Double hinge assembly and electronic device using the same

An electronic device comprising:

• a main body;
• a cover having a display body;
• and
• a double hinge assembly connecting the main body and the cover such that the cover is rotatable around two horizontal axes relative to the main body, the hinge assembly comprising:
• a first hinge assembly having a first noncircular rotatable pivot shaft;
• a second hinge assembly having a second noncircular rotatable pivot shaft;
• a first bracket having a noncircular hole and a second bracket having a noncircular hole;
• and
• a guide rail and a sliding member slidable on the guide rail;
• wherein the guide rail defines a first pivot hole, the sliding member defines a second pivot hole, the first rotatable pivot shaft extends through the first pivot hole of the guide rail and is nonrotatably extended through said noncircular hole in said first bracket, the second rotatable pivot shaft extends through the second pivot hole of the sliding member and is nonrotatably extended through said noncircular hole in said second bracket, and a rotating axis of the first noncircular pivot shaft is substantially parallel to a rotating axis of the second noncircular rotatable pivot shaft;
• wherein said guide rail, said sliding member and said second bracket are rotatable with respect to said first bracket, said sliding member and said second bracket are slidable with respect to said guide rail and said first bracket for positioning of the first member with respect to the second member;
• wherein the double hinge assembly further comprises two positioning assemblies, the two positioning assemblies are positioned in opposite ends of the sliding member correspondingly, thus defining a largest sliding length of the sliding member on the guide rail;
• wherein each positioning assembly comprises a fixing piece, a spring and a positioning ball;
• the sliding member defines two receiving holes on opposite ends of the sliding member;
• the spring and the positioning ball are received in the receiving hole of the sliding member, the fixing piece is fixed to one end of the sliding member, such as to make the positioning ball partially extending out of the receiving hole, the guide rail defines a blind hole to partially receive the positioning ball.