US Patent 7401382 Hinge assembly for a foldable electronic device

A hinge assembly (100) includes a shaft (10), a rotary cam (20), a follower cam (30), a positioning member (50), and an urging means (40). The shaft includes a securing portion (12) at one end thereof and has a slot (166) defined therealong. The rotary cam is substantially cylindrical and includes a cam surface (24). The rotary cam has a cam hole (22) extending therethrough. The cam hole receives the shaft therethrough. The follower cam includes a cylindrical portion (34) and two symmetrically protruding portions (36). The cylindrical portion includes a pinhole (346). The positioning member is received in the pinhole and the slot, thereby connecting the follower cam and shaft. The urging means biases against both the shaft and the rotary cam. The cam surface of the rotary cam is rotatably engaged with the protruding portion of the follower cam under a force generated by the urging means.