im with the other two on this one, you are going to want to stabilize the base with the legs on the outside rim (or close to it). the last thing you want is for the table to tip over because there is too much stuff on one side.
maybe you could weld small steel tubing to the underside and slip on another tube just slightly larger and place a codder pin in to keep it secured. then when you want to stow it, all you need to do is remove the pins, turn the table up and put the legs under the table. You might even be able to weld some clips under the table to attach the legs too.
i guess my second part was just an elongation and elaboration of what motorhead already posted.