This is an example of a properly functioning mirror charging mechanism.

The large gear on the far left is driven by the film advance lever on top of the camera.

The long silver lever is the mirror charging lever. It pushes the black bar to the top of the slot when the camera is wound, which charges the main mirror spring.

The lever on the right holds the black bar in place while the camera is cocked and ready to shoot.

At the end of an exposure, the large black gear pushes the release lever, returning the mirror to the viewing position.