US Patent 7168133 Hinge for a portable electronic device

A hinge (300) includes a cam (32), a cam follower (30), a torsional spring (31), and a can (33). The cam includes a round flange (321), with a notch (321b) defined therein. The cam follower connects with the cam, and includes an engaging ring (301) around an open end thereof and a projection (303) on an inner wall thereof. The projection is removably engaged in the notch of the cam. The spring is twisted and attached in the cam follower, with one end fixed on the cam follower and the other end fixed on the cam. The can defines a groove (334) rotatably receiving the engaging ring of the cam follower, and a guiding hole (335) movably receiving the cam. The hinge has a relatively simple and stable unified structure.