Abstract:
A hinge assembly includes a shaft, a follower and an elastic element. The shaft forms a projection. The follower defines a through hole and forming an inner peripheral wall surrounding the through hole. A threaded portion is formed on the inner peripheral wall, and the projection engages with the threaded portion of the follower. The elastic element provides an axial force to push the follower rotatable about and simultaneously longitudinally movable along the shaft.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a divisional application of U.S. Ser. No. 11/946,434, filed Nov. 28, 2007. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates to hinge assemblies and, particularly, to a hinge assembly for foldable electronic devices such as mobile phones, portable computers, and so on. 
         [0004]    2. Description of Related Art 
         [0005]    At present, perhaps the most popular portable electronic device in the marketplace is the foldable mobile phone, 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. 
         [0006]    One kind of hinge assembly employs a cam and a follower, which makes the cover section fold outward from the body section and then hold 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 with the convex portion. The cover section rotates about the body section of the mobile phone by overcoming the force of the spring, thus making the concave portion rotate about the convex portion. 
         [0007]    However, although the hinge assembly may achieve the opening and closing of the foldable electronic device, the manufacture of the cam and the follower is complicated owing to the concave portion and convex portion. Furthermore, tip portions of the concave portion and the convex portion are sharp and easily abraded. In addition, during the process of opening and closing of the cover section of the foldable electronic device, one of the cam and the follower is quickly rotated under the elastic force of the spring, which produces a large impact on the cover section. The damage caused by this may also eventually lead to premature malfunction or failure of the foldable electronic device. 
         [0008]    Therefore, a new hinge assembly is desired in order to overcome the above-described shortcoming. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Many aspects of the present hinge assembly can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn 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. 
           [0010]      FIG. 1  is an exploded, isometric view of a first embodiment of the hinge assembly; 
           [0011]      FIG. 2  is a front view of a follower of the hinge assembly shown in  FIG. 1 ; 
           [0012]      FIG. 3  is an assembled view of the hinge assembly shown in  FIG. 1 ; 
           [0013]      FIG. 4  is an exploded, isometric view of the first embodiment of the hinge assembly shown in  FIG. 1 , as used in a mobile phone; 
           [0014]      FIG. 5  is an assembled view of the present hinge assembly of  FIG. 1 , applied in the portable electronic device; 
           [0015]      FIG. 6  is an exploded, isometric view of a second embodiment of the hinge assembly; 
           [0016]      FIG. 7  is an assembled view of the second embodiment of the hinge assembly shown in  FIG. 6 ; 
           [0017]      FIG. 8  is an exploded, isometric view of a third embodiment of the hinge assembly; 
           [0018]      FIG. 9  is an exploded, isometric view of a forth embodiment of the hinge assembly; 
           [0019]      FIG. 10  is a front view of a follower of the hinge assembly shown in  FIG. 9 ; 
           [0020]      FIG. 11  is an assembled view of the hinge assembly shown in  FIG. 10 ; and 
           [0021]      FIG. 12  is an exploded, isometric view of the hinge assembly shown in  FIG. 9 , applied in a mobile phone. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0022]    The present hinge assembly is suitable for a foldable electronic device such as a flip type mobile phone, for pivotably coupling a cover section and a body section. It is to be understood, however, that the present hinge assembly could be advantageously used in other environments (e.g. cabinet doors). As such, although proving particularly advantageous when used in foldable electronic devices, the present hinge assembly should not be considered limited in scope solely to them. 
         [0023]    Referring now to  FIG. 1 , a hinge assembly  10  according to a first embodiment is provided. The hinge assembly  10  includes a shaft  12 , a spring  14 , and a follower  16 . 
         [0024]    The shaft  12  is substantially cylindrical, and has a longitudinal axis A. One end of the shaft  12  defines a screw portion  122  at an outer peripheral surface thereof, and the other end of the shaft  12  forms a deformed portion  124  functioning as a securing portion. The screw portion  122  is a singe thread, which is formed by a helical groove  1220  and a raised helical or spiral rib/ridge  1222  on the shaft  12 . The helical groove  1220  has a width L 1 . The shaft  12  defines a pin hole  126  at the outer peripheral surface thereof adjacent to the deformed portion  124 . 
         [0025]    The spring  14  is preferably helical and metallic. The spring  14  has an inner diameter larger than a diameter of the shaft  12 . Thus, the spring  14  can be placed around the shaft  12 . One end of the spring  14  extends radially to a fixing end  142 . A diameter of the fixing end  142  is same as that of the pin hole  126  of the shaft  12 , therefore the fixing end  142  can be inserted into the pin hole  126  for attaching the spring  14  to the shaft  12 . 
         [0026]    Referring now to  FIG. 2 , the follower  16  is generally cylindrical in shape and defines a through hole  164  therein. The follower  16  includes two opposite planar surfaces  162  at an outer peripheral wall thereof. A projection  166  is formed on an inner peripheral wall of the follower  16  and the projection  166  interacts with the screw portion  122  of the shaft  12 . The projection  166  is substantially a half-cylinder, and includes a front planar surface  1660 , a rear planar surface  1662  and a curved main surface  1664 . The front and rear planar surfaces  1660 ,  1662  are planar and substantially have a semi-circular cross-section. The curved main surface  1664  extends towards a center of the through hole  164 , and has a longitudinal axis (not shown) parallel to and offset from the longitudinal axis A of the shaft  12  and therefore also the through hole  164 . When the projection  166  engages with the screw portion  122  of the shaft  12 , one of the front or rear surfaces  1660 ,  1662  contact the helical ridge  1222  at a time, depending on the direction of movement of follower  16 , and the curved main surface  1664  is disposed in the helical groove  1220 . In this embodiment, the width L 2  of the projection  166  is substantially less than the width L 1  of the helical groove  1220 . When the projection  166  engages in the groove  1220 , one of the front and rear surfaces  1660 ,  1662  at a time contact/resist with the side surface of the helical ridge  1222 . In this embodiment, since the front and rear surfaces  1660 ,  1662  are planar, the projection  166  is in linear contact with the helical ridge  1222  of the shaft  12 . It is to be understood that the front and rear surface  1660 ,  1662  may be curved surfaces, e,g, as suggested in  FIG. 8 , so that the projection  166  is in point or surface contact with the helical ridge  1222  of the shaft  12 . 
         [0027]    Referring to  FIG. 3 , in assembly, firstly, the spring  14  is placed around the shaft  12 , and the fixing end  142  is inserted into the pin hole  126  of the shaft  12  for fixing one end of the spring  14  to the shaft  12 . Then, the shaft  12  passes through the through hole  164  of the follower  16  and the projection  166  engages into the screw portion  122  of the shaft  12 . A thread lead angle of the screw portion  122  is larger than a friction angle thereof so that when an axial force of the spring  14  applied on the follower  16 , the projection  166  may overcome the frictional force of the screw portion  122  to slide and rotate along the screw portion  122 . 
         [0028]    When the hinge assembly  10  is applied in a mobile phone including a cover section and a body section, the shaft  12  and the follower  16  respectively connect with the cover section and the body section. Referring to  FIG. 4 , the mobile phone  100  includes a cover section  110  and a body section  120 . The cover section  110  has a connecting portion  112  at one end thereof. The connecting portion  112  defines a receiving cavity  1122  and a first reverse rotating groove  1124  at one end thereof. The receiving cavity  1122  is adjacent to the first reverse rotating groove  1124 . The connecting portion  112  has a bottom wall  1125  at one side of the first reverse rotating groove  1124 . The connecting portion  112  defines a cylindrical groove  1126  at the other end on the opposite side of the receiving cavity  1122 . The body section  120  has two opposite engaging portion  121 ,  127  formed at one side thereof for connecting to the connection portion  112  of the cover section  110 . The engaging portion  121  defines a second reverse rotating groove  1212  at one side thereof toward the engaging portion  127 . The engaging portion  127  axially extends a connecting shaft  1214  at one side thereof toward the second reverse rotating groove  1212 . 
         [0029]    Referring to  FIG. 5 , the hinge assembly  10  is assembled in the mobile phone  100 . One end of the assembled hinge assembly  10  with the follower  16  is inserted into the receiving cavity  1122 . The follower  16  is engaged in the first reverse rotating groove  1124  via the planar surfaces  162 . The deformed portion  124  of the shaft  12  reveals out of the receiving cavity  1122 . 
         [0030]    After that, the connecting portion  112  of the cover section  110  is disposed between the two engaging portions  121 ,  127 . The connecting shaft  1214  of the body section  120  rotatably engages in the cylindrical groove  1126 , and the deformed portion  124  engages in the second reverse rotating groove  1212 . The cover section  110  can rotate relative to the body section  120  between an open position and a closed position via the hinge assembly  10 . 
         [0031]    In an initial state, the cover section  110  is closed relative to the body section  120 . The follower  16  cannot rotate relative to the cover section  110 , but can slide relative to the cover section  110 . The shaft  12  cannot rotate relative to the body section  120 . One end of the spring  14  is fixed in the shaft  12 , and the other end of the spring  14  resists the follower  16 . The spring  14  is in a compressed state, and the follower  16  has the tendency to rotate relative to the shaft  12  under an axial force provided by the spring  14 . However, the cover section  110  or the follower  16  is locked in the body section  120  by a latch mechanism (not shown) so that the cover section  110  cannot rotate relative to the body section  120 . 
         [0032]    When opening the cover section  110 , the latch mechanism is unlocked, and the cover section  110  and the follower  16  are released from the limitation of the latch mechanism. Then, the spring  14  pushes the follower  16  to make the follower  16  rotate and slide axially along the shaft  12  under the continuous engagement between the projection  166  and the screw portion  122 . As the follower  16  slides, the spring  14  is relaxed. The follower  16  does not stop to slide until it reaches the bottom wall  1125  inside the first reverse rotating groove  1124 . Thus, the cover section  110  is automatically opened relative to the body section  120  when the latch mechanism is unlocked. 
         [0033]    When the cover section  110  rotates from the open position to the closed position, the follower  16  is rotated relative to the shaft  12 . Simultaneously, the follower  16  moves axially along the shaft  12  and compresses the spring  14 . The cover section  110  rotates continuously until the cover section  110  is locked on the body section  120  by the latch mechanism. When the cover section  110  is locked on the body section  120  by the latch mechanism, the spring  14  accumulates a predetermined elastic energy. At that time, the cover section  110  is completely closed relative to the body section  120 . When the cover section  110  is opened, as long as the latch mechanism is unlocked, the cover section  110  automatically resumes to an open state under the role of the elastic energy of the spring  14 . 
         [0034]    In the embodiment described above, one of the advantage of the hinge assembly  10  is that it only has three main components, and occupies a relatively small volume. Accordingly, the occupied space of the hinge assembly  10  required in an application such as the mobile phone  100  is reduced. In addition, the engagement of the screw portion  122  and the projection  166  of the follower  16  can dampen the opening of the cover section  110 , so that the cover section  110  is protected from damage, thus prolonging the lifetime of the mobile phone  100 . Furthermore, using a projection engaging a thread having a groove that is wider than the length of the projection is simpler and creates smaller contact patches having less friction than the structure of two elongated spiral threads engaging with each other. 
         [0035]    Referring to  FIG. 6 , a hinge assembly  20  is provided according to a second embodiment. The hinge assembly  20  includes a shaft  22 , a spring  24 , a follower  26 , and a locking element  28 . The shaft  20  includes a securing portion  222  at one end thereof, and a loop groove  226  at the other end thereof. The securing portion  222  of the shaft  22  is engaged in the body section  120  of the mobile phone  100 , and cannot rotate relative to the body section  120 . A projection  224  is formed at the shaft  12  adjacent to the securing portion  222 . The projection  224  includes a front surface  2240 , a rear surface  2242  and a curved main surface  2244 . The front and rear surfaces  2240 ,  2242  are planar and have a semi-circular cross-section. The curved main surface  2244  has a longitudinal axis parallel to the longitudinal axis D of the shaft  20 . 
         [0036]    The spring  24  is preferably helical and metallic, and can be located around the shaft  22 . The follower  26  is generally cylindrical in shape. The follower  26  includes two opposite planar surfaces  262 . The follower  26  has an inner peripheral wall and a through hole  264  extending therethrough. A threaded portion  266  is formed on the inner peripheral wall corresponds to the projection  224  of the shaft  22 . The threaded portion  266  is a singe thread, which is formed by a helical groove and a raised helical or spiral rib/ridge around a center of the through hole  264 . When the projection  224  engages with the threaded portion  266  of the follower  26 , one of the front or rear surfaces contact the helical ridge, and the curved main surface  2244  is disposed in the helical groove. In this embodiment, the width L 4  of the projection  224  is substantially less than the longitudinal length of a helical groove of the threaded portion  266 . In this embodiment, when the projection  224  engages in the helical groove, one of the front and rear surfaces  2240 ,  2242  at a time contact/resist helical ridge of the threaded portion  2662 . Since the front and rear surfaces  2240 ,  2242  are planar, the projection  224  is in linear contact with the helical ridge of the follower  26 . The follower  26  may be placed around the shaft  22  by the through hole  264 , with the projection  224  engaging with the threaded portion  266 . The locking element  28  is a C-shaped ring, and is used for engaging in the loop groove  226  of the shaft  22 . 
         [0037]    Referring to  FIG. 7 , in assembly, the locking element  28  is locked in the loop groove  226  of the shaft  22 . The spring  24  is placed around the shaft  22  so that one end of the spring  24  resists the locking element  28 . Then, the shaft  22  passes through the through hole  264  of the follower  26 , and the projection  224  of the shaft  22  engages in the threaded portion  266  of the follower  26 . The other end of the spring  24  resists the follower  26 . The spring  24  is compressed so as to accumulate a predetermined spring force. Finally, the hinge assembly  20  is assembled in the mobile phone. The assembled process of the hinge assembly  20  and the mobile phone is similar to the first embodiment, and is not detailed herein. In use, either of the follower  26  or the cover section is unlocked, the follower  26  rotates and slides relative to the shaft  22  so as to achieve the cover section to be opened relative to the body section. 
         [0038]    Referring to  FIG. 8 , a hinge assembly  30  is provided according to a present third embodiment. The hinge assembly  30  includes a shaft  32 , a projection in the form of a rolling element  34 , a spring  36 , and a follower  38 . The shaft  30  has a flange  322  formed at one end thereof. The flange  322  is engaged in a body section of a mobile phone, and made unable to rotate relative to the body section. A semi-spherical groove  324  is defined in a middle upper portion of the shaft  22 . 
         [0039]    The rolling element  34  is sphere-shaped made of stainless iron. A diameter of the rolling element  34  is substantially similar to that of the groove  324  so that the rolling element  34  can be received in the groove  324 . 
         [0040]    The spring  36  is preferably helical and metallic, and can be placed around the shaft  32 . The follower  38  is generally cylindrical in shape. The follower  38  includes two opposite planar surfaces  382 . The follower  38  has an inner peripheral wall and a through hole  384  extending therethrough. A threaded portion  386  is formed on the inner peripheral wall corresponds to the rolling element  34  received in the shaft  32 . The threaded portion  386  is formed by a helical groove and a raised helical or spiral rib/ridge around a center of the through hole  3844 . The rolling element  34  may be engaged with the threaded portion  386 . In this embodiment, the rolling element  34  is in point contact with the helical ridge of the follower  38 . 
         [0041]    In assembly, the spring  36  is placed around the shaft  32 . Then, the rolling element  34  is disposed in the groove  324  of the shaft  32 . After that, the follower  38  is placed around the shaft  32 , and the rolling element  34  of the shaft  32  engaging in the threaded portion  386  of the follower  38 . One end of the spring  36  resists the follower  38 , the other end of the spring  36  resists the flange  322 . The spring  24  is compressed so as to accumulate a predetermined spring force. The hinge assembly  30  is assembled in the mobile phone. The assembled process of the hinge assembly  30  with the mobile phone is similar to the first embodiment, and is not detailed herein. In use, either of the follower  38  or the cover section is unlocked, the follower  38  rotates and slides relative to the shaft  32  so as to realize the cover section to be opened relative to the body section. 
         [0042]    Referring now to  FIG. 9 , a hinge assembly  40  according to a fourth embodiment is provided. The hinge assembly  40  includes a shaft  42 , a spring  44  and a follower  46 . 
         [0043]    The shaft  42  has an outer peripheral surface thereof. One end of the shaft  42  defines a screw portion  424  at the outer peripheral surface thereof, and the other end of the shaft  42  forms a deformed portion  422  functioning as a securing portion. The screw portion  424  includes two threads with two spaced raised helical or spiral rib/ridge going around the shaft  12 . The spring  44  is preferably helical and metallic. The spring  44  has an inner diameter larger than a diameter of the shaft  42 . Thus, the spring  44  can be placed around the shaft  42 . 
         [0044]    Referring now to  FIG. 10 , the follower  46  is generally cylindrical in shape. The follower  46  includes two opposite planar surfaces  462 . The follower  46  has an inner peripheral wall and a through hole  464  extending therethrough. Two symmetrically projections  466  are formed on the inner peripheral wall corresponds to two threads of the screw portion  424  of the shaft  42 . Each projection  466  is substantially a semicircular cylinder, and includes an arcuate surface toward a center of the through hole  464 . The structure of each projection  466  is similar to the first embodiment, and thus is not detailed. 
         [0045]    Referring to  FIG. 11 , in assembly, the spring  44  is placed around the shaft  42 . The shaft  42  passes through the through hole  464  of the follower  46  and the projections  466  engage into the screw portion  424  of the shaft  42 . 
         [0046]    Referring to  FIG. 12 , the mobile phone  400  includes a cover section  410  and a body section  420 . The cover section  410  has a connecting portion  412  at one end thereof. The connecting portion  412  defines a receiving cavity  4122  and a first reverse rotating groove  4124  at one end thereof. The receiving cavity  4122  is adjacent to the first reverse rotating groove  4124 . The connecting portion  412  has a bottom wall  4125  adjacent to the first reverse rotating groove  4124 . One end of the body section  420  has an engaging portion  421 . The engaging portion  421  defines a second reverse rotating groove  4212  and a receiving groove  4214 . 
         [0047]    The hinge assembly  40  is assembled in the mobile  400 , one end of the assembled hinge assembly  40  with the follower  46  is inserted into the receiving cavity  4122 . The follower  46  is engaged in the first reverse rotating groove  4124  via the planar surfaces  462 , and the end of the deformed portion  422  of the shaft  42  is engaged with the second reverse rotating groove  4212 . One part of the spring  44  is received in the receiving groove  4214 . One end of the spring  44  resist the bottom wall  4125  of the receiving groove  4214 , the other end resists the follower  46 . 
         [0048]    Understandably, the thread number of the shaft may be more than two. Accordingly, the number of the projection in the follower corresponds to the thread number. If the thread of the screw portion is a single thread, the projection of the follower may be disposed two. The axial and radial distance between the projections, beneficially, corresponds to the thread distance of the shaft so that the two projections may engage in the thread of the shaft. 
         [0049]    In further alternative embodiments, the spring can be made of a nonmetallic material such as plastic. Furthermore, the spring can instead be made of other kind of elastic element or driving structure such as a resilient cylinder. Understandably, a diameter of the spring may be smaller than that of the shaft. Accordingly, the spring does not place around the shaft, instead, the spring directly resists one end of the shaft for providing a force allowing the follower to move relative to the shaft. Alternatively, the spring may be omitted, and an axial push force is provided for the shaft or the follower so that the shaft and the follower move relative to each other. 
         [0050]    The deformed portion of the shaft may be replaced with other configuration securing portion. In addition, the planar faces of the follower may be replaced with other configuration structure. 
         [0051]    Alternatively, the groove of the rolling element may be not semicircular, and the groove may be half-cylindrical as long as the rolling element is received in the groove and not rotate along a peripheral direction. In addition, the groove may be a helical thread. 
         [0052]    Alternatively, the shape of the projection or the rolling element is not limited as functioning a resisting portion for resisting the thread to realize the movement between the shaft and the follower. In addition, the spring may be not limited to resist the body section, and may resist the cover section. 
         [0053]    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.