A mechanical gear apparatus that provides power transmission wherein a gear that is driven moves only in a forward direction when the driving gear is driven forward or in reverse. It is a mechanical gear apparatus comprising a support base, a drive gear, and, a directional gear assembly comprising three gears and, another configuration in which there is a mechanical gear apparatus comprising a support base, a driven gear, and a directional gear assembly comprising two directional gears and a drive gear. The gears in the mechanical gear apparatus can be substituted by smooth or rough surface rubber rollers.