The forces on that latch pawl are ~tremendous~ with this hitch system. I would think a special kind of trailer coupler with a completely different ball latching design would have to be welded to the trailer frame, in order to use this chain tension hitch reliably over time/miles.
That would mean cutting off the trailer's standard coupler and only being able to use the hitch with that particular modified trailer. I don't see where that is a benefit to make me want to not use a common round bar or trunion bar hitch that can work with just about any a-frame trailer by just adding to 2 snap-up brackets to the side of the frame....
This hitch might work better if designed for a pintle & ring hitch, or maybe a kingpin & jaws (like a fifth wheel), rather than a common round ball.