joint with two axis

What you've drawn is not one joint, even in the real world. If you replaced each label 'axis' in your drawing with a hinge joint, and connect them with a new, proposed object "ConnectingRod", the result would work as you expect.

However, while that would work, it isn't what a 'trailer hitch' or 'boxcar hitch' does. In those, the objects A and B have a fixed part extending from them, and the one joint in the system is between them, about where you have the label joint. However, the point is that the line between boxes A and B is not one line, it is comprised of two shorter lines where the joint is half way between them.