permitting further downsizing. 
     Further, the invention provides a reproduction/recording apparatus for disk-shaped recording carriers, capable of housing a plurality of such disk-shaped recording carriers in an enclosure, the reproduction/recording apparatus comprising: 
     divisible housing means having a holding section for holding the recording carriers; 
     reproduction/recording means capable of advancing into and retreating from a space expandable by dividing the housing means; 
     attaching means provided in the reproduction/recording means, for attaching the recording carriers; and 
     control means for, in the case of reproduction/recording, advancing the reproduction/recording means into the divided space of the housing means to attach the recording carriers to the attaching means, and thereafter retreating the reproduction/recording means to release holding of the recording carriers by a holding section of the housing means, thereby controlling the reproduction or recording of the recording carriers. 
     According to the invention, the divisible housing means is provided with a holding section to make it possible to hold a plurality of disk-shaped recording carriers. It is possible to cause the reproduction/recording means to advance into, and retreat from, the space expandable by dividing the housing means. In reproduction/recording, the control means performs reproduction or recording of the recording carrier by causing the reproduction/recording means to advance into the space expanded by the division, attaching the recording carriers to the attaching means to release holding by the holding section, and causing the reproduction/recording means to retreat. The space necessary for the move of the housing means and the reproduction/recording means can be reduced, thus permitting downsizing of the apparatus. 
     Further, the invention provides a reproduction/recording apparatus for disk-shaped recording carriers, permitting individual insertion or ejection of a plurality of disk-shaped recordings, each having a center hole, through an opening of an enclosure housing of the plurality of recording carriers, the reproduction/recording apparatus comprising: 
     divisible housing means having a holding section for holding the recording carriers; 
     transfer means for transferring the recording carriers between the opening and the housing means; 
     reproduction/recording means for performing reproduction or recording of the recording carriers, the reproduction/recording means being capable of advancing into and retreating from a space expandable by dividing the housing means, and including attaching means with which the center hole of the recording carrier is to be engaged; and 
     control means for, in the case of insertion or ejection of the recording carrier, aligning the position of the transfer means with that of the housing means, and for, in the case of reproduction/recording of the recording carrier, aligning the position of the reproduction/recording means with that of the space resulting from the division of the housing means to advance the reproduction/recording means into the space formed by the dividing, and engage the attaching means with the center hole of the recording carrier, and thereafter retreating the reproduction/recording means to release holding by the holding section, thereby controlling to perform reproduction or recording. 
     According to the invention, the housing means has a holding section capable of holding a plurality of disk-shaped recording carriers, and is divisible. The reproduction/recording means can be caused to advance into, and retreat from, the space expanded by the division of the housing means. In reproduction/recording, the control means causes the reproduction/recording means to advance into the space expanded by the division and engages the center hole of the disk-shaped recording carrier with the attaching means. The reproduction/recording means is caused to retreat to perform reproduction or recording of the recording carrier. The recording carriers individually inserted or ejected through the opening are housed in the housing means by the transfer means aligned by the control means. It is possible to reduce the size of the space necessary for displacement of the housing means, the transfer means and the reproduction/recording means, thus permitting downsizing. 
     Further, the invention is characterized by comprising first lifting means for moving up and down the housing means. 
     According to the invention, in which the housing means moves up and down by the first lifting means, it is possible to easily carry out expansion of the space resulting from the division of the housing means and aligning with the opening of the enclosure. 
     Further, the invention is characterized by comprising second lifting means for moving up and down the reproduction/recording means. 
     According to the invention, the reproduction/recording means is moved up and down by the second lifting means. It is therefore possible to easily select a recording carrier to be reproduced or recorded from among the plurality of recording carriers housed in the housing means. 
     The invention is further characterized in that the control means in the case of insertion or ejection controls the housing means to integrally move up or down so as to align the housing position of the recording carrier in the housing means with the position of the opening, and in the case of reproduction or recording, divides the housing means at a specific position corresponding to the housing position to moves the reproduction/recording means up or down to align the position of the divided space of the housing means with the position of advance or retreat of the reproduction/recording means. 
     According to the invention, in individual insertion or ejection of the recording carrier, the housing means is integrally moved up or down to align the housing position with the position of the opening, thus making it possible to reduce the size of the space necessary for up or down movement of the housing means. In reproduction or recording, the housing means can be divided by the utilization of the space. 
     Further, the invention is characterized in that the housing means has a holding section for holding an outer periphery of the recording carrier inserted in a predetermined direction, and upon retreat of the reproduction/recording means, the recording carrier is pulled out from the housing means in a direction counter to the insertion direction so as to release the holding. 
     According to the invention, the holding section of the housing means can hold the outer periphery of the recording carrier by only inserting the recording carrier in a predetermined direction, and holding can be released by only pulling out in a direction counter to the predetermined direction. It is therefore possible to reduce the size of the space necessary for holding of the recording carrier by the holding section, thus allowing a compact housing means to house many recording carriers. 
     Further, the invention is characterized in that the operation of reproduction/recording of the recording carrier by the reproduction/recording means is accomplished in a state in which at least a part of the recording carrier remains within the housing means. 
     According to the invention, the operation of reproduction/recording is conducted in a state in which at least a part of the recording carrier remains within the housing means. It is therefore possible to reduce the size of the space necessary for displacement of the reproduction/recording means, thus permitting achievement of downsizing. 
     Furthermore, the invention is characterized in that the attaching means of the recording carrier elastically supports from inside the center hole formed in the recording carrier by inserting a shaft from one surface side of the recording carrier. 
     According to the invention, attachment of the recording carrier to the reproduction/recording means can easily be accomplished by elastically supporting through insertion of the shaft into the center hole of the recording carrier from one surface side. 
     Further, the invention is characterized in that in the case of reproduction or recording of the recording carrier, the control means controls the reproduction/recording means to advance it into the divided space to bring the divided portion of the housing means closer to the reproduction/recording means side to attach the recording carrier at the specified housing position to the attaching means. 
     According to the invention, it is possible to attach the recording carrier from the housing means to the attaching means by movement of the housing means, and utilize the displacement mechanism for dividing the housing means. 
     Further, the invention is characterized in that upon completion of the reproduction/recording operation, the control means controls the reproduction/recording means to advance it into the divided space of the housing means, and to expand to the divided portion of the housing means in the direction of division to detach the recording carrier attached to the attaching means of the reproduction/recording means. 
     According to the invention, the recording carrier can be attached from the reproduction/recording means and housed in the housing means through displacement of the housing means, and the displacement mechanism for the division of the housing means can be utilized. 
     Furthermore, the invention is characterized in that the housing means comprises a plurality of housing members, and on any one surface side of each of the plurality of housing members, there is formed a holding section of which the leading end extends toward an inner periphery of the recording carrier so as to embrace at least a part of a peripheral edge of the recording carrier, and on the other surface side of the housing member, there is formed a recess or a throughhole into which at least a part of the holding section formed on the other housing member can be inserted. 
     According to the invention, the recording carrier is held between one surface side of the housing member and the leading end of the holding section. Because the housing member has a recess or a throughhole engageable with a holding section provided on one surface side and the holding section formed on the other surface side, it is possible, when laminating another housing member on then other surface side, to reduce the lamination thickness since the holding section of the other housing member engages with the recess or the throughhole. As a result, it is possible to laminate the housing members holding the recording carriers at narrow intervals and house a number of recording carriers efficiently in a narrow space. 
     Furthermore, the invention is characterized in that the housing means comprises a plurality of laminated housing members, and a long hole extending in a retreating direction of the reproduction/recording means from a proximity of the center of the recording carrier being held, and is formed in each of the housing members. 
     According to the invention, a long hole extending in the ejection direction from the proximity of the center is formed in the housing member. When engaging the center shaft with the central hole of the recording carrier held by the housing member, and pulling it out in the ejection direction, the leading end of the center shaft, even when protruding beyond the central hole of the recording carrier, never comes into contact with the housing member. Insertion and ejection of the recording carrier into and from the housing member can be accomplished smoothly while inserting the recording carrier onto the center shaft. It is therefore possible to house many recording carriers efficiently in a narrow space. 
     The invention is characterized in that the reproduction/recording apparatus further comprises: 
     displacement means for causing the reproduction/recording means to advance to or retreat from, the expanded space resulting from the dividing; 
     transfer means driving means for driving the transfer means; and 
     transmission means for transmitting the driving force of the transfer means driving means via a disconnectible route to the displacement means of the reproduction/recording means. 
     According to the invention, it is possible to transmit the driving force of the transfer means driving means via a disconnectible route to the displacement means of the reproduction/recording means. Since the transmission means is disconnectible, only transfer of the recording carrier can be performed in the disconnected state when transferring the recording carrier. When conducting reproduction or recording of the recording carrier, the displacement means is driven with the driving force from the transfer means driving means. Therefore, the transfer means driving means is shared by the displacement means and the transfer means, thus reducing the space in the enclosure and reducing the size of the enclosure. It is thus possible to effectively utilize a narrow space and efficiently perform transfer of the recording carriers and reproduction and recording of the recording carriers. 
     The invention is characterized in that the transmission means includes a gear train engaged with a plurality of gears, and the gear train includes displaceable gears. 
     According to the invention, transmission of the driving force to the displacement means from the transfer means driving means can be disconnected by only releasing the engagement state of the displaceable gears in the gear train. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other and further objects, features, and advantages of the invention will be more explicit from the following detailed description taken with reference to the drawings in which: 
     FIG. 1 is a block diagram illustrating an entire configuration of an autochanger apparatus  11  constructed in accordance with an embodiment of the invention; 
     FIG. 2 is a perspective view illustrating a disk loading state of the autochanger apparatus  11  shown in FIG. 1; 
     FIG. 3 is a perspective view illustrating a pickup unit loading state of the autochanger apparatus  11  shown in FIG. 1; 
     FIG. 4 is a perspective view illustrating a disk clamping operation of the autochanger apparatus  11  shown in FIG. 1; 
     FIG. 5 is a perspective view illustrating a reproduction operating state of the autochanger apparatus  11  shown in FIG. 1; 
     FIG. 6 is a plan view of a chassis  20  of the autochanger apparatus  11  shown in FIG. 1; 
     FIG. 7 is a front view of the chassis  20  shown in FIG. 1; 
     FIG. 8 is a rear view of the chassis  20  shown in FIG. 1; 
     FIG. 9 is a right side view of the chassis  20  shown in FIG. 1; 
     FIG. 10 is a left side view of the chassis  20  shown in FIG. 1; 
     FIG. 11 is a plan view of a stocker  13  shown in FIG. 1; 
     FIG. 12 is a front view of the stocker  13  shown in FIG. 1; 
     FIG. 13 is a rear view of the stocker  13  shown in FIG. 1; 
     FIG. 14 is a right side view of the stocker  13  shown in FIG. 1; 
     FIG. 15 is a left side view of the stocker  13  shown in FIG. 1; 
     FIG. 16 is a whole perspective view illustrating division of the stocker  13  shown in FIG. 1; 
     FIG. 17 is a partial perspective view of a divided state of the stocker  13  shown in FIG. 1; 
     FIG. 18 is an exploded perspective view of the stocker  13  shown in FIGS. 11 to  16 ; 
     FIG. 19 is a side view illustrating lamination of a portion of a CD mounting pawl  110  in the stocker  13  shown in FIGS. 11 to  16 ; 
     FIG. 20 is a plan view of the individual stocker members forming the stocker  13  shown in FIGS. 11 to  16 ; 
     FIG. 21 is a front view of the stocker member  100  shown in FIG. 20; 
     FIG. 22 is a right side view of the stocker member  100  shown in FIG. 20; 
     FIG. 23 is a left side view of the stocker member  100  shown in FIG. 20; 
     FIG. 24 is a plan view of the uppermost stocker member  101  of the stocker  13  shown in FIGS. 11 to  16 ; 
     FIG. 25 is a front view of the uppermost stocker member  101  shown in FIG. 24; 
     FIG. 26 is a right side view of the uppermost stocker member  101  shown in FIG. 24; 
     FIG. 27 is a left side view of the uppermost stocker member  101  shown in FIG. 24; 
     FIG. 28 is a plan view of a rack  16  shown in FIG. 1; 
     FIG. 29 is a front view of the rack  16  shown in FIG. 1; 
     FIG. 30 is a right side view of the rack  16  shown in FIG. 1; 
     FIG. 31 is a left side view of the rack  16  shown in FIG. 1; 
     FIG. 32 is a plan view of a disk identifying mechanism provided on the rack  16  shown in FIGS. 28 to  31 ; 
     FIG. 33 is a plan view illustrating component parts of the disk identifying mechanism provided on the rack  16  shown in FIGS. 28 to  31 ; 
     FIG. 34 is a plan view of a PU unit  15  shown in FIG. 1; 
     FIG. 35 is a front view of the PU unit  15  shown in FIG. 1; 
     FIG. 36 is a left side view of the PU unit  15  shown in FIG. 1; 
     FIG. 37 is a sectional front view illustrating a configuration of the center shaft  191  of a turntable  27 ; 
     FIG. 38 is a right side view of the PU unit  15 ; 
     FIG. 39 is a plan view illustrating the PU unit  15  displaced to a PLAY position; 
     FIG. 40 is a schematic sectional side view illustrating the effect of shift of a roller of transfer means  24 ; 
     FIG. 41 is a left side view illustrating a gear train provided to the left of the rack  16 ; 
     FIG. 42 is a left side view of a sliding plate  135  for locking, the sliding plate is arranged to the left of the rack  16 ; 
     FIG. 43 is a perspective view illustrating the relationship between a stair sliding member  35  and a locking sliding member  45  shown in FIGS. 6 to  10 ; 
     FIG. 44 is a left side view illustrating an interlocking portion of a stair rack  40  of the stair sliding member  35  and a locking rack  46  of the locking sliding member  45 ; 
     FIG. 45 is a perspective view of a stair sliding member  36  shown in FIGS. 6 to  10 ; 
     FIG. 46 is a schematic plan view illustrating operation of the locking mechanism shown in FIGS. 6 to  10 ; 
     FIG. 47 is a perspective view illustrating a configuration associated with a push lever  72  shown in FIGS. 6 to  10 ; 
     FIG. 48 is a perspective view illustrating a configuration associated with a dump lever  140  shown in FIGS. 28 to  31 ; 
     FIG. 49 is a schematic front view illustrating a configuration associated with a shutter  22  shown in FIG. 1; 
     FIG. 50 is a block diagram illustrating an electric configuration associated with a control circuit  19  shown in FIG. 1; 
     FIG. 51 is a flowchart illustrating entire operations of the control circuit  19  shown in FIG. 50; 
     FIG. 52 is a flowchart illustrating operations of the electric configuration shown in FIG. 50; 
     FIG. 53 is a time chart illustrating the operations of the electric configuration shown in FIG. 50; 
     FIG. 54 is a flowchart illustrating the operations of the electric configuration shown in FIG. 50; 
     FIG. 55 is a time chart illustrating the operations of the electric configuration shown in FIG. 50; 
     FIG. 56 is a flowchart illustrating the operations of the electric configuration shown in FIG. 50; 
     FIG. 57 is a time chart illustrating the operations of the electric configuration shown in FIG. 50; 
     FIG. 58 is a flowchart illustrating the operations of the electric configuration shown in FIG. 50; 
     FIG. 59 is a time chart illustrating the operations of the electric configuration shown in FIG. 50; 
     FIG. 60 is a flowchart illustrating the operations of the electric configuration shown in FIG. 50; 
     FIG. 61 is a time chart illustrating the operations of the electric configuration shown in FIG. 50; 
     FIG. 62 is a flowchart illustrating the operations of the electric configuration shown in FIG. 50; 
     FIG. 63 is a time chart illustrating the operations of the electric configuration shown in FIG. 50; 
     FIG. 64 is a flowchart illustrating the operations of the electric configuration shown in FIG. 50; 
     FIG. 65 is a time chart illustrating the operations of the electric configuration shown in FIG. 50; and 
     FIGS. 66A and 66B includes a plan view and a front view illustrating a schematic configuration of a conventional autochanger apparatus. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Now referring to the drawings, preferred embodiments of the invention are described below. 
     FIG. 1 illustrates a schematic configuration of an automotive autochanger apparatus  11  constructed in accordance with an embodiment of the invention. An enclosure  12  has a certain size, for example known as the 1DIN size, and has substantially a rectangular shape. A stocker  13 , which is a housing means, is housed in the enclosure  12  and can house a plurality of, for example six, CDs  14 . Each CD  14 , which is a disk-shaped recording carrier, can be individually inserted and ejected. The CD  14  housed in the stocker  13  can be individually and optically reproduced by means of a PU unit  15  which is reproduction/recording means. The PU unit  15  has an optical pickup and is attached to a rack  16  which is a displacement means. The enclosure  12  elastically supports internal mechanisms such as the rack  16  and the stocker  13  by means of a floating mechanism  17  which is a floating means for reducing the effects of external vibration. The stocker  13  can move up and down as a whole, and only an upper portion from the housing position of a particular CD  14  can move up and down, by the action of a lifting/dividing mechanism  18  which is a replacement member. Operations of the PU unit, the rack  16  and the lifting/dividing mechanism  18  are controlled by a control circuit  19 . The control circuit  19  is arranged on one side of the enclosure  2 . The floating mechanism  17  supports a chassis  20 , which is a supporting means for supporting the rack  16  and the stocker  13 , in floatation relative the enclosure  12 . When inserting and discharging one of the CDs  14 , a locking pawl  21  which is a locking means secures the chassis  20  to the enclosure  12 . A shutter  22  which is an opening/closing means is provided in front of the rack  16  and can open or close an opening  23  provided in the enclosure  12 . A transfer roller  24  which is a transfer means is also provided on the rack  16 . 
     FIGS. 2 to  5  illustrate operations ranging from insertion to reproduction of the CD  14  in the autochanger apparatus  11  shown in FIG.  1 . FIG. 2 illustrates a disk loading state in which the CD  14  is inserted through the opening of the enclosure  12  up to a holding position in the stocker  13  while holding the CD  14  between an upper roller  25  and a lower roller  26  of transfer rollers  24 . The PU unit  15  comprises a turntable  27  for rotation-driving the CD  14 , a PU  28  for reproducing information stored in the CD  14 , and a tracking mechanism  29  for causing the PU  28  to move in the radial direction of the CD  14 . FIG. 3 illustrates a loading state of a pickup unit for causing the PU unit  15  to advance into a space formed by upward movement of the upper portion of the stocker  13  divided at a specified holding position, alignment of the PU unit  15  with a specified holding position through lifting of the rack  16 , and upward movement of the divided portion of the stocker  13 . FIG. 4 illustrates a disk clamping state in which the divided portion of the stocker  13  holding the CD  14  moves down, and the CD  14  is clamped on the rotation shaft of the PU unit  15 . FIG. 5 illustrates a reproduction state in which, after releasing the holding state by the stocker  13  brought about by retreat of the PU unit  15 , the divided portion of the stocker  13  moves up again, and the CD  14  is reproduced by the PU unit  15 . 
     FIGS. 6 to  10  illustrate a configuration associated with the chassis  20  of the autochanger apparatus  11 . FIG. 6 is a plan view; FIG. 7 is a front view; FIG. 8 is a rear view; FIG. 9 is a right side view; and FIG. 10 is a left side view. A stair motor  31  is attached to the lower portion of a base  30  on the rear left side, and a stocker motor  32 , to the upper portion. The top of the base  30  is covered with a cover  33 . 
     Stair sliding members  35  and  36  are arranged on the right and left sides of the base  30 . Stair grooves  37  and  38  are formed on the stair sliding members  35  and  36 , respectively, so that the rack  16  can move up and down along six steps in response to forward/back displacement of the stair sliding members  35  and  36 . The left stair sliding member  35  is provided with a slit  39  so as to permit optical detection of the position of the rack  16 . The left stair sliding member  35  has a stair rack  40  formed on an upper portion of the rear side for forward/back driving, and a stair upper limit contact section  41  and a stair origin contact section  42  are formed on an inside portion of the front side. The left stair sliding member  35  and the right stair sliding member  36  are connected with a transmission lever  43  provided at the front of the base  30 . A center shaft  44  is provided at the center of the transmission lever  43 , and the transmission lever  43  can oscillate (rotate) around the center shaft  44  relative to the base  30 . Since the stair sliding members  35  and  36  are connected via the transmission lever  43 , right and left sliding members  35  and  36  are displaceable in reverse directions. As a result, the stair groove  38  provided in the right stair sliding member  36  has a direction counter to the stair groove  37  provided in the left stair sliding member  35 . 
     A locking sliding member  45  is arranged between the left stair sliding member  35  and the base  30 . A locking rack  46  is formed on the upper rear side of the locking sliding member  45 . An interlocking pin  47  is attached to the locking sliding member  45 , and inserted into an interlocking long hole  48  formed in the stair sliding member  35 . The interlocking pin  47  is freely displaceable in the interlocking long hole  48  within a range of up/down displacement of the rack  16  by the stair sliding member  35  to any position of second to sixth stages. When the stair sliding member  35  pulls down the rack  16  to the position of the first stage, the interlocking pin  47  comes into contact with the front end of the interlocking long hole  48 , and causes the locking sliding member  45  to displace to the rear side. A transfer switching cam  49 , for switching between connecting and not connecting a mechanism for advance and retreat of the PU unit  15  provided on the rack  16  to a mechanism for driving the transfer roller  24 , is formed in the middle of the locking sliding member  45 . A stocker guide  50  and a stocker stopper  51  are formed in the rear portions of the stair sliding members  35  and  36  and are used for up/down displacement and division of the stocker  13  as described later. The left stair sliding member  35  and the locking sliding member  45  are pulled toward each other by a spring  52  so as to impart a force to cause the interlocking pin  47  to come into contact with the front end of the interlocking long hole  48 . 
     A transmission rack  53  is formed toward an inside portion of the locking sliding member  45 . The transmission rack  53  engages with a gear  55  formed on a portion of the outer periphery of a cam member  54  attached to the rear center portion of the base  30 . The cam member  54  is substantially circular, and angularly displaceable around a center shaft  56  thereof. A rear locking cam groove  57 , a side locking cam groove  58  and a shutter contact section  59  are formed on portions toward the rear, right side and front, respectively, of the cam member  54 . A follower  60  of a locking pawl  21  is inserted into the rear locking cam groove  57 . A long hole  61  extending in the forward/back direction is provided at the center of the locking pawl  21 , and a pin  62  provided upright on the base  30  engages with the long hole  61 . When the rear locking cam groove  57  pushes out the follower to the rear in response to an angular displacement of the cam member  54 , pushing out the locking pawl  21  rearward, the front end side of the chassis  20  can be pressed against the front side of the enclosure  12  with the rear end thereof so as to bring chassis  20  farther from the rear end of the enclosure  12 . A follower  64  provided at the base of the side locking lever  63  engages with the side locking cam groove  58 . The side locking lever  63  has substantially an L-shape. A pin provided upright on the base  30  is inserted into a throughhole provided at the bend of the side locking lever  63  so that the lever can be displaced by oscillating (pivoting) around a pin  65 . The leading end of the side locking lever  63  projects to the right of the base  30 , and can press the base  30  so as to leave the right side of the enclosure  12 . The shutter contact section  59  presses a pin  67  provided at the base of the shutter transmission lever  66  from a side to cause an angular displacement around an oscillation shaft  68  which rotatably supports the shutter transmission lever  66 . A force is imparted to the shutter transmission lever  66  by a spring  69  in a direction to close the shutter  22 . 
     Rotary outputs of the stair motor  31  and the stocker motor  32  transmitted via gear trains  70  and  71 , respectively. A pushing lever  72  is provided at the rear end of the base  30  toward the left side, and can push out the CD  14  held in the stocker  13  from the holding state. A transmission lever  73  is provided below the pushing lever  72 , and can come into contact with the rear end of the locking sliding member  45 . In a state in which the locking sliding member  45  fully retreats, the leading end of the pushing lever  72  pushes out the CD  14  held in the stocker  13  via the transmission lever  73 . Springs  74  and  75  are provided between the pushing lever  72  and the transmission lever  73 , and between the transmission lever  73  and the base  30 , respectively. Between the pushing lever  72  and the transmission lever  73 , the spring  74  imparts a force in a direction of pushing out the leading end of the pushing lever  72 . A force is imparted to the transmission lever  73  by the spring  75  so as to cause contact with the rear end of the locking sliding member  45  in order to advance it. 
     A gear train  76  for transmitting a rotation-driving force transmitted via the gear train  71  from the stair motor  31  is attached to the cover  33 . Spur gears  77  and  78 , engaging with the gear train  76 , are attached to the upper surface of the cover  33 . The spur gears can be inserted after assembly of the gear train  76 . A spur gear  79 , similar to the spur gears  77  and  78 , is attached to the lower surface of the cover  33 . The spur gears  77 ,  78  and  79  engage with spur gears  83 ,  84  and  85 , respectively, attached to the upper parts of the feed screws  80 ,  81  and  82  provided on the stocker  13 . 
     A switch (hereinafter sometimes referred to as “SW”) board  86  is attached near the cam member  54  toward the front of the base  30 . The base portion of the stair upper/lower limit lever  87  is attached to the left side of the switch board  86 . The leading end of the stair upper/lower limit lever  87  can come into contact with the stair upper limit contact section  41  and the stair origin contact section  42  of the stair sliding member  35 . When the stair upper/lower limit lever  87  comes into contact with the stair upper limit contact section  41 , the stair upper limit SW  88  at the base portion of the stair upper/lower limit lever  87  is turned on. When the stair sliding member  35  retreats and the stair origin contact section  42  is in contact with the leading end of the stair upper/lower limit lever  87 , the base portion of the stair upper/lower limit lever  87  turns on the stair origin SW  89 . 
     Further, a lock position SW  90  is attached to the switch board  86 . The lock position SW  90  is turned on when the SW  90  is pressed by the circumferential portion following the gear  55  of the outer periphery of the cam member  54 , and is turned off upon completion of this circumferential portion. When the cam member  54  angularly displaces and a locking state is achieved by the locking pawl  21  and the side locking lever  63 , the lock position SW  90  is turned off. An insert/ejection position SW  91 , which is turned on by the shutter transmission lever  66  at a position for insertion or ejection of the CD  14  by the transfer roller  24  in response to the height of the rack  16  aligned with the height of the opening  23 , is further provided on the base  30 . 
     FIGS. 11 to  15  are a plan view, a front view, a rear view, a right side view and a left side view of the stocker  13  in combination, respectively. In this embodiment, the stocker  13 , capable of housing six stages of CDs  14 , is formed by a stocker member  100  for five stages, which is a housing member, and an uppermost-stage stocker member  101 . The feed screws  80 ,  81  and  82  engage with the uppermost-stage stocker member  101  at two positions toward the rear and a position to the right. The feed screw  80  at the left rear end engages directly with the uppermost-stage stocker member  101 . The other feed screws  81  and  82  are connected to the uppermost-stage stocker member  101  via lifting members  102  and  103 , respectively. Female screws are formed in the lifting members  102  and  103  to engage with the feed screws  81  and  82  to make the uppermost-stage stocker member  101  vertically displaceable. However, because the female screws are formed so as to make the uppermost-stage stocker member  101  displaceable with the lifting members  102  and  103 , it is possible to adjust engagement of the individual spur gears  83 ,  84  and  85  with the spur gears  77 ,  78  and  79 . A position detecting piece  104  is arranged at the rear end of the uppermost-stage stocker member  101 . The position detecting piece  104  is used for detecting the position with a high degree of accuracy as described later. 
     Dividing sliding members  105  and  106  are attached to the uppermost-stage stocker member  101 . Each of the dividing sliding members  105  and  106  has a flat portion sliding with the upper surface of the uppermost-stage stocker member  101  and a pawl  107  having a tip which hangs on a side and bends toward the interior. Two pawls  107  hang from the right dividing sliding member  105 , and a pawl  107  hangs from the left dividing sliding member  106 . Each of one of the pawls  107  of the right dividing sliding member  105  and the pawl  107  of the left dividing sliding member  106  is provided with a projection  108  protruding toward outside. The projection  108  engages with a long hole provided in the stocker guide of each of the stair sliding members  36  and  35 , and is vertically displaceable while being guided by the long hole. A driving force for advancing or retreating displacement is transmitted from the stair sliding members  36  and  35 . 
     A holding leaf spring  109  for holding the CD  14  is provided for the stocker member  100  and the uppermost-stage stocker member  101  at a position slightly toward the front from the both sides. In the portion toward the rear from that having the holding leaf spring  109 , CD mounting pawls  110 , which are a plurality of holding sections, are formed at certain intervals. The portion of the outer periphery toward the rear of the CD  14  held by the stocker member  100  or the uppermost-stage stocker member  101  is placed on the leading end of the CD mounting pawl  110 , and is further held by the holding leaf spring by pressing. Dividing projections  111 , which are selecting sections, are formed with equal heights on the sides of the stocker member  100  and the uppermost-stage stocker member  101 , and are selectively divisible by the stocker stoppers  51  of the stair sliding members  35  and  36  and the pawls  107  of the dividing sliding members  105  and  106 . 
     FIG. 16 is a whole perspective view of the division of the stocker  13 , and FIG. 17 is a perspective view of the dividing projection  111 . The dividing projections  111  are arranged at a position, and the pawls  107  of the dividing sliding members  105  and  106  and the stocker stoppers  51  of the stair sliding members  35  and  36  come into contact with the adjacent dividing projections  111  from below and from above, respectively. When the feed screws  80 ,  81  and  82  are rotated by rotation-driving the stocker motor  32 , the upper stocker  13  which is closer to the uppermost-stage stocker member  101  from the stocker member  100  selected by the pawl  107  is lifted and divided. 
     FIG. 18 is an exploded view of the stocker  13 , and FIG. 19 illustrates lamination of the stocker members  100 . For each stocker member  100 , a throughhole  110   a  permitting insertion of the CD mounting pawl  110 , having a diameter larger than the outside diameter of the CD mounting pawl  110  is provided on the inside on a surface side other than the surface having the CD mounting pawl. In a lamination state as shown in FIG. 19, the CD mounting pawl  110  is inserted into the throughhole  110   a , thus making it possible to reduce the thickness as a whole. 
     FIGS. 20 to  23  are a plan view, a front view, a right side view and a left side view of the individual stocker member  100 . FIGS. 24 to  27  are a plan view, a front view, a right side view and a left side view of the uppermost-stage stocker member  101 . While the uppermoststage stocker member  101  should also have a CD mounting pawl  110  formed on one surface side, it is not always necessary to form a throughhole  110   a , because no stocker member  100  is laminated at the portion above the uppermost-stage stocker member  101 . Dividing sliding member  105  and  103  are attached to the uppermost-stage stocker member  101  as shown in FIGS. 11 to  16 . A position detector  104  is formed at the rear end. 
     A turntable long hole  112 , allowing insertion of the center shaft of the turntable  27  described later, is formed in a portion closer to the front than the center of each of the stocker members  100  and the uppermost-stage stocker member  101 . A pushing notch  113  is formed at the rear end of the stocker member  100 , into which the leading end of the foregoing pushing lever  72  can advance. 
     A stocker position sensor  114 , to be connected to the position detector  104  provided on the uppermost-stage stocker member  101 , is attached to the rear end of the base  30  as shown in FIG.  6 . The stocker position sensor  114 , achieved by a variable resistor in which a slider linearly displaces, can detect a displacement of the uppermost-stage stocker member  101  through vertical linear displacement of the slider. An adjusting screw  115  is provided for adjusting the attachment position of the stocker position sensor  114 , and a fixing screw  116  is provided for fixing the adjusted position. When adjusting the position of the stocker position sensor  114 , the vertical position of the adjusting screw  115  is adjusted with the adjusting screw  115  while being pulled upward with a spring  117 , and the adjusted position is fixed with the fixing screw  116 . 
     A lock positioning member  118 , horizontally extending from the locking sliding member  45  to a side, thereof projects on the left side of the base  30 . The lock positioning member  118  has a hand drum shape in which the diameter of the middle portion is smaller than that of the leading end and the base portion, and is connected to the long hole provided in the enclosure  12 . With a small diameter of the long hole to which the retreating locking sliding member  45  is connected, the small-diameter portion at the middle of the lock positioning member  118  guided in the long hole of a small diameter would be constrained for the displacement in the transverse direction, thus permitting positioning. A spring shoe  119 , for receiving the spring serving as a floating mechanism  17  for hanging the chassis  20  within the enclosure  12 , is provided on a side of the base  30 . Further, dumper attaching members  120  for performing dumping in a floating state are attached to the both sides of the base  30 . Another dumper attaching member  121 , which is slenderer than the other dumper attaching members  120 , is attached to the left rear portion of the base  30 , considering the attaching position. A leaf spring  122 , pressing the upper ends of the feed screws  80 ,  81  and  82 , is provided in the cover  33 . The position of the slit  39  is detected by a count sensor  123  of a photointerrupter to the effect that the rack is at a position permitting PLAY. When the pushing lever  72  is pressed to the rear, the insertion completion SW  124  is turned on. 
     FIGS. 28 to  31  are a plan view, a front view, a right side view and a left side view of the rack  16  shown in FIG.  1 . Driving of the transfer roller  24  for insertion and ejection of the CD  14  and driving for advance and retreat of the PU unit  15  are accomplished by sharing the rotation force generated by the insertion/ejection motor  130 . The insertion/ejection motor  130  is attached to the right front of the rack  16 , and the rotation force rotation-drives the right end of the upper roller  25  through a transmission gear  131 . The upper roller  25  simultaneously serves as the transfer roller  24  and as a transmission route of the rotation force for advancing and retreating of the PU unit  15 . When the upper roller  25  is rotation-driven via the transmission gear  131 , the rotation force is transmitted from the right end to the left end of the upper roller  25 , thus driving a left transmission gear  132  of the rack  16 . 
     A pinion gear  134  engages via a displacement gear  133  with the trailing end of the transmission gear  132  which is a transmission means. The displacement gear  133  is vertically displaceable under the effect of a transfer switching cam  49  formed on the foregoing locking sliding member  45 . When the displacement gear  133  displaces upward, transmission of driving force is disconnected between the final stage of the transmission gear  132  and the pinion gear  134 . In a state in which the displacement gear  133  engages between the transmission gear  132  and the pinion gear  134 , the pinion gear  134  is rotation-driven by the rotation force from the insertion/ejection motor  130 , thus making it possible to cause the PU unit  15  engaging with the pinion gear  134  to advance to the rear from the rack  16  or cause the PU unit  15  having advanced to retreat to return back to the rack  16  side. 
     A locking sliding plate  135 , comprising a thin metal sheet, is provided between the transmission gear  132  and the displacement gear  133 , on the one hand, and the side of the rack  16 , on the other hand, and a force is imparted thereto by a spring  136  toward the rear. The front end of the locking sliding plate  135 , which is an engagement keeping means, is arrested at the front end of the PU unit  15 . When the PU unit  15  displaces and the locking sliding plate  135  is pulled back by the spring  136 , the displacement gear  133  is secured in the locking section at a driving force transmitting position between the transmission gear  132  and the pinion gear  134 . More specifically, when the PU unit  15  begins displacing from the position at the leading end of the rack  16  to the rear, the displacement gear  133  enters into a state of continuously transmitting the driving force from the transmission gear  132  to the pinion gear  134 . Only when the PU unit  15  is in standby at the leading end position of the rack  16 , does the locking sliding plate  135  allow vertical displacement of the displacement gear  133 , thus making it possible to lift a shaft  137  of the displacement gear  133  projecting outside from a side of the rack  16  by the action of the transfer switching cam  49  of the locking sliding member  45 , and to disconnect the transmission route. Followers  138  and  139  engaging with stepping grooves  37  and  38  of the stair sliding members  35  and  36  project on the left side and the right side of the rack  16 . 
     A push-in lever  140  is provided to the left of the rack  16  and above the transmission gear  132 , the displacement gear  133  and the pinion gear  134 . The push-in lever  140  is used for pushing in the inserted CD  14  onto the stocker  13  side, while the leading end thereof angularly displaces around an oscillation shaft  141  provided near the base. A force acting in a direction counter to the push-in direction is imparted to the push-in lever  140  by a spring  142 . In order to cause an angular displacement to the push-in lever  140  for push-in, a transmission lever  143  is provided. A force acting in a direction counter to the push-in direction of the push-in lever  140  is imparted to the transmission lever  143  by a spring  144  having a spring force smaller than that of the spring  142  imparting the force to the push-in lever  140 . The transmission lever  143  is driven by a push-in cam formed in the locking sliding member  45 . 
     The lower roller  26  of the transfer rollers  24  is attached, not directly below the upper roller  25 , but at a position slightly shifted to the rear, i.e., in the inserting direction of the CD  14 . The lower roller  26 , of which both ends of the shaft thereof are supported in U-shaped grooves, is vertically displaceable, and is pulled onto the upper roller  25  side by a lower roller spring  146 . 
     When a CD  14  is inserted between the upper roller  25  and the lower roller  26 , the inserted CD  14  is pressed by the lower roller  26  since the position of the lower roller  26  shifts toward the rear. The leading end of the CD  14  therefore inclines upwardly, and the CD  14  is guided in contact with the front extension of the stocker  13  smoothly to the holding position by the holding leaf spring  109  and the CD mounting pawl  110 . When the lower roller  26  is directly below the upper roller  25 , the leading end of the inserted CD  14  drops, thus making it difficult to ensure smooth guiding. 
     A plurality of long holes  150 ,  151 ,  152 ,  153 ,  154  and  155  and stop-grooved long holes  156  and  157  are formed on the front upper surface of the rack  16 . The stop-grooved long holes  156  and  157  have long hole portions in parallel with the long holes  150  to  155  and substantially vertical short stop grooves. These long holes extend substantially in the width direction. A spring shoe  158  is also provided on the upper surface of the rack  16 . These long holes  150  to  157  and the spring shoe  158  are used for a disk identifying mechanism based on a pin  159  built in the front upper portion of the rack  16 . 
     FIG. 32 illustrates a configuration of the disk identifying mechanism built in the front upper portion of the rack  16 . A rack  161  is formed at a position closer to the rear of a sliding plate  160  arranged near the front, and followers  162  and  163  engaging with the long holes  150  and  151  are provided. A pin  164  is provided, and a spring shoe  166  is formed on the sliding plate  160 . The rack  161  of the sliding plate  160  engages with an interlocking gear  169 . The interlocking gear  169  engages also with a rack  171  formed on a portion closer to the front of the sliding plate near the rear. The sliding plate  170  is substantially L-shaped and comprises a portion extending in the width direction having the rack  171  formed thereon, and a portion extending from the left side toward the front. Followers  172  and  173 , engaging with the long holes  152  and  153  of the rack  16 , are provided on the portion extending in the width direction, and a follower  174 , engaging with the long hole  154 , is provided near the leading end of the portion extending toward the front. An oscillating shaft  176  of an oscillating lever  175  is secured to a position near the bent portion of the sliding member  170 . The oscillating lever  175  is also substantially L-shaped. A follower  177  is arranged at the leading end of one of the arms thereof, and engages with the stop-grooved long hole  156  formed on the rack  16 . A pin  159  is formed in the leading end of the other arm of the oscillating arm. A similar oscillating lever  175  is also provided to the right of the sliding plate  160 , and the follower  177  at the leading end of one arm engages with the stop-grooved long hole  157 . The follower  167 , engaging with the long hole  155 , is also provided on the sliding plate  160 . 
     A tension spring is attached between the spring shoe  166  of the sliding plate  160  and the spring shoe  158  of the rack  16 . The tension spring imparts a force so that the followers  162 ,  163  and  167 , provided on the sliding plate  160 , are biased into contact with the left ends of the long holes  150 ,  151  and  155 . The followers  172 ,  173  and  174 , provided on the sliding plate  170 , come into contact with the right ends of the long holes  152 ,  153  and  154 . Each of the oscillating levers  175  is imparted a force by a spring so that the follower  177  provided at the leading end of one arm of the oscillating lever  175  drops into the stop grooves of the stop-grooved long holes  156  and  157 . 
     Upon insertion of the CD, the interval between the pins  159  provided on the arm other than that having the follower  177  of the oscillating lever  175  provided thereon is broadened, and the follower  177  comes off the stop grooves of the stop-grooved long holes  156  and  157 . Thereupon, the sliding plate  160  becomes displaceable to the right by the action of the right oscillating lever  175 , and the sliding plate  170  becomes displaceable to the left under the effect of the left oscillating lever  175 . In a state in which the follower  177  remains in the stop grooves of the stop-grooved long holes  156  and  157 , the sliding plate  160  or  170  cannot displace. That is, the CD can be received only when the both oscillating levers  175  are separated to the right and to the left. It is thus possible to avoid insertion of a single CD having an outside diameter of, for example, 8 cm different from that of the CD  14  of 12 cm. The interval between the pins  159  provided on the oscillating lever  175  is slightly larger than the outside diameter of a single CD so that, upon insertion of a single CD, it is impossible to cause a transverse displacement of the sliding plate  160  or  170 . 
     As shown in FIGS. 28 to  31 , two light-emitting diodes (hereinafter abbreviated as “LED”)  180  and  181  are arranged on the rack  16  at an interval along a straight line in the front-back direction. The light emitted from the LEDs  180  and  181  is detected by a photosensor provided in the PU unit  15  as described later. Displacement of the sliding plate  160  within the rack  16  is detected by an insertion detecting SW  182 , thus permitting detection of the insertion of a CD. 
     FIG. 33 illustrates shapes of the main sliding plates  160  and  170  and the oscillating lever  175  of the disk identifying mechanism shown in FIG.  32 . Because the oscillating lever  175  constrains the sliding plates  160  and  170 , respectively, in a state in which the follower  177  at the leading end of one arm engages with the stop grooves of the stop-grooved long holes  156  and  157 , the sliding plates  160  and  170  cannot displace. The sliding plates  160  and  170  can displace in parallel with each other while rotating an interlocking gear  169  only when the followers  177  of the both oscillating levers  175  come off the stop grooves of the stop-grooved long holes  156  and  157 . 
     FIGS. 34 to  36  are a plan view, a front view and a left side view, respectively, of the PU unit  15  shown in FIG. 1. A turntable  27  is provided substantially at the center of the PU unit  15 , and a center shaft  191  is rotation-driven directly by a motor  190 . A plurality of pawls  192  are attached to the center shaft  191  shown in FIG. 37, and a force to expand radially outside is imparted by a spring  193  attached at a position toward the interior of the center shaft. The spring  193  is held by a cover  194 . The spring  193  is a compression spring having a small diameter, and it suffices to insert it in parallel with the axial direction of the center shaft  191 , thus permitting relatively easy assembly. A tracking mechanism  29  for moving the PU  28  is provided to the left of the turntable  27 . A rack  195  engaging with the pinion gear  134  provided on the rack  16  is attached to the left side of the PU unit  15  to convert the rotation force of the pinion gear  134  into linear motion of the PU unit  15 . The tracking mechanism  29  is driven by a motor  196  arranged to the right of the turntable  27  of the PU unit  15  and a transmission gear  197  transmitting the rotation driving force thereof. FIG. 38 is a right side view of the PU unit  15 . 
     A sensor board  200  is attached to the rear of a portion of the PU unit  15  to the right of the turntable  27 . An ejection end sensor  201  and a disk presence detecting sensor  202  are attached at an interval as photosensors for receiving the light from an LED  180  are attached to the rack  16  on a straight line extending from front to rear on the sensor board  200 . A clamping position SW  203 , which detects that the PU unit  15  advances to the rearmost position and arrives at a clamping position allowing insertion of the CD  14  held in the stocker  13  to the center shaft  191 , is provided at the rear end of the sensor board  200 . A PLAY position sensor  204  which detects the PLAY position, after retreat of the PU unit  15  from the clamping position, for reproduction of the CD  14 , is provided on the right side of the sensor board  200 . The PLAY position sensor  204  comprises a photointerrupter in which a member interrupting the light is arranged at the PLAY position. A PU origin SW  205 , for detecting the state in which the PU  28  is at the position of origin, is provided in the portion closer to the front below the turntable  27 . There is also provided a unit origin SW  206  having a detecting end projecting slightly from the front end of the PU unit  15  and detecting the presence of the PU unit  15  at the frontmost origin of the rack  16 . 
     FIG. 39 illustrates a state in which the PU unit  15  has advanced from the rack  16  and is present at the PLAY position. The PLAY position is detected by a PLAY position sensor  204 . The PLAY position sensor  204  comprises a photointerrupter, and can detect that the PLAY position has been reached by interrupting the light from the light-emitting element before reaching the photo-element. 
     FIG. 40 illustrates a state in which the upper roller  25  for transfer and the lower roller  26  for pressing of the transfer rollers  24  provided on the rack  16  have a vertical shift, such that the leading end of the CD  14  is inclined in an upward direction by locating the lower roller on the transfer direction. Because the leading end of the CD  14  is directed upward, it comes into contact with the front extension of the stocker member  100  of the stocker  13  or the uppermost-stage stocker member  101 , and insertion is ensured without dropping. 
     FIG. 41 illustrates a gear train comprising a transmission gear  132 , a displacement gear  133  and a pinion gear  134  provided on the left side of the rack  16 . Because the displacement gear  133  arranged between the transmission gear  132  and the pinion gear  134  is vertically displaceable, it is possible to interrupt transmission of the driving force from the transmission gear  132  to the pinion gear  134  in a state in which the transmission gear  133  is slightly displaced in an upward direction. 
     FIG. 42 illustrates the shape of the locking sliding plate  135  arranged between the gear train shown in FIG.  41  and the left side of the rack  16 . Since the right leading end  147  of the locking sliding plate  135  engages with the leading end of the PU unit  15 , displacement of the PU unit  15  causes the locking sliding plate  135 , elastically supported by a spring  136 , to displace toward the stocker  13 . A cam groove  148  holding the displacement gear in engagement in contact with the rotation shaft of the displacement gear  33  is formed on the locking sliding plate  135  which is held in engagement after the start of displacement of the PU unit  15 . 
     FIG. 43 illustrates interlocking of the left stair sliding member  35  and the locking sliding member  45 , and FIG. 44 shows driving of the stair rack  40  and the locking rack  46 . The locking sliding member  45  is arranged between the stair sliding member  35  and the base  30 , and the foregoing transfer switching cam  49  is formed thereon. The stair sliding member  35  has the stair rack  40  engaging with a pinion  210  rotation-driven by the stair motor  31 . The pinion  210  is engageable also with the locking rack  46  of the locking sliding member  45 . However, the stair rack  40  and the locking rack  46  are never in engagement simultaneously with the pinion  210 , i.e. only one engages at a time with the latter. To ensure smooth switching of engagement, gears  211  and  212  are deformed into a shape, for example, in which the thread width becomes narrower at the switching portions of the stair rack  40  and the locking rack  46 . A projection  224  will be described later in the description of FIG.  48 . 
     FIG. 45 illustrates a configuration of the right stair sliding member  36 . Because the right stair sliding member  36  displaces in a direction counter to that of the left stair sliding member  35 , the stair groove  38  is formed in a direction counter to that of the stair groove  37  formed in the left stair sliding member  35 . 
     FIG. 46 illustrates operation of the locking pawl  21 , the side locking lever  63  and the lock positioning member  118  along with an angular displacement of the cam member  54 . At the lock position at which the locking sliding member  45  retreats, the locking pawl  21  projects rearwardly, and the side locking lever  63  projects to the right, resulting in a displacement toward the rear of the lock positioning member  118 . The lock position SW  90  is turned off. 
     FIGS. 47 and 48 illustrate a configuration associated with the push-out lever  72  and the push-in lever  140 . The push-out lever  72 , shown in FIG. 47, has a spring  74  in the space separating the lever  72  from the transmission lever  73 , is pushed to the rear upon insertion of the CD into the stocker  13  and turns on the insertion end switch  124 . In the push-in lever  140 , of which a bottom view is shown in FIG. 48, a projection of the transmission lever  143  has a straight portion  222  and a curved portion  223 . When a projection  224  formed on the locking sliding member  45  is in contact with the straight portion  222 , therefore, a driving force causing an angular displacement of the push-in lever  140  is transmitted. When the projection  224  is in contact with the curved portion  223 , only the transmission lever  143  angularly displaces and no driving force is transmitted to the push-in lever  140 . 
     FIG. 49 illustrates a configuration associated with the shutter shown in FIG.  1 . The shutter  22  opens by the driving force imparted through the shutter transmission lever  66  only at a position at which the locking sliding member  45  fully retreats. In this state, the chassis  20  is fixed to the enclosure  12  by the locking pawl  21 , the side locking lever  63  and the lock positioning member  118 , thus permitting smooth insertion and ejection of the CD  14 . The leading end of the shutter transmission lever  66  causes a transverse displacement of the sliding plate  225 . The transverse displacement is converted into a vertical opening/closing operation through the pin of the shutter  22  engaging with a slant groove  226 . Whether or not the shutter  22  is closed is detected by a sampling detecting sensor  228  based on a photointerrupter. The sampling detection sensor  228  is turned on in a state in which the leading end of the shutter transmission levers  66  opens the opening  23  by means of the shutter  22 . After inserting the CD  14  in the opening state of the shutter  22 , the shutter  22  cannot be closed in the state of the CD  14  remaining in the opening  23 . The sampling detection sensor  228  maintenance the ON state. When the CD  14  is removed, the sampling detection sensor  228  is turned off. 
     FIG. 50 illustrates an electric configuration associated with the control circuit  19  of the autochanger apparatus  11  shown in FIG. 1. A voltage output corresponding to an absolute position of the position detector  104  is available from the stocker position sensor  114  detecting the lifted position of the stocker. This voltage output is converted by an analog/digital conversion (hereinafter abbreviated as “A/D”) circuit  230  into digital data, and entered into the control circuit  19  achieved by program operation of a microcomputer. Signals from the other switches and sensors are entered into the control circuit  19  as well, and the stair motor  31 , the stocker motor  32  and the insertion/ejection motor  130  are rotation-driven in accordance with a predetermined program. The displacement positions of the stair sliding members  35  and  36  can be detected as a count of the number of times of passage of the slit  39  through the gap between a light-emitting element and a light-receiving element of a count sensor  23  based on a photointerrupter. A key-input unit  231  which is instruction input means for entering the operating status of the autochanger apparatus  11 , and a timer  232  for setting and measuring time are also connected to the control circuit  19 . 
     FIG. 51 illustrates operations of the control circuit  19  shown in FIG.  50 . Operation is started in Step a 1 , and in Step a 2 , it is determined whether or not the apparatus is ready for insertion or ejection of the CD  14 . If ready, a mechanical initialization for the insertion/ejection state is carried out in Step a 3 . If not, a mechanical initialization other than that for the insertion/ejection state is performed in Step a 4 . Upon completion of the mechanical initialization in Step a 3  or a 4 , input of an instruction from the key-input unit  231  is waited for in Step a 5 . Upon input of an instruction, it is determined in Step a 6  whether insertion of a CD is instructed or not. If it is determined that insertion of a CD is instructed, it is determined in Step a 7  whether another CD is currently reproduced or not. If during reproduction, an operation for discharging the CD in reproduction is carried out as a preparatory operation for CD insertion in Step a 8 . Upon completion of the CD insertion preparatory operation in Step a 8 , or when it is determined that no CD is in reproduction in Step a 7 , a CD inserting operation is conducted in Step a 9 . 
     When it is determined in Step a 6  that a CD inserting operation is not instructed, it is determined in Step a 10  whether or not a ejection operation is instructed. When CD ejection operation is instructed, operation of discharging the CD is performed in Step a 11 . When it is determined in Step a 10  that a CD discharging operation is not instructed, it is determined in Step a 12  whether or not a CD retrieval operation is instructed. If instructed, an operation of retrieving the presence of a CD is carried out in Step a 13  for each stage of the stocker. If not, a CD changing operation is conducted as a remaining operation in Step a 14 . Upon completion of the operation in Step a 9 , Step a 11 , Step a 13  or Step a 14 , the process returns to Step a 5 . When any other operation such as an automotive audio equipment, for example, receiving of a broadcasting program from the tuner is instructed in the middle of reproduction, the reproduction is interrupted, and the apparatus is kept ready to resume reproduction at any time. 
     FIGS. 52 and 53 are a flowchart and a time chart, respectively, of the mechanical initializing operation in Step a 3 . The process comprises starting operation in Step b 1 , reversely rotation-driving the stair motor  31  to cause the rack  16  to go down in Step b 2 , and moving the rack  16  to the insertion/ejection position. When the insertion/ejection SW  91  is turned on in Step b 3 , the CD discharging operation is started in Step b 4 . When a ejection end sensor  201  is turn ed on in Step b 5 , the ejection of the CD is completed. Then, when an insertion detecting SW  182  is turned on in Step b 6 , the CD inserting operation is started in Step b 7 , and the inserting operation is continued until an insertion end SW  124  is turned on in Step b 8 . In Step b 9 , the stair motor  31  is driven in positive and reverse directions, and the lock position switch  90  is turned from OFF to ON. In Step b 10 , the lock position returning operation is carried out upon detection of the OFF state again in Step b 10 . Then, the stocker motor  32  is driven in the reverse direction in Step b 11  to cause the stocker  13  to go down to return to the original position. It is determined in Step b 12  whether or not the position of the stocker  13  corresponds to a predetermined value, for example, (1F)h with an output from the stocker position sensor  114  as the origin, and the operation is completed in Step b 13 . Hereinafter,  1 F of ( 1 F) represents a two-digit hexadecimal number. 
     FIGS. 54 and 55 are a flowchart and a time chart, respectively, corresponding to the mechanical initializing operations other than the insertion/ejection state in Step a 4  shown in FIG.  51 . Operations are started in Step c 1 . In Step c 2 , the stocker motor  32  is caused to rotate in the positive direction to raise the stocker  13  to the upper limit. When arrival at the upper limit is detected from an output of the stocker position sensor  114  in Step c 3 , the insertion/ejection motor  130  is caused to positively rotate in Step c 4 , and the PU unit  15  is caused to advance to reach the clamping position. Advance to the clamping position is detected by the ON operation of the clamping position SW  203  in Step c 5 . Then in Step c 6 , the insertion/ejection motor  130  is reversely rotated to cause the PU unit  15  to retreat to return to the PLAY position. Return to the PLAY position is detected by a PLAY position sensor  204  in Step c 7 . In Step c 8 , the stock motor  32  is caused to rotate in the reverse direction for descent of the stocker  13 . The descent position of the stocker  13  is detected from an output of the stocker position sensor  114  in Step c 9 . After the descent of the stocker  13 , the insertion/ejection motor  130  is positively rotated for advance of the PU unit  15 , thus inserting the CD  14  attached to the turntable  27  into the stocker  13 . 
     When the clamping position SW  203  is turned on in Step c 11 , the insertion/ejection motor  130  stops, and after the lapse of a certain period of time t 1 , the stocker motor  32  positively rotates. As a result, the CD  1  is pulled out from the center shaft  191  of the turntable, thus releasing clamping. When the lifted position of the stocker  13  is determined to reach a predetermined position from an output of the stocker position sensor in Step c 13 , the unit ejection operation in which the PU unit  15  retracts to the origin position of the rack  16  is conducted in Step c 14 . When return to the origin is detected by a unit origin SW  206  in Step c 15 , the stocker motor  32  is reversely rotated in Step c 16  to conduct origin returning operation of the stocker  13 . When the return to the origin is detected from an output of the stocker position sensor  114  in Step c 17 , the stair motor  31  is reversely rotated in Step c 18 , and the origin returning operation of the rack  16  is carried out. In Step c 19 , the stair origin SW  89  is turned on. When a portion of the stair sliding member  35  having a slit  39  comes off the count sensor  123 , return of the rack  16  to the origin is completed. The stair motor  31  once stops for a period of time t 1 , and then resumes reverse rotation. In the meantime, the rack engaging with the pinion  210  is switched over from the stair rack  40  of the stair sliding member  35  to the locking rack  46  of the locking sliding member  45 . When the lock position SW  90  is turned off in Step c 21 , the operations are completed in Step c 22 . 
     FIGS. 56 and 57 are a flowchart and a time chart, respectively, of the CD insertion preparatory operation in Step a 8 . Operations are started in Step d 1 , and in Step d 2 , the stocker motor is reversely rotated to move down the stocker  13 . When the stocker  13  goes down and reaches a predetermined position from an output of a stocker position sensor  114  in Step d 3 , the stocker motor  32  is stopped, and after the lapse of a certain period of time t 1 , the insertion/ejection motor  130  is positively rotated to cause the PU unit  15  to advance into the stocker  13 . When the clamping position SW  203  is turned on in Step d 5 , the insertion/ejection motor  130  is stopped, and after the lapse of a certain period of time t 1 , the stocker motor  32  is positively rotated to raise the stocker  13  to perform clamping releasing operation to pull out the CD  14  from the center shaft  191 . 
     When the rise of the stocker  13  to a predetermined position is detected from an output of the stocker position sensor  114  in Step d 7 , the motor  130  is reversely rotated in Step d 8  to carry out a unit ejection operation to cause the PU unit to retreat from the stocker  13 . When the unit origin SW  206  is turned on in Step d 9 , the insertion/ejection motor  130  is stopped. Then after the lapse of a certain period of time t 1 , the stocker motor  32  is reversely rotated in Step d 10  to return the stocker  13  to the origin. When an output of the stocker position sensor  114  reaches a predetermined value in Step d 11 , the stocker motor  32  is stopped, and after the lapse of a certain period of time t 1 , the stair motor  31  is reversely rotated in Step d 12  to return the rack  16  to the origin. After the stair origin SW  89  is turned on, the rack engaging with the pinion  210  is switched over from the stair rack  40  of the stair sliding member  35  to the locking rack  46  of the locking sliding member  45 , and a lock position return operation is performed in Step d 15 . The lock position return operation is completed when the lock position SW  90  is turned off in Step d 14 , and the stair motor  31  is stopped. In Step d 15 , the stocker  32  is positively rotated to conduct an ascending operation of the stocker  13 . When arrival at a predetermined position is detected in Step d 16  from an output of the stocker position sensor  114 , the stocker motor  32  is stopped. After the lapse of a certain period of time t 1 , the insertion/ejection mode switching operation in Step d 17  is carried out by reversely rotating the stair motor  31 . When the insertion/ejection position SW  91  is turned on in Step d 19 , the operations are completed in Step d 20 . 
     FIGS. 58 and 59 are a flowchart and a time chart, respectively, of a CD inserting operation in Step a 9  shown in FIG.  51 . Operations are started in Step e 1 . In Step e 2 , the insertion detecting SW  182  is turned off on a high level, thus detecting insertion of the CD  14  of 12 cm. After the lapse of a certain period of time t 1 , the insertion/ejection motor  130  is positively rotated in Step e 3 , thus starting the disk inserting operation. The inserted CD  14  is displaced in a backward direction, and at the same time, the output of the ejection end sensor  201  becomes on a high level. The insertion detecting SW  182  is turned on of a low level, and the output of the disk presence detecting sensor  202  changes from a high level to a low level. When the CD  14  is inserted into the stocker  13  and the insertion end SW  124  is turned on in Step e 4 , the stair motor  31  is positively rotated in Step e 5 , the operation of returning from the insertion/ejection to the lock position is started. When the lock position SW  90  is turned on, the insertion/ejection motor  130  is stopped, and after stoppage for a time t 1 , the step motor is reversely rotated, and the lock position SW  90  is stopped at the OFF position, thus completing the CD inserting operation in Step e 6 . 
     FIGS. 60 and 61 are a flowchart and a time chart, respectively, of the CD ejection operation in Step all shown in FIG.  51 . Operations are started in Step f 1 , and in Step f 2 , the stocker motor  32  is reversely rotated to cause the stocker  13  to move downwardly. When a descent to a predetermined position is determined from an output of the stocker position sensor  114  in Step f 3 , the stocker motor  32  is stopped. To return the disk in Step f 54 , the insertion/ejection motor  130  is positively rotated after the lapse of a certain period of time t 1 , to cause the PU unit  15  to advance into the stocker  13 . When the clamping position SW  203  is turned on in Step f 5 , the insertion/ejection motor  130  is stopped, and the stocker motor  32  is operated to conduct the clamping releasing operation in Step f 6  after the lapse of a certain period of time t 1 , thus causing the stocker  13  to go up. When the stocker  13  is determined to have reached a predetermined height from an output of the stocker position sensor  114  in Step f 7 , the insertion/ejection motor  130  is reversely rotated after the lapse of a certain period of time t 1  in Step f 8 , and the unit ejection operation for causing the PU unit  15  to retreat from the stocker  13  is performed. When the unit origin SW  206  is turned on in Step f 9 , the insertion/ejection motor  130  is stopped. In Step f 10 , the stocker motor  33  is reversely rotated to cause the stocker  13  to go down after the lapse of a certain period of time t 1  for carrying out the return of the stocker  13  to the origin. When a descent to a predetermined position is detected from an output of the stocker position sensor  114  in Step f 11 , the stocker motor  32  is stopped. In step f 12 , the stair motor  31  is reversely rotated after the lapse of a certain period of time t 1 . The origin position of the rack is detected in Step f 13 , and after a temporary stoppage for rack switching, the locking sliding member  45  is further moved in step f 14  to return to the lock position in Step f 15 . 
     In step f 16 , the stocker motor  32  is positively rotated to cause the stocker  13  to move upwardly. In Step f 17 , ascent of the stocker  13  to a predetermined position is detected from an output of the stocker position sensor  114 . When the stocker  13  goes up to the predetermined position, the stair motor  31  and the insertion/ejection motor  130  are reversely rotated in step f 18 , and the disk ejection operation for discharging the CD  14  is conducted. When the insertion/ejection position switch  91  is turned on in Step f 19 , the stair motor  31  is stopped, whereas the reverse rotation of the insertion/ejection motor  130  is continued to continue the CD ejection operation in Step f 20 . When the ejection end sensor  201  becomes on at a low level in Step f 21  and detects the CD, the insertion/ejection motor  130  is stopped. After the lapse of a certain period of time t 1  in Step f 22 , the stair motor  31  is positively rotated, and after the lock position SW  90  once becomes ON, the stair motor  31  is reversely rotated to return to the lock position. 
     FIGS. 62 and 63 are a flowchart and a time chart, respectively, of the CD retrieving operation in Step a 12  shown in FIG.  51 . Operations are started in Step g 1 , and in Step g 2 , the stocker motor  32  is positively rotated to conduct the stocker raising operation. When it is determined that the stocker  13  has been lifted up to the sixth-stage position from an output of the stocker position sensor  114  in Step g 3 , the stocker motor  32  is stopped, and after the lapse of a certain period of time t 1  the CD ejection operation is performed in Step g 4 . At this point, the stair motor  31  and the insertion/ejection motor  130  are reversely rotated. A case where a CD is housed in the sixth stage is assumed here. 
     When the CD is ejected by the push-out lever  72  to the position of the ejection end sensor  201  in step g 5 , the light from the LED  180  to be received by the ejection end sensor  201  is interrupted, and the ejection end sensor  201  is turned off. In Step g 6 , the stair motor  31  and the insertion/ejection motor  130  are positively rotated as a CD inserting operation for disk push-in by the push-in lever  140 , and disk push-in operation is continued until the insertion end switch  124  is turned on in Step g 7 . In Step g 8 , the stair motor  31  is reversely rotated. The lock position SW  90  is once changed from OFF to ON in Step g 9 , and is stopped at a position for resuming the ON state. Then, as a stocker lifting operation in Step g 10 , the stocker motor  32  is positively rotated to raise the stocker  13 . In Step g 11 , lifting of the stocker  13  to the position of the fifth stage is detected from an output of the stocker position sensor  114 . In Step g 12  after the lapse of a certain period of time t 1 , the stair motor  31  and the insertion/ejection motor  130  are reversely rotated, respectively, to conduct the CD ejection operation. The CD is assumed in this case not to be house in the fifth stage. 
     In Step g 13 , the insertion/ejection position SW  91  is turned on. As a result, it is detected that the rack  16  has reached the insertion/ejection position, and the stair motor  31  and the insertion/ejection motor  130  are once stopped. Subsequently, it is determined in Step g 14  whether or not the CD  14  is held in the stocker of the second stage; it is determined in Step g 15  whether or not the CD  14  is held in the first-stage stocker; and the operations are completed in Step g 16 , in the same manner as above. 
     FIGS. 64 and 65 are a flowchart and a time chart, respectively, of the CD detecting operation in Step a 14  shown in FIG.  51 . Operations are started in Step h 1 , and in Step h 2 , the stocker motor  32  is reversely rotated to cause the stocker  13  to move downwardly. When the descent of the stocker  13  to a predetermined position is detected from an output of the stocker position sensor  114  in Step h 3 , the stocker motor  32  is stopped. After the lapse of a certain period of time t 1  in Step  4 , the insertion/ejection motor  130  is positively rotated, to return to a CD  14  attached to the PU unit  15  to the stocker  13 . When the clamping position SW  203  is turned on in Step h 5 , the insertion/ejection motor  130  is stopped. After the lapse of a certain period of time t 1  in Step h 6 , the stocker motor  32  is positively rotated, to carry out the clamping releasing operation for pulling out the CD  14  from the center shaft  191 . When the stocker  13  is determined in Step h 7  to have risen to the uppermost position from an output of the stocker position sensor, the stocker motor  32  is stopped. After the lapse of a certain period of time t 1  in Step h 8 , the insertion/ejection motor  130  is reversely rotated to cause the PU unit  15  to retreat from the stocker  13  for unit ejection. When the unit origin SW  206  is turned on in Step h 9 , the insertion/ejection motor  130  is stopped. After the lapse of a certain period of time t 1  in Step h 10 , the stocker motor  32  is reversely rotated, to perform stocker origin return by causing the stocker  13  as a whole to move downwardly. When the stocker  13  is determined in Step h 11  to have gone down to the origin position from an output of the stocker position sensor  114 , the stair motor  31  is rotated after the lapse of a certain period of time t 1  in Step h 12 , and in Step h 13 , the rack  16  is stopped at a predetermined position from an output of the count sensor  232 . 
     In Step h 14 , the stocker motor  32  is positively rotated after the lapse of a certain period of time t 1  to cause the stocker  13  to go up in division. In Step h 15 , it is detected that the upper half of the divided stocker rises to the upper limit position from an output of the stocker position sensor  114 . 
     In Step h 16 , the insertion/ejection motor  130  is positively rotated to cause the PU unit  15  to advance into the stocker  13 . When the clamping position SW  203  is turned on in Step h 17 , the insertion/ejection motor  130  is stopped. After the lapse of a certain period of time t 1  in Step h 18 , the stocker motor  32  is reversely rotated. When descent to a pressing position is determined from an output of the stocker position sensor  114  in Step h 19 , the stocker motor  32  is stopped. After the lapse of a certain period of time t 2  in Step h 20 , the stocker motor  32  is positively rotated to cause the upper half of the divided stocker  13  to go up again. This ascent position is determined in Step h 21  from an output of the stocker position sensor  114 . After the lapse of a certain period of time t 1  in Step h 22 , the insertion/ejection motor  130  is reversely rotated to withdraw the CD  14  transferred to the PU unit  15  from the stocker  13  along with the retreat of the PU unit  15 . When the PU unit  15  is determined to reach the PLAY position from an output of the PLAY position sensor  204 , the insertion/ejection motor  130  is stopped in Step h 23 . Then, after the lapse of a certain period of time t 1  in Step  24 , the stocker motor  32  is positively rotated to cause the stocker  13  to move further up. When the stocker  13  is determined to reach the upper limit stocker standby position in Step h 25 , the operations are completed in Step h 26 . 
     In the foregoing operations, the certain period of time t 1  is for example 100 msec, and t 2  is 500 msec. In the embodiments presented above, the stocker member  100  and the first uppermost-stage stocker member  101  of the stocker  13  have substantially the same shape of the front portion as that of the CD  14 . As a result, because the upper roller  25  and the lower roller  26  are not positively aligned, leading end of the inserted CD  14  is directed upward, thus permitting smooth guidance. By ensuring almost horizontal insertion of the CD  14 , for example, by increasing the number of rollers of the transfer rollers  24 , it is possible to omit the front side portion of the stocker member  100  or the uppermost-stage stocker member  101 . It is needless to mention that the number of stages is not limited to six. Applicable disk-shaped recording carriers include, in addition to a CD-ROM for a personal computer, and also a laser disk (LD) and a mini-disk (MD). 
     The invention may be embodied in other specific forms without departing from the sprit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention is indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and the range of equivalency of the claims are therefore intended to be embraced therein.