Mounting 'shelves' on a 57518 Lego conveyor belt For a school project I'm trying to build a conveyor belt out of LEGO. I'm currently just working on the design so I haven't ordered anything yet. I think that for my build the 57518 pieces are perfect. My question is pretty simple: is there a way to mount some sort of 'shelves' onto it? I'm completely new to LEGO (and not a native English speaker) so I can't explain it any better. The picture below from the GBC Homepage shows exactly what I'm talking about:

I believe that the pieces used in the picture are 3873 (not sure). I can also see that in each of these light grey horizontal 'bars' there are two vertical rods that mount it on the conveyor belt itself. The 3873 pieces are not useful for me because they have too many openings.
I spent long times browsing Bricklink trying to find fitting pieces but I just don't know where to look. It would be great if somebody could provide me with links or numbers of the pieces that I need.
The picture you have does show a 57518 thread link, which is what you wanted to use.  For that, you can use the 1/2 and 3/4 pins to attach a liftarm.  A 1x5 liftarm would match the width of the 57518 thread.  What's shown in the picture is a 1x7 liftarm which allows the module to lift more balls.
For the pins, you should use the 3/4 pins part 32002 to be perfectly legal, but some might also use the 1/2 pins part 4274 to add friction to the connection.