Silly me on a Saturday

I have started to use my old Minox 35 cameras. For the GTE model it is possible to find batteries so I loaded the camera with film and started to shot.  After 15 images I was no longer able to advance the film.  As I have five or six Minoxes I decided to do something very silly.  I opened the bottom of one the oldest and no longer working cameras.  I could almost hear spring coming and I have no idea where it should be replaced.  With all the dust collected in this camera I think it is a miracle that it has ever worked.

I made another silly thing.  I opened my GTE but it was not as dirty as this.  I found a small metallic rod between the gears.  I removed it and reassambled the camera and I am now able to advance the film. But I guess the small part (see today's extra) had some kind of function.  Any suggestion is much appreciated.