rotating bed

12.31: gear/rotating bed:
. the bed is a cage with foam fit all around
with hole for face .
. it provides movement to avoid bed sores .
. the pivot points for head-to-foot axis rotation
are at adjustable heights like so:
change the angle of the head-to-foot from horz'al
by having 2 pulleys at foot and head,
so the bed is held at either end
by a single chain that is held by both pulleys
such that lowering the foot of bed
will in turn raise the head of the bed .
. the rotation engine can use it's own weight
for the torque to slowly rotate the cage;
it hangs like a balast from one end,
and as it cranks on the bed,
it either has to raise itself or turn the cage .