Patent Publication Number: US-2009235287-A1

Title: Conveyance Device and Recording Meduim Drive Device

Description:
TECHNICAL FIELD 
     The present invention relates to a transfer unit for inserting and ejecting a disc recording medium, and a recording-medium driver provided with the transfer unit. 
     BACKGROUND ART 
     There have been conventionally known disc units capable of internally holding disc recording mediums of different diameters. (e.g., see Patent Document 1). 
     Patent Document 1 discloses a disc reproducer that transfers a disc by a transferring roller and positions the disc above a turntable by a positioning mechanism. The positioning mechanism includes: right and left positioning levers rotatably supported by fulcrum pins and crossed with each other; a switching lever having fulcrum pins engaged with engaging holes of the positioning levers, the switching lever being rotated by a solenoid. In addition, in the vicinity of a disc insertion opening of the disc reproducer, a central sensor, right and left sensors provided respectively to the right and the left of the central sensor and an outer sensor are provided so as to judge the diameter of a disc inserted from the disc insertion opening. When the insertion of a large-diameter disc is detected by the sensor(s), the switching lever is rotated to rotate the right and left positioning levers so that positioning pins are the most remotely spaced apart from each other. On the other hand, when the insertion of a small-diameter disc is detected, the right and left positioning levers are rotated so that the positioning pins comes the closest to each other. 
     [Patent Document 1] JP-A-02-118955 (pages 3 to 5, FIGS. 1 to 7) 
     DISCLOSURE OF THE INVENTION 
     Problems to be Solved by the Invention 
     However, according to such a conventional disc reproducer as disclosed in Patent Document 1, the disc is clamped on the turntable after the disc is held by the right and left levers. At this time, since a clearance is not sufficient when the disc is kept guided by the right and left levers, rotation of the disc may be hampered. 
     An object of the present invention is to provide a transfer unit and a recording-medium driver that can favorably hold a disc without hampering a rotation of the disc. 
     Means for Solving the Problems 
     A transfer unit according to an aspect of the present invention includes: a guide member that guides a disc recording medium to a position where a disc holder disposed inside a unit body is capable of holding the recording medium, the guide member being movable in a direction to be close to or away from the recording medium; a guide-movement controlling member that moves the guide member away from the recording medium while the disc holder holds the recording medium. 
     A recording-medium driver according another aspect of the present invention includes: the above-described transfer unit; the disc holder that holds the recording medium transferred by the transfer unit; a mount on which the disc holder is provided, the mount being movable in an up-and-down direction; an information processor that performs at least one of writing information in the recording medium held by the disc holder and reading information from the recording medium; and the unit body that internally houses the transfer unit, the disc holder, the mount and the information processor, the unit body comprising an insertion-and-ejection opening for inserting and ejecting the recording medium. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a top view showing an inside of a unit body of a disc unit according to an embodiment of the present invention. 
         FIG. 2A  is an enlarged top view showing a push arm provided inside the disc unit, in which the push arm is not in engagement with a guide lever. 
         FIG. 2B  is an enlarged top view showing the push arm provided inside the disc unit, in which the push arm is in engagement with the guide lever. 
         FIG. 2C  is an enlarged top view showing the push arm provided inside the disc unit, in which the push arm in  FIG. 2B  is moved toward a left wall. 
         FIG. 3  is a top view showing the inside of the unit body of the disc unit when an insertion of a large-diameter disc is initiated or when the large-diameter disc has been ejected. 
         FIG. 4  is a top view showing the inside of the unit body of the disc unit when a large-diameter disc is being transferred. 
         FIG. 5  is a top view showing the inside of the unit body of the disc unit when a large-diameter disc has been inserted. 
         FIG. 6  is a top view showing the inside of the unit body of the disc unit when a large-diameter disc is being clamped against a turntable. 
     
    
    
     EXPLANATION OF CODES 
     
         
           1  . . . optical disc serving as a recording medium 
           1 A . . . large-diameter disc serving as a recording medium 
           10  . . . unit body 
           11  . . . slot serving as an insertion-and-ejection opening 
           21  . . . mount 
           23  . . . turntable serving as a disc holder 
           24  . . . information processor 
           41  . . . disc guide mechanism serving as a transfer unit 
           100  . . . disc unit serving as a recording-medium driver 
           411  . . . guide lever (a component of a guide member) 
           411 C . . . rotation-restricting pin serving as an engaging portion 
           412  . . . disc guide (a component of a guide member) 
           416  . . . push arm serving as a guide-engaging member (a component of a guide-movement controlling member) 
           416 A . . . pin-locking groove serving as an engaging groove 
           416 C . . . push arm-biasing spring as a biasing member 
           424  . . . slide stopper serving as a movement controlling member (a component of a guide-movement controlling member) 
       
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     An embodiment of the present invention will be described below with reference to the attached drawings.  FIG. 1  is a top view schematically showing an inside of a disc unit according to an embodiment of the present invention.  FIG. 2A  is an enlarged top view showing a push arm provided inside the disc unit, in which the push arm is not in engagement with a guide lever.  FIG. 2B  is an enlarged top view showing the push arm provided inside the disc unit, in which the push arm is in engagement with the guide lever.  FIG. 2C  is an enlarged top view showing the push arm, in which the push arm in  FIG. 2B  is moved toward a left wall. 
     [Arrangement of Disc Unit] 
     In  FIG. 1 , the numeral  100  denotes a disc unit serving as a recording medium driver according the embodiment of the present invention. The disc unit  100  performs such information processing as reading-processing or recording-processing on an optical disc  1  (disc recording medium) detachably mounted thereon, thereby reading information recorded in a recording surface (not shown) provided on at least one surface of the optical disc  1  or recording a variety of information on the recording surface of the optical disc  1 . Although an example of the disc unit  100  is a so-called thinned slot-in type unit that is mounted on an electrical equipment such as a portable personal computer, the disc unit  100  itself may be configured as, for instance, a game machine or a reproducer that performs processing for recording (e.g. video-recording) or reproducing image data. In addition, the disc unit  100  can accept a large-diameter disc  1 A having a diameter of 12 cm and a small-diameter disc  1 B having a diameter of 8 cm as the optical disc  1 . The disc recording medium is not limited to the optical disc  1  but may be other disc recording mediums such as a magnetic disc or a magnetic optical disc. The disc unit  100  includes a substantially box-shaped unit body  10  having an inner space, an exemplary material of which is a metal. In the unit body  10 , a lower side of the unit body  10  shown in  FIG. 1  may be referred to as a front face  10 A, a left lateral wall of the unit body  10  shown in  FIG. 1  may be referred to as a left wall  10 B, a right lateral wall of the unit body  10  shown in  FIG. 1  may be referred to as a right wall  10 C and a side opposite to the front face  10 A of the unit body  10  shown in  FIG. 1  may be referred to as a rear face  10 D. 
     The unit body  10  internally includes a disc processor  20  (a so-called traverse mechanism), a transfer unit  30  for transferring the optical disc  1 , and a control circuit (not shown) serving as a circuit board. The front face  10 A of the unit body  10  is provided with a slot  11  (insertion-and-ejection opening) for inserting/ejecting the optical disc  1 , the slot  11  extending in the right-and-left direction of  FIG. 1 . 
     The disc processor  20  includes a plate-like mount  21  whose one end is swingably supported by the unit body  10 , an exemplary material of which is metal plate. The mount  21  longitudinally extends from the left wall  10 B of the unit body  10  near the front face  10 A toward the center position of the unit body  10 . The mount  21  is longitudinally cut out to substantially centrally form a longitudinal processor opening  21 A. A disc rotation driver  22  is disposed near a first end of the processor opening  21 A of the mount  21 , i.e., substantially at the center of the unit body  10 . The disc rotation driver  22  includes a spindle motor (not shown), and a turntable  23  (disc holder) provided integrally with an output shaft of the spindle motor. The spindle motor is controllably connected to the control circuit and driven by electricity supplied from the control circuit. The turntable  23 , which is provided substantially at the center inside the unit body  10 , is a driver for rotating the optical disc  1 . 
     The mount  21  includes an information processor  24 . The information processor  24 , which is supported by a pair of guide shafts  25  while bridging the guide shafts  25 , is moved toward and away from the turntable  23  within the processor opening  21 A by a moving mechanism (not shown). The information processor  24  has a pickup that includes: a light source (not shown); a pick-up lens  24 A for converging light of the light source; and a light sensor (not shown) for detecting specular light reflected from the optical disc  1 . 
     The transfer unit  30  includes: a transfer motor  31  disposed in the unit body  10  to be operationally controlled by, for instance, the control circuit; and a link mechanism  32  operated by driving of the transfer motor in an interlocking manner. 
     The link mechanism  32  includes: a disc guide mechanism  41  disposed inside the unit body  10  near the slot  11  and the left wall  10 B; a disc-diameter detecting mechanism  42  disposed inside the unit body  10  near the slot  11  and the right wall  10 C; a disc ejecting mechanism  43  for ejecting the optical disc mounted on the turntable  23 ; and a first driving cam  44  and a second driving cam  45  for swinging the mount  21 . 
     The disc guide mechanism  41  includes: a guide lever  411  (guide member) for guiding the insertion and ejection of the optical disc  1 ; a disc guide  412  connected to the guide lever  411  near the front face  10 A; a bridge plate  413  as a protection plate; an 8 cm arm  414  rotatably provided on the bridge plate  413 ; and a push arm  416  as a guide engaging member. The guide member according to the present invention is provided by the guide lever  411  and the disc guide  412  while a guide-movement controlling member is provided by the push arm  416  and a slide stopper  424  serving as a later-described movement controlling member. The transfer unit of the present invention is provided by the guide lever  411 , the disc guide  412 , the push arm  416  and the slide stopper  424 . 
     The guide lever  411  is a rod-like member that is longitudinal in the disc inserting/ejecting direction. A plastic guide portion  411 A for guiding the movement of the optical disc  1  in the inserting/ejecting direction is fixed on an inward lateral of the guide lever  411  (lateral facing the direction in which the optical disc  1  is inserted). The guide portion  411 A, which is provided with a guide groove concaved toward the left wall  10 B, guides the optical disc  1  by slidably contacting the periphery of the optical disc  1  with the guide groove. The lateral of the guide lever  411  is inwardly bent where the lateral is continued from the guide portion  411 A near the rear face  10 D, thereby restricting the movement of the optical disc  1 . The guide portion  411 A is provided with a rotation-restricting pin  411 C (engaging portion) that downwardly protrudes. The rotation-restricting pin  411 C is positioned so as not to interfere with the mount  21  when the guide lever  411  is moved to a position corresponding to the small-diameter disc  1 B near the disc guide  412  (i.e., near the front face  10 A). 
     A guide pin  411 B that penetrates from the top to the bottom is fixed on an end of the guide lever  411  adjacent to the rear face  10 D. The guide pin  411 B is locked by the later-described bridge plate  413  and the 8 cm arm  414 . The disc guide  412  is rotatably connected to an end of the guide lever  411  adjacent to the front face  10 A. 
     The end of the guide lever  411  adjacent to the front face  10 A is further provided with a plate spring  411 D opposed to the left wall  10 B. The plate spring  411 D inwardly biases a connecting portion of the guide lever  411  and the disc guide  412  when the guide lever  411  is moved toward the left wall  10 B. With this arrangement, the connecting portion of the guide lever  411  and the disc guide  412  is prevented from bending outwardly. 
     The disc guide  412  is longitudinally formed, whose first end is rotatably mounted in the vicinity of the left wall  10 B of the unit body  10 . In addition, as described above, a second end of the disc guide  412  is rotatably connected to the end of the guide lever  411 . With this arrangement, the end of the guide lever  411  adjacent to the front face  10 A can be rotationally moved along a circular arc described around the first end of the disc guide  412  with radius of a length of the disc guide  412 . An inwardly-protruding flange  412 A is formed below the disc guide  412 . A slide-contact surface  412 B, with which the optical disc  1  is slidably in contact when being inserted, is formed along the flange  412 A. The connecting portion of the disc guide  412  and the guide lever  411  serves as a pressing portion  412 C for pressing the periphery of the optical disc  1  toward the front face  10 A when the optical disc  1  is ejected. 
     The bridge plate  413  extends both in the right and left directions near the rear face  10 D of the unit body  10 . The bridge plate  413  covers the above-described control circuit from the above so as to protect the control circuit. Near the left wall  10 B, the bridge plate  413  is provided with a leading guide groove  415  (leading guide portion) that extends from a rear corner of the unit body  10  toward the inner central position. 
     The leading guide groove  415  includes: an arc groove  415 A (first guide) formed to be substantially parallel to the rotation locus described by the connecting portion of the guide lever  411  and the disc guide  412 ; a linear groove  415 B (second guide) continued from the arc groove  415 A to extend substantially along the inserting/ejecting direction of the optical disc  1 ; and an oblique groove (second groove) continued from the linear groove  415 B to be oblique to the linear groove  415 B by a predetermined angle toward the center position of the unit body  10 . The leading guide groove  415  is engaged with the guide pin  411 B that downwardly protrudes from the guide lever  411 , thereby guiding the movement of the guide lever  411 . The linear groove  415 B is arranged such that a perpendicular line drawn from the center of the turntable  23  to the extension of the linear groove  415 B substantially equals to the radius of the small-diameter disc  1 B. 
     The bridge plate  413  rotatably supports the 8 cm arm  414  near the right wall  10 C. The bridge plate  413  is provided with arm restricting grooves  413 A centrally and near the right wall  10 C. The arm restricting grooves  413 A are arced around the support position of the 8 cm arm  414  to restrict a rotation region of the 8 cm arm  414 . 
     The bridge plate  413  also rotatably supports an assist arm  431  of the later-described disc ejecting mechanism  43  near the right wall  10 C. An assist restricting groove  413 B is arced around the rotation center of the assist arm  431 . Substantially at the center of the bridge plate  413 , an ejection arm  432  meshed with the assist arm  431  is rotatably supported. The bridge plate  413  is provided with a control groove  413 C near the front face  10 A, which longitudinally extends in the right-and-left direction. 
     As described above, the 8 cm arm is rotatably supported by the bridge plate  413  near the right wall  10 C. The 8 cm arm  414  includes an arm restricting pin  414 A that downwardly protrudes. The arm restricting pin  414 A is locked with the arm restricting groove  413 A of the bridge plate  413 . The distal end of the 8 cm arm  414  is provided with a guide link groove  414 B that extends along the longitudinal direction of the 8 cm arm  414 . The guide link groove  414 B is locked with the guide pin  411 B that upwardly protrudes from the guide lever  411 . In the vicinity of the support position of the 8 cm arm  414 , an arm biasing spring  414 C for biasing the distal end (i.e., end adjacent to the left wall  10 B) of the 8 cm arm toward the front face  10 A is provided. The arm biasing spring  414 C constantly biases the 8 cm arm  414  counterclockwise. The 8 cm arm  414  biases the guide lever  411  such that the guide pin  411 B returns to an initial state to be positioned at a distal position of the oblique groove  415 C of the leading guide groove  415 . 
     The push arm  416  is rotatably provided on the bridge plate  413  near the left wall  10 B. As shown in  FIG. 2A , the push arm  416 , which is longitudinally formed, is provided with the pin locking groove  416 A (engaging groove) that extends from a first longitudinal end of the push arm  416  to the supporting position of the push arm  416 . As shown in  FIG. 2B , the pin locking groove  416 A accepts insertion of the rotation-restricting pin  411 C provided on the guide portion  411 A when the guide pin  411 B of the guide lever  411  moves along the arc groove  415 A of the leading guide groove  415 . When the guide lever  411  is further moved toward the left wall  10 B and the rotation-restricting pin  411 C pushes the pin locking groove  416 A, the push arm  416  is rotated toward the left wall  10 B. Where facing the right wall  10 C, the push arm  416  is additionally provided with a press piece  416 B that downwardly protrudes. The press piece  416 B is brought into abutment with a push stopper  424 D of the later-described slide stopper  424  while the optical disc  1  is clamped on (i.e., held by) the turntable  23 , such that the push arm  416  is further rotated toward the left wall  10 B as shown in  FIG. 2C . With this arrangement, the guide lever  411  is moved away from the periphery of the optical disc  1 , so that a predetermined clearance is formed between the guide portion  411 A of the guide lever  411  and the optical disc  1 . 
     Between the distal end of the push arm  416  and the bridge plate  413 , a push arm-biasing spring  416 C (biasing unit) is provided. The push arm-biasing spring  416 C inwardly biases the push arm  416  (in other words, biases the guide lever  411  toward the optical disc  1  while the rotation restricting pin  411 C is in engagement with the pin locking groove  416 A) and inwardly rotates the push arm  416  when the slide stopper  424  is moved away from the press piece  416 B. At this time, since the rotation-restricting pin  411 C is provided on the guide lever  411  adjacently to the front face  10 A, the push arm-biasing spring  416 C inwardly biases a front portion the guide lever  411  (i.e., portion adjacent to the front face  10 A). With this arrangement, the connecting portion of the guide lever  411  and the disc guide  412  does not protrude toward the left wall  10 B when the guide lever  411  is moved, whereby the guide lever  411  can be moved without problems. 
     The disc-diameter detecting mechanism  42  removes movement restriction of the guide lever  411  of the disc guide mechanism  41  when the optical disc  1  inserted in the slot  11  is the large-diameter disc  1 A while restricting the movement of the guide lever  411  when the inserted optical disc  1  is the small-diameter disc  1 B. 
     Specifically, the disc-diameter detecting mechanism  42  includes: a load arm  421  (detector) whose first end abuts on the optical disc  1  and whose second end is rotatable relative to the unit body  10 ; and an arm link mechanism  422  connected to the load arm  421  for removing the movement restriction of the guide lever  411  when the rotation angle of the load arm  421  is large while restricting the movement of the guide lever  411  when the rotation angle of the load arm  421  is small. 
     The first end of the load arm  421  is provided with a roller-type abutment portion  421 A for abutting on the periphery of the optical disc  1  while the second end of the load arm  421  is rotatably supported by the unit body  10 . The load arm  421 , which is made of an elongated rectangular plate member, includes a guide groove  421 B that extends along the longitudinal direction of the load arm  421 . The load arm  421  is biased by a biasing unit (not shown) clockwise so as to return to the initial position as shown in  FIG. 1 . 
     The arm link mechanism  422  includes: a substantially-tabular link arm  423  whose first end is provided with a projection  423 A guided by the guide groove  421 B; and the substantially-tabular slide stopper  424  (restricting unit) whose first end is coupled to the link arm  423 . 
     The load arm  421  and the link arm  423  are located adjacently to the right wall  10 C inside the unit body  10  and disposed on substantially the same plane as the guide lever  411  and the disc guide  412  of the disc guide mechanism  41 . 
     A second end of the link arm  423 , which is supported in a manner rotatable around a rotary shaft  423 B fixed on the unit body  10 , is provided with an engaging projection  423 C positioned to be opposite to the projection  423 A relative to the rotary shaft  423 B. In addition, the second end of the link arm  423  (the end where the engaging projection  423 C is provided) is provided with a biasing unit (not shown) for biasing the link arm  423  toward the right wall  10 C. With this arrangement, the load arm  421  is inwardly biased, i.e., biased clockwise. 
     The slide stopper  424 , which is disposed below the bridge plate  413  to be closer to the rear face  10 D than the turntable  23 , is movable both in the right and left directions in the drawing(s). A right end of the slide stopper  424  is provided with an oblique abutment portion  424 A that is oblique to the inserting/ejecting direction of the optical disc  1  for abutting on the engaging projection  423 C. When the large-diameter disc  1 A is inserted as the optical disc  1  and the load arm  421  is rotated, the link arm  423  is also rotated, such that the engaging projection  423 C is moved toward the front face  10 A to press the oblique abutment portion  424 A abutting the engaging projection  423 C, thereby sliding the slide stopper  424  toward the right wall  10 C. In addition, the slide stopper  424  is provided with a restricting stopper  424 B adapted to partially block the arm restricting groove  413 A of the bridge plate  413 . When the slide stopper  424  is moved toward the right wall  10 C by the rotation of the load arm  421  as described above, the restricting stopper  424 B clears the arm restricting groove  413 A, so that the arm restricting pin  414 A of the 8 cm arm  414  can be moved along the groove  413 A. On the other hand, when the load arm  421  returns to the initial position and the slide stopper  424  returns to the initial position, the restricting stopper  424 B blocks the arm restricting groove  413 A, thereby preventing the movement of the arm restricting pin  414 A. With this arrangement, the rotation of the guide lever  411  coupled to the 8 cm arm  414  is also restricted, thereby allowing the guide lever  411  to be moved toward the left wall  10 B. 
     Adjacently to the front face  10 A, the slide stopper  424  is provided with a cam interlocking groove  424 C adapted to interlock with the second driving cam  45 . With this arrangement, when the second driving cam  45  is moved, the slide stopper  424  is also moved in the right-and-left direction. Adjacently to the left wall  10 B, the slide stopper  424  is provided with the push stopper  424 D. When the slide stopper  424  is moved toward the left wall  10 B by the movement of the second driving cam  45 , the push stopper  424 D abuts on the press piece  416 B of the push arm  416  to restrict the rotation of the push arm  416 . 
     Substantially the center of the slide stopper  424  is opened to provide an ejection-restricting window  424 E. The ejection-restricting window  424 E includes an ejection-restricting groove  424 E 1  for the large-diameter disc and an ejection-restricting groove  424 E 2  for the small-diameter disc that extend in the right-and-left direction. When the slide stopper  424  is moved toward the left wall  10 B by the movement of the second driving cam  45 , the ejection-restricting grooves  424 E 1 ,  424 E 2  are engaged with an ejection-restricting pin  431 A of the later-described assist arm  431 , thereby restricting the rotation of the assist arm  431 . The ejection-restricting grooves  424 E 1 ,  424 E 2  each have a distal end that is sloped in a direction to be away from the turntable  23 . By engaging the sloped portions of the distal ends with the ejection-restricting pin  431 A, a clearance can be secured between the ejection arm  434  and the optical disc  1 . 
     The disc ejecting mechanism  43  presses the optical disc  1  toward the slot  11  for ejection. The disc ejecting mechanism  43  includes the assist arm  432  and the ejection arm  432 . 
     As described above, the assist arm  431 , which is rotatably provided on the bride plate  413  near the right wall  10 C, includes the ejection restricting pin  431 A engageable with an assist restricting groove  413 B. With this arrangement, the rotation region of the assist arm  431  is restricted to the assist restricting groove  413 B. As also described above, the ejection restricting pin  431 A, which is inserted in the ejection restricting window  424 E, is engaged with the ejection restricting groove  424 E 1  for the large-diameter disc or the ejection restricting groove  424 E 2  for the small-diameter disc due to the movement of the slide stopper  424 , thereby restricting the rotation of the assist arm  431 . An end of the assist arm  431  adjacent to the left wall  10 B is provided with a gear  431 B. The assist arm  431  is biased by a biasing member (not shown) counterclockwise, i.e., a direction in which the gear  431 B is turned toward the front face  10 A. 
     The ejection arm  432 , which is rotatably provided on the bridge plate  413  as described above, includes: a gear portion  432 A located below the bridge plate  413  while sandwiching the bridge plate  413  against the ejection arm  432 ; and a longitudinal arm  432 B located above the bridge plate  413 . The gear portion  432 A is meshed with the gear  431 B of the assist arm  431  and biased clockwise by biasing force of the assist arm  431 . The biasing force biases the arm  432 B clockwise, i.e., a direction to press the optical disc  1  to the slot  11 . A distal end of the arm  432 B is provided with a roller-type abutment portion  432 C for abutting on the periphery of the optical disc  1 . Further, an arm controlling projection  432 D is provided at a position opposite to the arm  432 B relative to the rotary center of the ejection arm  432 . The arm controlling projection  432 D abuts on the periphery of the 8 cm arm  414  when the ejection arm  432  is rotated. 
     The first driving cam  44  and the second driving cam  45  are respectively provided with engaging grooves that are engaged with locking cam projections (not shown) formed on two laterals of the mount  21 . The first driving cam  44  and the second driving cam  45 , which are elongated members, are advanced and retracted by a motor and a gear mechanism (not shown) along the longitudinal direction. With this arrangement, the mount  21  is swung so as to be closer to or away from the recording surface of the optical disc  1  mounted on the turntable  23 . 
     The link arm  423  and the first driving cam  44  each include a disc transferring cam  51  for decreasing a transfer amount of the optical disc  1  to be transferred to the turntable  23  when the optical disc  1  is the large-diameter disc  1 A and for increasing the transfer amount of the optical disc  1  to be transferred to the turntable  23  when the optical disc  1  is the small-diameter disc  1 B. 
     The disc transferring cam  51  includes a projection  52  provided on the link arm  423 , and a cam groove  53  provided on the first driving cam  44  to be engageable with the projection  52 . 
     The cam groove  53  includes: a first cam groove  53 A for transferring the large-diameter disc  1 A; a second cam groove  53 B for transferring the small-diameter disc  1 B; and a common cam groove  53 C whose one end is linked with the first cam groove  53 A and the second cam groove  53 B. The first cam groove  53 A and the second cam grove  53 B extend in a direction of the movement of the first driving cam  44 . 
     The second driving cam  45 , which is coupled to the first driving cam  44 , advances and retracts in the right-and-left direction in interlock with the advancement and retraction of the first driving cam  44 . When a sensor (not shown) detects that the center of the optical disc  1  is located above the turntable  23 , the first driving cam  44  is moved toward the rear face  10 D and the second driving cam  45  is moved toward the left wall  10 B. The movement of the second driving cam  45  moves the mount  21  closer to the recording surface of the optical disc  1 , such that the optical disc  1  is clamped on the turntable  23 . The turntable  23  is rotated in this state, such that information is recorded and/or reproduced in or from the optical disc  1 . 
     [Operation of Disc Unit] 
     Next, operation(s) of the disc unit  100  will be described by reference to  FIGS. 1 to 6 .  FIG. 3  is a top view showing the inside of the unit body of the disk unit when the insertion of the large-diameter disc is initiated or when the ejection of the large-diameter disc is completed.  FIG. 4  is a top view showing the inside of the unit body of the disk unit when the large-diameter disc is being transferred.  FIG. 5  is a top view showing the inside of the unit body of the disk unit when a disc (large-diameter disc) has been inserted.  FIG. 6  is a top view showing the inside of the unit body of the disk unit when the large-diameter disc has been clamped on the turntable. 
     (Insertion of Large-Diameter Disc) 
     Operation(s) of the disc unit when the large-diameter disc  1 A having a disc diameter of 12 cm is inserted in the disc unit  100  in the initial state shown in  FIG. 1  will be explained below. When the large-diameter disc  1 A is inserted in the slot  11  of the disc unit  100  in the initial state, the periphery of the large-diameter disc  1 A presses the abutment portion  421 A of the load arm  421  toward the right wall  10 C as shown in  FIG. 3 , thereby rotating the load arm  421 . With this operation, the link arm  423  is rotated counterclockwise, such that the slide stopper  424  is slid toward the right wall  10 C. The movement of the slide stopper  424  disengages the restricting stopper  424 B from the arm restricting groove  413 A of the bridge plate  413 , thereby removing regulation of the rotation region of the 8 cm arm  414 . 
     When the large-diameter disc  1 A is further inserted in the unit in this state, the periphery of the large-diameter disc  1 A laterally abuts on the slide contact surface  412 B of the disc guide  412  as shown in  FIG. 4 , thereby rotating the disc guide  412  toward the left wall  10 B. At this time, the guide lever  411  is also pressed toward the rear face  10 D, thereby moving the guide pin  411 B from the oblique groove  415 C and the linear groove  415 B of the leading guide groove  415  to the arc groove  415 A. Then, with the guide pin  411 B moving toward the left wall  10 B along the arc groove  415 A, the guide lever  411  is moved toward the left wall  10 B while remaining substantially parallel to the disc inserting/ejecting direction, so that the guide portion  411 A guides the periphery of the large-diameter disc  1 A. In addition, the rotation-restricting pin  411 C of the guide portion  411 A is engaged with the pin locking groove  416 A of the push arm  416  at this time, such that the push arm  416  is also rotated toward the left wall  10 B. 
     When a half or more of the large-diameter disc  1 A has been subsequently inserted in the unit body  10 , the inwardly-biased load arm  421  (i.e., biased clockwise) is moved along the periphery of the large-diameter disc  1 A. Then, the load arm  421  presses the large-diameter disc  1 A from the front face  10 A toward the rear face  10 D by the biasing force applied on the load arm  421 . When the half or more of the large-diameter disc  1 A subsequently passes the connecting portion of the guide lever  411  and the disc guide  412 , the guide lever  411  is slanted by the inwardly-biased plate spring  411 D such that a portion of the lever  411  adjacent to the front face  10 A inwardly protrudes, thereby guiding the large-diameter disc  1 A further into the unit body  10 . 
     When the center of the large-diameter disc  1 A is transferred to the above of turntable  23  as shown in  FIG. 5 , the mount  21  is upwardly moved by the movement of the first driving cam  44  and the second driving cam  45 , such that the large-diameter disc  1 A is clamped on the turntable  23  as shown in  FIG. 6 . More specifically, the insertion of the large-diameter disc  1 A presses an insertion detecting switch (not shown), such that the first driving cam  44  moved toward the front face  10 A. At this time, the projection  52  is inserted into the first cam groove  53 A of the first driving cam  44 , thereby fixing the position of load arm  421  while maintaining a clearance between the load arm  421  and the large-diameter disc  1 A. The second driving cam  52  is also moved toward the left wall  10 B in interlock with the movement of the first driving cam  44 . Then, the mount  21  is upwardly moved in interlock with the first and second driving cams  44 ,  45 , thereby clamping the large-diameter disc  1 A on the turntable  23 . 
     By moving the second driving cam  45  toward the left wall  10 B, the slide stopper  424  is also moved toward the left wall  10 B. With this operation, the push stopper  424 D presses the press piece  416 B of the push arm  416  toward the left wall  10 B, thereby restricting the movement of the push arm  416 . The guide lever  411 , whose rotation-restricting pin  411 C has been locked with the pin locking groove  416 A, is consequently pressed toward the left wall  10 B, thereby providing a clearance of a predetermined size between the guide lever  411  and the large-diameter disc  1 A. 
     In addition, the ejection restricting pin  431 A of the assist arm  431  is engaged with the ejection-restricting groove  424 E 1  for the large-diameter disc by the movement of the slide stopper  424 , thereby restricting the movement of the abutment portion  432 C of the ejection arm  432  while providing a clearance of a predetermined size between the abutment portion  432 C and the large-diameter disc  1 A. 
     (Ejection of Large-Diameter Disc) 
     Next, operation(s) of ejecting the large-diameter disc  1 A will be described. When, for example, an operator presses an ejection button, the first driving cam  44  is initially moved toward the rear face  10 D, such that the second driving cam  45  is also moved toward the right wall  10 C in interlock with the first driving cam  44 . With this operation, the mount  21  is downwardly moved to stop clamping the large-diameter disc  1 A. In addition, with the second driving cam  45  being moved toward the right wall  10 C, the slide stopper  424  is also moved toward the right wall  10 C, such that the push stopper  424 D is moved away from the push arm  416 . Then, the push arm  416  is inwardly rotated (i.e., toward the right wall  10 C) by the biasing force of the push arm-biasing spring  416 C. With this operation, the guide portion  411 A of the guide lever  411  abuts on the periphery of the large-diameter disc  1 A to hold the optical disc  1 A. With the movement of the slide stopper  424  toward the right wall  10 C, the ejection arm  432  and the load arm  421  also become free from the movement restriction in the same manner to hold the periphery of the large-diameter disc  1 A. Then, the biasing force of the ejection arm  432  presses the large-diameter disc  1 A toward the front face  10 A. 
     When the left-lateral periphery of the large-diameter  1 A passes the connecting portion of the guide lever  411  and the disc guide  412  to be further ejected toward the front face  10 A, the pressing portion  412 C of the disc guide  412  presses the periphery of the large-diameter disc  1 A toward the front face  10 A. Specifically, when the guide pin  411 B is pressed by the 8 cm arm  414  toward the front face  10 A to pass the linear groove  415 B, the guide lever  411  is also pressed toward the front face  10 A. At this time, the connecting portion of the guide lever  411  and the disc guide  412  inwardly protrudes along the rotation arc of the disc guide  412 , such that the guide lever  411  is slanted. With this operation, the end of the guide lever  411  adjacent to the front face  10 A can press the periphery of the large-diameter disc  1 A. When the guide pin  411 B further passes the oblique groove  415 C, the guide lever  411  is moved to protrude more inwardly, thereby promoting the ejection of the large-diameter disc  1 A. 
     On the other hand, when the right-lateral periphery of the large-diameter disc  1 A passes the abutment portion  421 A of the load arm  421  to be further ejected toward the front face  10 A, the first driving cam  44  is further moved toward the rear face  10 D, such that the projection  52  is engaged with the common cam groove  53 C and the load arm  421  is inwardly rotated. The rotation of the load arm  421  presses the large-diameter disc  1 A toward the front face  110 A, thereby ejecting the large-diameter disc  1 A. 
     [Effect and Advantage of Disc Unit] 
     As described above, the disc unit  100  according to the above embodiment includes the push arm  416  for providing the predetermined clearance between the periphery of the large-diameter disc  1 A and the guide lever  411  by moving the guide lever  411  for guiding the insertion and ejection of the large-diameter disc  1 A toward the left wall  10 B when the large-diameter disc  1 A is clamped on the turntable  23 . With this arrangement, when the large-diameter disc  1 A is mounted on the turntable  23 , the guide lever  411  does not hinder the rotation of the large-diameter disc  1 A. Accordingly, the large-diameter disc  1 A can be favorably clamped, thereby avoiding such errors as a reading error due to the rotation hindrance. 
     The push arm  416  is inwardly biased, i.e., biased to be rotated toward the mounting position of the large-diameter disc  1 A, by the push arm-biasing spring  416 C. With this arrangement, when the large-diameter disc  1 A is not clamped on the turntable  23  while the rotation-restriction pin  411 C is in engagement with the pin locking groove  416 A, the guide lever  411  is constantly biased inwardly by the push arm  416 . Accordingly, the guide lever  411  can reliably hold the large-diameter disc  1 A and also favorably guide the large-diameter disc  1 A with the guide portion  411 A. 
     The first end of the push arm  416  is rotatable relative to the bridge plate  413  while the second end of the push arm  416  is inwardly biased by the push arm-biasing spring  416 C. Accordingly, the movement region of the push arm  416  can be made small, such that the movement of the guide lever  411  can be restricted with a simple arrangement. 
     The push arm  416  includes the pin locking groove  416 A with which the rotation-restricting pin  411 C provided on the guide lever  411  is engaged. When the guide lever  411  is moved toward the left wall  10 B, the rotation-restricting pin  411 C is engaged with the pin locking groove  416 A to restrict the movement of the guide lever  411 . Accordingly, the push arm  416  can restrict the movement of the guide lever  411  by simply engaging the rotation-restricting pin  411 C of the guide lever  411  with the groove  416 A. 
     According to the present embodiment, the disc unit  100 , in which the guide lever  411  is moved along the arc groove  415 A substantially parallel to the inserting/ejecting direction of the optical disc  1 , employs the above-described push arm  416  that includes the rotatably-mounted first end and the pin locking groove  416 A extending from its second end to the rotary center. Accordingly, by engaging the rotation-restricting pin  411 C of the guide lever  411  with the pin locking groove  416 A, the push arm  416  can restrict the movement of the guide lever  411  with the minimum movement. Thus, the size of the push arm  416  can be reduced and the arrangement can be simplified, thereby contributing to size reduction and thickness reduction of the disc unit  100 . 
     The rotation-restricting pin  411 C is provided on the guide lever  411  adjacently to the front face  10 A. With this arrangement, the connecting portion of the guide lever  411  and the disc guide  412  is prevented from being rotated outwardly, i.e., toward the left wall  10 B. 
     The rotation-restricting pin  411 C is positioned not to interfere with the mount  21  when the guide lever  411  is guiding the small-diameter disc  1 B. Specifically, even the mount  21  is upwardly moved to clamp the small-diameter disc  1 B on the turntable  23 , the rotation-restricting pin  411 C does not contact the mount  21 . Accordingly, it is possible to prevent errors such as a clamping error caused by contacting of the mount  21  and the rotation-restricting pin  411 C or an information-processing error of the small-diameter disc  1 B. 
     [Modifications of Embodiment] 
     It should be noted that the present invention is not limited to the exemplary embodiments described above, but may include modifications described below within a scope where an object of the present invention can be achieved. 
     Although the rotation-restricting pin  411 C to be engaged with the pin locking groove  416 A of the push arm  416  is exemplarily provided on the guide lever  411  adjacently to the front face  10 A, positioned not to interfere with the mount  21  and protrudes downwardly in the above embodiment, the arrangement of the rotation-restricting pin  411 C is not limited thereto. For instance, since the rotation-restricting pin  411 C does not contact the mount  21  when upwardly protruding from the guide lever  411 , the rotation-restricting pin  411 C may be provided on the guide lever  411  adjacently to the front face  10 A. At this time, the push arm  416  may be provided at an upper position corresponding to the rotation-restricting pin  411 C. 
     Although the rotation-restricting pin  411 C is provided on the guide lever  411  adjacently to the front face  10 A, the pin  411 C may be provided thereon adjacently to the rear face  10 D. At this time, in order not to outwardly rotate the connecting portion of the guide lever  411  and the disc guide  412 , another rotation-restricting member or another biasing member for preventing the outward protrusion and outward rotation of the connecting portion may be provided. 
     Although the rotation-restricting pin  411 C of the guide lever  411  is exemplarily engaged with the pin locking groove  416 A provided to the push arm  416  in the above embodiment, another arrangement may be employed in which, for example, a locking pin is provided on the push arm  416  while a groove to be engaged with this pin is formed on the guide lever  411 . According to such an arrangement, since the pin does not interfere with the mount, the push arm  416  may be provided more adjacently to the front face  10 A. With this arrangement, the outward rotation of the connecting portion of the guide lever  411  and the disc guide  412  can be more reliably prevented. 
     Although the first end of the push arm  416  is exemplarily supported to be rotatable relative to the bridge plate  413  while the second end of the push arm  416  is exemplarily provided with the push arm-biasing spring  416 C in the above embodiment, the arrangement of the push arm  416  is not limited thereto. As long as the push arm  416  is moved in a direction crossing the movement direction of the guide lever  411 , the push arm  416  may be, for instance, a member that is moved parallel in the same direction as the right-and-left direction of the guide lever  411 . By moving such a member toward the left wall  10 B while being engaged with the rotation-restricting pin  411 C of the guide lever  411 , the guide lever  411  can be moved toward the left wall  10 B. 
     Although the slide stopper  424  exemplarily serves as the movement restricting member, the arrangement is not limited thereto. For instance, a mount interlocking member connected to the mount  21  for moving the push arm  416  toward the left wall  10 B in accordance with the up-and-down movement of the mount  21  may be provided. 
     Specific configurations when implementing the present invention may be other configurations or the like as long as an object of the present invention can be attained. 
     [Effects and Advantages of Embodiment] 
     The disc unit  100  according to the above embodiment includes the push arm  416  for providing the predetermined clearance between the periphery of the large-diameter disc  1 A and the guide lever  411  by moving the guide lever  411  for guiding the insertion and ejection of the large-diameter disc  1 A toward the left wall  10 B when the large-diameter disc  1 A is clamped on the turntable  23 . With this arrangement, when the large-diameter disc  1 A is mounted on the turntable  23 , the guide lever  411  does not hinder the rotation of the large-diameter disc  1 A. Accordingly, the large-diameter disc  1 A can be favorably clamped, thereby avoiding such errors as a reading error due to the rotation hindrance. 
     INDUSTRIAL APPLICABILITY 
     The present invention is applicable to a transfer unit for inserting and ejecting a disc recording medium and a recording-medium driver provided with the transfer unit.