I have a new Halverson bar in my collection also. It was sent to us to try but never used it. It has as v shaped piece inside of the bar. The middle fingers on the nose acted like a spring against the v and kept the chain tensioned. It never took off.
The chain in the middle with the wings is a Kolve chain. Lots of trouble with this also. One big thing was it couldn't pass the kickback tests.
Sven .