Made myself an adapter to pull with a ball. Adjustable coupler height so it works with polaris ranger, stock height 4x4 truck, and lifted Blazer.
You seem to have a very well thought out design there.
I see just one place where I would suggest improvement....
The nut atop the threaded post the captures the Lunette Ring is your "single point of failure" and with vibration can loosen in spite of the lock washer you've employed. Lock washers, although reasonably reliable DO NOT constitute a POSITIVE LOCKING MECHANISM.
THEREFORE, I would suggest one SIMPLE modification.....
Drill a hole through the threaded post to use either a castle-type nut and cotter pin OR one of the caps typically found on the spindle/wheel bearing assembly as on most passenger cars and light trucks that will capture the nut and prevent its loosening rotation due to the cotter pin's mechanical anti-rotation assurance.
This simple mod should negate the single point of failure concerns.
Great idea !!! I agree, you should seek a patent and go into production.