Haven't had one of those in a car or truck for years. In the late '60's, you could get one that had a little lever on the side. You pushed this, and the knob would tip down and lay flat till you wanted to use it. These were rather cheaply made and didn't hold up very well.
Most trucks steer easy enough that you don't really need them.
Old tractors are another story. Usually one of the first things I do when I get another tractor is put a knob on it, if it doesn't already have one.
