The device shown has only a small baseplate, so the load, via the baseplate imposes a large vertical tensile load onto the floor fixings, Depending upon the orientation of the load, the load could all be borne by only one fixing.
So it bis imperative that the fixings are securely fixed to the floor, with ground anchors, such as Rawlbolts, in concrete floors, or with a reinforcing plate beneath a wooden floor.
Needless to say, the fixings should be the largest diameter possible and of the highest grade.
My choice would be to fit thick load spreading washers under the bolt heads and nuts, as an additional safeguard..
The conventional garage type of crane carries nearly all the load on the wheels at the front of the long legs, so is preferable, if space allows.
Howard (aka fat Fingers )
Edited By Howard Lewis on 03/02/2020 14:54:36