Patent ID: 8578559

Claim:
A hinge mechanism used in a clamshell device, the clamshell device comprising a first cover and a second cover, wherein the first cover can rotate with respect to the second cover via the hinge mechanism, the hinge mechanism comprising: a main body connected to the first cover, the main body comprising a shaft and a projecting part; an elastic component covering the shaft of the main body, an internal diameter of the elastic component matching with an outer diameter of the shaft so as to generate a friction force, wherein the first cover can be maintained at any angle by the friction force; the elastic component comprising a groove used for connecting the projecting part when the shaft of the main body rotates to a specific angle; wherein when the shaft of the main body does not rotate to the specific angle, the projecting part does not engage with the groove; and a base connected to the second cover, the base comprising a stop structure used for fixing the elastic component.