Patent ID: 8292309

Claim:
A supporting device comprising: a tray configured for supporting a payload; a plurality of wheel assemblies secured to the tray, each wheel assembly comprising a wheel, the wheel assemblies being rotatable between a first position and a second position, a distance between each wheel and the tray in the first position being smaller than a distance between each wheel and the tray in the second position; a handle attached to the tray and rotatable to rotate the wheel assemblies from the first position to the second position; a handgrip attached to the tray and slidable to rotate the wheel assemblies from the second position to the first position; two pivot pieces located on the tray; and two mounting pieces located on the tray; wherein the handle comprises two arm portions secured to the pivot pieces; the handle is rotatable relative to the pivot pieces; the handgrip comprises two arm segments secured to the pivot pieces; and the arm segments are slidable relative to the mounting pieces.