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CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    Pursuant to 35 U.S.C. §119(a), this application claims the benefit of earlier filing date and right of priority to the Korean Patent Application No. 2002-75485, filed on Nov. 29, 2002, the content of which is hereby incorporated by reference in its entirety. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to a hinge apparatus for a mobile communication terminal, and more particularly, to a hinge apparatus for a folding type mobile communication terminal that facilitates user manipulation of the opening angle between the first and second bodies.  
           [0004]    2. Description of Related Art  
           [0005]    In general, mobile communication terminals include cellular phones or Personal Communication Systems (PCS) having wireless communication capabilities. As the need for smaller devices for communication grows, several folding type mobile communication terminals having clam-shell designs have been suggested to satisfy this demand.  
           [0006]    Referring to FIG. 1, a folding type mobile terminal is shown. The folding type conventional mobile terminal comprises a lower body  1 , on which one or more terminal manipulation devices  1   a , for example buttons, are disposed on the upper surface of the lower body  1 . A hinge H is installed on the top edge of the upper surface and rotatively couples the upper body  2  of the terminal. A display screen  2   a  is disposed on the lower surface of the upper body  2  to display message and terminal information. Benefits of the folding type construction of mobile communication terminal include additional protection of the display screen  2   a  and terminal manipulation devices la from physical damage and exposure to moisture. Also, the overall size of the terminal is reduced, thereby reducing the carrying burden on the user and facilitating transportation.  
           [0007]    Several types of a hinge apparatus have also been suggested for folding type mobile communication terminals. In FIGS.  2 - 3 B, a click hinge apparatus according to the related art is shown. A first hinge housing  1   b  is formed on opposing side edges of the lower body  1  of the terminal. A first hinge member  11  is inserted into the first hinge housing  1   b . A second hinge housing  2   b  is formed on the lower side edge of the upper body  2  of the terminal. A second hinge member  12  is inserted into the second hinge housing  2   b . Hinge contact surfaces  1   c  and  2   c  are formed on the inner surfaces of the first and second hinge housings  1   b  and  2   b , respectively. Rotation-preventing surfaces  11   a  and  12   a , which are formed on the outer circumferential surfaces of the first and second hinge members  11  and  12 , respectively, engage the hinge contact surfaces  1   c  and  2   c , respectively, to prevent axial rotation of the hinge members  11  and  12 . A shaft  14  supports a spring  13  and the first and second hinge members  11  and  12 .  
           [0008]    Opposing surfaces of the first and second hinge members  11  and  12  each contain corresponding concave (  11   c ,  12   b ) and convex ( 11   b ,  12   c ) portions. The elastic force of the spring  13  ensures contact between the concave portion  11   c  and convex portion  12   b  and between the concave portion  12   c  and the convex portion  1   b , thereby “locking” the terminal in a folded or unfolded state. Consequently, when a user folds or unfolds the terminal, the second hinge member  12  rotates with the upper body  2  of the terminal (as indicated by the rotational arrow in FIG. 3A). Accordingly, the convex portion of the second hinge member  12   b  pushes against the convex portion  11   b  of the first hinge member  11  during rotation, thereby compressing the spring  13  (as indicated by the direction arrow in FIG. 3A). As the convex portion  12   b  passes over the convex portion  11   b , the elastic force of the spring  13  restitutes the first and second hinge members so that the convex portions  11   c  and  12   b  engage the concave portions  11   b  and  12   c.    
           [0009]    In FIGS.  4 - 5 B, a free stop hinge apparatus according to related art is shown. Similar to the click hinge apparatus described above, the free stop hinge apparatus for a folding type mobile communication terminal includes: first and second hinge housings  1   b ,  2   b ; first and second hinge members  15 ,  16 ; first and second hinge contact surfaces  1   c ,  2   c ; and first and second rotation-preventing surfaces  15   a ,  16   a . A shaft  18  supports a spring  17 , and first and second hinge member  15  and  16 . When the hinge contact surfaces  1   c  and  2   c  engage the rotation-preventing surfaces  15   a  and  16   a , respectively, axial rotation of the first and second hinge members  15  and  16  is prevented within the first and second hinge housings  1   b  and  2   b , respectively.  
           [0010]    Opposing surfaces of the first and second hinge members  15  and  16  contain guiding surfaces  15   b  and  16   b , respectively. The guiding surface  15   b  includes a groove  15   c , which corresponds to and engages with a protrusion  16   c  on the guiding surface  16   b . The elastic force of the spring  17  ensures contact between the guiding surfaces  15   b  and  16   b  so that when the protrusion  16   c  is operationally engaged with the groove  15   c , the terminal is “locked” in a folded or unfolded state. Consequently, when a user folds or unfolds the terminal, the second hinge member  16  rotates with the upper body  2  of the terminal (as indicated by the rotational arrow in FIG. 5A). Accordingly, the protrusion  16   c  disengages the groove  15   c , thereby compressing the spring  17  (as indicated by the direction arrow in FIG. 5A). The elastic force of the spring  17  creates friction between the protrusion  16   c  and the guiding surface  15   b  during rotation. This frictional force allows a user to maintain a desired opening angle when unfolding or folding a terminal.  
           [0011]    As shown by the click hinge apparatus, when the user unfolds the terminal, the opening angle created by the upper and lower bodies of the terminal is maximized. Although this type of hinge apparatus may prevent unintentional folding and unfolding of the terminal, a user cannot maintain privacy when utilizing the terminal for non-voice communications, such as text messaging.  
           [0012]    With respect to a free stop hinge apparatus, friction between moving parts within the hinge is utilized to allow the user to maintain an opening angle that is neither the maximum (i.e., fully open) or the minimum (i.e., fully closed). Unfortunately, general erosion by friction of such moving parts after repetitive movement occurs, thereby decreasing the effectiveness of friction as a single and only means for angle control and locking.  
           [0013]    Therefore, an improved solution is required to effectively allow a user to manipulate the opening angle of a folding type mobile communication terminal.  
         SUMMARY OF THE INVENTION  
         [0014]    Accordingly, the present invention is directed to a hinge apparatus for a folding type mobile communication terminal that substantially obviates one or more problems due to limitations and disadvantages of the related art above.  
           [0015]    An object of the present invention is to provide a hinge apparatus of a folding type mobile communication terminal, wherein the opening angle can be controlled by the user.  
           [0016]    Another object of the present invention is to provide a hinge apparatus of a folding type mobile communication terminal, wherein convenience in folding and unfolding the terminal is improved.  
           [0017]    Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.  
           [0018]    To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a mobile communication terminal comprising a first body, a second body and a hinge apparatus, which rotatively couples the first body to the second body. The hinge apparatus comprises a first hinge unit; a second hinge unit; a coupling hinge member disposed between the first and second hinge units; and a rotation control device.  
           [0019]    According to one aspect of the present invention, the first hinge unit comprises a first hinge housing formed approximate to a side edge of the first body, and a first hinge member inserted into the first hinge housing. Also, the second hinge unit comprises a second hinge housing formed approximate to a bottom edge of the second body, a second hinge member inserted into the second hinge housing, and a spring disposed adjacent to the second hinge member in the second hinge housing.  
           [0020]    According to another aspect of the present invention, guiding surfaces are formed on opposing surfaces of the first hinge member and coupling hinge member. Furthermore, a groove is formed on the guiding surface of the first hinge member and engages a corresponding protrusion formed on the guiding surface of the coupling hinge member.  
           [0021]    According to another aspect of the present invention, a convex portion and a concave portion are each formed on opposing surfaces of the coupling hinge member and the second hinge member such that the convex and concave portions of the coupling hinge member correspond to the concave and convex portions, respectively, of the second hinge member.  
           [0022]    According to another aspect of the present invention, the terminal may further comprise rotation-preventing surfaces formed on a circumferential surface of each of the first, second and coupling hinge members. Furthermore, first and second hinge contact surfaces are formed on an inner surface of each of the first and second hinge housing members, respectively. The first and second hinge contact surfaces engage the rotation-preventing surfaces of the first and second hinge members, respectively, to prevent rotation of the first and second hinge members, respectively.  
           [0023]    According to another aspect of the present invention, the rotation control device may comprises a cap receiving portion formed on an inner surface of the first hinge housing; a rotation control cap; a cap receiving groove formed on the cap receiving portion; a cap protrusion formed on a outer circumferential surface of the rotation control cap; a female screw thread formed on an inner circumferential surface of the rotation control cap; and a male screw thread formed on a circumferential surface of the first hinge member. The rotation control cap has an exposed portion to serve as a receiving point for torque applied by a user. Also, the cap receiving groove receives the cap protrusion and the male screw thread engages the female screw thread of the rotation control cap.  
           [0024]    According to one aspect of an alternative embodiment of the present invention, a protrusion is formed on each of the inner surfaces of the first hinge housing and rotation control caps such that the protrusion formed on the inner surface of the first hinge housing prevents lateral movement of the rotation control cap towards the second hinge housing.  
           [0025]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to further describe the invention as claimed. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]    The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.  
         [0027]    In the drawings:  
         [0028]    [0028]FIG. 1 illustrates a perspective view of a folding type mobile communication terminal according to the related art;  
         [0029]    [0029]FIG. 2 illustrates a disassembled perspective view of a hinge apparatus according to the related art;  
         [0030]    [0030]FIGS. 3A and 3B illustrate sectional views of the hinge apparatus of FIG. 2 during operation;  
         [0031]    [0031]FIG. 4 illustrates a disassembled perspective view of a hinge apparatus according to the related art;  
         [0032]    [0032]FIGS. 5A and 5B illustrate sectional views of the hinge apparatus of FIG. 4 during operation;  
         [0033]    [0033]FIG. 6 illustrates a perspective view of a folding type mobile communication terminal with a hinge apparatus according to one embodiment of the present invention;  
         [0034]    [0034]FIG. 7 illustrates a disassembled perspective view of a hinge apparatus according to one embodiment of the present invention;  
         [0035]    [0035]FIG. 8 illustrates a sectional view of a hinge apparatus according to one embodiment of the present invention;  
         [0036]    [0036]FIG. 9 illustrates a cross sectional view of the hinge apparatus along line I in FIG. 4;  
         [0037]    [0037]FIG. 10 illustrates a cross sectional view of the hinge apparatus along line II in FIG. 4;  
         [0038]    [0038]FIG. 11 illustrates a cross sectional view of the hinge apparatus along line III in FIG. 4;  
         [0039]    [0039]FIGS. 12A and 12B illustrate sectional views of a hinge apparatus, according to one embodiment of the present invention, during operation;  
         [0040]    [0040]FIGS. 13A and 13B illustrate sectional views of a hinge apparatus, according to one embodiment of the present invention, during operation; and  
         [0041]    [0041]FIG. 14 illustrates a sectional view of a hinge apparatus, according to an alternative embodiment of the present invention, during operation.  
         [0042]    Features, elements, and aspects of the invention that are referenced by the same numerals in different figures represent the same, equivalent, or similar features, elements, or aspects in accordance with one or more embodiments. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0043]    Reference will now be made in detail to one or more embodiments of the invention, examples of which are illustrated in the accompanying drawings.  
         [0044]    In FIG. 6, a folding type mobile communication terminal with a hinge apparatus  100 , in accordance with one embodiment of the present invention, is illustrated. The terminal comprises a first body  1  on which one or more terminal manipulation devices  1   a , for example buttons, are disposed on an inner surface of the first body  1 . The hinge apparatus  100 , which is situated on the top edge of the inner surface of the first body  1 , rotatively couples the first body  1  to the second body  2 . A screen display  2   a , such as a liquid crystal display screen, for example, is disposed on the inner surface of the second body  2  to provide message and terminal information to the user.  
         [0045]    Referring to FIGS. 7 and 8, the hinge apparatus  100  comprises a first hinge housing  1   b  disposed on preferably both opposing side edges of the first body  1 , on its inner surface and approximate to the top edge. A first hinge member  110  is inserted into the first hinge housing  1   b . A second hinge housing  2   b  is formed approximate to the center of the bottom edge of the second body  2 . A second hinge member  120  is inserted into the second hinge housing  2   b . A coupling hinge member  130  is installed between the first hinge member  110  and the second hinge member  120 . The coupling hinge member  130  is selectively engaged by the user to rotate with either the first hinge housing  1   b  or the second hinge housing  2   b , as described in greater detail below.  
         [0046]    A spring  140  is installed adjacent to the second hinge member  120  opposite the coupling hinge member  130 . A shaft  141  is installed in the second hinge housing  2   b  and passes through the centers of the spring  140 , the second hinge member  120 , and the coupling hinge member  130 . The second hinge member  120  and the coupling hinge member  130  to slidingly move along the shaft  141 .  
         [0047]    A rotation control device  150  is installed on the outer edge of the first hinge housing  1   b . Manipulation of the rotation control device  150  engages the device  150  with the first hinge member  110  so as to operationally engage and rotate the coupling hinge member  130 .  
         [0048]    The rotation control device  150  comprises a cap receiving portion  151  formed on the inner surface of the first hinge housing  1   a , which receives the rotation control cap  152 . A cap receiving groove  154  is formed on the cap receiving portion  151  and engages with a protruding cap thread  155 , which is formed on the circumferential surface of a rotation control cap  152 . The operational relationship of the receiving groove  154  and the protruding cap thread  155  prevents the rotation control cap from disengaging with the terminal as well as preventing the first hinge member  110  from falling out of the first hinge housing  1   b . Female screw threads  152   a  are formed on the inner circumferential surface of the rotation control cap  152  and engage male screw threads  113  formed on the circumferential surface of the first hinge member  110 . The exposed portion  152   b  of the rotation control cap  152  is preferably fitted with gripping means, such as knurls for example, to prevent slippage when rotating the cap  152 .  
         [0049]    Guiding surfaces  112  and  132  are formed on opposing surfaces of the first hinge member  110  and the coupling hinge member  130 , respectively. A groove  112   a  is formed, preferably diametrically, on the guiding surface  112 . Correspondingly, a protrusion  132   a , which engages the groove  112   a , is formed, preferably diametrically, on the guiding surface  132 . Furthermore, a convex portion  122   a  and a concave portion  122   b  are formed on a guiding surface  122  of the second hinge member  120 . The guiding surface  122  is opposite a guiding surface  133  of the coupling hinge member  130 . A concave portion  133   a  and convex portion  133   b  are formed on the guiding surface  130  to correspond and operationally engage with the convex portion  122   a  and concave portion  122   b , respectively.  
         [0050]    Referring to FIGS.  9 - 11 , a first hinge member contact surface  1   c  is formed on the inner surface of the first hinge housing  1   b . Similarly, a second hinge member contact surface  2   c  is formed on the inner surface of the second hinge housing  2   b . Rotation-preventing surfaces  111  and  121 , are formed on the circumferential surfaces of the first and second hinge members  110 ,  120 , respectively. Preferably, the rotation-preventing surface  111  is formed on the circumferential surface of the first hinge member  110  adjacent to the male screw threads  113  away from the outer edge of the terminal&#39;s first body  1 . The rotation-preventing surfaces  111  and  121  correspond to and operationally engage with the first and second member contact surfaces  1   c ,  2   c , respectively. The coupling hinge member  130  also comprises a rotation-preventing surface  131  on its circumferential surface. The rotation-preventing surface  131  is selectively engaged by the user to operationally engage with either of the first or second hinge member contact surfaces  1   c ,  2   c , as discussed in greater detail below.  
         [0051]    [0051]FIGS. 12A and 12 b  illustrate the operation of a hinge apparatus according to one embodiment of the present invention. In FIG. 12A, a user rotates the rotation control cap  152  in a clockwise direction (as indicated by the circular arrow). Consequently, the female screw threads  152   a  operationally engage the male screw threads  113  of the first hinge member  110 , resulting in lateral movement of the first hinge member  110  towards the outer edge of the terminal&#39;s first body  1  (as indicated by the directional arrow). In other words, the first hinge member  110  is pulled outwards. Also, the first hinge member is pushed outwards from the elastic force released by the compressed spring  140 . Furthermore, expansion of the spring  140  results in the coupling hinge member  130  being slidingly moved so that the rotation-preventing surface  131  is now in contact with the first hinge member contact surface  1   c.    
         [0052]    At this stage, when a user unfolds the terminal, the second hinge member  120  rotates with the second body  2 . Consequently, the convex portion  133   b  of the coupling hinge member  130  pushes against the convex portion  122   a  of the second hinge member  120 . Accordingly, the second hinge member  120  is pushed inwards (opposite the direction of the coupling hinge member  130 ), thereby compressing the spring  140 .  
         [0053]    Referring to FIG. 12B, continued unfolding of the terminal results in the convex portion  122   a  of the second hinge member  120  passing over the convex portion  133   b  of the coupling hinge member  130 . At this moment, restitution force of the spring  140  results in complete unfolding of the terminal. The convex and concave portions  122   a ,  122   b  of the second hinge member  120  correspondingly fit the concave and convex portions  133   a ,  133   b , respectively, of the coupling hinge member  130 . This corresponding fit between the second coupling hinge member  120  and the coupling hinge member  130  acts as a locking mechanism to prevent unintentional folding of the terminal and maintain the maximum opening angle.  
         [0054]    [0054]FIGS. 13A and 13B also illustrate operation of a hinge apparatus according to one embodiment of the present invention. In FIG. 13A, a user rotates the rotation control cap  152  in a counter-clockwise direction (as indicated by the circular arrow). Consequently, the female screw threads  152   a  operationally disengage the male screw threads  113  of the first hinge member  110 , resulting in lateral movement of the first hinge member  110  inwards with respect to the terminal&#39;s first body  1 (as indicated by the directional arrow). In other words, the first hinge member  110  is pushed inwards from the rotational force generated by the user on the cap  152 . Furthermore, the coupling hinge member  130  and second hinge member  120  are pushed inwards as well by the movement of the first hinge member, thereby compressing the spring  140 .  
         [0055]    Prior to rotation of the cap  152  either clockwise (as shown in FIG. 12A) or counter-clockwise (as shown in FIG. 13A), the engagement of the groove  112   a  to the protrusion  132   a  acts as a locking mechanism to prevent unintentional unfolding of the terminal. However, as the user unfolds the terminal at the stage shown in FIG. 9A (after counter-clockwise rotation of the cap  152 ), the coupling hinge member  130  rotates with the second body  2  of the terminal. The rotation-preventing surface  131  of the coupling hinge member  130 , which is in contact with the second hinge member contact surface  2   c , prevents rotation of the member  130 . Furthermore, unfolding the terminal results in the application of shear force to the guiding surfaces  112 ,  132 .  
         [0056]    Referring to FIG. 13B, further unfolding of the terminal results in the protrusion  132   a  rotating and disengaging with the groove  112 . Thereinafter, the protrusion is in contact with the guide surface  112 . As a result, a frictional force is generated by this contact, which allows the user to select and maintain an opening angle of the terminal. Preferably, complete unfolding of the terminal preferably results in the protrusion  132   a  completing one revolution so that it engages the groove  112   a , once again, and thereby locking the terminal in this position.  
         [0057]    [0057]FIG. 14 illustrates a sectional view of an operation of a hinge apparatus according to an alternative embodiment of the present invention. In this embodiment, a stopping protrusion  156  is formed on the inner circumferential surface, preferably towards the inner edge, of the first hinge housing  1   b . The protrusion  156  prevents excess lateral movement of the first hinge member  110  towards the second hinge housing  2   b , on which a corresponding protrusion  157  is also formed on the first hinge member  110 . Therefore, unfolding of the terminal would not result in the first hinge member  110  rotating with the second body  2  of the terminal.  
         [0058]    It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the foregoing description of these embodiments of the present invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. Preferred embodiments were shown in the context of folding type mobile communication terminals.

Summary:
A folding type mobile communication terminal, wherein a hinge apparatus rotatively couples an upper body to a lower body, is disclosed. The hinge apparatus includes first and second hinge housings, first and second hinge members, a coupling hinge member, a spring, and rotation control device. The first and second hinge members are inserted into the first and second hinge housings, respectively. The coupling hinge member is disposed between the first and second hinge members. Relationships between the first and second hinge members and the coupling hinge member include interlocking features assisted by the elastic force of the spring. A user manipulates the rotation control device to effect an opening angle of the folding type terminal.