Patent Publication Number: US-2010125973-A1

Title: Hinge assembly and electronic device using the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is related to four co-pending U.S. patent applications, application Ser. No. 12/261,225 filed on Oct. 30, 2008, entitled “HINGE ASSEMBLY”, application Ser. No. 12/261,230 filed on Oct. 30, 2008, entitled “HINGE ASSEMBLY”, application Ser. No. 12/396,557 filed on Mar. 3, 2009, entitled “HINGE ASSEMBLY”, application Ser. No. 12/417,817 filed on Apr. 3, 2008, entitled “HINGE ASSEMBLY”. The co-pending applications have the same assignee as the present application. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates generally to hinge assemblies and electronic devices using the same and, more particularly, to a hinge assembly for a foldable electronic device. 
     2. Description of Related Art 
     A typical foldable electronic device such as a notebook computer generally has a main body and a cover with a display pivotally mounted on the main body via a typical hinge. The cover is latched to the main body via a hook positioned on the main body. However, the appearance of the notebook computer is unappealing because of the hook. Therefore the typical hinge generally has a fastening assembly to replace the hook positioned on the main body. 
     The typical hinge includes a pivot shaft, a first stand, a second stand, a fastening assembly, and a plurality of spring washers. The pivot shaft includes a shaft portion and a connecting portion formed on an end of the shaft portion. The first stand, the fastening assembly, and the spring washers are sleeved on the shaft portion. The second stand is non-rotatably sleeved on the connecting portion. The fastening assembly includes a cam and a cam follower. The cam is rotatably connected to the shaft portion, and the cam follower is non-rotatably connected to the shaft portion. A plurality of peaks is formed on a side surface of the cam. The cam follower defines a plurality of valleys receiving the peaks. The first stand has a first fixing plate, and the first fixing plate is fixed to the main body. The second stand has a second fixing plate, and the second fixing plate is fixed to the cover. When the cover is rotated towards the main body, the peaks of the cam engage with the valleys of the cam follower, and the first fixing plate is substantially parallel to the second fixing plate. Since the first fixing plate is fixed to the cover, and the second fixing plate is fixed to the main body, the cover is also substantially parallel to main body. Thus, a gap may be formed between the cover and the main body, and a height of the gap is substantially the same along a direction away from the hinge assembly. The cover may wobble relative to the main body due to this gap. That is, the cover cannot be firmly folded over the main body. 
     Therefore, a hinge assembly and an electronic device using the same to solve the aforementioned problems are desired. 
    
    
     
       BRIEF DESCRIPTION OF THE 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 disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an exploded, isometric view of an embodiment of an electronic device, the electronic device including a main body, a cover, and an embodiment of a hinge assembly. 
         FIG. 2  is an exploded, isometric view of the hinge assembly in  FIG. 1 , the hinge assembly including a cam and a cam follower. 
         FIG. 3  is an isometric view of the cam and the cam follower of the hinge assembly in  FIG. 2 . 
         FIG. 3  is an assembled, isometric view of the hinge assembly in  FIG. 1 , but viewed from another aspect. 
         FIG. 4  is a side view of the electronic device of  FIG. 1 , with the cover closed over the main body. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , an embodiment of an electronic device  100  includes a main body  10 , a cover  30 , and two hinge assemblies  50  connecting the cover  30  with the main body  10 . 
     Referring to  FIG. 2 , an embodiment of the hinge assembly  50  includes a pivot shaft  51 , a rotatable stand  52 , a fixed stand  53 , a cam follower  54 , a cam  55 , a restricting member  56 , an elastic member  57 , a fastening member  58 , two friction members  591 , and a flat washer  592 . 
     The pivot shaft  51  includes a shaft portion  513 . The shaft portion  513  has two first positioning surfaces  5131  on opposite sides of the shaft portion  513 . A flange  511  is formed on a proximal end of the shaft portion  513 , and a threaded portion  514  is formed on a distal end of the shaft portion  513 . A shaft head  515  is formed on the flange  511  along an extending direction of the shaft portion  513 . The shaft head  515  defines two second positioning surfaces  5151  on opposite sides of the shaft head  515 . Each second positioning surface  5151  is coplanar with one corresponding first positioning surface  5131 . 
     The rotatable stand  52  includes a first base plate  521  and a first fixing plate  523  extending substantially perpendicularly from a side of the first base plate  521 . The first base plate  521  defines a connecting hole  5211  corresponding to the shaft head  515 . Two connecting surfaces  5213 , corresponding to the two second positioning surfaces  5151  of the shaft head  515 , are formed on the sidewall in the connecting hole  5211 . When the shaft head  515  is received in the connecting hole  5211  of the first base plate  521 , the second positioning surfaces  5151  resist the connecting surfaces  5213 , thus non-rotatably connecting the rotatable stand  52  to the pivot shaft  51 . The first fixing plate  523  is fixedly connected to the cover  30 . The connecting surfaces  5213  of the rotatable stand  52  are oblique to the first fixing plate  523 . 
     The fixed stand  53  includes a second base plate  531  and a second fixing plate  533  extending substantially perpendicularly from a side of the second base plate  531 . The second base plate  531  defines a circular pivot hole  5313  in an end away from the second fixing plate  533 , and a fixing hole  5315  in a middle portion. A limiting protrusion  5311  is formed on the second base plate  531  adjacent to the pivot hole  5313 . The second fixing plate  533  is fixedly connected to the main body  10 . 
     The cam follower  54  is substantially cylindrical. A center of the cam follower  54  defines a non-circular through hole  541  corresponding to the shape of the shaft portion  513  of the pivot shaft  51 . The cam follower  54  defines two positioning cutouts  543  in a side surface. 
     The cam  55  includes a cylindrical assembling portion  551  and a positioning portion  552  formed at one end of the assembling portion  551 . In this embodiment, the positioning portion  552  is substantially triangular-shaped. A center of the assembling portion  551  defines a substantially circular cam hole  5511 . Referring also to  FIG. 3 , two positioning protrusions  5512  are formed on a side surface of the assembling portion  551 . Each positioning protrusion  5512  is configured for engaging with one corresponding positioning cutout  543  of the cam follower  54 . A positioning pole  5521  extends from the positioning portion  552 . 
     The restricting member  56  includes a circular main portion  561 . A center of the main portion  561  defines a non-circular through hole  563  corresponding to the shape of the shaft portion  513  of the pivot shaft  51 . A restricting portion  562  is formed at an edge of the main portion  561 . In this embodiment, the first restricting portion  562  is an arched protrusion radially extending from an edge of the main portion  561 . 
     In the illustrated embodiment, the elastic member  57  is composed of a plurality of spring washers  57 , and the fastening member  58  is a nut configured to engage with the threaded portion  514  of the pivot shaft  51 . 
     Referring to  FIGS. 2 through 4 , in assembling the hinge assembly  50 , the threaded portion  514  of the pivot shaft  51  extends through one friction member  591 , the through hole  563  of the restricting member  56 , the pivot hole  5313  of the fixed stand  53 , the other friction member  591 , the cam hole  5511  of the cam  55 , the through hole  541  of the cam follower  54 , the elastic member  57 , the flat washer  592 , and engages with the fastening member  58 . The shaft head  515  engages with the rotatable stand  52 . Therefore, the rotatable stand  52 , the restricting member  54 , and the cam follower  54  are non-rotatably connected to the pivot shaft  31 . The positioning pole  5521  of the cam  55  is inserted into the fixing hole  5315  of the fixed stand  53 . The positioning protrusions  5512  of the cam  55  are capable of engaging in the positioning cutouts  543  of the cam follower  54 . The fastening member  58  can be adjusted on the pivot shaft  51 , such that the elastic member  57  becomes elastically deformed and applies an elastic force on the cam follower  54 . After the hinge assembly  50  is assembled, the rotatable stand  52  is fixedly connected to the main body  10 , and the fixed stand  53  is fixedly connected to the main body  10 . 
     When the electronic device  100  needs to be closed, the cover  30  is rotated towards the main body  10 , and the rotatable stand  52  is rotated on the pivot shaft  51 , for example, in a clockwise direction. The pivot shaft  51  rotates together with the rotatable stand  52 , and the restricting member  56  and the cam follower  54  rotate together with the pivot shaft  51 . When the restricting portion  562  of the restricting member  56  resists the limiting protrusion  5311  of the fixed stand  53 , the rotatable stand  52  has reached a clockwise rotatable limit and cannot rotate any further in the clockwise direction. At the clockwise rotatable limit, the positioning protrusions  5512  of the cam  55  engage in the corresponding positioning cutouts  543  of the cam follower  54  driven by the elastic force of the elastic member  57 . Then, the cover  30  is closed to the main body  10  as shown in the  FIG. 5 . 
     Since the connecting surfaces  5213  of the rotatable stand  52  is oblique to the first fixing plate  523 , and the second positioning surfaces  5151  is substantially parallel to the first positioning surfaces  5131 , when the shaft head  515  is received in the connecting hole  5211 , the first positioning surfaces  5131  of the shaft portion  513  is also oblique to first fixing plate  523 . Therefore, the second fixing plate  533  of the fixed stand  53  is oblique to the first fixing plate  523  of the rotatable stand  52 , because the fixed stand  53  is non-rotatably connected to the shaft portion  513 . When the cover  30  is brought towards the main body  10 , the cover  30  is oblique to the main body  10 , with the cover  30  contacting the main body  10  at an end away from the hinge assembly  50  as shown in  FIG. 5 . Thus, the cover  30  does not wobble relative to the main body  10 . That is, the cover  30  is firmly closed to the main body  10 . 
     It should be pointed out that the cover  30  can also be oblique to the main body  10  in a closed state by changing a structure of the hinge assembly  50 . For example, the first positioning surfaces  5131  of the shaft portion  513  can be oblique to the second positioning surfaces  5151  of the shaft head  515 , and the connecting surfaces  5213  of the rotatable stand  52  are substantially parallel to the first fixing plate  523 . When the pivot shaft  51  is engaged with the rotatable stand  52 , the first positioning surfaces  5131  are oblique to the first fixing plate  523 . Thus, when the positioning protrusions  5512  of the cam  55  engage in the corresponding positioning cutouts  543  of the cam follower  54 , the second fixing plate  533  is oblique to the first fixing plate  523 . That is, the cover  30  is oblique to the main body  10  in the closed state. In addition, the cover  30  can be oblique to the main body  10  in the closed state by changing the positions of the positioning protrusions  5512  on the cam  55 . Moreover, one or more positioning protrusions can be formed on the cam follower  54 , and the cam  55  can define one or more positioning cutouts corresponding to the one or more positioning protrusions. The cam  55  can also be non-rotatably connected to the pivot shaft  51 , and the cam follower  54  is rotatably connected to the pivot shaft  51 . 
     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 disclosure or sacrificing all of its material advantages.