welding cylinder cart?

Like at

I think it's a transport-safety thing.

The above cart is shown in the tilted-for-transport position, where its center of gravity is inside a bigger footprint than a vertical arrangement would have. It is statically stable in this position, ie, won't fall over if you let go of it. The caster frame on this one can be folded forward when the tanks are in use and upright.

-jiw

I guess it is like a three legged stool. Always steady.

STeve