CmA Use your brain and be responsible for your actions. I'm not an engineer and can't possibly think of all the ways this idea could be misused or go wrong. It works for me on a clean, flat, smooth, LEVEL! concrete floor.

One issue I have had with my Quick Jack setup is getting enough leverage on my garage floor to slide them into position for lifting my cars. I wanted a simple solution that would not impact the stability or strength of the units.

Various brain storms (brain farts) led me to look at ball transfer bearings. Some measuring and fiddling with wedges and shims gave me dimensions for searching on line.

I found these Hudson Bearings on Amazon.

Hudson Bearings SBT-1CS 1/4 Stud Mounted Ball Transfer, Carbon Steel, 1" Diameter, 75 lbs Load Capacity, 1/4"-20 Thread Stem (Case of 10) They arrived in 2 days.

Placing them on the upper deck in the right locations gave me moving casters that lift up and drop the lower frame to the garage floor. There is just enough weight from the upper deck to raise the lower frame between 1/16 and 3/16 of an inch when the jacks are fully lowered. You can add washers between the bearings and the jack frame to adjust for clearance as needed. On a clean smooth floor the friction is low enough to slide the jacks into position as needed.