This is my stair climbing hand truck prototype. I used 16 gauge steel for the wheel assembly, which proved strong enough for most loads but were starting to bend under 200lb loads. Next prototype will have the metal stamped for added rigidity.
Close up view of the stair climbing hand truck
SolidWorks modeled version of the stair climbing hand truck
This is the stair climbing hand truck shown in drafting lines
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Prototypes
Stair Climbing Hand Truck