The chains pull the bottom of the ball shank. The trailer coupler pushes the ball, which is the other end of the shank.
I used it on a 16' TT with about 350-380 lb hitch weight, and it worked well for me.
Mike G.
Liberty is meaningless where the right to utter one's thoughts and opinions has ceased to exist. That, of all rights, is the dread of tyrants. --Frederick Douglass
photo: Yosemite Valley view from Taft Point