Hinge for a flexible electronic device

1. A hinge mountable between two casing parts of a flexible electronic device for mounting a flexible display thereon, comprising:

a base seat unit including a base seat which is elongated in a front-rear direction and which has left and right sides opposite to each other in a left-right direction that is transverse to the front-rear direction; and

two rotating modules respectively disposed at said left and right sides of said base seat, and respectively for mounting the casing parts thereon, each of said rotating modules including a primary support plate which is pivotably connected to a respective one of said left and right sides of said base seat and which has a primary support surface for resting the flexible display thereon, and a secondary support plate which is pivotably connected to said primary support plate and which has a secondary support surface that extends toward the other secondary support plate, said secondary support plate of each of said rotating modules having a plurality of holding protrusions which extend toward said primary support plate;

said rotating modules being rotatable relative to said base seat between an initial position and a terminal position to shift the casing parts between an unfolded state and a folded state, respectively, in the initial position, said secondary support plates being spaced apart from each other in the left-right direction by a distance which is smaller than a distance between said primary support plates such that said secondary support surfaces are flush with said primary support surfaces in the left-right direction for resting the flexible display thereon, said secondary support plates having a width which is measured in the left-right direction and which is larger than a height of said base seat that is measured in an up-down direction transverse to both the front-rear direction and the left-right direction such that, in the terminal position, said secondary support plates are turned relative to said primary support plates away from the flexible display to abut against said base seat so as to provide a leeway between said secondary support plates, said holding protrusions abutting against a bottom of said primary support plate in the initial position so as to keep said primary support surface flush with said secondary support surface and to restrain turning of said secondary support plate toward said base seat.

2. The hinge as claimed in claim 1 , wherein each of said rotating modules further includes a rotating frame unit which is rotatable relative to said base seat and on which a respective one of the casing parts is mounted, said primary support plate being connected between said rotating frame unit and said base seat and being rotatable relative to said base seat along with rotation of said rotating frame unit.

3. The hinge as claimed in claim 2 , wherein said rotating frame unit of each of said rotating modules has two rotating brackets respectively and rotatably disposed to front and rear ends of said base seat, and two connecting brackets respectively extending from said rotating brackets in the front-rear direction and toward each other such that said primary support plate is rested on said connecting brackets to be rotated therewith.

4. The hinge as claimed in claim 3 , wherein said rotating frame unit of each of said rotating modules further has two rotating shafts which are respectively and rotatably mounted on said front and rear ends of said base seat and which extend in the front-rear direction to be rotatable about a shaft axis in the front-rear direction, said rotating brackets being in spline engagement with said rotating shafts, respectively, so as to be rotated with rotation of said rotating shafts about the shaft axis.

5. The hinge as claimed in claim 4 , wherein said base seat unit further includes two gear housings which are respectively disposed on said front and rear ends of said base seat, two gear trains each of which includes a plurality of gears received in a respective one of said gear housings, arranged along the left-right direction, and meshing with each other, and two cover plates which are respectively disposed outboard of said gear housings to cover said gear trains, left and right ones of said gears of each gear train being respectively connected and rotatable with said rotating shafts of said rotating modules at either said front end or said rear end of said base seat so as to make synchronous rotations of said rotating modules between the initial position and the terminal position to shift the casing parts between the unfolded state and the folded state.

6. The hinge as claimed in claim 5 , wherein said rotating brackets of said rotating modules at either said front end or said rear end of said base seat respectively have elongated sliding slots which are elongated to terminate at inner ends and outer ends, and guiding pegs which extend in the front-rear direction, said rotating shafts of said rotating modules at either said front end or said rear end of said base seat being respectively and non-rotatably extended into and slidable along said elongated sliding slots, each of said gear housing having two arcuate guide slots which are disposed opposite to said cover plate in the front-rear direction and into which said guiding pegs are slidably extended, such that, when said rotating modules are in the initial position, said elongated sliding slots extend in the left-right direction and said rotating shafts are disposed in said outer ends of said elongated sliding slots, and such that, when said rotating modules are in the terminal position, said elongated sliding slots extend in the up-down direction and said rotating shafts are disposed in said inner ends.

7. The hinge as claimed in claim 1 , wherein said primary support plate of each of said rotating modules has a plurality of openings spaced apart from each other in the front-rear direction, each of said rotating modules further including a plurality of pivot members which are securely mounted on said base seat and which are respectively disposed in said openings to be pivotally connected to said primary support plate so as to permit rotation of said primary support plate relative to said base seat.

8. The hinge as claimed in claim 1 , wherein, when said rotating modules are in the initial position, said secondary support surfaces of said secondary support plates have a total width which is measured in the left-right direction and which is substantially equal to a clearance between said primary support surfaces of said primary support plates.

9. The hinge as claimed in claim 1 , wherein, when said rotating modules are in the initial position, said secondary support surfaces of said secondary support plates have a total width which is measured in the left-right direction and which is larger than a clearance between said primary support surfaces of said primary support plates.