Abstract:
A hinge assembly ( 100 ) includes a cam ( 13 ), a follower ( 14 ), a first spring ( 12 ), a press rod ( 17 ), a control member ( 18 ) and a second spring ( 16 ). The cam has a cam surface. The follower has a latching cam surface engaging with the cam surface. The first spring provides an elastic force causing the cam surface of the cam and the latching cam surface of the follower to abut each other. The press rod includes a threaded portion ( 173 ). The control member threadedly engages with the threaded portion of the press rod. The second spring provides an elastic force to return the control member. When the press rod is pushed, the control member rotates to cause the follower to rotate whereby the cam surface of the cam rotates relative to the latching cam surface of the follower.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to hinge assemblies and, particularly, to an automatically opening hinge assembly for foldable devices such as portable telephones, portable computers, and so on. 
         [0003]    2. Discussion of the Related Art 
         [0004]    At present, one of the most popular portable electronic device in the marketplace is the foldable cellular telephone, which generally includes a cover section and a body section. The cover section and the body section are rotatably interconnected through a hinge assembly, for switching the telephone between an in-use position and a closed position. 
         [0005]    One kind of hinge assembly employs a cam and a follower, which allows the cover section to fold outwards from the body section and then be held in an open position. The hinge assembly typically includes a cam having a concave portion, a follower having a convex portion, a shaft having a fixing end, and a spring. The cam and the follower are placed around the shaft. The spring resists the follower to make the concave portion tightly contact the convex portion. The cam, the follower, the shaft and the spring are received in a housing. A flip cover rotates about a main body of the mobile phone by overcoming the force of the spring, thus allowing the concave portion to rotate about the convex portion. However, a user must typically open the mobile phone using both hands. This makes the mobile phone awkward to use in situations when the user has only one hand free. 
         [0006]    Therefore, there is a room for improvement within the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Many aspects of the hinge assembly can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, the emphasis instead being placed upon clearly illustrating the principles of the present hinge assembly. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views, in which: 
           [0008]      FIG. 1  is an isometric view of an exemplary embodiment of the present hinge assembly, as used in a mobile phone; 
           [0009]      FIG. 2  is an exploded, isometric view of the exemplary embodiment of the hinge assembly shown in  FIG. 1 ; 
           [0010]      FIG. 3  is similar to  FIG. 2 , but viewed from another aspect; 
           [0011]      FIG. 4  is an enlarged view of the cam in  FIG. 2 ; 
           [0012]      FIG. 5  is an enlarged view of the follower in  FIG. 2 ; 
           [0013]      FIG. 6  is an assembled view showing the hinge assembly in  FIG. 2 ; and 
           [0014]      FIG. 7  is a cut-away view of  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0015]    Referring now to the drawings in detail,  FIG. 1  shows a hinge assembly  100 , applied to a foldable electronic device  200  such as a flip type mobile phone, for pivotably coupling a cover section  210  and a body section  220 . It is to be understood, however, that the hinge assembly  100  could be advantageously used in other environments (e.g. cabinet doors). As such, although proving particularly advantageous when used in foldable electronic devices, the hinge assembly  100  should not be considered limited in scope solely to foldable electronic devices. 
         [0016]    Referring to  FIGS. 2 and 3 , the hinge assembly  100  in the embodiment illustrated includes a locking module  10 , a first sleeve  11 , a first spring  12 , a cam  13 , a follower  14 , a barrel  15 , a second spring  16 , a press rod  17 , a control member  18 , a third spring  19  and a second sleeve  20 . 
         [0017]    The locking module  10  includes a washer  101  and a stopper  102 . The washer  101  is substantially C-shaped. The stopper  103  is substantially cylindrical, and includes an extending end  1030  and a smooth end  1032 . A ring rib  1031  is formed between the extending end  1030  and the smooth end  1032 . The extending end  1030  defines a loop groove  1033  for locking with the washer  101 . 
         [0018]    The first sleeve  11  is a substantially hollow cylinder, and has an outer wall  111  and an inner wall  112 . The inner wall  112  is recessed toward the outer wall  111  to form two symmetrical sleeve blocks  113 . Correspondingly, two sleeve grooves  114  are defined in the inner wall  112 . The sleeve blocks  113  of the sleeve  11  may engage with the cover section  210  of the mobile phone  200  so that the sleeve  11  and the cover section  210  cannot rotate relative to each other. The sleeve  11  includes an open end and a partially-closed end. The partially-closed end of the sleeve  11  defines a circular hole  115  at a central area thereof. 
         [0019]    The first spring  12  is a cylindrical helical spring (i.e., occupying a cylindrical volume). An outer diameter of the first spring  12  is smaller than the diameter of the inner wall  112  of the sleeve  11  so that the first spring  12  may be received in the first sleeve  11 . 
         [0020]    Referring to  FIG. 4 , the cam  13  is substantially cylindrical, and has a peripheral wall  132 . The diameter of the peripheral wall  132  matches the inner diameter of the first sleeve  11 . The peripheral wall  132  forms two latching blocks  133  for engaging in the sleeve grooves  114  of the sleeve  11  so the cam  13  may be non-rotatably received in the first sleeve  11 . The cam  13  defines a through hole  131 . One end of the cam  13  has an end surface  134 , and the other end of the cam  13  has a cam surface  135 . The cam surface  135  includes two symmetrical peaks  1351 , two vertical surfaces  1352 , two connecting surfaces  1353 , two symmetrical valleys  1354 , and two sloped surfaces  1355  therebetween. 
         [0021]    Referring to  FIG. 5 , the follower  14  is substantially a cylinder, and includes a cylindrical circumferential wall  140 . The circumferential wall  140  forms two engaging blocks  146 . The follower  14  defines a through hole  141  therein. One end of the follower  14  has a latching cam surface  143 , the other end thereof has two symmetrical thumb projections  145 . The latching cam surface  143  includes two symmetrical peaks  1431 , two symmetrical vertical surfaces  1432 , two connecting surfaces  1433 , two symmetrical valleys  1434 , and two sloped surfaces  1435  for engaging with the cam surface  135  of the cam  13 . 
         [0022]    The barrel  15  is a hollow cylinder, and includes a barrel portion  151  and a fixing portion  152  formed at one end of the barrel portion. The barrel portion  151  defines a barrel hole  153  partially extending one part thereof. The fixing portion  152  defines a fixing hole  154  communicating with the barrel hole  153 . A diameter of the barrel hole  153  is larger than the diameter of the fixing hole  154 . The follower  14  is abuttingly engaged with the fixing portion  152  of the barrel  15 . 
         [0023]    The second spring  16  is substantially cylindrical. A diameter of the second spring  16  is substantially equal with the diameter of the barrel hole  153  so that the second spring  16  may be received in the barrel  15 . 
         [0024]    The press rod  17  includes a flange portion  172 , a rod portion  171  and a threaded portion  173  integrally formed together. A diameter of the flange portion  172  is substantially equal with that of the barrel hole  153 , and is larger than that of the fixing hole  154 . The press rod  17  may be received in the barrel hole  153  and the fixing hole  154  of the barrel  15 . The threaded portion  173  defines a single thread  1731 , which is a recessed helical or spiral groove on the press rod  17 . 
         [0025]    The control member  18  is substantially disked-shaped, includes a body  181  defining a threaded hole  1813  surrounding by an inner circumferential wall. A single thread  1814  is defined in the inner circumferential wall of the threaded hole  1813 , which is a raised helical or spiral rib/ridge on the inner circumferential wall of the control member  18 . The threaded portion  173  of the press rod  17  may be received in the threaded hole  1813 . One end of the body  181  forms two symmetrical slots  1811  at an outer peripheral along an axial thereof, the other end of the body forms an annular groove  1812 . 
         [0026]    The third spring  19  is substantially cylindrical. A diameter of the third spring  19  is slightly smaller than a diameter of the control member  18 , and may be received in the annular groove  1812  of the control member  18 . 
         [0027]    The second sleeve  20  is substantially cylindrical, and includes an open end and a partially-closed end. The second sleeve  20  has an outer wall  201  and an inner wall  202 . The inner wall  202  is recessed toward the outer wall  201  to form two symmetrical sleeve blocks  203 . Correspondingly, two sleeve grooves  204  are defined in the inner wall  202 . The sleeve blocks  203  of the second sleeve  20  may engage with the body section  220  of the mobile phone  200  so that the second sleeve  20  and the body section  220  cannot rotate relative to each other. The partially-closed end of the second sleeve  20  has a round hole  205 . 
         [0028]    In assembly, referring to  FIGS. 6 to 7 , one end of the barrel  15  firstly passes through the through hole  141  of the follower  14  to allow the fixing portion  152  to resist the follower  14 . The cam  13  is placed around the barrel  15 , with the cam surface  135  of the cam  13  engaging with the latching cam surface  143  of the follower  14 . The press rod  17  is inserted into the barrel hole  153  and the fixing hole  154 . The threaded portion  173  extends out from the fixing hole  154 . After that, the control member  18  is placed around the threaded portion  173 . The thread  1731  is engaged with the thread  1814 . At the same time, the projections  145  of the follower  14  are received in the slots  1811  of the control member  18  resist. The second spring  16  is received in the barrel hole  153 , and one end of the second spring  16  resists the flange portion  172  of the press rod  17 . 
         [0029]    After that, the smooth end  1032  of the stopper  103  presses the other end of the second spring  16  to lock in the barrel hole  153 . Then, the third spring  19  is received in the annular groove  1812 . The press rod  17  together with the above elements is received in the second sleeve  20 , with one end of the third spring  19  resisting the partially end of the second sleeve  20 . The threaded portion  173  is extended out from the round hole  205  of the second sleeve  20 . 
         [0030]    Finally, the first spring  12  is placed around the barrel  15  adjacent to the cam  13 . The first sleeve  11  receives the first spring  12  and the cam  13 . The latching blocks  133  are received in the sleeve groove  114  of the first sleeve  11 . The first sleeve  11  is pushed to compress the first spring  12  until the stopper  103  is extended out from the circular hole  115 . The washer  101  is locked in the loop groove  1033 . Accordingly, the hinge assembly  100  is thus completely assembled. 
         [0031]    If incorporated into a mobile phone during manufacture, the first sleeve  11  can engage in a cavity (not shown) of the cover section  210  of the mobile phone  200 , and the second sleeve  20  can connect with the body section  220  of the mobile phone  200 . When the cover section  210  of the mobile phone  200  is in a fully open position, the peaks  1351  of the cam surface  135  of the cam  13  abuts the valley  1434  of the latching cam surface  143 . The first spring  12  exerts a predetermined pressure on the cam  13  and the follower  14 . The second spring  16  exerts a predetermined pressure on the press rod  17 . The third spring  19  exerts a predetermined pressure on the control member  18 . 
         [0032]    When the cover section  210  of the mobile phone  200  is being closed, the cover section  210  can be closed by hand by pushing the first sleeve  11  to rotate relative to the body section  220 . The first sleeve  11  further brings the cam  13  to rotate relative to the follower  14 . The follower  14  limited by the second sleeve  20  cannot rotate. When the cam  13  rotates, the follower  14  is pushed to only slide along an axial direction until the cam  13  passes over the peaks  1431  of the follower  14  to hold at the connecting surface  1433 . At that time, the cover section  210  becomes closed relative to the body section  220  of the mobile phone  200 . 
         [0033]    When a user wants to automatically open the cover section  210  of the mobile phone  200  automatically, he/she may press the threaded portion  173  of the press rod  17  exposed from the second sleeve  11 . In this process, the control member  18  cannot move axially and only rotate a small angle under the role of the third spring  19 , and the follower  14  is caused to rotate a small angle until the cam surface  135  of the cam  13  then rotates relative to the latching cam surface  143  of the follower  14  under urging of the first spring  12 . Furthermore, the cam  13  brings the first sleeve  11  to rotate so that the cover section  210  of the mobile phone  200  is opened. The cam  13  stops rotating when the cover section  210  of the mobile phone  200  is completely opened. Then, the press rod  17  is released. The elastic potential energy of the second spring  16  then pushes the press rod  17  to move toward the second sleeve  20 , and the control member  18  reversely rotates along the threaded portion  173  until the control member  18  returns to an original position. The hinge assembly  100  may be opened manually. 
         [0034]    In an alternative embodiment, the first spring  12 , the second spring  16  and the third spring  19  may be replaced by other elastic elements such as an elastic sponge. 
         [0035]    In an alternative embodiment, the configuration of the cam surface  135  of the cam  13  may be different from the latching cam surface  143  of the follower  14  as long as the cam surfaces  135  do not interfere with the latching cam surface  143  of the follower  14 . 
         [0036]    Understandably, the first sleeve  11  and the second sleeve  20  may be omitted. The number of the thread  1731  may be more than two. Correspondingly, the thread  1814  may be adjusted according to the number of the thread  1731 . 
         [0037]    As described above, the present invention provides a hinge assembly  100  for use with various portable devices, beyond the mobile phone illustrated, and/or with other devices needing a hinge assembly that facilitates the achievement of fully open and fully closed positions. 
         [0038]    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.