Patent Abstract:
A hinge mechanism includes two pivoting shafts substantially parallel to each other, two main gears non-rotatably sleeved on the pivoting shafts, respectively. The hinge mechanism further includes two transmission gears positioned between the main gears, and two brackets sleeved on the pivoting shafts, respectively. Each transmission gear meshes with the other transmission gear and one main gear. Each pivoting shaft includes a flange which defines two locking portions, and each bracket forms two latching portions engaging with the locking portions of each pivoting shaft. The locking portions and the latching portions are selected from the structures of groove and hook.

Full Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure generally relates to hinges, and more particularly to a hinge mechanism applied in an electronic device. 
     2. Description of Related Art 
     There are many electronic devices that include hinged elements. To ensure that one part of the electronic device is capable of rotating relative to the other part thereof, a hinge mechanism applied in an electronic device often includes a first bracket, a second bracket, and two pivoting shafts. The first bracket and the second bracket are respectively sleeved on the pivoting shafts. The hinge mechanism further includes other elements, such as a plurality of friction members, resilient members, and fasteners sleeved on the pivoting shafts to provide axial force between the elements. 
     In use, the first bracket is rotated, and it drives one of the pivoting shafts to rotate relative to the other one of the pivoting shafts. Therefore, the two parts of the electronic device are capable of rotating relative to each other. 
     However, in order to open or close the electronic device, a user must exert continuous force on one part of the electronic device, and may take a relatively long time to open or close. 
     Therefore, there is room for improvement within the art. 
    
    
     
       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 several views, and all the views are schematic. 
         FIG. 1  is an assembled, isometric view of one embodiment of a hinge mechanism. 
         FIG. 2  is a partially exploded, isometric view of the hinge mechanism of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     The hinge mechanism as described in the embodiment as presented herein may be applied in any electronic device having two or more hinged parts, such as notebook computers, LCD monitors, and DVD (digital video disc) players. 
     Referring to  FIGS. 1 and 2 , a hinge mechanism  100  includes a first rotation assembly  10 , a second rotation assembly  30  substantially parallel to the first rotation assembly  10 , a transmission assembly  50 , a first resisting member  70 , and a second resisting member  90 . The transmission assembly  50  is positioned between the first rotation assembly  10  and the second rotation assembly  30 , and is held by the first resisting member  70  and the second resisting member  90 . 
     The first rotation assembly  10  includes a pivoting shaft  11 , and a main gear  12 , a bracket  13 , a friction member  14 , a plurality of resilient members  15 , a flat washer  16 , and a fastener  17  sleeved on the pivoting shaft  11  in that order. 
     The pivoting shaft  11  includes a non-circular shaft portion  111 , a circular shaft portion  113 , a first flange  115  between the non-circular shaft portion  111  and the circular shaft portion  113 , and a second flange  117  adjacent to one end of the circular shaft portion  113  and away from the non-circular shaft portion  111 . The non-circular shaft portion  111  defines a threaded portion  1111  at a distal end thereof. The second flange  117  defines two locking portions  1171 , which are separated by 180 degrees at a circumferential periphery of the second flange  117 . In the illustrated embodiment, the locking portions  1171  are a plurality of grooves recessing from the circumferential periphery of the second flange  117 . Alternatively, the second flange  117  may define one or more than two locking portions  1171  or form a plurality of hooks thereon. 
     The locking portions  1171  of the second flange  117  of the pivoting shaft  11  are shaped by a gear shaping machine (not shown), which reduces the production cost. 
     The main gear  12  defines a non-circular hole  121  therein. 
     The bracket  13  includes a pivotal portion  131 , a connection portion  133 , and at least one latching portion  135 . The pivotal portion  131  is connected to the connection portion  133 , and the at least one latching portion  135  is formed on the pivotal portion  131 . The pivotal portion  131  defines a sleeve hole  1311  therein, the connection portion  133  defines two connection holes  1331  therein; and therefore, the bracket  13  is capable of being connected to one part of an electronic device (no shown). In the illustrated embodiment, the bracket  13  includes two latching portions  135 , and the latching portions  135  are a plurality of hooks substantially perpendicularly protruding from and 180 degrees apart at the circumferential periphery of the pivotal portion  131 . Alternatively, the bracket  13  may include one or more than two latching portions  135 , and the latching portions  135  may be grooves recessing from the circumferential periphery of the pivotal portion  131 . 
     Both the friction member  14  and the flat washer  16  define a plurality of non-circular holes corresponding to a profile of the non-circular shaft portion  111  of each pivoting shaft  11 . In the illustrated embodiment, the resilient members  15  are a plurality of disk-shaped elastic washers resisting one another, and the fastener  17  is a screw nut. Alternatively, the first rotation assembly  10  may include a helical spring, an elastic sleeve, or other elastic members instead, and the fastener  17  may be a rivet penetrating the distal end of the pivoting shaft  11 , and the pivoting shaft  11  may define a through hole adjacent to the distal end thereof. 
     The second rotation assembly  30  is similar to the first rotation assembly  10  but without the friction member  14  and the resilient members  15 . Alternatively, the second rotation assembly  30  may have a same structure as the first rotation assembly  10 . 
     The transmission assembly  50  includes two rotation shafts  51  and two transmission gears  53 , and the transmission gears  53  are respectively sleeved on the rotation shafts  51 . 
     The first resisting member  70  is a plate, which includes a resisting portion  71  and a fixing portion  73  extending from one edge of the resisting portion  71 . In the illustrated embodiment, the fixing portion  73  is substantially perpendicular to the resisting portion  71 . 
     The second resisting member  90  is a plate, which defines two pivot holes  91 , and two shaft holes  93  positioned between the pivot holes  91 . 
     During assembly of the hinge mechanism  100 , the rotation shafts  51  of the transmission assembly  50  pass through the shaft holes  93  of the second resisting member  90 , and the transmission gears  53  are respectively sleeved on the rotation shaft  51 . The non-circular shaft portion  111  of the pivoting shaft  11  of the first rotation assembly  10  passes through the resisting portion  71  of the first resisting member  70 , one main gear  12 , one pivot hole  91  of the second resisting member  90 , the friction member  14 , the resilient members  15 , the flat washer  16 , and the fastener  17 ; the fastener  17  engages with the threaded portion  1111  of the pivoting shaft  11 . Therefore, the first flange  115  resists the resisting portion  71  of the first resisting member  70 . The other end of the pivoting shaft  11  adjacent to the second flange  117  passes through the sleeve hole  1311  of the pivotal portion  131  of the bracket  13 , and the latching portions  135  engage with the locking portions  1171  of the second flange  117  of the pivoting shaft  11  by interference fit. 
     The second rotation assembly  30  is assembled to the transmission assembly  50 , the first resisting member  70 , and the second resisting member  90  in a same manner. The first resisting member  70  and the second resisting member  90  defines a receiving space (not shown) in which the transmission assembly  50 , the main gear  12  of the first rotation assembly  10 , and the main gear (not labeled) of the second rotation assembly  30  are received and held by the resisting portion  71  of the first resisting member  70  and the second resisting member  90 . 
     When the hinge mechanism  100  is applied in an electronic device, an external force is exerted on one part of the electronic device to drive the first rotation assembly  10 , for example, to rotate together with the side part of the electronic device. The transmission assembly  50  transmits the torque to the main gear of the second rotation assembly  30 , thus that the main gear of the second rotation assembly  30  rotates in an opposite direction to the main gear  12  of the first rotation assembly  10 . The second rotation assembly  30  transmits the torque to the bracket (not labeled) of the second rotation assembly  30  by the pivoting shaft (not labeled) of the second rotation assembly. Therefore, the two parts of the electronic device may be opened or closed at double-speed, and that it requires a user when using the electronic device to exert a force for a relatively shorter duration to open or close the electronic device. 
     In the hinge mechanism  100 , the locking portions  1171  of the second flange  117  of the pivoting shaft  11  engage with the latching portions  135  of the bracket  13  with grooves and hooks, and therefore, the pivoting shaft  11  and the bracket  13  are non-rotatable relative to each other. Because the hooks are received in the grooves, which are capable of bearing a relative larger amount of torque than simply the engagement of the non-circular shaft and non-circular holes, as a result, the pivoting shaft  11  is more securely maintained to synchronously rotate with the bracket  13 . Additionally, the pivoting shaft  11  and the bracket  13  are not easily damaged, and therefore the hinge mechanism  100  has a longer life-span. 
     The pivoting shaft  11  and the bracket  13  of the first rotation assembly  10  are engaged by interference fit, and the pivoting shaft and the bracket of the second rotation assembly  30  are engaged in a same manner, which further improves the engagement therebetween. 
     The locking portions  1171  of the second flange  117  of the pivoting shaft  11  are separated by 180 degrees at the circumferential periphery of the second flange  117 , and the latching portions  135  are separated by 180 degrees at the circumferential periphery of the pivotal portion  131  of the bracket  13 . Thereby, the torque is symmetrically divided to opposite sides of the pivoting shaft  11  and the bracket  13 , and a stability of the first rotation assembly  10  is further improved. For the same reason, a stability of the second rotation assembly  30  is also further improved. 
     The transmission assembly  50 , the main gear  12  of the first rotation assembly  10 , and the main gear of the second rotation assembly  30  are received in the receiving space defined by the first resisting member  70  and the second resisting member  90 . Thereby, the dust is prevented from entering the gaps between the gears, and the gears are capable of rotating more smoothly. 
     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.

Technology Classification (CPC): 8