Patent Publication Number: US-6993776-B2

Title: Disc centering device

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to a disc centering device in a disc player having a disc insertion slot for centering a disc such as a compact disc as information carrier, which is transferred from the disc insertion slot to a playback position such that the center of the disc is held on a turntable. 
   2. Description of the Prior Art 
   A disc player having a disc insertion slot usually has a disc centering mechanism to make the center of a disc inserted from the disc insertion slot to be coincident with the turntable center. For first centering, the centering mechanism stops a disc transferred from the disc insertion slot after the disc center slightly passes beyond the turntable center. For second centering, the centering mechanism pulls back the disc center to be coincident with the turntable center. The first centering is effected by a mechanism, which is disclosed in Japanese Patent Laid Open Publication No. 2001-110117, and comprises a pair of disc sensors  22  coupled to the disc insertion slot for in opposite directions, a lever  54  to be rocked or pivoted with insertion of a large-size disc, and a small-size disc stopper part  52 . When the lever  54  is rocked by a large-size disc, it causes rocking or pivoting of a centering guide arm to cause retreat of the small-size disc stopper  52  from a disc transport path. 
   The above mechanism for effecting the first centering is complicated in construction with the provision of the lever  54 , which is rocked with insertion of the large-size disc, for causing advancement and retreat of the small-size disc to and from the disc transport path. Besides, the mechanism performs complicated disc transport such that the small-size disc is transported in a slightly upwardly slanted state to the playback position. 
   The present invention has an object of providing a disc centering mechanism, which permits simplification of the construction. 
   SUMMARY OF THE INVENTION 
   In a disc centering device according to a first aspect of the invention, disc sensors have stoppers for a small-size disc having a diameter of, for example 8 cm, which are brought into contact with the outer periphery of the small-size disc transported by a transporting means when the small-size disc slightly passes beyond the turntable center. The above stoppers will be explained hereinafter as “smallsize disc stoppers” or “stopper portions”. The disc centering device also has guide portions or pieces, which serve such that when insertion of a large-size disc having a diameter of, for example 12 cm, causes rocking or pivoting of the disc sensors against biasing forces, they engage with the disc sensors and move the small-size disc stoppers to the outside of a disc transport path. The disc sensors are locked in their rocked positions when the large-size disc is inserted. First centering thus can be obtained by merely providing the disc sensors themselves with the small-size disc stoppers, and it is thus possible to simplify the centering mechanism. 
   As an alternative, it is also possible to form the disc sensors themselves from an elastic material. In this case, when the disc sensors are pushed against the guide surfaces, the disc sensors undergo elastic deformation to move the small-size disc stoppers to the outside of the disc transport path. As a further alternative, it is possible to provide the disc sensors such as to be capable of being brought into contact with and separated from the support member and provide the support member with elastic members for pushing the disc sensors against the guide surfaces. In any case, when large-size disc insertion causes rocking of the disc sensors against biasing forces, the small-size disc stoppers are brought into engagement with the guide surfaces and moved to the outside of the disc transport path, and thus they do not interfere with the large-size disc insertion. Further simplification of the construction is obtainable by providing the guide pieces on the support member supporting the disc sensors. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features and advantages of the invention will become more apparent upon reading of the following detailed description when the same is read with reference to the accompanying drawings, in which: 
       FIG. 1  is a perspective view showing a disc centering device of a first embodiment according to the present invention; 
       FIG. 2  is the plan view showing the disc centering device of the first embodiment; 
       FIG. 3  is a fragmentary side view showing a turntable and a clamper of the first embodiment; 
       FIG. 4  is a perspective view of the first embodiment illustrating small-size disc centering; 
       FIG. 5  is a side view of the first embodiment illustrating small-size disc centering; 
       FIG. 6  is a side view of the first embodiment illustrating large-size disc centering; 
       FIG. 7  is a perspective view of the first embodiment illustrating large-size disc centering; and 
       FIG. 8  is a perspective view showing an alternative to the first embodiment according to the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The disc centering device according to the invention will now be described with reference to  FIGS. 1 to 8 .  FIG. 1  is a perspective view showing a mechanical part of a disc player for a car. Shown by phantom lines is a cabinet  1 , in which a disc player  2  is assembled. The disc player  2  has an outer chassis  3  and a sub-chassis  5  assembled therein via a damper (not shown) A turntable  6  is mounted on the sub-chassis  5  at the center thereof. A pick-up (not shown) is mounted movably such that it is directed toward a sub-chassis corner. Above the turntable  6 , a clamper  7  is disposed, which serves to clamp a disc  28  or  29  between it and the turntable  6 . The clamper  7  is supported by a mounting member  8  for rocking. When a clamper drive mechanism (not shown) is started, the mounting member  8  is caused to undergo rocking so as to bring the clamper  7  into contact with the turntable  6  or separate the clamper  7  therefrom. 
   The cabinet  1  has a disc insertion slot  9  for inserting a disc. Between the disc insertion slot  9  and the turntable  6 , a transport roller  10  for transporting the disc and a guide  11  are mounted on the sub-chassis  6 . The transport roller  10  serves to push an inserted disc against the guide  11  and withdraw, with rotation of a transport motor (not shown), the disc from the disc insertion slot into the cabinet  1 . The guide  11  is mounted on a support member  12  as disc guide member describing a disc transport path, which is located on the top sized of the sub-chassis  5 . The support member  12  has upwardly projecting cam pieces or guide pieces  13   a  as guide portions, and torque pieces  13   b , which are located at positions on the opposite sides of the turntable  6 . 
   A pair of disc sensors  14  and  15  is mounted for rocking on the support member  12 . The disc sensors  14  and  15  have detecting pieces  14   a  and  15   a , respectively, with free ends thereof for engagement with the outer periphery of a disc inserted into the disc insertion slot  9 , and they are mounted on the support member  12  such that the centers of their rocking are located at positions intermediate between the turntable  6  and the disc insertion slot  9 . The two disc sensors  14  and  15  are coupled to each other by a coupling member  16  such that they can be rocked in opposite directions. A torsion spring  17  (or spring member) for biasing the detecting pieces  14   a  and  15   a  of the two disc sensors directed toward the disc insertion slot, is provided between the coupling member  17  and the support member  12 . 
   Near or adjacent to the disc sensor  14 , a locking lever  18  has it central part mounted for rocking on the support member  12 . The locking lever  18  has, at one end, a pin  18   a  for being engaged in a U-shaped notch  14   b  of the disc sensor  14  and, at the other end, a frictional contact pin  1   b  located in a disc transport path and serving to be in frictional contact with the outer periphery of a large-size disc  29  being transported. The locking lever  18  is normally biased by a very weak spring force spring for rocking in a direction of being detached from the U-shaped groove  14   b . When the pin  18   a  is brought into the U-shaped groove  14   b  of the disc sensor  14 , the locking lever  18  locks the two disc sensors  14  and  15  at the rocked positions. 
   As shown in  FIG. 2 , a movable member  19 , which is movable for advancement and retreat with rocking of the disc sensor  14 , has one end coupled to the disc sensor  14  and the other end coupled to a trigger lever  20 , which is disposed behind the turntable  6 . The trigger lever  20  has, at one end, a contact pin  20   a  which is located in the disc transport path. When the contact pin  20   a  is brought into contact with the outer periphery of the disc being pulled in by the disc transport means, it causes rocking of the trigger lever  20  about the coupled part of the movable member  10 . With this rocking, the trigger lever  20  starts a clamper drive mechanism and a transport roller release mechanism (these mechanisms being not shown). 
   The pair disc sensors  14  and  15  each have a stopper portion  21  (i.e., small-size disc stoppers), which is to be in contact with the outer periphery of a small-size disc  28  when the center thereof has been transported to slightly exceed the center of the turntable  6 . When the outer periphery of the small-size disc  28  is brought into contact with the stopper parts  21 , first centering of the small-size disc  28  is effected. The stopper portions  21  are formed at the ends of thin elongate extensions  14   c  and  15   c  of the disc sensors  14  and  15  extending from the centers of rotation of the disc sensors  14  and  15  beyond the positions of the cam pieces  13   a.    
   As the disc sensors  14  and  15  are rocked, side faces of the extensions  14   c  and  15   c  are brought into contact with the stems of the cam pieces  13   a , and as they are rocked, the extensions  14   c  and  15   c  come to ride on the cam pieces  13   c  while undergoing elastic deformation. At this time, the ends of the stopper parts  21  are moved toward the top surface of the small-size disc  28 . The tongue pieces  13   b  are formed to lap over the top surfaces of the extensions  14   c  and  15   c  when the disc sensors are not rocked. When the small-size disc  28  is brought into contact with the stopper parts  21 , the tongue pieces  13   b  prohibit elastic deformation of the extensions  14   c  and  15   c.    
   The top surface of the sub-chassis  5  has bent pieces (i.e., large-size disc stoppers)  22 , which serve to stop a large-size disc  29  transported by the disc transporting means when it is brought into engagement with the outer periphery of the large-size disc  29 . The bent pieces  22  are provided at positions to be contacted by the outer periphery of the large-size disc  29  when the center of the large-size disc  29  being transported slightly exceeds the center of the turntable  6 . The position of the large-size disc  29 , at which the center thereof slightly exceeds the center of the turntable  6 , is the first centering position of the large-size disc  29 . 
   As shown in  FIG. 3 , the damper  7  has a cylindrical projection  23 , which can be snugly engaged in the center hole of the disc. The cylindrical projection  23  has a tapered end surface  24 , and it also has a recess  25 . The turntable  6 , on the other hand, has an accommodation recess  26  for accommodating the cylindrical projection  23  and also a cylindrical part  27 , which projects from the bottom of the accommodation recess  26  and can be snugly engaged in the recess  25 . After the transported small- or large-size disc  28  or  29  has been stopped in contact with stopper parts  21  or the bent pieces  22 , the damper  7  approaches the turntable  6 . As a result, the damper pulls back the center of the disc, which has slightly overshot beyond the center of the turntable  8 , up to the center thereof. Thus, the outer periphery of the disc is separated from stopper parts  21  or the bent pieces  22 , and the disc is now ready for rotation. This position is the second centering position. 
   The process in which the large- and small-size discs are transported until the second centering is effected is illustrated in  FIGS. 4 to 7 . When the small-size disc  28  as shown by broken line in  FIG. 2  is clamped between the transport roller  10  and the guide  11 , the outer periphery of the disc  28  pushes the detecting pieces  14   a  and  15   a  of the two disc sensors  14  and  15 . As a result, the detecting pieces  14   a  and  15   a  are slightly rocked in opposite directions. With this rocking, the disc sensors  14  and  15  causes a switch (not shown) to be operated to start the transport motor. With the rotation of the transport roller  10 , the small-size disc  28  is withdrawn from the disc insertion slot  9 . When the diametrical part of the small-size disc  28  clears the detecting pieces  14   a  and  15   a  of the two disc sensors  14  and  15 , the force of the torsion spring restores the disc sensors  14  and  15  to the initial positions thereof. Subsequently, the outer periphery of the small-size disc  28  is brought into contact with the two stopper parts  21 , as shown in  FIG. 4 , and the disc is thus stopped. In this way, the first centering of the small-size disc  28  is completed. 
   Meanwhile, as the outer periphery of the small-size disc  28  pushes the contact pin  20   a  of the trigger lever  20 , the trigger lever  20  is rocked to start the clamper drive mechanism. Thus, the clamper  7  is caused to approach the turntable  6 , thus bringing the taper surface  24  into contact with the edge of the center hole of the small-size disc and pulling back the disc  28  to the position, at which the center of the disc  28  is coincident with the center of the turntable  6 . In this way, the second centering of the small-size disc  28  is completed, as shown in  FIG. 5 . 
   As for the large-size disc  29 , when the disc  29  as shown in  FIG. 2  by a phantom line is clamped between the transport roller  10  and the guide  11 , the two disc sensors  14  and  15  have been greatly rocked or pivoted with their detecting pieces  14   a  and  15   a  pushed by the outer periphery of the disc  29 . When the diametric part of the large-size disc  29  is withdrawn from the disc insertion slot  9  into the cabinet with rotation of the transport roller  10 , and clears the detecting pieces  14   a  and  15   a , it engages with the contact pin  18   b  of the locking lever  18  and causes rocking thereof in the counterclockwise direction in the Figure. With this rocking, the pin  18   a  is pushed into the U-shaped notch  14   b  against the spring force. 
   Meanwhile, with great rocking or pivoting of the disc sensors  14  and  15 , the extensions  14   c  and  15   c  thereof come to ride on the cam pieces  13   a . As a result, the ends of the stopper parts  21  are detached from the disc transport path, as shown in  FIG. 7 . The, as shown in  FIG. 6 , the center of the large-size disc  29  is transported to slightly pass the center of the turntable  6 . When the outer periphery of the large-size disc  29  is eventually brought into contact with the contact pieces  22 , the large-size disc  29  is stopped. In this way, the first centering of the large-size disc  29  is effected. 
   At this time, the disc sensors  14  and  15  are biased by the spring force of the torsion spring  17  for rocking in a direction to restore their initial positions. However, the pin  18   a  of the locking lever  18  has been received in the U-shaped notch  14   b , and the restoration of the disc sensors  14  and  15  has been prevented. Thus, the extensions  14   c  and  15   c  are held in a state that they are on the cams  13   a , and the ends of the stopper parts  21  are at positions out of the disc transport path. Also, with great rocking of the disc sensors  14  and  15 , the movable member  19  has been moved in the direction of inserting the disc  29 . The contact pin  20   a  of the trigger lever  20  thus has been moved to a more rearward position corresponding to the large-size disc  29 . 
   In this state, the outer periphery of the large-size disc  29  pushes and causes rocking of the contact pin  20   a , thus starting the clamper drive mechanism to cause the clamper  7  to approach the turntable  6 . At this time, the taper surface  24  of the clamper  7  is brought into contact with the edge of the center hole of the large-size disc  29  to pull back the outer periphery thereof from the contact pieces  22  and thus bring the center of the disc  29  into coincidence with the center of the turntable  6 . In this way, the second centering of the large-size disc  29  is completed. 
   While in the above embodiment the cam pieces  13   a  serving as guide surfaces have been provided on the support plate  12 , it is also possible to provide the cam pieces  13   a  on the side of the disc sensors  14  and  15 . Also, while the stopper parts  21  have been provided at the ends of the extensions  14   c  and  15   c  of the disc sensors  14  and  15 , it is also possible to adopt an arrangement as shown in  FIG. 8 . As shown, a compression coil spring  33  as spring member is provided on a pin  31  supporting a disc sensor  30  for rocking such that it biases the disc sensor  30  toward the support plate  12 . In this case, when the extension  30   c  comes to ride on the cam piece  13   a , the entire disc sensor  30  is pushed up by the cam piece  13   a  from the support plate  12 . Furthermore, it is also possible to provide the two disc sensors  14  and  15 , the coupling member  16 , the torsion spring  17 , the trigger bar  16 , the trigger lever  20  and the cam pieces  13   a  not on the support plate  12  but on the side of the sub-chassis  5 . 
   In the disc centering device according to the Invention, the stopper parts  21  for effecting the first centering of the small-size disc  28  are provided on the disc sensors  14  and  15 , and also guide portions  13   a  are provided, which, when the disc sensors  14  and  15  are rocked with insertion of the large-size disc, engage with the disc sensors  14  and  15  to bring the stopper parts  21  to the outside of the disc transport path. Thus, the centering of both large- and small-size discs can be obtained by merely providing the small-size disc stoppers  21  on the disc sensors  14  and  15  themselves. It is thus possible to simplify the disc centering device.