cantilever question

could someone explain to me how you can have a pivot point on the bag side of a cantilever arm. I would think the bag would want to roll over on itself. mid way through extension and compression. Or is it that since the bag follows certain path more inline with the canti that it stays straight?

thanks

It can be done but there needs to be some sort of linkage to keep the bag travel linear because it will want to bow out.

you could use those air ride tech bags i guess...