A FRIEND CALLED ME AND ASED ME WHY HE CAN'T KEEP THE FOCUSING RAILS ALIGNED.HE SAID THE BELLOWS SLIPS OFF WHEN HE EXTENDS IT.THE ONLY THING I COULD THINK OF WOULD BE THE BED DROPPED.DOES THIS MAKE SENSE?

It is possible that the short inner rails do not line up with the long outside rails,
Tighten screws to start with, then check for alignment with a straightedge....
also check the ends of the rails! Rails broken by closing the cover before the rails are fully retracted, can also cause this problem!
Have a nice day.....Bert