US Patent 10328862 Adjustable receiver structure

The adjustable receiver structure has a tongue which is mountable into a standard receiver and can be clamped therein. The tongue carries a body and inner and outer arms successively pivoted on the body. The outer arm carries a lock bar and an auxiliary receiver. The lock bar is releasably attached to the body so that it is secured in place during locked condition. When unlocked, the lock bar and auxiliary receiver can swing to an out of the way position. Assembly positions can be selected to choose the assembled height.