I really like my Lippert jacks. They are a really ingenious design.
I know quite a bit about how they work, due to a unfortunate oops. I gor interrupted when breaking camp before dawn, and forgot to raise the jacks.
I was horrified at the twisted metal that resulted.
After pricing new ones, I decided to try and fix them. It went really well, and nobody can tell it ever happened. In the process I learned just how they work. It keeps equal pressure on each pair of jacks making it impossible to rack the frame.
Hard to describe how it does it, but it is clever.