Patent ID: 8015668

Claim:
A hinge assembly comprising: a pivotal shaft; a connecting member; a supporting member; a stationary member comprising an engaging surface; a rotating member comprising a receiving surface; and a locking member, wherein a first end of the pivotal shaft is fixed to the connecting member, and a second end of the pivotal shaft opposite to the first end is passed through the supporting member, the stationary member, the rotating member, and the locking member in that order; the stationary member is fixed on the supporting member and is rotatable relative to the pivotal shaft; the rotating member is non-rotatable relative to the pivotal shaft; the engaging surface forms a plurality of first positioning protrusions; the receiving surface defines a plurality of first positioning grooves to receive the first positioning protrusions; one of the engaging surface and the receiving surface forms a plurality of second positioning protrusions and the other one of the engaging surface and the receiving surface defines a plurality of second positioning grooves to receive the second positioning protrusions; a height of each second positioning protrusion is larger than a height of each first positioning protrusion.