Patent ID: 7383616

Claim:
An automatic opening hinge assembly for joining a flip cover section to a body section of a foldable electronic device, comprising: a main shaft having an outer thread at one end thereof, and an engaging portion at an opposite end thereof; a cam comprising a cam surface at an one end thereof, the cam defining an inner thread engaging with the outer thread of the main shaft; a follower comprising a latching cam surface at one end thereof, a central hole receiving the main shaft therethrough, and at least one groove at the central hole, the latching cam surface abutting the cam surface of the cam; a first elastic element; a control having at least one projection at one end thereof, the projection comprising at least one block and engaging with the engaging portion of the main shaft; a sleeve having at least one latching portion at an outer wall thereof, and defining a central reduced hole and at least one restraining groove at the reduced hole, the latching portion engaging in the groove of the follower, the projection of the control being receivable in the reduced hole, and the block of the projection being engageable in the restraining groove under biasing by the first elastic element whereby rotation of the control relative to the sleeve is blocked; and a second elastic element for biasing the follower.