US Patent 7111361 Hinge assembly

A hinge assembly for joining a cover to a main body of a folding phone, includes a housing (1), a cam (2), a cam follower (3), a spring (4), and an end cover (5). The cam and the cam follower are received in the housing with a connector (21) of the cam extending through a rear end (11) of the housing. The cam follower has a cylindrical main body (30) with a protrusion (31) extending from each opposite end thereof. The cylindrical main body can move along a cam surface (20) of the cam for being received in valleys (22) of the cam surface while the protrusions sliding in the housing. The end cover is inserted into the housing for locking the hinge components in the housing. The spring is compressively coupled between the cam follower and the end cover.