A hinge assembly includes a shaft, a cam, a follower, and an resilient member. The follower is mounted on the shaft. One end of the follower has a first cam surface. The first cam surface defines a groove. The cam is mounted on the shaft and adjacent to the follower. The cam has a second cam surface, and the second cam surface engages with the first cam surface. The second cam surface forms a protrusion, and the protrusion is received in the groove. The resilient member is placed around the shaft forcing the first cam surface to engage with the second cam surface.