On 13/06/2020 14:06, Lee Nowell wrote:
The joists are 8 X 2 in the ceiling of this room. They are the floor joists for the room above.

In that case, get some steel U channel made-up to straddle the joist and
extend below the ceiling, put a bolt (horizontally) between the two
cheeks of the U and hang the thing off that bolt. Rebate the back of the
floorboards above the U so that they sit flat.