Rotational hinge

1. A rotational hinge comprising: a first casing linkage; a second casing linkage; a hinge linkage; and a synchronization linkage that extends in a first direction and a second direction to form a bend, wherein the synchronization linkage is coupled to the first casing linkage and the second casing linkage and synchronizes a fixed rotational axis and a moving rotational axis that provides one or more degrees of rotation,

wherein the first casing linkage comprises a first shaft and the second casing linkage comprises a second shaft, each include shafts to which the synchronization linkage is coupled, wherein a distance between a central axis of the first shaft and an axis passing through a first coupling point of the synchronization linkage to the first shaft is different from a distance between a central axis of the second shaft and an axis passing through a second coupling point of the synchronization linkage to the second casing linkage.

2. The rotational hinge of claim 1 , wherein the first casing linkage comprises a first stabilizer and the second case linkage comprises a second stabilizer, wherein the first stabilizer and the second stabilizer are engaged when the rotational hinge is in a first position and the first stabilizer and the second stabilizer are not engaged when the rotational hinge is in a second position.

3. The rotational hinge of claim 2 , wherein the first position corresponds to a 180 degrees position, and wherein the second position corresponds to 0 degrees position.

4. The rotational hinge of claim 1 , wherein the hinge linkage rotates 90 degrees to position the rotational hinge to a 180 degrees position.

5. The rotational hinge of claim 1 , wherein the hinge linkage rotates 180 degrees to position the rotational hinge to a 360 degrees position.

6. The rotational hinge of claim 1 , wherein the first casing linkage is in a fixed position when the rotational hinge moves from a 0 degrees position to a 360 degrees position.

7. The rotational hinge of claim 1 , wherein the first casing linkage comprises a first shaft and the second casing linkage comprises a second shaft, wherein a distance between an axis point of the first shaft and a first coupling point of the synchronization linkage to the first shaft is different from a distance between an axis point of the second shaft and a second coupling point of the synchronization linkage to the second casing linkage, wherein the axis point of the first shaft, the axis point of the second shaft, the first coupling point, and the second coupling point are on a same imaginary plane.

8. The rotational hinge of claim 1 , wherein the second casing linkage rotates about the first casing linkage during rotation of the rotational hinge.

9. The rotational hinge of claim 1 , wherein the first casing linkage is configured to couple to a casing of a user device.

10. The rotational hinge of claim 1 , wherein the second casing linkage rotates 180 degrees when the rotational hinge moves from a 0 degrees position to a 180 degrees position.

11. A user device comprising:

a first casing and a second casing; and

a rotational hinge comprising:

a first casing linkage coupled to the first casing;

a second casing linkage coupled to the second casing;

a synchronization linkage that extends in a first direction and a second direction to form a bend, wherein the synchronization linkage is coupled to the first casing linkage and the second casing linkage and synchronizes a fixed rotational axis and a moving rotational axis that provides one or more degrees of rotation;

and a hinge linkage to support the first casing, the second casing, and the synchronization linkage;

wherein the first casing linkage comprises a first shaft and the second casing linkage comprises a second shaft, each include shafts to which the synchronization linkage is coupled, wherein a distance between a central axis of the first shaft and an axis passing through a first coupling point of the synchronization linkage to the first shaft is different from a distance between a central axis of the second shaft and an axis passing through a second coupling point of the synchronization linkage to the second casing linkage.

12. The user device of claim 11 , wherein the user device includes at least one of a wireless telephone, a voice recognition application, a video application, a multi-media application, a music player application, an e-mail application, a contacts application, a calendar application, an instant messaging application, a web browsing application, a location-based application.

13. The user device of claim 11 , wherein the first casing includes at least one of a display or a key.

14. The user device of claim 11 , wherein the hinge linkage includes an “H” configuration, and wherein a first portion of the synchronization linkage that extends in the first direction is of a different length than a second portion of the synchronization linkage that extends in the second direction.

15. The user device of claim 11 , wherein when the rotational hinge is in a 180 degrees position, the first casing linkage, the second casing linkage, the synchronization linkage, and the hinge linkage are positioned on a same plane.

16. The user device of claim 11 , further comprising:

a processing system; and

a memory.

17. The user device of claim 11 , wherein the hinge linkage rotates 180 degrees to position the rotational hinge to a 360 degrees position.

18. The user device of claim 11 , wherein the hinge linkage rotates 90 degrees to position the rotational hinge to a 180 degrees position.

19. The user device of claim 11 , wherein the first casing linkage comprises a first shaft and the second casing linkage comprises a second shaft, wherein the synchronization linkage is coupled to the first shaft and the second shaft.

20. The user device of claim 19 , wherein a distance between an axis point of the first shaft and a first coupling point of the synchronization linkage to the first shaft is different from a distance between an axis point of the second shaft and a second coupling point of the synchronization linkage to the second casing linkage, wherein the axis point of the first shaft, the axis point of the second shaft, the first coupling point, and the second coupling point are on a same imaginary plane.