Patent ID: 7111361

Claim:
A hinge assembly for joining a cover to a main body of a folding device, comprising: a housing; a cam having a cam surface forming a pair of valleys opposite to each other and a pair of peaks opposite to each other; a generally cylindrical cam follower including cylindrical main body with two concentric protrusions, an axis of the cam follower being perpendicular to an axis of the cam; and an urging mechanism to urge the folding device into or out of an open or a closed position during rotation of the cover; wherein the cam and the cam follower are received in the housing, the cam is rotatably engaged with the housing, the cam follower is movably engaged with the cam surface for being received in the pair of valleys of the cam while slidably engaging with the housing, and the urging mechanism is coupled to the cam follower and a front end of the housing.