Abstract:
Provided is a case for a portable electronic device. The case includes an outer part; an inner part coupled to an inner surface of the outer part and including a plurality of holes; and fastening members, each including a main body having an outer diameter corresponding to an inner diameter of the hole in the inner part and a flange portion, wherein the flange portion is connected to an end portion of the main body, has an outer diameter greater than the outer diameter of the main body to be depressed into the inner part.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
       [0001]    This application claims the benefit of Korean Patent Application No. 10-2005-0135903, filed on Dec. 30, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to a case for a portable electronic device. More particularly, the present invention relates to a case having improved reliability, durability, and reinforcing an assembling property with inner elements. 
         [0004]    2. Description of the Related Art 
         [0005]    Cases (also known as housings) made of plastic or magnesium, which are relatively inexpensive and have high plasticity and workability, are conventionally used for portable electronic devices such as mobile phones, digital cameras, laptop computers, MP3 players and portable media players (PMPs) to enclose and protect internal components of the portable electronic devices. However, in line with demands for sophistication of cases, diversification of materials for forming the cases, differentiation from other cases, increase of mass-production, and users&#39; requests for certain form-factors or esthetics, metal cases have been developed that include thin metal plates formed of aluminum, stainless steel, or titanium. 
         [0006]    Fastening members such as bosses are typically configured inside a case to couple inner elements to the case and/or couple portions of the case together (e.g., front and back housing portions). Conventionally, threaded bosses are attached onto an inner surface of a thin metal plate case using an electric welding process, however, welded bosses may be separated from the surface due to a deformation of the thin plate or external shocks. Meanwhile, a plastic case can be attached onto an inner surface of an outer thin metal plate case so that bosses can be coupled to the plastic case. However, a coupling force between the inner plastic case and the metal boss is weak. In addition, if bosses formed of a plastic material are used, strength of a screw tap in the boss is degraded. 
         [0007]    Due to the above problems, a metal case is mainly used to support a plastic case, that is, to decorate, reinforce the structure of the case, or protect a liquid crystal display (LCD) window. Therefore, in order to use a metal case, an assembling property with fastening members in the case and the durability of the case must be improved. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention provides a metal case for a portable electronic device, the case having an improved durability and an improved assembling property with fastening members in the case. 
         [0009]    According to an aspect of the present invention, there is provided a case for a portable electronic device including an outer part; an inner part coupled to an inner surface of the outer part and including a plurality of holes; and fastening members extending through the holes to be coupled to the inner case. 
         [0010]    Each of the fastening members may include: a main body having an outer diameter corresponding to an inner diameter of the hole in the inner part; and a flange portion, which is connected to an end portion of the main body, that includes an outer diameter greater than the outer diameter of the main body, and is to be connected to the inner part. 
         [0011]    The inner part may include a depressed area about each hole on its outer surface, and the depressed area may be configured to receive the flange portion of the fastening member so that the outer surface of the inner part can be in intimate contact with the inner surface of the outer part. Alternatively, the flange portion may be depressed onto the outer surface of the inner part after heating the inner part to a softening temperature. In another alternative, the fastening member may be formed of a material that is harder than a material of the inner part so that softening of the inner part is not required. In yet another alternative, the fastening member and the inner part may be coupled by welding the flange portion onto a portion of the inner part corresponding to the flange portion. 
         [0012]    Each of the fastening members may further include: a rotation prevention portion that prevents the fastening member from rotating relative to the inner part. The rotation prevention portion may be formed on at least a part of the fastening member that contacts the inner part. The rotation prevention portion may be formed on an edge of the flange portion. Furthermore, the rotation prevention portion may include one or more protrusions. Moreover, the rotation prevention portion may be formed on an outer surface of the main body adjacent to the flange portion. In some embodiments, the rotation prevention portion may be provided by the flange portion that includes a polygonal perimeter. 
         [0013]    The outer part of the case/housing may include a frontal outer part and a rear outer part, and the inner part includes a frontal inner part and a rear inner part. In one embodiment, the frontal inner part includes a protrusion portion on a lateral edge and the rear inner part includes a receiving portion on a lateral edge so that the protrusion portion and the receiving portion are coupled to each other. The protrusion portion may include a convex portion formed perpendicularly to the protruding direction and the receiving portion includes a concave portion corresponding to the convex portion so that the receiving portion and the protrusion portion are fixed to each other by the convex portion and the concave portion. In another embodiment, the frontal inner part includes a receiving portion on a lateral edge and the rear inner part includes a protrusion portion on a lateral edge so that the protrusion portion and the receiving portion are coupled to each other. The protrusion portion may include a convex portion formed perpendicularly to the protruding direction and the receiving portion includes a concave portion corresponding to the convex portion so that the receiving portion and the protrusion portion are fixed to each other by the convex portion and the concave portion. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a partially exploded perspective view of a frontal part of a metal case according to an embodiment of the present invention; 
           [0015]      FIG. 2  is a cross-sectional view of an inner coupling structure in the metal case of  FIG. 1 ; 
           [0016]      FIG. 3A  is a cross-sectional view illustrating coupling of a fastening member to an inner part of the metal case of  FIG. 1 ; 
           [0017]      FIG. 3B  is a bottom view of the inner part of the metal case of  FIG. 1  with the fastening member coupled thereto; 
           [0018]      FIG. 4  is a perspective view of a first embodiment of a fastening member; 
           [0019]      FIG. 5  is a perspective view of a second embodiment of a fastening member; 
           [0020]      FIGS. 6A and 6B  are a perspective view and a cross-sectional view of a third embodiment of a fastening member; 
           [0021]      FIG. 7  is a perspective view of a fourth embodiment of a fastening member; 
           [0022]      FIG. 8  is a perspective view of the inner part of the metal case of  FIG. 1  showing embossed portions formed thereon; 
           [0023]      FIG. 9  is a cross-sectional view of the inner part of  FIG. 8 , taken along line IX-IX; 
           [0024]      FIG. 10  is a partially exploded perspective view showing assembly of the metal case of  FIG. 1 ; and 
           [0025]      FIG. 11  is a cross-sectional view of the metal case of  FIG. 10  taken along line XI-XI. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    Referring now to the Figures,  FIG. 1  is a partially exploded perspective view of a frontal part  10  ( FIG. 10 ) of a metal case according to an embodiment of the present invention, and  FIG. 2  is a cross-sectional view of an inner coupling structure in the metal case of  FIG. 1 . Referring to  FIGS. 1 and 2 , the frontal part  10  ( FIG. 10 ) includes an inner part  12 , to which bosses  14  are coupled, and an outer part  11 . The inner part  12  and the outer part  11  are formed by, for example, a pressing method, of a metal material such as aluminium, stainless steel, or titanium. Fastening members such as the bosses  14 , ribs, hooks may also be formed of the same metal material when the inner part  12  is formed. The bosses  14  extend through a plurality of holes  12   a  formed in the inner part  12 . The bosses  14  may be fixed to the inner part  12  using thermal bonding, gluing or the like. After fixing the bosses  14  to the holes  12   a  of inner part  12 , the inner part  12  is fixedly coupled to the outer part  11  using a welding process, for example, spot welding, arc spot welding, or laser beam welding. In particular, since the inner part  12  and the outer part  11  are formed of the same metal and have large bonding areas, the spot welding can be performed many times to improve an adhesive force between the inner part  12  and the outer part  11 . 
         [0027]    Hereinafter, a process of coupling fastening members such as the bosses  14  to the inner part  12  will be described. In the drawings, the bosses  14  are shown as an example of suitable fastening members, however, the fastening members can be any members, such as ribs or hooks, for supporting and coupling inner elements onto the metal case  11 ,  31  ( FIG. 10 ).  FIG. 3A  illustrates an example process of coupling the boss  14  to the inner part  12 , and  FIG. 3B  is a bottom view of the inner part  12  to which the boss  14  was coupled. An example process of connecting the fastening member to the inner part  12  will now be described with reference to  FIGS. 3A and 3B . As shown in  FIG. 3A , an outer diameter of a main body  14   a  of the boss  14  corresponds substantially to a diameter of a hole formed in the inner part  12 . A diameter of a flange portion  14   b  formed on the lower portion of the main body  14   a  is larger than the outer diameter of the main body  14   a , and a thickness or height of the flange portion  14   b  is smaller than that of the inner part  12 . In some instances, the boss  14  may be formed of a material that is harder than the material of the inner part  12 . Thus, as shown in  FIG. 3A , when the boss  14  is inserted into the hole  12   a  of the inner part  12 , the flange portion  14   b  may bite into or otherwise deform the inner part  12  so that the bottom surface of inner part  12  is substantially planar for intimate contact with the outer part  11 . In addition, as shown in  FIG. 4 , rotation prevention portions  14   c  formed as saw teeth may be formed on an outer circumferential portion of the flange portion  14   b , and the flange portion  14   b  can be inclined toward the outer portion thereof (e.g., generally frustoconically-shaped). As shown in  FIG. 5 , the rotation prevention portions  14   c  formed on the flange portion  14   b  as saw teeth may be configured to be planar or otherwise have a constant height. 
         [0028]    In some instances, to fixedly couple the bosses  14  to the inner part  12 , the main body  14   a  of each of the bosses  14  is inserted into the hole  12   a  ( FIG. 1 ) in the inner part  12 , and then, the inner part  12  is heated to a softening temperature, after which the inner part  12  and the boss  14  are pressed together to deform the inner part  12 . At this time, upon heating the inner part  12  formed of a material softer than that of the boss  14 , the inner part  12  is depressed so as to correspond to the shape of the flange portion  14   b  during pressing, and then, fixedly coupled to the boss  14  in the depressed state. The rotation prevention portions  14   c  formed as saw teeth thus bites into the inner portion  12  to prevent rotation of the boss  14 . As will be discussed hereinafter, the rotation prevention portions  14   c  may be configured otherwise to prevent rotation, for example with a polygonal or non-circular perimeter for the flange portion  14   b.    
         [0029]    Another example method of coupling the fastening member to the inner part  12  according to another embodiment of the present invention is to insert a main body  14   a  of the boss  14  into the hole of the inner part  12 , and to couple the flange portion  14   b  to an abutment surface of the inner part  12  using a welding process. A spot welding or a laser beam welding can be used. Here, in order to perform the welding process easily, an upper surface of the flange portion  14   b  can be parallel, instead of being inclined as shown in  FIG. 3A . Of course, coupling of the boss  14  with the inner part  12  may be accomplished by other methods, for example adhesive bonding, cohesive bonding, etc. 
         [0030]    Meanwhile, a bottom surface of the boss  14 , that is, of the flange portion  14   b , and a bottom surface of the inner part  12  are substantially the same height as each other so that the bottom surfaces are coplanar for intimate contact with the outer part  12 . As shown in  FIG. 3A , the flange portion  14   b  can be pushed upward into the inner part  12  for the inner part  12  to be depressed so that an upper surface of the inner part  12  can be flat. Otherwise, the flange portion  14   b  can push the inner part  12  upward so that a portion around the hole in the inner part  12  can be curved upward. This is dependent on the thickness of the inner part  12  and a degree of hardness of the material forming the inner part  12 . 
         [0031]    In addition, the inner part  12 , to which the bosses  14  are fixed, and the outer part  11  are fixedly coupled to each other using the welding method. The inner part  12  can reinforce the structure of the outer part  11  so that a utility function of the thin metal plate case can be improved. In addition, since the fastening members are not directly coupled to the outer part  11  but are instead coupled to the inner part  12 , an outer appearance of the outer part  11  is not deteriorated. 
         [0032]    Since the saw-tooth type rotation prevention portions  14   c  protrude from an edge of the flange portion  14   b , the rotation of bosses  14  after performing the coupling process can be prevented. In addition, the flange portion  14   b  of the boss  14  is held captive between the inner part  12  and the outer part  11  once the inner part  12  and the outer part  11  are coupled, and thus, the boss  14  is not separated from the parts  11  and  12  even if an external shock is applied thereto. Also, since the assembling property between the boss  14  and the parts  11  and  12 , as can be appreciated, there is no limitation in a height or a diameter of the boss  14  so that various types of inner elements can be appropriately accommodated in the metal case. 
         [0033]    The rotation prevention portions  14   c  can be formed on the edge of the flange portion  14   b  as shown in  FIGS. 4 and 5 . However, as shown in  FIGS. 6A and 6B , the rotation prevention portions  14   c  can be formed on a boundary between the flange portion  14   b  and the main body  14   a , that is, an outer surface of the main body  14   a , which is close to the flange portion  14   b . In addition, although four rotation prevention portions  14   c  are shown in  FIG. 6B , fewer or additional rotation prevention members  14   c  can be provided. Moreover, the flange portion  14   b  is not necessarily formed as a circle, and as shown in  FIG. 7 , a flange portion  24   b  can be formed as a polygon having a perimeter that is greater than an outer circumference of a main body  24   a . Because the flange portion  24   b  is non-circular, has a perimeter that is greater than a diameter of the hole  12   a  ( FIG. 1 ), and is depressed into the inner part  12  during coupling thereto, the polygonal flange portion  24   b  cannot rotate. 
         [0034]      FIG. 8  is a perspective view of embossed portions formed on the inner part  12  according to an embodiment of the present invention, and  FIG. 9  is a cross-sectional view of the inner part  12  on which an embossed portion is formed, taken along line IX-IX of  FIG. 8 . The embossed portions  12   a  protruding from the inner part  12  can reinforce the strength of the inner part  12 , and thus, a thickness of the inner part  12  and a weight of the metal case can be reduced. 
         [0035]      FIG. 10  is a partially exploded perspective view showing the metal case of  FIG. 1  after coupling a protrusion portion  13  of the frontal part  10  with a receiving portion  33  of a rear part  30  of the metal case, and  FIG. 11  is a cross-sectional view of the metal case of  FIG. 10  taken along line XI-XI of  FIG. 10 . Referring to  FIGS. 10 and 11 , the protrusion portion  13  protruding toward the rear part  30  is formed on a lateral edge of the frontal inner part  12  that is coupled to the outer part  11 . The receiving portion  33  that can receive the protrusion portion  13  is formed on a lateral edge of a rear inner part  32  that is coupled to a rear outer part  31 . Additionally a convex portion  13   a  is formed on an inner side of the protrusion portion  13  and a concave portion  33   a  is formed on the receiving portion  33  to correspond to the convex portion  13   a . Thus, the convex portion  13   a  is inserted into the concave portion  33   a  when the protrusion portion  13  is coupled with the receiving portion  33 . Therefore, the frontal part  10  and the rear part  30  of the metal case become removably coupled to each other. 
         [0036]    In contrast to the configuration shown in  FIG. 10 , the frontal and rear parts  10 ,  30  may be configured vice versa with respect to the convex portion  13   a  and the concave portion  33   a  and/or the protrusion portion  13  and receiving portion  33 . For example, a protrusion portion protruding toward the frontal part  10  can be formed on a lateral edge of the rear inner part  32  that is coupled to the rear outer part  31 . A receiving portion that can receive the protrusion portion can be formed on a lateral edge of a frontal inner part  12  that is coupled to the frontal outer part  11 . Additionally, a convex portion is formed on an inner side of the protrusion portion and a concave portion is formed on the receiving portion to correspond to the convex portion. Thus, the convex portion can be inserted exactly into the concave portion when the protrusion portion is inserted into the receiving portion. Therefore, the frontal part and the rear part of the metal case can be exactly arranged and fixed to each other. 
         [0037]    In the above embodiments, the outer part  11  and the inner part  12  of the metal case are formed of metal, however, the present invention is not limited thereto. For example, the outer part  11  can be formed of a non-metallic material, and accordingly, the outer part  11  and the inner part  12  can be coupled to each other appropriately. 
         [0038]    While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.