Patent ID: 7971317

Claim:
A hinge assembly for pivotally connecting a first device to a second device, the hinge assembly comprising: a pivot element configured for being formed on the first device, and for being partially and rotatably received in the second device, the pivot element comprising a pivot shaft and a guide shaft parallel to the pivot shaft, wherein the first device is pivotally connected to the second device by the pivot shaft of the pivot element; a torsion spring configured for being assembled between the first device and the second device, wherein when the first device is in a closed position with respect to the second device, the torsion spring becomes constricted and accumulates potential energy, and when the first device is opened from the second device, the potential energy of the torsion spring is released to drive the first device to rotate to an open position with respect to the second device; and a hinge brace configured for being attached to the second device, the hinge brace defining a sliding slot for slidably receiving the guide shaft, wherein the sliding slot comprises an entrance for allowing the guide shaft sliding thereinto and an end terminal opposite to the entrance, the sliding slot gets narrow from the entrance to the end terminal such that a resistance gradually increasing is generated between the sliding slot and the guide shaft to block the movement of the guide shaft when the first device rotates from the closed position to the open position.