US Patent 8621714 Hinge assembly for foldable electronic device

A hinge assembly includes a shaft, a main body drive member, a follower, and a resilient member. The main body drive member, the follower, and the resilient member are mounted with the shaft in turn. One end of the main body drive member has a cam. One end of the follower has a cam engaging with the cam of the main body drive member. The resilient member causes the cam of the follower to resist the cam of the main body drive member due to the decompression of the resilient member, and when the follower is manually rotated relative to the main body drive member about an angle, the follower automatically rotates relative to the main body drive member due to the decompression of the resilient member.