Smoothly openable and closable dual-shaft hinge

Abstract

A smoothly openable and closable dual-shaft hinge includes an axle housing, and a pivot shaft set including a first pivot shaft and a second pivot shaft respectively pivotally coupled to first and second pivot shaft chambers of the axle housing and respectively affixed to a cover member and a base member. When the cover member is turned between opposing top side and bottom side of the base member first pivot shaft, the friction resistance produced between the first pivot shaft and the axle housing is different from the friction resistance produced between the second pivot shaft and the axle housing.

What the invention claimed is: 
     
         1 . A smoothly openable and closable dual-shaft hinge, comprising:
 an axle housing comprising a base defining a first surface at a top side thereof and a second surface at an opposing bottom side thereof, a first bearing portion smoothly curved from one lateral side of said first surface of said base in direction toward an opposite lateral side of said first surface, a first pivot shaft chamber defined between said first bearing portion and said first surface, a second bearing portion smoothly curved from one lateral side of said second surface of said base in direction toward an opposite lateral side of said second surface, a second pivot shaft chamber defined between said second bearing portion and said second surface, said first bearing portion and said second bearing portion extending in reversed directions; and   a pivot shaft set comprising a first pivot shaft and a second pivot shaft, said first pivot shaft comprising a first shaft body located at one end thereof and a first connection bar located at an opposite end thereof, said first shaft body being pivotally coupled to said first pivot shaft chamber of said axle housing, said first connection bar being disposed outside said axle housing and connected to a cover member, said second pivot shaft comprising a second shaft body located at one end thereof and a second connection bar located at an opposite end thereof, said second shaft body being pivotally coupled to said second pivot shaft chamber of said axle housing, said second connection bar being disposed outside said axle housing and connected to a base member;   wherein when turning said cover member toward a bottom side of said base member, said first pivot shaft is rotated with said cover member in said first pivot shaft chamber and said axle housing is turned about said second pivot shaft in accordance with the turning direction of said cover member, and at this time, the rotating direction of said first pivot shaft is reversed to the extending direction of said first bearing portion from said first surface and the turning direction of said axle housing is reversed to the extending direction of said second bearing portion from said second surface, and thus, the friction resistance produced between said first shaft body of said first pivot shaft and said first bearing portion is smaller than the friction resistance produced between said second shaft body of said second pivot shaft and said second bearing portion; when turning said cover member toward an opposing top side of said base member, said first pivot shaft is rotated with said cover member in said first pivot shaft chamber in accordance with the turning direction of said cover member and said axle housing is turned about said second pivot shaft in accordance with the turning direction of said cover member, and at this time, the rotating direction of said first pivot shaft is same as the extending direction of said first bearing portion from said first surface and the turning direction of said axle housing is same as the extending direction of said second bearing portion from said second surface, and thus, the friction resistance produced between said first shaft body of said first pivot shaft and said first bearing portion is larger than the friction resistance produced between said second shaft body of said second pivot shaft and said second bearing portion.   
     
     
         2 . The smoothly openable and closable dual-shaft hinge as claimed in  claim 1 , wherein said first surface and said second surface of said axle housing are planar surfaces; said first shaft body of said pivot shaft set comprises a first positioning plane located at the periphery thereof and extending along the length thereof; said second shaft body of said second pivot shaft set comprises a second positioning plane located at the periphery thereof and extending along the length thereof. 
     
     
         3 . The smoothly openable and closable dual-shaft hinge as claimed in  claim 1 , wherein said first pivot shaft further comprises a first positioning tip extended from a distal end of said first shaft body opposite to said first connection bar; said second pivot shaft further comprises a second positioning tip extended from a distal end of said second shaft body opposite to said second connection bar; the dual shaft hinge further comprises a transmission mechanism and a link disposed at one side relative to said axle housing, said transmission mechanism comprising a first transmission member and a second transmission member, said first transmission member comprising a first connection hole located at the center thereof and fixedly connected to said first positioning tip and a first position-limit rod located at a front side adjacent to said first connection hole, said second transmission member comprising a second connection hole located at the center thereof and fixedly connected to said second positioning tip and a second position-limit rod located at a front side thereof adjacent to said second connection hole, said link comprising a first position-limit hole located at one end thereof and coupled to said first position-limit rod and a second position-limit hole located at an opposite end thereof and coupled to said second position-limit rod, said first position-limit hole defining a first abutment portion at one side near said second position-limit hole and a second abutment portion at an opposite side remote from said second position-limit hole, the distance between said first abutment portion and said second abutment portion being larger than the outer diameter of said first position-limit rod 
     
     
         4 . The smoothly openable and closable dual-shaft hinge as claimed in  claim 1 , further comprising a first positioning member and a second positioning member respectively disposed at opposing front and back sides of said axle housing, said first positioning member comprising a first positioning hole and a second positioning hole respectively disposed near two distal ends thereof, said second positioning member comprising a third positioning hole and a fourth positioning hole respectively disposed near two distal ends thereof, said first positioning hole and said third positioning hole being respectively pivotally connected to two opposite ends of said first shaft body of said e pivot shaft set, said second positioning hole and said fourth positioning hole being respectively pivotally connected to two opposite ends of said second shaft body of said pivot shaft set. 
     
     
         5 . The smoothly openable and closable dual-shaft hinge as claimed in  claim 1 , further comprising a first positioning member disposed at one side relative to said axle housing, said first positioning member comprising a first positioning hole and a second positioning hole respectively disposed near two distal ends thereof and respectively pivotally coupled with said first shaft body and said second shaft body of said pivot shaft set, and a stop block disposed between said first positioning hole and said second positioning hole, said stop block comprising a first abutment surface and a second abutment surface bilaterally disposed near said first positioning hole and a third abutment surface and a fourth abutment surfaces bilaterally disposed near said second positioning hole; said first pivot shaft further comprises a first position-limit flange extending around the periphery of said first shaft body and disposed adjacent to said first positioning member and stoppable by said first abutment surface and said second abutment surface to limit the range of rotation of said first shaft body; said second shaft body comprises a second position-limit flange extending around the periphery of said second shaft body and disposed adjacent to said second positioning member and stoppable by said third abutment surface and said fourth abutment surface to limit the turning range of axle housing about said second pivot shaft.