Abstract:
A mobile phone. The mobile phone comprises a first housing, a second housing sliding on the first housing, a track disposed on the second housing and having a specific shape and a cam element disposed on the first housing, wherein when the second housing slides on the first housing, the cam element abuts a track to provide at least one stopping position.

Description:
BACKGROUND 
   The present invention relates to a mobile phone with sliding housings, and in particular to a mobile phone positioning the sliding housings thereof by a cam abutting a track. 
   Mobile phones with two housings are generally either rotatable with one housing hinged on the other or with one housing slidably disposed on the other. With sliding mobile phones, the housings, by sliding from each other, allow more display space. Japan application publication No. 2001-24762 discloses a mobile phone with two phone housings. One main housing is provided with a display and the other provided with a keypad thereon. The keypad retracts to reveal the display. 
   However, in this structure, the keypad is fixed in position by friction only, a neither precise nor reliable means, with unexpected sliding possibly interrupting use of the display. 
   SUMMARY 
   Embodiments of the invention provide a mobile phone comprising a first housing, a second housing sliding on the first housing, a track disposed on the second housing and having a specific shape and a cam element disposed on the first housing. When the second housing slides on the first housing, the cam element abuts the track, fixing the position thereof. 
   The first housing has a plane on which the cam element is disposed, and the second housing has another plane facing the first housing plane, to which the track is fixed. 
   The mobile phone further comprises a bias element disposed on the first housing plane biasing the cam element to abut the track. The bias element can comprise a compression spring, or two magnets aligned with the same polarity, one fixed on the cam element and the other fixed to the first housing. Repellent force between the magnets, oppositely disposed, abuts the cam element to the track. 
   The track has at least one portion curved in a first direction parallel to the second housing plane and opposite the bias of the bias element. The track has hooked ends to prevent the cam element from escaping therefrom. 
   The first housing further has a slot formed on the first housing plane accommodating the cam element and the bias element. The cam element includes a finger abutting the track and a base portion sliding in the slot and contacting the bias element. The finger and the base portion are integrally formed and configured in a T shape. The slot has a notch defined through which the finger extends, to abut the track. 
   The first housing has a groove and the second housing has a flange seating therein to enable the second housing to slide on the first housing. 
   A detailed description is given in the following embodiments with reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
       FIG. 1  is a perspective view of a closed mobile phone of embodiments of the invention; 
       FIG. 2  is a perspective view of an open mobile phone of embodiments of the invention; 
       FIG. 3  is an exploded view of a mobile phone of the first embodiment of the invention; 
       FIG. 4   a  is a perspective view of an upper housing of a mobile phone of the first embodiment of the invention; 
       FIG. 4   b  is a perspective view of an alternative upper housing of a mobile phone of the first embodiment of the invention; 
       FIG. 5  is a perspective view of a lower housing of a mobile phone of the first embodiment of the invention; 
       FIGS. 6   a ,  6   b ,  6   c  show the upper housing sliding on the lower housing in the first embodiment of the invention; and 
       FIGS. 7   a ,  7   b ,  7   c  show the upper housing sliding on the lower housing in the second embodiment of the invention. 
   

   DETAILED DESCRIPTION 
   First Embodiment  
   Referring to  FIGS. 1 and 2 , a mobile phone of this embodiment comprises an upper housing (described as a second housing in claims)  10  and a lower housing (described as a first housing in claims)  20 . In this embodiment, the rectangular upper housing  10  is slidably disposed on the rectangular lower housing  20 . A display  101  and a plurality of function keys  102  (two in this embodiment) is disposed on the front of the upper housing  10 . A flange  13  is formed at the edge of the upper housing  10 , seating in a groove  23  on the edge of the lower housing  20  to guide sliding motion. A plurality of keys  201  is disposed on the front (described as a first housing plane in claims) of the lower housing  20 . The housings  10  and  20  slide apart to reveal the keys  201  when using the mobile phone. 
   The upper housing  10  must be retracted to expose keyspad  201  during use. In this embodiment, position holders are disposed on the upper and lower bodies  10 ,  20  to prevent unwanted sliding. 
     FIG. 3  is an exploded view of the embodiment. The upper housing  10  has a track  11  fixed on the back (described as a second housing plane) as shown in  FIG. 4   a , and the lower housing  20  has a slot  202  provided with a flange. A compression spring  301  and a cam element  302  (shown in  FIG. 5 ) are accommodated in the slot  202 . The cam element  302  has a base portion  3021  sliding in the slot  202  and contacting the compression spring  301 . The cam element  302  further has a finger  3022  extending through a notch  2021  formed on the flange of the slot  202  to abut the sliding track  11  when the upper housing  10  slides on the lower housing  20 . The base portion  3021  and the finger  3022  are integrally formed and configured in a T shape. The compression spring  301  biases the base portion  3021  to ensure the finger  3022  abuts the track  11 . 
   In the embodiment, the track  11  has a curved portion opposite the biasing direction of the compression spring  301 . A hooked end  115  of the track  11  stops the finger  3022 , preventing the upper housing  10  from escaping therefrom when the upper housing  10  slides on the lower housing  20 . 
     FIGS. 6   a ,  6   b  and  6   c  show the upper housing  10  sliding on the lower housing  20  in the embodiment. The sliding motion between the cam element  302  and the track  11  is shown in these FIGS, and the upper housing  10  is shown in a dashed line for clarity. In  FIG. 6   a , when the upper housing  10  slides from an initial position (the mobile phone is in a close state), the track  11  pushes the cam element  320  (finger  3022 ) to compress the compression spring  301 . As shown in  FIG. 6   b , when the track  11  contacts the finger  3022  at a critical point A, the compression spring  301  is fully compressed. When the track  11  passes critical point A, the compression spring  301  is gradually released, allowing the upper housing  10  to easily slide to a terminal position (the mobile phone is open) as shown in  FIG. 6   c.    
   In addition, as shown in  FIG. 4   a , the track  11   a  can have a plurality of curved portions providing several stop positions for the upper housing  10 . Thereby, the mobile phone is provided with multiple operating configurations. 
   Second Embodiment 
   In this embodiment, referring to  FIGS. 7   a ,  7   b  and  7   c , the compression spring  301  of the first embodiment is replaced by two magnets  401 , with other structures the same as the first embodiment. only the function of the two magnets is described here, with description of other elements omitted. 
   In this embodiment, one of the magnets  401  is fixed on the cam element  302  (base portion  3021 ), and the other fixed on the wall of the slot  202  opposite the base portion  3021 . Like poles of the magnets are correspondingly disposed to exert repellent force on the cam element  302  to abut the track  11 . 
   While the invention has been described by way of example and in terms of preferred embodiments, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.