Abstract:
A hinge assembly includes a shaft, a rotary member, and a tube. The rotary member includes a friction body and is fixed to the shaft. The tube rotatably engages with the friction body of the rotary member. When the tube rotates to a predetermined position relative to the rotary member, the friction body deforms, thereby generating friction between the friction body and the tube.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure generally relates to hinge assemblies, and particularly, to a self-retaining hinge assembly. 
         [0003]    2. Description of Related Art 
         [0004]    As consumer demand for portable electronic devices, such as mobile phones, to be progressively smaller and lighter, hinge assemblies applied therein must provide for the corresponding minimalization. 
         [0005]    A frequently used hinge assembly includes a shaft, a friction member fixed on the shaft, a cam rotatably sleeved on the shaft, a cam follower non-rotatably sleeved on the shaft and engaging the cam, a friction member non-rotatable relative to the cam, and at least one resilient member sleeved on the shaft and resisting the cam towards the cam follower. However, such hinge assembly includes numerous components and is very complex, with high manufacturing costs. 
         [0006]    Therefore, a hinge assembly is desired to overcome the described limitations. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout several views. 
           [0008]      FIG. 1  is an isometric, assembled view of an embodiment of a hinge assembly as disclosed. 
           [0009]      FIG. 2  is an isometric, exploded view of the hinge assembly of  FIG. 1 . 
           [0010]      FIG. 3  is a cross-section of the hinge assembly taken along line III-III of  FIG. 1 . 
           [0011]      FIG. 4  is a cross-section of the hinge assembly taken along line IV-IV of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    Referring to  FIG. 1 , an embodiment of a hinge assembly  100  applied in electronic devices such as mobile phones and personal digital assistants, includes a shaft  10 , a rotary member  30 , a tube  50 , and a fastener  70 . 
         [0013]    Referring to  FIG. 2  and  FIG. 3 , the shaft  10  includes a cap  11  and a shaft portion  13 . The shaft portion  13  includes a latching portion  131  engaging with the fastener  70 . 
         [0014]    The rotary member  30  can be integrally formed with the shaft  10  by insert-molding. During manufacture, the shaft  10  is positioned in an injection mold, and melted plastic is injected thereinto. When the plastic is cooled and solidified, the rotary member  30  is formed, fixed to the shaft  10 . The rotary member  30  includes a mounting portion  31  packaging a cap  11  of the shaft  10  and a friction body  33  packaging a part of the shaft portion  13 . In use, the mounting portion  31  is fixed to a cover of an electronic device (not shown). The friction body  33  includes a main body  331 , two friction portions  333  at opposite sides of the main body  331 , and two connecting portions  335 . Each connecting portion  335  protrudes from the main body  331  and each friction portion  333  protrudes from a corresponding connecting portion  335 . That is, a distance between utmost points of the two friction portions  333  exceeds a distance between utmost points of the two connecting portions  335 . The distance between utmost points of the two connecting portions  335  exceeds that between utmost points of the main body  331 . In the illustrated embodiment, the friction portion  333  and the connecting portion  335  are substantially rectangular. The friction portions  333  and the connecting portions  335  are elastic, thus capable of deforming. In the illustrated embodiment, the entire rotary member  30  is deformable and elastic. 
         [0015]    The tube  50  includes an outer surface  51 , a first end surface  53 , and a second end surface  55  opposite the first end surface  53 . The tube  50  defines a circular receptacle  57  at the first end surface  53  and a shaft hole  59  at the second end surface  55 . The receptacle  57  communicates with the shaft hole  59 . The tube  50  defines a connecting hole  511  in the outer surface  51 . The tube  50  is fixed to a main body (not shown) of the electronic device. The tube  50  may be fixed to the main body via the connecting hole  511 . The tube  50  includes an inner sidewall  571  enclosing the receptacle  57 . The inner sidewall  571  defines at least one positioning slot  573 . In the illustrated embodiment, four positioning slots  573  are evenly arranged. A diameter of the receptacle  57  is slightly less than the distance between utmost points of the two friction portions  333  and substantially the same as or slightly less than the distance between utmost points of the two connecting portions  335 . Alternatively, the receptacle  57  may have other shapes. The friction body  33  may also include one or more than two friction portions  333  and one or more than two connecting portions  335 . 
         [0016]    The fastener  70  is a closed ring having a latching hole  71  in which a latching portion  131  is riveted. After the latching portion  131  is riveted in the latching hole  71  by, for example, revolving-riveting, the latching hole  71  is slightly smaller than the latching portion  131 . 
         [0017]    Referring also to  FIG. 4 , during assembly of the hinge assembly  100 , the shaft  10  is fixed to the rotary member  30  by insert-molding. The shaft portion  13  passes through the receptacle  57  and the shaft hole  59  of the tube  50 , and the fastener  70  latches the shaft portion  13  to securely fix the tube  50  onto the shaft  10 . The friction body  33  engages in the receptacle  57 . The friction portions  333  deform to cause an interference fit with the inner sidewall  571  of the tube  50 , since the diameter of the receptacle  57  is slightly less than the distance between utmost points of the two friction portions  333 . 
         [0018]    When the shaft  10  is rotated, the rotary member  30  rotates relative to the tube  50  accordingly. The friction portions  333  deform to resist the inner sidewall  571  of the tube  50 . Friction generated between the friction portions  333  and the inner sidewall  571  enable retention of the shaft  10  in any position. That is, the hinge assembly  100  is self-retaining. When the friction portions  333  move to the positioning slots  573 , the friction portions  333  reset somewhat, such that friction between the friction portions  333  and the inner sidewall  571  decreases. When the shaft  10  is rotated further so that the friction portions  333  pass the positioning slots  573 , the friction increases. As such, it is apparent through a change in tension when the friction portions  333  reach the positioning slots  573 , that the shaft  10  may be positioned in that position. It can be understood that the shaft  10  may retain different positions by changing positions of the positioning slots  573 . 
         [0019]    The hinge assembly  100  is self-retaining by engagement of the elastic friction body  33  and the tube  50 , and simple in structure, facilitating ease of manufacture and assembly. The shaft  10  and the rotary member  30  can be integrally formed by insert-molding and can rotate together, reducing pressure on the shaft  10  such that the shaft  10  is small while satisfying strength requirements. Therefore, the hinge assembly  100  is correspondingly compact. The connecting portions  335  with height between the main body  331  and the friction portions  333  can reduce abrasion of the friction portions  333 . Compared with other structures, the closed fastener  70  can more firmly latch with the shaft  10  and is not easily broken. 
         [0020]    The fastener  70  may alternatively take the form of another member, such as a nut, or may even be omitted, in which case the end of the shaft  10  is riveted to the latching portion  131 . The shaft  10  may be fixed to the rotary member  30  by other means such as by co-engaged latches. In use, the rotary member  30  may be fixed to the main body of the electronic device, and the tube  50  is fixed to the cover accordingly. The rotary member  30  may be inelastic and non-deformable; with, the tube  50  being elastic and deformable instead. 
         [0021]    Finally, while various embodiments have been described and illustrated, the disclosure is not to be construed as being limited thereto. Various modifications can be made to the embodiments by those skilled in the art without departing from the true spirit and scope of the disclosure as defined by the appended claims.