Abstract:
The invention relates to an optical disk drive, and more particularly, to a holder for disk drives having an improved chuck structure for seating a disk. The holder of the invention, in use, is inserted into a central opening of a disk for detachably seating the disk, and comprises: a circular hub projected upward and sized equal to the central opening of the disk; a chuck projected from a lateral portion of the hub, wherein the chuck includes a rear portion elastically connected with the hub, a peak formed in a front portion of the chuck and a lower circular face of a curvature extended downward from the peak; and a support formed integral with the hub for contacting the lower circular face of the chuck to enable circular motion of the chuck.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The invention relates to an optical disk drive, and more particularly, to a holder for disk drives having an improved chuck structure for seating a disk.  
         [0003]     2. Description of the Related Art  
         [0004]     Optical disk drives, in particular, slim optical disk drives include a CD-ROM drive, a DVD-ROM drive, a CD R/W drive and so on. Such an optical disk drive receives a disk to write or read records into/from the disk while turning the disk. A slim optical disk drive is particularly mounted on a slim computer such as a notebook computer.  
         [0005]     The slim optical disk drive is limited in height. That is, since the slim optical disk drive is mounted on a thin main body, the height of the disk drive itself is limited. Therefore, the slim optical disk drive requires a holder structure for grasping a disk unlike a disk drive mounted on a typical desktop computer.  
         [0006]      FIG. 1  shows a conventional holder structure. As shown in  FIG. 1 , the conventional holder for disk drives comprises a flat cylindrical hub  103  sized equal to a central opening of a disk for being inserted into the central opening of disk and chucks  101  for elastically projecting from lateral regions of the hub  103  under the force of springs  102 . The holder is placed in a central portion of a circular base  110 , and a lower base  140  is provided with a stator assembly and a rotor assembly.  
         [0007]     A rubber turntable  130  is provided around the holder for wrapping the holder therein so that the disk is seated or mounted on the turntable  130 . The rotor and stator assemblies in the lower base  140  of the holder cooperate to turn the turntable  130  and the holder, and thus the disk grasped by the holder along with the turntable  130 . As the disk is turned, writing or reading means write or read desired data into/from the disk while moving in a radial direction of the disk.  
         [0008]     Each of the chucks  101  used in the conventional holder grasps a disk according to a process shown in  FIG. 2 .  FIG. 2 ( a ) illustrates that the disk  100  contacts an upper portion of one of the chucks  101 . As the user further moves the disk  100  downward, the chuck  101  is pushed backward slowly. As the disk  100  is further moved downward, the chuck  101  is pushed to the innermost position thereof in the holder hub  103  as shown in  FIG. 2 ( b ). When the disk  100  is completely seated on the turntable, the chuck  101  projects again toward the disk as shown in  FIG. 2 ( c ).  
         [0009]     The chuck  101  has upper and lower faces, which taper at predetermined inclinations, and a peak portion at leading edges of the upper and lower faces. The chuck  101  functions to press the disk under a predetermined amount of force so that the disk may not slip upward out of the turntable while it is turning.  
         [0010]     The disk holder structure using the above chucks has the following drawbacks. First, the central chucks are moved only in a horizontal direction, thereby enhancing seating force, i.e., force for seating the disk. The enhanced seating force causes inconvenience to the user in using the disk drive, and thus the user applies excessive force to the disk holder thereby potentially damaging the disk drive and even the main body.  
         [0011]     If the tension of the springs which are mounted on rear of the chucks is adjusted to decrease the seating force, restraining force against separation or simply restraining force, i.e., force required for separating the disk or resisting against separation of the disk will be also reduced. Then, the disk may be separated even under slight impact during high speed rotation so that the disk drive may not properly perform its function. Therefore, the art requires a novel holder structure which can maintain sufficient amount of restraining force against separation while decreasing seating force.  
         [0012]     As shown in  FIG. 1 , the peak of the chuck  101  has a semicircular configuration on a horizontal plane. In this configuration, the peak of the chuck  101  performs point-to-point contact with the periphery of the central opening of the disk, which does not increase the restraining force against separation of the disk. Further, in the case of a DVD for example having a double layer structure, an intermediate groove of the double layer structure may trap the chuck (i.e., half chucking) potentially causing problems to the seating process of the disk.  
         [0013]     Therefore, the art also requires a structure capable of preventing half chucking in which the chuck is trapped by an intermediate portion of the disk while increasing the restraining force against separation.  
       SUMMARY OF THE INVENTION  
       [0014]     The present invention has been made to solve the foregoing problems, and it is therefore an object of the present invention to provide a holder for disk drives having an improved structure of chucks and chuck supporting portions so that the chucks can perform downward circular motion along circular paths so as to reduce disk-seating force while enhancing restraining force against separation of a disk.  
         [0015]     It is another object of the invention to provide a disk holder having an improved configuration of a peak portion of a chuck in order to prevent half chucking by the disk while enhancing restraining force against separation of the seated disk.  
         [0016]     According to an aspect of the invention, there is provided a holder for disk drives which is inserted into a central opening of a disk for detachably seating the disk. The holder of the invention comprises: a circular hub projected upward and sized equal to the central opening of the disk; a chuck projected from a lateral portion of the hub, wherein the chuck includes a rear portion elastically connected with the hub, a peak formed in a front portion of the chuck and a lower circular face of a curvature extended downward from the peak; and a support formed integral with the hub for contacting the lower circular face of the chuck to enable circular motion of the chuck.  
         [0017]     In the holder for disk drives, a contact face of the support contacting the lower circular face of the chuck is preferably an inclination sloped at a predetermined angle in respect to a horizontal plane, and the inclination more preferably has an inclination angle of about 5 to 25 degree in respect to the horizontal plane.  
         [0018]     Also in the holder for disk drives, a contact face of the support contacting the lower circular face of the chuck is an arc face, and the lower circular face of the chuck more preferably has a curvature radius smaller than that of the arc face of the support.  
         [0019]     In addition, the holder of the invention may further comprise a guide provided in rear of the chuck, wherein the guide contacts the inside of the hub to restrict vertical circular motion of the chuck.  
         [0020]     According to another aspect of the invention, there is provided a holder for disk drives which is inserted into a central opening of a disk for detachably seating the disk. The holder of the invention comprises: a circular hub projecting upward and sized equal to the central opening of the disk; a chuck projected from a lateral portion of the hub, wherein the chuck includes a rear portion elastically connected with the hub, a peak formed in a front portion of the chuck and a lower circular face of a curvature extended downward from the peak; and a support formed integral with the hub for contacting the lower circular face of the chuck to enable circular motion and linear motion of the chuck in sequence.  
         [0021]     In the holder for disk drives, a contact face of the support contacting the lower circular face of the chuck preferably includes an inclined portion having a predetermined angle in respect to a horizontal plane and a horizontal portion connected with the inclined portion, and the inclined portion of the contact face more preferably has an inclination angle of about 5 to 25 degree. Also, a contact face of the support contacting the lower circular face of the chuck includes an arc face and a horizontal face connected with the arc face, and the lower circular face of the chuck more preferably has a curvature radius smaller than that of the arc face.  
         [0022]     In addition, the holder of the invention may further comprise a guide provided in rear of the chuck, wherein the guide contacts the inside of the hub to restrict vertical circular motion of the chuck.  
         [0023]     According to further another aspect of the invention, there is provided a holder for disk drives which is inserted into a central opening of a disk for detachably seating the disk. The holder of the invention comprises: a circular hub projected upward and sized equal to the central opening of the disk; a chuck projected from a lateral portion of the hub, wherein the chuck includes a rear portion elastically connected with the hub, a peak formed in a front portion of the chuck and having a curvature radius on a horizontal plane equal to a radius of the central opening and a lower circular face of a curvature extended downward from the peak; and a support formed integral with the hub for contacting the lower circular face of the chuck to enable circular motion of the chuck.  
         [0024]     In the holder of the invention, a contact face of the support is preferably an inclination sloped at a predetermined angle in respect to the horizontal plane, the inclination more preferably has an inclination angle of about 5 to 25 degree in respect to the horizontal plane. Further, a contact face of the support is preferably an arc face, and the lower circular face of the chuck more preferably has a curvature radius smaller than that of the arc face of the support. Also, the holder of the invention may further comprise a guide provided in rear of the chuck, wherein the guide contacts the inside of the hub to restrict vertical circular motion of the chuck.  
         [0025]     According to yet another aspect of the invention, there is provided a holder for disk drives which is inserted into a central opening of a disk for detachably seating the disk. The holder of the invention comprises: a circular hub projected upward and sized equal to the central opening of the disk; a chuck projected from a lateral portion of the hub, wherein the chuck includes a rear portion elastically connected with the hub, a peak formed in a front portion of the chuck and having a curvature radius on a horizontal plane equal to a radius of the central opening and a lower circular face of a curvature extended downward from the peak; and a support formed integral with the hub for contacting the lower circular face of the chuck to enable circular motion and linear motion of the chuck in sequence.  
         [0026]     In the holder of the invention, a contact face of the support preferably includes an inclined portion having a predetermined angle in respect to a horizontal plane and a horizontal portion connected with the inclined portion, and the inclined portion of the contact face more preferably has an inclination angle of about 5 to 25 degree. Further, a contact face of the support contacting the lower circular face of the chuck preferably includes an arc face and a horizontal face connected with the arc face, and the lower circular face of the chuck more preferably has a curvature radius smaller than that of the arc face. In addition, the holder of the invention may further comprise a guide provided in rear of the chuck, wherein the guide contacts the inside of the hub to restrict vertical circular motion of the chuck. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0027]     The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:  
         [0028]      FIG. 1  is plan view of a conventional holder for disk drives;  
         [0029]      FIG. 2  illustrates a process of seating a disk on the conventional holder for disk drives;  
         [0030]      FIG. 3  is a plan view of a holder for disk drives of the invention;  
         [0031]      FIG. 4  is sectional view of a holder chuck in  FIG. 3 ;  
         [0032]      FIG. 5  illustrates motion of the holder chuck in a seating process of a disk performed by the holder for disk drives of the invention;  
         [0033]      FIG. 6  is a sectional view illustrating an important part of the holder chuck of the holder for disk drives of the invention;  
         [0034]      FIG. 7  is a sectional view of a support of the holder for disk drives of the invention;  
         [0035]      FIG. 8  is a sectional view of an alternative to the holder chuck of the holder for disk drives of the invention;  
         [0036]      FIG. 9  is a sectional view of another alternative to the holder chuck of the holder for disk drives of the invention;  
         [0037]      FIG. 10  is a sectional view illustrating elastic coupling of the chuck of the holder for disk drives of the invention;  
         [0038]      FIG. 11  is a plan view of a peak portion of the chuck of the holder for disk drives of the invention; and  
         [0039]      FIG. 12  illustrates the chuck of the holder for disk drives of the invention, which is trapped by an intermediate portion of a disk. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0040]     The following detailed description will present a preferred embodiment of the invention in reference to the accompanying drawings.  FIG. 3  is a plan view of a holder for disk drives of the invention, and  FIG. 4  is sectional view of a holder chuck in  FIG. 3 .  
         [0041]     The disk holder of the invention comprises a hub  3 , chucks  1  mounted on the hub  3  and supports  2  for supporting the chucks  1 .  
         [0000]     Holder Structure  
         [0042]     The hub  3  has a generally circular sectional configuration, as shown in  FIG. 3 , to match an opening of a predetermined diameter formed in a central portion of a disk. The hub  3  is made of resin, and projected from an upper central portion of drive means including a stator assembly and a rotor assembly.  
         [0043]     As shown in  FIG. 4 , each of the chucks  1  is mounted on the hub  3  so that the each chuck  1  can perform elastic motion in respect to the hub  3 . The chuck  1  is elastically connected by its rear portion with the inside of the hub  3 . That is, the rear portion of the chuck  1  is connected with the inside of the hub  3  via elastic means such as a spring so that the chuck  1  can perform elastic motion in respect to the hub  3 .  
         [0044]     The chuck  1  is projected from a lateral portion of the hub  3 , and provided with a peak  13  projected from a front portion thereof. Upper and lower faces  11  and  12  formed in the chuck  1  are inclined upward and downward, respectively, from the peak  13  at predetermined angles so that the disk can be fixed in position by the peak structure.  
         [0045]     A support  2  as shown in  FIG. 4  is placed under the chuck  1 . The support  2  allows the chuck  1  to perform downward or upward circular motion rather than horizontal motion. The support  2  is formed integral with the hub  3 , and a contact face  14  in contact with the chuck  1  is formed at an angle inclined in respect to a horizontal plane.  
         [0046]     The lower face  12  of the chuck  1  has a curved region of a predetermined curvature under the peak  13 . The curved region of the lower face  12  slides on the contact face  14  of the support  2  so that the chuck  1  moves along a circular path.  
         [0000]     Operation  
         [0047]      FIG. 5  illustrates motion of the holder chuck in a seating process of a disk performed by the holder for disk drives of the invention.  FIG. 5 ( a ) illustrates an initial stage of seating a disk  100  on the holder. In  FIG. 5 ( a ), the disk  100  primarily contacts the upper face  11  of the chuck  1 , in which the upper face  11  of the chuck  1  is inclined at a predetermined angle so that the disk  100  slides down along the upper face  11 .  
         [0048]     Under the pressing force of the disk  100 , the peak of the chuck  1  moves downward along the same path, that is, the curved region formed in the lower face of the chuck  1  as shown in  FIG. 5 ( b ). When the later portion of the disk  100  reaches beyond the peak of the chuck  1  as the disk  100  further moves downward, the peak of the chuck  1  returns over the disk, as shown in  FIG. 5C , resulting from the elastic force of the spring.  
         [0000]     Chuck Structure  
         [0049]     The following will detail the structure of the chuck  1  and the support  2  having the above operation.  FIG. 6  is a sectional view illustrating an important part of the holder chuck of the holder for disk drives of the invention, and FIG.  7  is a sectional view of the support of the holder for disk drives of the invention.  
         [0050]     In order to perform the above operation as shown in  FIG. 5 , the lower face of the chuck  1  is curved to have a predetermined value of curvature, and the contact face of the support  2  in contact with the chuck  1  is also inclined at a predetermined angle. The curved lower face  12  of the chuck  1  cooperates with the inclined contact face  14  of the support  2  so that the chuck  1  can perform circular motion along the curved lower face  12 .  
         [0051]     Such circular motion functions to reduce the seating force applied to the disk and but to enhance the restraining force against separation of the disk after the disk is seated on the holder.  
         [0052]     The contact face  14  of the support shown in  FIG. 4  is in the form of an arc. That is, the contact face  14  of the support can be also arc-shaped so that the chuck of the invention can perform circular motion. Then, the arc is so formed that an imaginary straight line connecting between ends of the arc has a downward inclination angle in respect to a horizontal plane.  
         [0053]     Further, the curvature radius of the arc forming the contact face  14  is preferably at least same as that of the curved lower face  12  of the chuck  1 . If the curvature radius of the arc is smaller than that of the lower face of the chuck, contact between the chuck and the support is made according to a two-point support structure, which is too unstable to endure the seating force which is applied downward via the disk. Therefore, the curvature is determined so that the arc face and the lower face can perform face-contact or at least line-contact.  
         [0054]     As shown in  FIG. 6 , the reference mark A indicates an inclination angle of the upper face  11  of the chuck  1 , extended upward from the peak  13 , in respect to an upper horizontal plane. The reference mark B indicates an angle of a lower face of the chuck  1 , extended downward from the peak  13 , in respect to a vertical plane. As shown in  FIG. 7 , the reference mark C indicates an angle of the contact face  14  of the support  2 , which contacts the chuck  1 , in respect to a horizontal plane. These angles are important factors related to the seating force applied to the holder chuck and the restraining force against separation (or detachment) of the disk from the chuck.  
         [0055]     Experiments were performed varying the above three angles to compare seating forces and restraining forces of the holder of the invention with those of a conventional holder structure.  
                                                                                               TABLE 1                                               Mounting   Restraining               Measuring Factors   Force   Force                Group   A(°)   B(°)   C(°)   gf   gf                            1   5   30   0   1400   330               10   30   10   1000   370               12   30   20   800   350               12   30   25   700   400               15   30   20   900   370               15   30   25   900   370           2   5   35   0   1300   400               10   35   10   1050   430               12   35   20   950   450               12   35   25   850   400               15   35   20   700   330               15   35   25   800   360           3   5   40   0   1250   450               10   40   10   900   450               12   40   20   1000   450               12   40   25   900   350               15   40   20   850   320               15   40   25   820   360                      
 
         [0056]     In the above experiments, it is to be noted that first values in respective groups where C is 0 degree indicate seating and restraining forces of the disk measured in the conventional holder structure. That is, the seating force is in a range of about 1400 to 1250 gf, and the restraining force is in a range of about 330 to 450 gf. The holder of the invention can seat the disk under the seating force which is smaller than that of the conventional holder as well as maintain the disk under the restraining force which is larger than that of the conventional holder.  
         [0057]     Where B is 30 degree, the conventional holder has the seating force of about 1400 gf and the restraining force of about 330 gf. If the contact face of the support of the chuck is formed as an inclined face as in the invention, however, the respective seating forces are smaller than those of the conventional holder, wherein C is in a range of about 10 to 25 degree, B is about 30 degree, and A is about 10 to 15 degree. Where A is in a range of about 10 to 15 degree, the respective seating forces are smaller that those of the conventional holder. In this case, the restraining forces are also smaller than those of the conventional holder.  
         [0058]     Similarly, where B is about 35 degree, the seating force of the conventional holder is about 1300 gf and the restraining force thereof is about 400 gf. Also in this case, the seating force is smaller than the conventional holder and the restraining force can maintain a sufficient value. This is same where B is about 40 degree.  
         [0059]     As can be seen in Table 1, where the contact face of the support is inclined, the seating force is reduced compared with that of the conventional holder while the restraining force against separation of the disk can maintain a sufficient value. From the above result, it is possible to determine the configuration of the holder so that the restraining force is larger than that of the conventional holder if the angles A and B are properly adjusted according to the angle C. Where C is about 20 degree, A is about 12 degree, and B is about 35 degree, a result can be obtained that the seating force is about 950 gf and the restraining force is about 450 gf.  
         [0060]      FIG. 8  is a sectional view of an alternative to the holder chuck of the holder for disk drives of the invention. As described above, the holder for disk drives of the invention comprises a support  2  for supporting a chuck  1  which is so constructed to have a face inclined in respect to a horizontal face. As shown in  FIG. 8 , the support  2  can have a contact face including an inclined face  16  and a horizontal face  18  connected with the inclined face  16 .  
         [0061]     According to the afore described contact face structure of the support, downward motion of a disk primarily causes the chuck  1  to perform circular motion, which is followed by downward movement of a peak  13  of the chuck  1 . As directed downward, the peak  13  is moved horizontally backward along the horizontal face  18  of the support.  
         [0062]     This structure further provides horizontal motion to afore described downward or upward circular motion, and advantageously increases the path of the chuck  1 . The holder can be also designed so that the chuck can further project in a forward direction to increase the restraining force against separation of the disk.  
         [0063]      FIG. 9  is a sectional view of another alternative to the holder chuck of the holder for disk drives of the invention. As shown in  FIG. 9 , a support  2  includes an arc face  17  of a predetermined curvature and a horizontal face  19  connected with a rear portion of the arc face  17 . With the support shown in  FIG. 9 , the chuck likewise performs circular motion along the arc face and then horizontal backward motion.  
         [0064]     This structure also increases in effect the path of the chuck as well as enhances the restraining force of the disk as in  FIG. 8 . Further, this structure forms the arc face instead of the inclined face in  FIG. 8  so that friction areas can be increased. As a result, abrasion of the chuck and/or support can be prevented.  
         [0065]     The arc face  17  functions as a contact face of the support  2 , and is so formed that an imaginary straight line connecting between ends of the arc has an angle inclined downward in respect to a horizontal plane. The curvature radius of the arc of the contact face  17  is at least same as that of a curved lower face  12  of the chuck  1 , and preferably larger than that of the curved lower face  12  of the chuck  1 . If the curvature radius of the arc is smaller than that of the lower face of the chuck, contact between the chuck and the support is made according to a two-point support structure, which is too unstable to endure the seating force which is applied downward via the disk. Therefore, the curvature is determined so that the arc face and the lower face can perform face-contact or at least line-contact.  
         [0000]     Guide  
         [0066]      FIG. 10  is a sectional view illustrating elastic coupling of the chuck of the holder for disk drives of the invention. In  FIGS. 4 and 10 , a guide  5  is provided in rear of the chuck  1 . The guide  5  contacts the inside of the hub  3  to restrict vertical motion of the chuck  1 . That is, if the chuck  4  moves downward in  FIG. 4 , an upper face of the guide  5  will contacts an inner upper face of the hub, thereby restricting downward motion of the chuck.  
         [0067]     The guide is placed in rear of the chuck to prevent the chuck from performing circular motion to the extent that it cannot return to the original position. The guide also prevents the chuck from moving excessively upward to the extent that it separates from the hub during detachment of the disk.  
         [0068]     Further, as shown in  FIG. 10 , a spring  4  is connected between a rear portion of the chuck  1  and the inside of the hub. In order to connect the spring with the rear portion of the chuck, spring guides  41  are projected from both of the rear portion of the chuck  1  and the inside of the hub.  
         [0000]     Planar Configuration of Peak  
         [0069]      FIG. 11  is a plan view of a peak portion of the chuck of the holder for disk drives of the invention. The chuck  1  includes upper and lower faces, which are formed at predetermined inclination angles in a vertical cross section of the chuck  1 , and a peak  13  formed at leading edges of the upper and lower faces. The lower face has a curved portion of a predetermined curvature.  
         [0070]     The chuck has a planar configuration as shown in  FIG. 11 . That is, the peak  13  of the chuck  1  on a horizontal plane has a curvature radius same as the radius of a central opening of the disk. The curvature radius of the peak  13  is formed same as the radius of the disk opening to increase the contact area between the peak  13  and the disk. As the contact area between the disk and the chuck is increased, the disk is not readily separated from the holder after seated thereby.  
         [0071]     As afore described, the planar configuration of the chuck has the curvature same as that of the central opening of the disk to provide a structure which can further enhance the restraining force against separation of the disk.  
         [0000]     Prevention of Half Chucking  
         [0072]     The afore described curvature structure of the chuck peak also functions to prevent half chucking in which the chuck is trapped by an intermediate portion of the disk. That is, in the event of seating a double-layer disk  200  such as a DVD disk having two plates stacked one on the other, the peak  13  of the chuck  1  may be trapped by a groove  20  which is formed along the periphery of the central opening of the disk  200  as shown in  FIG. 12 .  
         [0073]     Because the conventional peak is rounded in the shape of a substantial semi-circle at a curvature radius smaller than the radius of the central opening of the disk, the chuck substantially performs a point contact. This causes the force for pushing the hub outward to concentrically act on the disk so that the peak of the chuck is trapped sometimes by the groove  20  of the disk.  
         [0074]     Therefore, the invention provides the horizontal peak plane having a curvature radius same as the radius of the central opening of the disk to disperse elastic force acting on the peak. Further, the vertical cross section of the peak is rounded to have a curvature radius larger than that of the groove  20  of the disk  200 . This configuration also functions to prevent half chucking in which the chuck is trapped by the groove of the disk.  
         [0075]     The process of seating the disk on the holder has been described as above, whereas separation of the disk from the holder will follow a process reverse to the above seating process.  
         [0076]     According to the present invention as set forth above, the support is provided with the inclined face or both the inclined face and the horizontal face so that the chuck performs downward circular motion along a circular path and both circular motion and linear motion in sequence along circular and linear paths so as to enhance the restraining force.  
         [0077]     Further, the present invention improves the configuration of the peak portion in the chuck of the holder to enhance the restraining force while the disk is seated as well as to prevent half chucking in which the chuck is trapped by the intermediate portion of the disk.  
         [0078]     While this invention has been described in connection with the preferred embodiments in the specification of the invention, it is also understood that various modifications and variations can be made without departing from the scope of the invention, which is not restricted to the above described embodiments but shall be defined by the appended claims and equivalents thereof.