You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to hinge technology, and more particularly to an improved structure of planetary type dual-shaft hinge, which provides a variable radius in a flip-up electronic device by using a female shaft to match with two male shafts so that when the cover member of the flip-up electronic device is opened from the base member thereof, the female shaft and the male shafts are rotated to smoothen the pivoting motion of the cover member, enabling the cover member and base member of the flip-up electronic device to be kept on one same plane after the flip-up electronic device is fully opened. 
     2. Description of the Related Art 
     Hinges are intensively used in flip-up mobile electronic devices such as notebooks, smart phones, and etc. to pivotally connect a base member and a cover member together, allowing only a limited angle of rotation between them. Some flip-up mobile electronic devices allow the cover member to be turned from the top side of the base member to the bottom side thereof, enabling the flip-up mobile electronic devices to be used as a tablet computer. 
     A hinge for this application is a dual-shaft design. Taiwan Patent Publication Number M413776 discloses a dual-shaft hinge design. According to this design, first coupling means and second coupling means are provided at two opposite sides of connection plate means; the first coupling means provides a first opening at an end edge thereof adjacent to one side of connection plate means; the second coupling means provides a second opening at an end edge thereof adjacent to an opposite side of connection plate means; a first male shaft and a second male shaft are respectively mounted in the first coupling means and the second coupling means. When opening a cover member from a base member of a flip-up electronic device using the hinge, the first male shaft and the second male shaft are rotated one after another in a proper order, allowing the cover member to be easily lifted with less effort. However, when reversing the cover member relative to the base member to close the flip-up electronic device, mush resisting force will be produced. According to this conventional design, the first coupling means and the second coupling means can wear quickly with use, resulting in elastic fatigue losing and losing their functions to rotate in sequence. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a planetary type dual-shaft hinge for use in a flip-up electronic device, which uses a transmission mechanism to couple a first male shaft and a second male shaft in a female shaft, enabling the first male shaft to be turn around the second male shaft when the user opens the cover member of the flip-up electronic device from the base member, smoothening the operation. 
     To achieve this and other objects of the present invention, a planetary type dual-shaft hinge of the invention comprises a female shaft, a male shaft set and a transmission mechanism. The female shaft comprises a shaft body defining a first barrel and a second barrel in a parallel manner. The male shaft set comprises a first male shaft rotatably inserted through the first barrel of the female shaft, and a second male shaft rotatably inserted through the second barrel of the female shaft. The first male shaft comprises a first hinge plate located at one end thereof. The first hinge plate defines a first mounting portion. The second male shaft comprises a second hinge plate located at one end thereof. The second hinge plate defines a second mounting portion. The transmission mechanism comprises a first transmission member, a second transmission member and a link. The first transmission member is fixedly connected to an opposite end of the first male shaft opposite to the first hinge plate. The second transmission member is fixedly connected to an opposite end of the second male shaft opposite to the second hinge plate. The link has two opposite ends thereof respectively pivotally coupled to the first transmission member and the second transmission member. The first transmission member and the second transmission member are disposed at one same side relative to the female shaft. Further, the pivoting point between the link and the first transmission member is disposed within the area between the central axis of the first transmission member and the first mounting portion. Further, the pivoting point between the link and the second transmission member is disposed at one lateral side relative to the central axis of the second transmission member and remote from the second mounting portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an elevational view of a planetary type dual-shaft hinge in accordance with the present invention. 
         FIG. 2  is an exploded view of the planetary type dual-shaft hinge in accordance with the present invention. 
         FIG. 3  corresponds to  FIG. 1 , illustrating the angular position between first hinge plate and the second hinge plate changed. 
         FIG. 4  is a schematic side plain view of the planetary type dual-shaft hinge in accordance with the present invention. 
         FIG. 5  is a schematic applied view of the present invention, illustrating the first hinge plate and second hinge plate of the planetary type dual-shaft hinge respectively affixed to a cover member and a base member of a flip-up electronic device. 
         FIG. 6  corresponds to  FIG. 5 , illustrating the cover member of the flip-up electronic device opened from the base member and the first transmission member turned around the second transmission member. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1 and 2 , a planetary type dual-shaft hinge in accordance with the present invention is shown. The planetary type dual-shaft hinge comprises a female shaft  1 , a male shaft set  2 , and a transmission mechanism  3 . 
     The female shaft  1  comprises a shaft body  11  defining a first barrel  12  and a second barrel  13  in a parallel manner. 
     The male shaft set  2  comprises a first male shaft  21 , a second male shaft  22 , and a constraint plate  23 . The constraint plate  23  defines a first constraint hole  231  and a second constraint hole  232 . Further, the constraint plate  23  is disposed at one side relative to the female shaft  1 . The first male shaft  21  is inserted through the first constraint hole  231  of the constraint plate  23  and the first barrel  12  of the female shaft  1 . The second male shaft  22  is inserted through the second constraint hole  232  of the constraint plate  23  and the second barrel  13  of the female shaft  1 . Further, the first male shaft  21  and the second male shaft  22  are respectively affixed to a first hinge plate  24  and a second hinge plate  25 . The first hinge plate  24  comprises a first connection portion  241  connected to the first male shaft  21 , and a first mounting portion  242  extended from the periphery of the first connection portion  241 . The second hinge plate  25  comprises a second connection portion  251  connected to the second male shaft  22 , and a second mounting portion  252  extended from the periphery of the second connection portion  251 . 
     The transmission mechanism  3  comprises a first transmission member  31 , a second transmission member  32 , a link  33 , a first coupling shank  34 , and a second coupling shank  35 . The first transmission member  31  is a circular plate member, defining a first non-circular center mounting hole  311  attached to one end of the first male shaft  21  remote from the first hinge plate  24  for synchronous rotation with the first male shaft  21 , a first pivot hole  312  disposed at one side relative to the first non-circular center mounting hole  311  in a parallel manner, and a first bearing surface  313  extending around the periphery thereof. The second transmission member  32  is a circular plate member, defining a second non-circular center mounting hole  321  attached to one end of the second male shaft  22  remote from the second hinge plate  25  for synchronous rotation with the second male shaft  22 , a second pivot hole  322  disposed at one side relative to the second non-circular center mounting hole  321  in a parallel manner, and a second t bearing surface  323  extending around the periphery thereof. Further, the combined length of the radius of the first transmission member  31  and the radius of the second transmission member  32  is equal to the distance between the central axis of the first shaft  21  and the central axis of the second male shaft, enabling the first bearing surface  313  of the first transmission member  31  to be abutted against the second bearing surface  323  of the second transmission member  32 . The link  33  is an elongated plate member defining a first through hole  331  and a second through hole  332 . The first coupling shank  34  has its two opposite ends respectively pivotally coupled to the first pivot hole  312  of the first transmission member  31  and the first through hole  331  of the link  33 . The second coupling shank  35  has its two opposite ends respectively pivotally coupled to the second pivot hole  322  of the second transmission member  32  and the second through hole  332  of the link  33 . Because the first pivot hole  312  and the second pivot hole  322  are respectively disposed at one side relative to the first non-circular center mounting hole  311  and the second non-circular center mounting hole  321 , the pivoting point between the link  33  and the first transmission member  31  is deviated from the connection point between the first transmission member  31  and the first male shaft  21 , and the pivoting point between the link  33  and the second transmission member  32  is deviated from the connection point between the second transmission member  32  and the second male shaft  22 . 
     Referring to  FIGS. 3 and 4  and  FIG. 2  again, when biasing the first hinge plate  24  to rotate the first male shaft  21 , the first male shaft  21  drives the first transmission member  31  to rotate. Because the pivoting point between the link  33  and the first transmission member  31  is disposed within the area between the central axis of the first transmission member  31  and the first mounting portion  242  and the pivoting point between the link  33  and the second transmission member  32  is disposed at one lateral side relative to the central axis of the second transmission member  32  and far from the second mounting portion  252 , rotating the first transmission member  31  can drive the first coupling shank  34  to push the link  33 . Further, because the two opposite ends of the link  33  are respectively pivotally coupled to the first transmission member  31  and the second transmission member  32 , the thrust force produced during rotary motion of the first coupling shank  34  can drive the first transmission member  31  to turn about the second transmission member  32 , causing the first male shaft  21  to rotate. 
     Referring to  FIGS. 5 and 6  and  FIG. 2  again, when using the planetary type dual-shaft hinge in a flip-up electronic device  5 , the first mounting portion  242  of the first hinge plate  24  and the second mounting portion  252  of the second hinge plate  25  are respectively affixed to cover member  51  and base member  52  of the flip-up electronic device  5 . When opening the cover member  51  from the base member  52 , the first transmission member  31  will be turned about the second transmission member  32 . 
     In the present preferred embodiment, the first transmission member  31  is turned around the second transmission member  32  from the top side to the bottom side through 180-degrees angle, and the pivoting point between the link  33  and the first transmission member  31  is turned around the first male shaft  21  through 360-degrees angle, allowing the cover member  51  of the flip-up electronic device  5  to be turned from the top side of the base member  52  to the bottom side thereof. When the cover member  51  is turned to one lateral side of the base member  52  and kept on the same plane relative to the base member  52 , the pivoting point between the link  33  and the first transmission member  31  is turned around the first male shaft  21  through 180-degrees angle, and the first transmission member  31  is turned around the second transmission member  32  through 90-degrees angle. Further, because the first bearing surface  313  of the first transmission member  31  is abutted against the second bearing surface  323  of the second transmission member  32 , the second bearing surface  323  of the second transmission member  32  provides support to the first transmission member  31  during turning of the first transmission member  31  around the second transmission member  32 , smoothening the motion of the first transmission member  31 . 
     As stated above, the key technology of the present invention to eliminate the drawbacks of conventional designs is that the female shaft  1  accommodates the first male shaft  21 , which is affixed to the first transmission member  31 , and the second male shaft  221 , which is affixed to the second transmission member  32 ; the link  33  is pivotally coupled with the first transmission member  31  and the second transmission member  32 ; the pivoting point between the link  33  and the first transmission member  31  is disposed within the area between the central axis of the first transmission member  31  and the first mounting portion  242  of the first hinge plate  24  of the male shaft set  2 ; the pivoting point between the link  33  and the second transmission member  32  is disposed at one lateral side relative to the central axis of the second transmission member  32  and far from the second mounting portion  252  of the second hinge plate  25  of the male shaft set  2 . Thus, rotating the first male shaft  21  can drive the first transmission member  31  to turn around the second transmission member  32  smoothly, eliminating the drawbacks of the prior art design. The pivoting point between the link  33  and the first transmission member  31  and the pivoting point between the link  33  and the second transmission member  32  are disposed in reversed directions relative to the central axes of the first male shaft  21  and second male shaft  22  so that the cover member  51  and the base member  52  can be kept on the same plane after turning of the cover member  51  through 180-degrees angle relative to the base member  52 , avoiding any elevation difference between the cover member  51  and the base member  52 . 
     Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention.

Summary:
A planetary type dual-shaft hinge includes a female shaft, a male shaft set including first and second male shafts respectively inserted through the female shaft, and a transmission mechanism including first and second transmission members respectively connected to the first and second male shafts and a link pivotally coupled between the first and second transmission members in such a manner that the pivoting points between the link and the first and second transmission members are disposed at two opposite sides relative to the central axes of the first and second transmission members so that when the user opens the cover member of the flip-up electronic device in which the hinge is used, the first male shaft is turned around the second male shaft to smoothen the movement of the cover member.