The cradle slides onto the hinge pins at the back edge of the cabinet and those are tightened with (darn I forgot the word) nuts - screws that have no head.
The cradle has two tabs on the side facing you, which lock into the brackets when the front lid is lifted and closed at the same time as the cradle is lowered.
The machine doesn't touch the brackets - it snaps down into the cradle, first into the handwheel end, then the needle end. It's *very* snug most of the time. To release it, unplug the machine, push down on the lever at the needle end and use the handle to lift the machine from the cradle.
I posted pictures on this thread:
http://www.quiltingboard.com/vintage...ml#post5390643 Hope that helps you!
