Abstract:
The present invention provides a locking mechanism for an external optical disk drive. The locking member is positioned on the upper housing to release or lock the cover. The cover has a projection extending downwardly from its front end and three journals are integrally formed with the cover. Three grooves are defined on the upper housing and sized to receive three corresponding journals of the cover. Besides, both ends of a resilient member are respectively adapted to be received in hubs. The resilient member is restrained by the upper housing and the hubs. Viscous material can be applied between the hubs and the shallow shaft. When the locking member disengages from the opening of the cover, the cover will be opened smoothly due to the viscosity of the viscous material.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a locking mechanism for an external optical disk drive, and in particular to a locking mechanism for releasing or locking a cover of an external optical disk drive. 
   2. Description of the Prior Art 
   Optical disk drives are becoming more popular in the market, and the optical disk drives are considered as standard equipment on personal computer for several years. Generally speaking, optical disk drives are used to read information stored on optical disks. Examples of optical disk drives are known as compact disk drives (CD-ROM drives) and digital versatile disk drives (DVD-ROM drives) in prior art. Some optical disk drives have the additional capability of being able to write data onto an optical disk, i.e., CD-RW drivers. Optical disk drives are used in music and video playback and are implemented in recording devices and other electronic devices. 
   In prior art, the conventional disk drives are categorized into two types: disk-tray disk drive and cover-lifting disk drive. Regarding the disk-tray type disk drive, optical disk can be placed on the disk tray when a disk tray motor pulls the disk tray to what so called pull-out position. As shown in  FIG. 1 , the disk-tray optical disk drive includes a rectangular-shaped slit  1  a surrounding the disk tray. However, due to the slit  1   a , the disk tray may be jammed by foreign objects during loading and ejection of the optical disk. 
   Another type of optical disk drives has an independent housing (often referred as an external type) and is coupled to a host computer via a signal cable to transmit data to the host computer. In addition, the external optical disk drive may transmit music data to the users via an earphone cable. 
     FIG. 2  illustrates a conventional external optical disk drive. Referring to  FIG. 2 , the conventional external optical disk drive includes a cover  1 , an upper housing  2  and a lower housing  3 . 
     FIG. 3  illustrates a cover of the conventional external optical disk drive of  FIG. 2 . Referring to  FIG. 3 , the cover  1  includes a protrusion  11  extending downwardly from its front end, and an opening  12  is defined in the protrusion  11 . A rotary shaft  13  is integrally formed at the rear edge of the cover  1 , and a gear rack  14  is integrally formed with the rotary shaft  13  of the cover  1 . 
     FIG. 4  illustrates the conventional external optical disk drive of  FIG. 2  with the cover  1  opened. Referring to  FIG. 4 , the upper housing  2  is positioned at the lower housing  3 . The rotary shaft  13  of the cover  1  is pivotally coupled to the upper housing  2  so that the cover  1  can be pivoted with respect to the upper housing  2  and the lower housing  3 . To effectively utilize the space occupied by the external optical disk drive, the rotary shaft  13  is not located at a central portion of the rear edge of the cover  1 . 
     FIG. 5  is a perspective view of assembly of the cover  1  and the upper housing  2  of the conventional external optical disk drive as viewed from the bottom of the upper housing  2 . As shown in  FIG. 5 , a locking member  4  indicated by phantom line is defined on the bottom surface of the upper housing  2 . When the cover  1  is closed, the locking member  4  is used to engage with the opening  12  of the protrusion  11  for the purpose of locking the cover  1 . Further referring to  FIG. 5 , a mounting member  21  is positioned on the bottom of the upper housing  2  and is adapted to receive the rotary shaft  13  of the cover  1  and an elastic member  15 . The two ends of the elastic member  15  are respectively restrained by the mounting member  21  and the rotary shaft  13  of the cover  2 . The elastic member  15  is of metallic (plastic) and can be a torsion spring. Besides, the gear rack  14  is adapted to engage with a spur gear (not shown) of the upper housing  2 , so the cover  1  can be pivoted about the mounting member  21  because of a torsional moment of the elastic member  15 . 
   However, as described above, the torsional moment of the elastic member  15  is not applied at the central portion of the rear edge of the cover  1 , thereby causing the deformation of the cover  1 . Even worse, deformation of the cover  1  may be aggravated during shipping when the environmental temperature is high, thereby rendering the optical disk drive unusable. 
   Accordingly, there is a need to develop a locking mechanism for use in an external optical disk drive. 
   SUMMARY OF THE DISCLOSURE 
   It is an object of the present invention to provide a locking mechanism for an external optical disk drive that can effectively eliminate the deformation of a cover. 
   It is another object of the present invention to provide an external optical disk drive having a locking mechanism that is used to release or lock a cover smoothly. 
   In order to accomplish the object of the present invention, the present invention provides a locking mechanism for use in the optical disk drive. The locking member is positioned on the upper housing to release or lock the cover. The cover has a projection extending downwardly from its front end and three journals are integrally formed with the cover. Three grooves are defined on the upper housing and sized to receive three corresponding journals of the cover. Besides, both ends of a resilient member are respectively adapted to be received in hubs. The resilient member is restrained by the upper housing and the hubs. Viscous material is applied between the hubs and the shallow shaft. When the locking member disengages from the opening of the cover, the cover will be opened smoothly and the journals of the cover are subjected to substantially even torsional moment due to the viscosity of the viscous material and resilience of the resilient member. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     The present invention can be fully understood from the following detailed description and preferred embodiment with reference to the accompanying drawings in which: 
       FIG. 1  is a perspective view of a conventional disk-tray optical disk drive; 
       FIG. 2  is a perspective view of a conventional external optical disk drive; 
       FIG. 3  is a perspective view of a cover for use in the conventional external optical disk drive of  FIG. 2 ; 
       FIG. 4  is a perspective view of a conventional external optical disk drive of  FIG. 2  with the cover opened; 
       FIG. 5  is a perspective view of an upper housing of the conventional external optical disk drive of  FIG. 2  as viewed from the bottom of an upper housing; 
       FIG. 6  is a perspective view of an external optical disk drive in accordance with the present invention; 
       FIG. 7  is a perspective view of an external optical disk drive of  FIG. 6  with the cover opened; 
       FIG. 8  is an exploded perspective view of an external optical disk drive of  FIG. 6  as viewed from the bottom of a lower housing; 
       FIG. 9  is an exploded perspective view of an external optical disk drive of  FIG. 6 ; 
       FIG. 10  is an exploded perspective view of an pivotal member of  FIG. 6 ; 
       FIGS. 11 and 12  are cross-sectional view of hubs of the pivotal member of  FIG. 10 ; and 
       FIG. 13  is a cross-sectional view of a hole of the upper housing of  FIG. 6 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The following detailed description is of the best presently contemplated modes of carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating general principles of embodiments of the invention. The scope of the invention is best defined by the appended claims. 
   Although the embodiments of the present invention are described below in connection with external DVD-ROM drives, the present invention can be applied to all optical disk drive, including but not limited to CD-ROM drives, CD-RW drives, DVD-RAM drives, DVD-RW drives, DVD+RW drives, COMBO drives, car audio players, external drives, as well as all other optical media recorders and players. 
     FIG. 6  illustrates an external optical disk drive in accordance with the present invention.  FIG. 7  illustrates an external optical disk drive of  FIG. 6  with the cover  30  opened. For simplicity, a playback unit is removed from the external optical disk drive, and the description about the playback unit is omitted. Referring to  FIG. 6 , the external optical disk drive of the present invention includes a cover  30 , an upper housing  40  and a lower housing  50 . Referring to  FIG. 7 , the cover  30  includes a protrusion  31  extending downwardly from its front end, and an opening  32  is defined in the protrusion  31 . In addition, the upper housing  40  is positioned at the lower housing  50 . Thus, the cover  30  can be pivoted with respect to the upper housing  40  and the lower housing  50  while the cover  30  is opened. 
     FIGS. 8 and 9  are exploded perspective views of the external optical disk drive in accordance with the present invention.  FIGS. 8 and 9  best illustrate the interconnections of various components of the present invention. Referring to  FIG. 8 , the external optical disk drive of the present invention has a locking member  60  that is indicated by phantom line and is defined on the bottom surface of the upper housing  40 . The external optical disk drive also has a pivotal member  70  including hubs  71  and  72 , a hallow shaft  73  and a resilient member  74 . The resilient member  74  can be made of, but not limited to metal, plastic, stainless steel or brass etc. As described above, the lower housing  50  and the locking member  60  of the present invention can be the same as the lower housing  3  and the locking member  4  of the conventional external optical disk drive. When the cover  30  is closed, the locking member  60  is used to engage with the opening  32  of protrusion  31  for the purpose of locking the cover  30 . 
   Further referring to  FIG. 8 , three journals  33 ,  34  and  35  are defined on the bottom surface of the cover  30  and integrally formed with the cover  30 . Referring to  FIG. 9 , a rotary socket  44  is integrally formed with the upper housing  40  and positioned at the rear end of the upper housing  40 . Three grooves  41 ,  42  and  43  of the rotary socket  44  correspond to the journals  33 ,  34  and  35  of the cover  30 . As used herein, the term “front” shall mean adjacent or towards a front wall  51  of the lower housing  50 , and the term “rear” shall mean adjacent or towards a rear wall  52  of the lower housing  50 . 
     FIG. 10  is an expanded perspective view of the pivotal member  70  in accordance with the present invention. The hubs  71  and  72  can be identical, and the hub  71  has a hole  75  that is sized to receive an extension  77  of the hallow shaft  73 . Like the hub  71 , the hub  72  also has a hole  76  that is sized to receive an extension  78  of the hallow shaft  73 . The resilient member  74  is substantially straight and has two triangle-shaped portions  741  and  742 , and the hallow shaft  73  is sized to receive the resilient member  74 . 
     FIG. 11  is a cross sectional view of the hub  71  of the  FIG. 10  as viewed from arrow A. Referring to  FIG. 11 , a slot  752  is defined within the hole  75  and integrally formed with the hub  71 . Besides, a protrusion  751  is integrally formed with the hub  71 . Like the hub  71 , a slot  762  is defined within the hole  76  and integrally formed with the hub  72  as shown in  FIG. 12 . Besides, a protrusion  761  is integrally formed with the hub  72 . 
   Further referring to  FIG. 9 , a hole  45  is integrally formed with the rotary socket  44  and is indicated by a solid line. Besides, the cross section of the hole  45  of the rotary socket  44  is substantially same as that of the hubs  71  and  72 , and the hole  45  of the rotary socket  44  is sized to receive the pivotal member  70 . The cross-section view of the hole  45  of the rotary socket  44  is shown in  FIG. 13 , and cross-section views of holes  36  and  37  of the journals  33  and  34  are substantially same as that of the hole  45 . In accordance with the present invention, the pivotal member  70  can be inserted into the hole  45  of the upper housing  40  in the direction of arrow A of  FIG. 8 . Thus, the cover  30  can be pivoted with respect to the upper housing  40  and the lower housing  50  by the pivotal member  70 . 
   To insert the pivotal member  70  into the hole  45  of the rotary socket  44  of the upper housing  40 , the resilient member  74  is fitted to the hole  79  of the hallow shaft  73  along the direction of arrow A of  FIG. 10 . The slot  752  of the hub  71  is sized to receive the triangle-shaped portion  741  of the resilient member  74 , and the extension  77  of the hallow shaft  73  is fitted to the hole  75  of the hub  1 . Then, the triangle-shaped portion  742  of the resilient member  74  is fitted to the slot  762  of the hub  72 , and the extension  78  of the hallow shaft  73  is fitted to the hole  76  of the hub  72 . Before the pivotal member  70  is fitted to the hole  45  of the rotary socket  44  of the upper housing  40 , the three journals  33 ,  34  and  35  of the cover  30  are positioned on corresponding three grooves  41 ,  42  and  43  of the upper housing  40 . 
   Furthermore, the protrusion  751  of the hub  71  can be in alignment with protrusions  731  and  732  of the hallow shaft  73 , and the protrusions  731  and  732  respectively correspond the grooves  41  and  42  of the upper housing  40 . When the cross section of the hub  71  matches that of the hole  45  of the rotary socket  44  of the upper housing  40 , the pivotal member  70  can be fitted to the hole  45  of the upper housing  40  along the direction of arrow A of  FIG. 9 . Before the hub  72  of the pivotal member  70  is fitted to the hole  45  of the rotary socket  44  of the upper housing  40 , the hub  72  is clockwise rotated around the axis of the arrow A and aligns with the hole  45  again. Thus, a torsional moment of the resilient member  74  is produced during the installation of the pivotal member  70 . The journals  33  and  34  of the cover  30  hold the protrusions  731  and  732  of the hallow shaft  73 , and the protrusions  731  and  732  can respectively rotate within the grooves  41  and  42  due to the resilience of the resilient member  74 . Then, referring to  FIGS. 8 and 9 , a pin  46  is fitted to a hole  38  of the journal  35  of the cover  30  and the hole  45  of the rotary socket  44  of the upper housing  40 , thereby causing the cover  30  being pivotally coupled to the upper housing  40 . 
   Further referring to  FIGS. 8 and 9 , when the cover  30  is closed, the locking member  60  is used to engage with the opening  32  of the protrusion  31  for the purpose of locking the cover  30 . When the cover  30  is released by the locking member  60 , the hallow shaft  73  together with the cover  30  will be pivoted around the axis of the arrow A because of the resilience of the resilient member  74 . Because the hubs  71  and  72  are restrained by the rotary socket  44  of the upper housing  40 , the upper housing  40  will not be rotated when the cover  30  is opened. In addition, viscous material can be applied on the extensions  77  and  78  of the hallow shaft  73 . Viscous material can be made of, but not limited to grease or lubricant. As described above, when the cover  30  is released by the locking member  60 , the cover  30  substantially pivots at a slower speed because of viscosity of viscous material. In this regard, when user would like to open the cover  30  of the optical disk drive, the cover  30  cannot cause potential injury to the user. 
   While the invention has been described with reference to the preferred embodiments, the description is not intended to be construed in a limiting sense. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as may fall within the scope of the invention defined by the following claims and their equivalents.