Abstract:
An exemplary sliding mechanism includes a main plate, a slide plate, and a clock spring positioned between the main plate and the slide plate. The slide plate is slidably connected to the main plate. The clock spring includes a first spiral portion fixed to the slide plate, a second spiral portion fixed to the main plate, and a connecting portion connecting the first spiral portion to the second spiral portion. The clock spring is configured for driving the slide plate and enabling the slide plate to slide along the main plate after the slide plate is manually moved to a predetermined position with respect to the main plate.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present invention generally relates to sliding mechanisms and, more particularly, to a sliding mechanism used for a portable electronic device with two or more housings. 
         [0003]    2. Discussion of the Related Art 
         [0004]    Sliding mechanisms are widely used in portable electronic devices, such as slide-type mobile phones and slide-type personal digital assistants. A typical slide mechanism generally includes a first sheet, a second sheet, and a torsion spring positioned between the first sheet and the second sheet. The first sheet is slidably connected to the second sheet. The torsion spring includes a spiral portion, and a first arm and a second arm extending from the spiral portion. The first arm is fixed to the second sheet, and the second arm is fixed to the first sheet. 
         [0005]    In use, the torsion spring provides an elastic force enabling the first plate to slide along the second plate after the first plate is manually moved to a predetermined position with respect to the second plate. 
         [0006]    However, when the torsion spring is deformed, the force applied on the torsion spring is concentrated on a portion between the first and second arms and the spiral portion. Thus, the portions between the first and second arms and the spiral portion are easily damaged, and a work life of the sliding mechanism is unduly shortened. 
         [0007]    What is needed, therefore, is a sliding mechanism which overcomes the above-described shortcomings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present sliding mechanism and portable electronic device. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views, and all the views are schematic. 
           [0009]      FIG. 1  is an isometric view illustrating a closed state of one embodiment of a sliding-type portable electronic device, the portable electronic device including a first housing, a second housing, and a sliding mechanism. 
           [0010]      FIG. 2  is similar to  FIG. 1 , but showing an opened state of the sliding-type portable electronic device. 
           [0011]      FIG. 3  is an assembled, isometric view of an embodiment of the sliding mechanism of the electronic device of  FIG. 1 , the sliding mechanism including a slide plate, a main plate, a clock spring, and a pair of guiding rails. 
           [0012]      FIG. 4  is an exploded, isometric view of the sliding mechanism of  FIG. 3 . 
           [0013]      FIG. 5  is similar to  FIG. 4 , but viewed from another aspect. 
           [0014]      FIG. 6  is an assembled, isometric view of the sliding mechanism of  FIG. 4 , showing the slide plate in a closed position relative to the main plate. 
           [0015]      FIG. 7  is similar to  FIG. 6 , but showing the slide plate in a half-closed position relative to the main plate. 
           [0016]      FIG. 8  is similar to  FIG. 6 , but showing the slide plate in an open position relative to the main plate. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0017]    Referring to  FIGS. 1 through 3 , one embodiment of a sliding mechanism  200  is adapted for use in a portable electronic device  100 . The portable electronic device  100  includes a first housing  102 , a second housing  104  engaging with the first housing  102 , and the sliding mechanism  200 . The sliding mechanism  200  is positioned between the first and second housings  102 ,  104  for making the second housing  104  slidable relative to the first housing  102 . The second housing  104  slides relative to the first housing  102 , to expose or cover a keypad (not labeled) on the first housing  102 . 
         [0018]    The sliding mechanism  200  includes a slide plate  21 , a main plate  22 , a clock spring  23 , and a pair of guiding rails  24 . The slide plate  21  is slidably connected to the main plate  22 . The clock spring  23  is positioned between the slide plate  21  and the main plate  22 . An end of the clock spring  23  is fixed to the slide plate  21  and another end is fixed to the main plate  22 . The clock spring  23  may be a spiral torsion spring. The clock spring  23  is on substantially a same plane as the main plate  22  and the slide plate  21 . 
         [0019]    Referring to  FIGS. 4 and 5 , in the illustrated embodiment, the slide plate  21  of the sliding mechanism  200  is substantially rectangular shaped. The slide plate  21  includes a main portion  211 . The slide plate  21  defines an engaging hole  2113  approximately in the main portion  211 . A pair of arched sidewalls  212  extend from opposite sides of the main portion  211 , thereby defining two receiving grooves  213  for receiving the guiding rails  24  of the sliding mechanism  200 . Each sidewall  212  defines a latching hole  2131 . 
         [0020]    In the illustrated embodiment, the main plate  22  of the sliding mechanism  200  is substantially rectangular shaped. The main plate  22  includes a main body  221  and a pair of slide strips  223  extending from opposite sides of the main body  221 . The main body  221  defines an oblong opening  224  adjacent to an end portion and a fixing hole  2213 . The oblong opening  224  is configured for assembling the sliding mechanism  200  easily. The fixing hole  2213  is adjacent to the slide strips  223 . The main plate  22  and the slide plate  21  may be metallic and made by punching. 
         [0021]    The sliding mechanism  200  further includes a first limiting portion  225  and a second limiting portion  226 . The first limiting portion  225  extends from a first end of the main plate  22 , and the second limiting portion  226  extends from a second end of the main plate  22  opposite to the first end of the main plate  22 . The first limiting portion  225  and the second limiting portion  226  are configured to restrict a sliding range of the slide plate  21 . In the illustrated embodiment, the sliding mechanism includes two first limiting portions  225  and two second limiting portions  226 . 
         [0022]    The clock spring  23  includes a first spiral portion  235 , a second spiral portion  236 , and a connecting portion  238  connecting the first spiral portion  235  to the second spiral portion  236 . A cross-section of the clock spring  23  may be circular, rectangular, or elliptical. The connecting portion  238  may be substantially curved. The first spiral portion  235  is positioned symmetrically to the second spiral portion  236 . The coil direction of the first spiral portion  235  is opposite to the coil direction of the second spiral portion  238 . The first spiral portion  235  has a first free end  2311 , and the second spiral portion  236  has a second free end  2321 . The first free end  2311  and the second free end  2321  are substantially ring-shaped. 
         [0023]    The guiding rails  24  may be substantially rectangular shaped. A first sidewall (not labeled) forms a latching protrusion  242 , and a second sidewall (not labeled) opposite to the first sidewall defines a guiding slot  244 . The guiding rails  24  may be integrally formed with the slide plate  21  by an insert-molded technology. The slide plate  21 , as an insert member, is inserted into an injection mold, and then melted plastic is injected into the injection mold to form the guiding rails  24  on the slide plate  21 . In an insert-molding process, the melted plastic flows into the latching holes  2131  and the receiving grooves  213  of the slide plate  21 . The melted plastic is joined around the latching holes  2131  to form a bonding structure for improving the bonding strength between the slide plate  21  and the guiding rails  24 . 
         [0024]    The sliding mechanism  200  further includes a first rivet  251  and a second rivet  252 . 
         [0025]    In assembly of the sliding mechanism  200 , the first spiral portion  235  of the clock spring  23  is attached to the main plate  22 , via the first rivet  251  engaging in the first free end  2311  and the fixing hole  2213  of the main plate  22 . The second spiral portion  236  of the clock spring  23  is attached to the slide plate  21 , by engaging the second rivet  252  in the second free end  2321  and the engaging hole  2113  of the slide plate  21 . The clock spring  23  is positioned between the slide plate  21  and the main plate  22 . The slide strips  223  of the main plate  22  are inserted into the guiding slots  244  of the corresponding guiding rails  24 , so that the guiding rails  24  are slidably connected to the main plate  22 . Accordingly, the slide plate  21  is slidable relative to the main plate  22  because the slide plate  21  is integrally formed with the guiding rails  24 . 
         [0026]    Referring to  FIG. 1  again, when the sliding mechanism  200  is adopted in the portable electronic device  100 , the first housing  102  of the portable electronic device  100  is firmly secured to the main plate  22 , and the second housing  104  of the portable electronic device  100  is firmly secured to the slide plate  21 . The portable electronic device  100  may be selectively opened or closed.  FIG. 6  shows the slide plate  21  in one position, for example, a closed position, relative to the main plate  22 .  FIG. 7  shows the slide plate  21  in a half-closed position relative to the main plate  22 .  FIG. 8  shows the slide plate  21  in an open position relative to the main plate  22 . 
         [0027]    Referring to  FIG. 6 , the slide plate  21  is at an end of the main plate  22 , the clock spring  23  is in a normal state, and a distance between the first and second free ends  2311 ,  2321  of the clock spring  23  is at the furthest distance. Referring also to  FIG. 1 , when the second housing  104  is moved along a direction of the arrow shown in  FIG. 1 , that is, towards an open position as shown in  FIG. 2 , the slide plate  21  slides relative to the main plate  22  as indicated by a direction of the arrow shown in  FIG. 7 . Therefore, the slide plate  21  together with the guiding rails  24  slide along the slide strips  223  of the main plate  22 . The second free end  2321  moves towards the first free end  2311  of the clock spring  23 . The distance between the first spiral portion  235  and the second spiral portion  236  decreases. The clock spring  23  is compressed, accumulating elastic force, and reaches the largest elastic force when the slide plate  21  reaches the middle of the main plate  22 . In this position, the distance between the first spiral portion  235  and the second spiral portion  236  is at the smallest distance, and the curvature of the connecting portion  238  is at its largest. 
         [0028]    As shown in  FIG. 7 , the clock spring  23  is at a largest compressed state when the slide plate  21  is in the middle of the main plate  22 , thereby accumulating the largest elastic force. At this time, if the second housing  104  is pushed longitudinally in either direction away from the middle, the elastic force of the clock spring  23  is released along the direction of movement and the slide plate  21  slides in the direction urged by the elastic force of the clock spring  23  to either the open position of  FIG. 6  or the closed position of  FIG. 8 . 
         [0029]    When moving the slide plate  21  to the open or close position, the first spiral portion  235  and the second spiral portion  236  of the clock spring  23  simultaneously compresses, and then the first spiral portion  235  and the second spiral portion  236  simultaneously decompresses. In this way, the force applied on the clock spring  23  is distributed evenly on the clock spring  23 , thereby preventing a stress concentration. 
         [0030]    The sliding mechanism  200  has many advantages. One advantage is that the clock spring  23  includes a first spiral portion  235  and a second spiral portion  236 . When the clock spring  23  is compressed, the external force applied on the clock spring  23  is distributed evenly on the whole clock spring  23 . Therefore, the life of the clock spring  23  is prolonged. Another advantage is that the clock spring  23  is on a same plane. Thus, the clock spring  23  occupies a relatively small space. Lastly, since the guiding rails  24  are integrally formed with the slide plate  21 , the sliding of the guiding rails  24  and the slide plate  21  is stable. 
         [0031]    It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the embodiments or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments.