Abstract:
A disk drive device ( 1 ) comprises a body chassis ( 2 ) and a tray ( 3 ) movable relative to the body chassis ( 2 ). The body chassis ( 2 ) is provided with a stage ( 6 ) at one side thereof, which is higher than the central bottom face. On the other hand, a part of the disk protective portion ( 11 ) of the tray ( 3 ), which overlaps the stage ( 6 ), is cut out at its rear end ( 20   a ) in an arc shape. As a result, the disk protective portion ( 11 ) covers the whole area of a disk ( 14 ) and, at the same time, forms a large space between it and the front end ( 6   a ) of the stage ( 6 ).

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a disk drive device for driving an information recording disk such as a compact disk (CD) or a digital video disk (DVD) loaded onto it and reading and writing information out of and into the disk. 
     2. Description of the Related Art 
     A disk drive device is built into a parent apparatus, such as a small computer. A first example of such conventional disk drive device will be below described below with reference to  FIG. 8 . This example is disclosed in the Japanese Patent Application Laid-Open No. 8-138296. 
     The disk drive device consists of a body chassis  102  to be fitted to a small computer and a tray  103  on which a disk is to be loaded. To the left side wall of the tray  103  is fitted a left slider  140 , and near the right end of the under face of the tray  103  is fitted a right slider  141 . 
     On the other hand, a left slider rail  150  is formed on the left side wall of the body chassis  102 , and a right slider rail  151 , on the right side wall of the same. By the mutual engagement of these sliders  140  and  141  and slider rails  150  and  151 , the tray  103  is supported by the body chassis  102  to be movable in the Y–Y′ direction. 
     A stage  106  protrudes horizontally outwards from the upper end of the right side wall of the body chassis  102 . The top face of the stage  106  is positioned higher than the central bottom face of the body chassis  102 . 
     The disk protective portion  111  of the tray  103  is in a rectangular shape large enough to cover the whole area of the under face of the disk. However, in a state in which the tray  103  is fully pulled out of the body chassis (in an unloaded position), there is a slight gap between the rear edge of the disk protective portion  11  (the edge on the body chassis side) and the front end of the body chassis  102  (the edge on the tray side). This gap is intended to prevent the disk, when it is unloaded from or loaded onto the tray  103 , from hitting the body chassis  102 . 
     In a state in which the tray  103  is fully pressed into the body chassis  102  (in a loaded position), the portion of the disk protective portion  111  protruding rightwards from the right slider  141  comes above the stage  106 . 
     In order to minimize the height of this disk drive device illustrated in  FIG. 8 , it is required to minimize the gap, if any, between the top face of the stage  106  of the body chassis  102  and the under face of the disk protective portion  111  of the tray  103 . 
     Then, when the tray  103  in the unloaded position is pressed into the body chassis  102 , the rear end of the disk protective portion  111  hits against the front end of the stage  106  of the body chassis  102 , making it impossible to press the tray  103  farther in. This occurs because, when the tray  103  begins to be shifted from the unloaded position into the body chassis  102 , the sliders  140  and  141  and the slider rails  150  and  151  are not yet engaged with each other for a sufficient length, and the tray  103  is made liable to oscillate vertically during its shifting. 
     On the other hand, if it is so arranged that part of the disk protective portion  111  overlaps part of the stage  106  even when the tray  103  is in the unloaded position, the shifting of the tray  103  is not obstructed by the stage  106  of the body chassis  102  when the tray  103  in the unloaded position is pressed into the body chassis  102 . In this case, however, there is a fear that the disk may be allowed to hit against the body chassis  102  when the disk is unloaded from, or loaded onto, the tray  103 . 
     Next will be described a second example of conventional disk drive device with reference to  FIG. 9 . This example is disclosed in the Japanese Patent Application Laid-Open No. 9-223347. 
     The disk drive device consists of a body chassis  202  fitted to a small computer and a rail tray  203  on which a disk is to be loaded. The tray  203  is supported by the body chassis  202  to be movable in the A-B direction. 
     To the left and right side walls of the body chassis  202  are fitted fixed side rails  207 , and to the left and right side walls of the tray  203  are fitted movable side rails  206 . Between these movable side rails  206  and fixed side rails  207  intervene intermediate rails  208 . 
     From the top end of the right side wall the body chassis  202  protrudes a stage  216  outwards horizontally. The top face of the stage  216  is positioned higher than the central bottom face of the body chassis  202 . 
     The disk protective portion  211  of the tray  203  is provided only in the area between the left and right movable side rails  206 , and the outer (right) side of the right rail  206  is cut off. This absence of the disk protective portion  211  outside the right rail  206  eliminates the overlapping of the stage  216  and the disk protective portion  211  when the tray  203  is pressed into the body chassis  202 , and results in the advantage that the disk drive device can be reduced in height. 
     However, the portion of the disk loaded on the tray  203  outside the right rail  206  (i.e. the portion overlapping the stage  216 ) is unprotected and exposed. Moreover, as the width of the disk protective portion  211  is smaller than the full diameter of the disk, the strength of the tray  203  is weakened. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a low profile disk drive device which allows a tray to be smoothly inserted into a body chassis. 
     In order to achieve the object stated above, a disk drive device according to a first aspect of the invention has a body chassis and a tray slidable between a first state in which it is drawn out of the body chassis and a second state in which it is pressed into the body chassis. Further a bottom plate constituting the body chassis has a stage, at one side thereof, formed higher than the central portion thereof, and the tray has a protruding protective portion in its position vertically overlapping the stage when pressed into the body chassis. The end of the protruding protective portion on the body chassis side is partly cut so that, when the tray is drawn out of the body chassis, a gap be formed between the tray and the end of the body chassis on the tray side. 
     A disk drive device according to a second aspect of the invention has a body chassis and a tray made slidable by a guide rail mechanism between a first state in which it is drawn out of the body chassis and a second state in which it is pressed into the body chassis. Further, the tray is provided with a tray base and a disk protective portion, and the guide rail mechanism is provided with chassis side guide rails arranged on the left and right sides of the body chassis and tray side guide rails arranged on the left and right sides of the tray base. The disk protective portion comprises a main protective portion corresponding to the area between the left and right tray side guide rails and a protruding protective portion protruding from the right tray side guide rail farther outwards. These main protective portion and protruding protective portion cover at least the whole area of the under face of the disk loaded on disk. The end of the protruding protective portion on the body chassis side is partly cut out so that, when the tray is drawn out of the body chassis, a gap be formed between the tray and the end of the body chassis on the tray side. 
     An end of the protruding protective portion is either cut out along the outer circle of the disk loaded on the tray or partly cut out in an inclined or curved shape. When the tray is drawn out of the body chassis, a gap is formed between the end of the protruding protective portion and the end of the body chassis on the tray side. 
     In the disk drive device according to the invention, the whole under face of the disk is protected by the disk protective portion and, at the same time, the tray can be easily drawn out of or pressed into the body chassis. Especially when the tray is to be pressed into the body chassis, the rear end of the disk protective portion provided on the tray side is structurally prevented from hitting against the front end of the stage of the body chassis, thereby enabling the disk protective portion to smoothly ride on the stage of the body chassis. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a perspective view of a disk drive device, which is a preferred embodiment of the present invention; 
         FIG. 2  shows a cross-sectional view of the disk drive device of  FIG. 1 ; 
         FIG. 3  shows the disk drive device of  FIG. 1  viewed from underneath, wherein the tray is fully drawn out of the body chassis and in a state to permit loading or unloading a disk onto or from it (in an unloaded position); 
         FIG. 4  shows a B-B section of  FIG. 1 ; 
         FIG. 5  shows the disk drive device of  FIG. 1  in a state wherein the tray is pressed in over the body chassis (in a loaded position); 
         FIG. 6  shows a section of a left side one, out of the left and right guide mechanisms which enable the tray shown in  FIG. 5  to be drawn out of or pressed into the body chassis; 
         FIG. 7  shows a section of the right side guide mechanism; 
         FIG. 8  shows a perspective view of a first example of conventional disk drive device; and 
         FIG. 9  shows a perspective view of a second example of conventional disk drive device. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A disk drive device  1  is provided with a body chassis  2  and a tray  3  as shown in  FIG. 1 . The body chassis  2 , produced by pressing a steel sheet, consists of a top plate  2   a  and a bottom plate  2   b.    
     On the left and right sides of the top plate  2   a  are formed side walls  9  and  10  and, as shown in the sectional view of  FIG. 2 , side walls  4  and  5  are also formed on the left and right sides of the bottom plate  2   b . The right side wall  5  consists of a first right side wall  5   c  rising from an end of the bottom face of the bottom plate  5   a , a stage  6  extending horizontally outwards (rightwards) from the upper end of a first right side wall  5   c , and a second right side wall  5   d  rising from the tip of the stage  6 . 
     When the top plate  2   a  is placed over the bottom plate  2   b , as shown in  FIG. 2 , the left side wall  9  of the top plate  2   a  engages with the left side wall  4  of the bottom plate  2   b , and the right side wall  10  of the top plate  2   a  engages with the second right side wall  5   d  of the bottom plate  2   b.    
     To the inner side faces of the left side wall  4  and the first right side wall  5   c  of the bottom plate  2   b  are fitted guide rails (hereinafter referred to as chassis side guide rails)  7  and  8 . 
     The tray  3  consists of a synthetic resin-made disk protective portion  11  and a synthetic resin-made tray base  12  supporting the disk protective portion  11 . 
     The disk protective portion  11  consists of an underside protective portion  11   a  for protecting the immediate underneath of a disk  14  and a peripheral protective portion  11   b  protecting the outer circumference of the disk  14 . The underside protective portion  11   a  has a circular area slightly greater in diameter than the disk  14 . A level difference is provided between the peripheral protective portion  11   b  and the underside protective portion  11   a  and, when the disk  14  is placed over the underside protective portion  11   a , the top face of the peripheral protective portion  11   b  comes to a higher position than the top face of the disk  14 . 
     A metallic thread chassis  13  is built into the tray base  12 . The thread chassis  13  is provided with a turntable  16  for holding the disk  14 , a motor (not shown) for rotationally driving the turntable  16 , ahead shifting mechanism (not shown) for shifting a head  28  and so forth. The power and control signals for driving these motor and shifting mechanism are transmitted by a flexible flat cable  31  connected to the main circuit board  30  on the body chassis  2  side. 
     As a slight gap is formed between the disk  14  and the underside protective portion  11   b  when the disk  14  is loaded on the turntable  16 , the disk  14 , when it turns, does not come into contact with the underside protective portion  11   b.    
     When the tray  3  is fully drawn out of the body chassis  2  to position the disk  14  at a position (hereinafter referred to as unloaded position) where it can be unloaded from the turntable  16 , there is formed a certain gap p between the rear end  11   c  of the disk protective portion  11  (the end on side of the body chassis  2 ) and the front end  2   c  of the body chassis  2  opposite thereto as shown in the underside view of  FIG. 3 . This arrangement is intended to prevent the disk  14  from hitting any end of the body chassis  2  when the disk  14  is loaded onto the tray  3  in the unloaded position or to unload the disk  14  from the tray  3 . 
     On the left and right sides of the tray base  12  are arranged guide rails (hereinafter referred to as tray side guide rails)  17  and  18  as shown in  FIG. 2 . The left guide rail  17  engages with the left chassis side guide rail  7  via an intermediate guide rail, and the right guide rail  18  engages with the right chassis side guide rail  8  via another intermediate guide rail. The structure of these intermediate guide rails will be described afterwards. 
     With these chassis side guide rails  7  and  8  and tray side guide rails  17  and  18 , the tray  3  can be slid in the direction of pressing it towards the chassis  2  or drawing it out of the chassis  2 . 
     The spacing between the tray side guide rails  17  and  18  fitted on the left and right sides of the tray base  12  is smaller than the diameter of the disk  14 . Therefore, when the disk  14  is so placed over the disk protective portion  11  that the tangent of its circle substantially coincide with the left guide rail  17 , part of the disk  14  protrudes from the right guide rail  18  farther outwards (rightwards) as shown in  FIG. 3 . 
     If the disk protective portion  11  were provided only between the left and right guide rails  17  and  18 , part of the underside of the disk  14  could not be protected by the disk protective portion  11 . 
     In view of the above, according to the invention, the disk protective portion  11  is extended beyond the space between the left and right tray side guide rails  17  and  18  farther outwards (rightwards) in order to protect the whole under face of the disk  14 . As a result, the disk protective portion  11  consists of a portion corresponding to the area between the left and right tray side guide rails  17  and  18  (a main protective portion  19 ) and an extend portion (a protruding protective portion  20 ) protruding from the right tray side guide rail  18  farther outwards (rightwards). 
     Out of the disk protective portion  11 , the main protective portion  19  has a substantially rectangular shape. On the other hand, the protruding protective portion  20  has a rectangular shape with its rear part (the part closer to the body chassis  2 ) cut out substantially along the outer circle of the disk  14  loaded on the tray  3  as shown in  FIG. 3 . The cut-out edge of the protruding protective portion  20  is denoted in  FIG. 3  by reference sign  20   a.    
     This rear edge  20   a  of the protruding protective portion has an arc shape substantially coinciding with the outer circumference of the disk  14  loaded on the turntable  16 . Therefore, when the tray  3  is in the unloaded position ( FIG. 3 ), the rear edge  20   a  of the protruding protective portion  20  is ahead of the front end of the stage  6  farther than the distance p (the gap between the rear end  11   c  of the main protective portion  19  of the disk protective portion  11  and the front end  2   c  of the body chassis  2  opposite thereto), with the result that, when the tray  3  is in the unloaded position, a large space is formed between the edge  20   a  of the protruding protective portion  20  and the front end  2   c  of the body chassis  2 . 
     Of the protruding protective portion  20  of the disk protective portion  11 , apart thereof constitutes the underside protective portion  11   a  to protect the immediate underside of the disk  14 , and the rest makes up the peripheral protective portion  11   b  to protect the outer circumference of the disk  14 . Incidentally, since the part of the protruding protective portion  20  immediately inside the rear edge  20   a  constitutes the underside protective portion  11   a , its rear edge  20   a  is provided with a side wall which gently curves upwards as shown in  FIG. 4  and opposes an end face of the disk  14 . The height of this side wall provided on the rear edge  20   a  is substantially equal to the level difference between the underside protective portion  11   a  of the disk protective portion  11  and the peripheral protective portion  11   b.    
     Reference numeral  21  denotes a hole to put a finger through, when a minidisk is mounted on the turntable  16 , to hook the finger on the outer circumference of the minidisk to load it onto or unload it from the turntable  16 . 
     In the state wherein the tray  3  is fully pressed into the body chassis  2  (the loaded position), the protruding protective portion  20  of the disk protective portion  11  is positioned above the stage  6  of the body chassis  2  as shown in  FIG. 2 . 
     In order to minimize the height of the disk drive device  1 , it is required to minimize the gap, if any, between the top face of the stage  6  of the body chassis  2  and the under face of the disk protective portion  11  (the protruding protective portion  20 ) of the tray  3 . Therefore, care should be taken, when the tray  3  in the unloaded position is pressed into the body chassis  2 , not to let the rear edge  20   a  of the protruding protective portion  20  in the disk protective portion  11  of the tray  3  hit against the front edge  6   a  of the stage  6  of the body chassis  2 . 
     Incidentally, the disk drive device  1  according to the invention has the following advantages, since (1) the rear edge  20   a  of the protruding protective portion  20  extends obliquely forward and (2) a large space is formed between the rear edge  20   a  of the protruding protective portion  20  and the front edge  2   c  of the body chassis  2  as described above. 
     (1) When the protruding protective portion  20  approaches the stage  6  of the body chassis  2 , as the rear edge  20  extends obliquely forward in an arc shape, the rear edge  20   a  in its whole does not become coincident with the front end  6   a  of the stage  6  of the body chassis  2  at once. The rear edge  20   a  gradually shifts backwards beyond the front end  6   a  of the stage  6  from its backward region towards the forward region. Therefore, the protruding protective portion  20  in the disk protective portion  11  can be smoothly superposed over the stage  6  of the body chassis. 
     (2) Unless the tray  3  in the unloaded position is shifted towards the body chassis  2  for a certain distance, the rear edge  20   a  of the protruding protective portion  20  does not reach the front end  6   a  of the stage  6  of the body chassis  2 . In other words, by the time a part of the rear edge  20   a  of the protruding protective portion  20  begins to reach the front end  6   a  of the stage  6  of the body chassis  2 , already the chassis side guide rails  7  and  8  and the tray side guide rails  17  and  18  are engaged with each other for some length. Therefore, there is no possibility for the protruding protective portion  20  in transit to oscillate to allow its rear edge  20   a  to hit against the front end  6   a  of the stage  6  of the body chassis  2 . 
     The shape of this rear edge  20   a  of the protruding protective portion  20  need not be an exact arc, but may be an inclined straight line or a curve close to an arc. 
     Next will described in detail the engagement between the tray side guide rails  17  and  18  and the chassis side guide rails  7  and  8 . 
       FIG. 5  shows a state wherein the tray  3  is pressed in over the body chassis  2  via the tray side guide rails  17  and  18  and the chassis side guide rails  7  and  8  (the loaded position). 
     Underneath the stage  6  in the bottom plate  2   b  of the body chassis  2  is formed a space, wherein components of the computer into which the disk drive device  1  is to be incorporated are arranged. 
     By cutting the upper edges of the left side wall  4  of the bottom plate  2   b  ( FIG. 6 ) and the first right side wall  5   c  ( FIG. 7 ) at several (e.g. three) positions, and then bending the upper edges inwards, chassis side guide rails  7  and  8  are formed. 
     In the left and right wall faces  12   a  and  12   b  of the tr ay base  12  of the tray  3 , protruding strips  40   a   1 ,  40   a   2 , and  40   b   1 ,  40   b   2  extending in the shifting direction of the tray are formed at the outside thereof. The left wall face  12   a  of the tray base  12  and the two protruding strips  40   a   1  and  40   a   2  formed thereon constitute the left tray side guide rail  17 , and the right wall face  12   b  of the tray base  12  and the two protruding strips  40   b   1  and  40   b   2  formed thereon constitute the right tray side guide rail  18 . These protruding strips  40   a   1 ,  40   a   2  and  40   b   2  have tips bent in an L shape. 
     The left tray side guide rail  17  engages with the left chassis side guide rail  7  via a left intermediate guide rail  41 , and the right tray side guide rail  18  engages with the right chassis side guide rail  8  via a right intermediate guide rail  42 . Both of these left and right intermediate guide rails  41  and  42  are extrusion-molded hard plastic products having a certain sectional shape. 
     The left intermediate guide rail  41 , as shown in  FIG. 6 , has on its outside a first engaging portion  41   a  to engage with the left chassis side guide rail  7  and on its inside a second engaging portion  41   b  to engaged with the protruding strips  40   a   1  and  40   a   2  constituting the left tray side guide rail  17 . 
     On the other hand, the right intermediate guide rail  42 , as shown in  FIG. 7 , has on its outside a first engaging portion  42   a  to engage with the right chassis side guide rail  8  and on its inside a second engaging portion  42   b  to engage with the protruding strips  40   b   1  and  40   b   2  constituting the tray side guide rail  18 . 
     The engagement of the L-shaped tip portion of the left chassis side guide rail  7  and the protruding strips  40   a   1  and  40   a   2  of the tray side guide rail  17 , whose tips are L-shaped, with the groove portion formed in the left intermediate guide rail  41  results in a structure which forbids the left chassis side guide rail  7  and the left tray side guide rail  17  from becoming disengaged laterally. 
     Also, the engagement of the L-shaped tip portion of the right chassis side guide rail  8  and the protruding strip  40   b   2  of the right tray side guide rail  18 , whose tip is L-shaped, with the groove portion formed in the right intermediate guide rail  42  results in a structure which forbids the right chassis side guide rail  8  and the right tray side guide rail  18  from becoming disengaged laterally. 
     Moreover, as shown in  FIG. 7 , the top face tq 1  of the first engaging portion  42   a  of the right intermediate guide rail  42  is formed in a position lower than the top face tq 2  of the second engaging portion  42   b . This enables the stage  6  of the body chassis  2  engaged with the first engaging portion  42   a  to be positioned sufficiently lower than the protruding protective portion  20  of the disk protective portion  11  placed above the second engaging portion  42   b.    
     As a result, between the top face of the stage  6  of the body chassis  2  and the portion protruded farther outwards (rightwards) beyond the right tray side guide rail  18  (the protruding protective portion  20 ) to protect the whole area of the disk, an appropriate gap can be created without increasing the overall height of the disk drive device. 
     To add, the right tray side guide rail  18  has a recess to engage with the second engaging portion  42   b  of the right intermediate guide rail  42 . The top portion of the recess is substantially equalized in height to the under face of (the protruding protective portion  20  of) the disk protective portion  11  of the tray  3 . Thus, by bringing the top face tq 2  of the second engaging portion  42   b  of the intermediate guide rail  42  as close as practicable to the under face of the disk protective portion  11  of the tray  3 , the overall dimensions of the disk drive device  1  can be reduced. 
     On the other hand, as shown in  FIG. 6 , the top face tp 1  of the first engaging portion  41   a  of the left intermediate guide rails  41  is formed in a position higher than the top face tp 2  of the second engaging portion  41   b . However, as is evident from  FIG. 6 , since there is a sufficient spacing between the top face tp 1  of the first engaging portion  41   a  and the under face of the top plate  2   a  of the body chassis  2 , there will be no particular problem even if the first engaging portion  41   a  of this left intermediate guide rail  41  is slightly increased in height.