US Patent 7623302 Cam drive mechanism, lens barrel and camera

A cam drive mechanism includes: a cylinder in which a cam groove is formed from one end face of an inner circumferential surface toward another end with a forming mold; a drive target object that comprises a cam follower to engage in the cam groove and is linearly driven along a rotational axis of the cylinder as the cylinder rotates; and a pressing member that presses the cam follower against a cam surface constituting a side surface of the cam groove. The cam surface is formed to have varying gradients so as to enable adjustment of an extent of displacement of the drive target object per unit of rotational angle by which the cylinder rotates and the cam groove is formed in a shape that allows the forming mold to be extracted from the cylinder through rotational extraction.