Abstract:
A hinge assembly ( 100 ) for a foldable electronic device includes a shaft ( 1 ), a housing ( 5 ) defining a guiding groove ( 56 ) therein, a spring ( 2 ), and a pin ( 7 ). A first end of the spring is coupled to the shaft, and an opposite second end of the spring is coupled to the housing. A first end of the pin is coupled to the shaft, and an opposite second end of the pin is slidable along the guiding groove of the housing. The shaft is rotatable relative to the housing between a first position where the second end of the pin is located in a first position of the guiding groove and a second position where the second end of the pin is located in a second position of the guiding groove. The hinge assembly is thus integrated into a complete unit which is capable of providing a wide range of rotation.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a hinge assembly, and particularly to a hinge assembly for a foldable electronic device such as a mobile phone, an electronic notebook, and so on.  
       GENERAL BACKGROUND  
       [0002]     Hinge assemblies are widely used in foldable electronic devices such as mobile phones and electronic notebooks. These foldable electronic devices typically include two housings. Normally, one of the housings called a main body contains most of the electronic elements of the foldable electronic device. The other housing called a cover contains fewer or even no electronic elements. The hinge assembly is used to interconnect the main body and the cover, and to enable the cover to be foldable relative to the main body.  
         [0003]     One kind of hinge mechanism is illustrated in  FIG. 5 . The hinge mechanism  500  includes: a cam  510 , having a wedge-shaped portion  512  on one end thereof, and an engaging portion  514  on the other end thereof which is used for engaging with a cover of a foldable mobile phone; a corresponding cam follower  520  having two jaws  522 ; and a spring  530  for pressing the cam follower  520  to urge against the cam  5 l 0 . The cam  5 l 0 , the cam follower  520  and the spring  530  are received in a hinge housing  540 , which is, in turn, covered by a hinge cover  550 . The hinge housing  540  and hinge cover  550  are engaged with a body of the foldable mobile phone. In use, the wedge-shaped portion  512  moves along the jaws  522 . The cam  510  together with the cover rotates relative to the body of the foldable mobile phone in a predetermined direction. However, the range of rotation of the cover is limited. In addition, the rotation of the hinge mechanism is unstable.  
         [0004]     What is needed, therefore, is a hinge assembly which is capable of providing a wide range of rotation and stable rotation.  
       SUMMARY  
       [0005]     A hinge assembly is provided. In a preferred embodiment, a hinge assembly according to the present invention comprises: a shaft, a housing defining a guiding groove therein, a spring, and a pin. A first end of the spring is coupled to the shaft, and an opposite second end of the spring is coupled to the housing. A first end of the pin is coupled to the shaft, and an opposite second end of the pin is slidable along the guiding groove of the housing. The shaft is rotatable relative to the housing between a first position where the second end of the pin is located in a first position of the guiding groove and a second position where the second end of the pin is located in a second position of the guiding groove.  
         [0006]     A main advantage of the hinge assembly is that an extent of rotation of the cover of the foldable electronic device is limited by the sliding groove of the housing of the hinge assembly, so that the main body of the foldable electronic device is not bumped or damaged when a user opens the cover of the foldable electronic device. The cover can open to different angles to the main body of the foldable electronic device by way of changing the shape of the sliding groove of the hinge assembly.  
         [0007]     Other advantages and novel features will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings, in which: 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is an exploded, isometric view of a hinge assembly in accordance with a first embodiment of the present invention;  
         [0009]      FIG. 2  is an enlarged view of the hinge assembly of  FIG. 1  fully assembled;  
         [0010]      FIG. 3  is an isometric view of a hinge assembly in accordance with a second embodiment of the present invention;  
         [0011]      FIG. 4  is an isometric view of a hinge assembly in accordance with a third embodiment of the present invention; and  
         [0012]      FIG. 5  is an exploded, isometric view of a conventional hinge assembly. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0013]      FIGS. 1 and 2  show a hinge assembly  100  in accordance with a first embodiment of the present invention, which is used to interconnect a main body (not shown) and a cover (not shown) of a foldable electronic device. The hinge assembly  100  includes a shaft  1 , two torsional springs  2 , a cap  3 , an elastic member  4 , a housing  5 , two retaining tabs  6 , and two pins  7 .  
         [0014]     The shaft  1  is substantially a round rod having a bifurcated portion. The shaft  1  includes a flange  12  at a first end thereof, and an engaging portion  14  formed on the flange  12 . The engaging portion  14  is adapted to fixedly engage with the cover of the foldable electronic device, so that the shaft  1  is jointly rotatable with the cover relative to the main body. The bifurcated portion comprises two branches  18 , and a gap  16  defined between the branches  18 . Each branch  18  defines a through hole  182 , and a blind hole  184  spaced a distance from the through hole  182 . The through hole  182  of each branch  18  is aligned with the blind hole  184  of the other branch  18 . The holes  182 ,  184  of the branches  18  receive the pins  7  (which will be described in detail below).  
         [0015]     The torsional springs  2  have a same structure, and are both cylindrical springs. Each torsional spring  2  has an inner finger  22  and an outer finger  24 . The torsional springs  2  surround the shaft  1 , with the inner fingers  22  being engaged in the gap  16  of the shaft  1 .  
         [0016]     The cap  3  is substantially a cylinder, and has an open end and a closed end. A post  32  extends from the closed end to the open end. The post  32  is configured to correspond to the shape of the gap  16  of the shaft  1 . The cap  3  is for receiving a second end of the shaft  1 , with the post  32  being received in the gap  16  of the shaft  1 .  
         [0017]     In the illustrated embodiment, the elastic member  4  is a cylindrical compression spring  4 . A first end of the compression spring  4  urges against the closed end of the cap  3 .  
         [0018]     The housing  5  is substantially a hollow cylinder. The housing  5  has an open end and a closed end. Two opposite raised platforms  52  are formed on opposite sides of the housing  5 , respectively. The raised platforms  52  are adapted to fixedly engage with the main body of the foldable electronic device, so that the housing  5  is jointly rotatable with the main body relative to the cover. Two recesses  54  are defined in the raised platforms  52 , respectively. One recess  54  is configured bias toward the other recess  54 . Two slots  542  are defined in bottoms of the recesses  54 , respectively. The housing  5  further defines two guiding grooves  56 , for receiving the pins  7 . One guiding groove  56  is spaced a distance from the other guiding groove  56 , as measured along an axial direction of the housing  5 . The distance spaced between the guiding grooves  56  is equal to the distance between the through holes  182  of the shaft  1 . In the illustrated embodiment, a longitudinal axis of the housing  5  is perpendicular to a main plane of each guiding groove  56 . A central angle subtended by each guiding groove  56  is about 160°. The compression spring  4 , the cap  3 , the torsional springs  2  and the branches  18  of the shaft  1  are received in the housing  5  in that order. A second opposite end of the compression spring  4  urges against an inner wall of the closed end of the housing  5 .  
         [0019]     The retaining tabs  6  are generally made of sheets of metallic material. A middle portion of each retaining tab  6  is bent inwardly to form a retaining portion  62 . The retaining portions  62  of the retaining tabs  6  are fittingly received in the slots  542  of the housing  5 .  
         [0020]     The pins  7  are cylinders. First ends of the pins  7  are extended through the through holes  182  and received in the blind holes  184 , respectively. Opposite second ends of the pins  7  are received in the guiding grooves  56  of the housing  5 , respectively.  
         [0021]     Referring to  FIG. 2 , in assembly of the hinge assembly  100 , one torsional spring  2  abuts against the flange  12 , with the inner finger  22  of the torsional spring  2  facing toward the flange  12 . The other torsional spring  2  abuts against the closed end of the cap  3 , with the inner finger  22  of the torsional spring  2  facing toward the cap  3 . Within the housing  5 , the cap  3  together with the shaft  1  is pressed by an expansion force exerted by the compression spring  4 . The outer fingers  24  of the torsional springs  2  are retainably received in the retaining portions  62  of the retaining tabs  6 , which, in turn, rest in the slots  542  of the housing  5 . The first ends of the pins  7  are fixedly engaged in the blind holes  184 , respectively. The second ends of the pins  7  are slidably received in the guiding grooves  56  of the housing  5 , respectively.  
         [0022]     Once the hinge assembly  100  is assembled to the foldable electronic device, the engaging portion  14  of the shaft  1  is fixedly engaged in a cavity of the cover of the foldable electronic device. The raised platforms  52  of the housing  5  are fixedly engaged in a cavity of the main body of the foldable mobile phone. The cover of the foldable electronic device can be held in closed position relative to the main body of the foldable electronic device by, for example, a mechanical latching mechanism. When the cover is in the closed position, the torsional springs  2  are in a torsional state, the compression spring  4  is in a compressed state, and the second ends of the pins  7  are located at corresponding first ends of the guiding grooves  56  of the housing  5 . To open up the foldable electronic device, the cover is unfolded from the main body by releasing the mechanical latching mechanism. The outer fingers  24  of the torsional springs  2  remain in position relative to the housing  5 , due to the engagement of the outer fingers  24  and the housing  5 . The shaft  1  is jointly rotated with the inner fingers  22  of the torsional springs  22  to an angle of 160° relative to the housing  5 , under a torsional force exerted by the torsional springs  2 . Correspondingly, the second ends of the pins  7  slide along the guiding grooves  56 . The cover of the foldable electronic device is thus automatically fully opened up, and the hinge assembly  100  is in a stable state. To close the cover of the foldable electronic device, the cover is manually rotated back toward the main body. The shaft  1  is jointly rotated with the cover relative to the housing  5 . The pins  7  slide from the second ends thereof to the original first ends thereof along the guiding grooves  56 . The torsional springs  2  are twisted when the cover is closed down onto the main body and is latched by the mechanical latching mechanism of the foldable electronic device. During the above-described opening and closing processes of the cover, the compression spring  4  is utilized to urge against the cap  3  together with shaft  1 , thereby the pins  7  are biased against edges of the guiding grooves  56  while sliding along the guiding grooves  56 . Thus, the shaft  1  and the cover are able to rotate stably relative to the housing  5 .  
         [0023]     Referring to  FIG. 3 , a hinge assembly  100 ′ in accordance with a second embodiment of the present invention is shown. Most of the structure of the hinge assembly  100 ′ of the second embodiment is similar to that of the hinge assembly  100  of the first embodiment, except that a longitudinal axis of the housing  5  obliquely intersects a main plane of a guiding groove  57 . Thus, when opening up the cover of the foldable electronic device, the shaft  1  is rotated relative to the housing  5  by the torsional force exerted by the torsional springs  2  and the expansion force exerted by the compression spring  4 .  
         [0024]     Referring to  FIG. 4 , a hinge assembly  100 ″ in accordance with a third embodiment of the present invention is shown. Most of the structure of the hinge assembly  100 ″ is similar to that of the hinge assembly  100 , except for the configuration of guiding grooves  58  of the housing  5 . Each guiding groove  58  includes a first end  582 , a first curved section  584  curved toward the engaging portion  14 , and a second curved section  586  curved toward the compression spring  4 , and an opposite second end  588 . The pins  7  are located at the first ends  582  of the guiding grooves  58  when the cover is in the closed position relative to the main body. When opening up the cover of the foldable electronic device, the shaft  1  is rotated relative the housing  5  by the torsional force exerted by the torsional springs  2  and the expansion force exerted by the compression spring  4 . The pins  7  are retained in the second curved sections  586 . At this position, the cover is opened up a small angle relative to the main body. When a user manually applies force to the cover, the pins  7  are caused to escape from the second curved section  586 . The shaft  1  is then rotated relative to the housing  5  by the torsional force exerted by the torsional springs  2  and the expansion force exerted by the compression spring  4 . The cover of the foldable electronic device is then opened up automatically to a fully open position, with the pins  7  sliding from the second curved sections  586  to the second ends  588  of the guiding grooves  58 .  
         [0025]     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 invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.