pic: 1918 pneumatic hub concept

[Wayne TenBrink]

Originally Posted by topgun

Wayne,
I am not seeing/understanding the use of shoulder bolts at each end of the axle. Wouldn't it be easier if the axle is essentially a 3/4" round standoff with holes in the end? Then you come in with a 3/8" SHCS from the outside of the frame rails to tighten them down to the standoff/axle. As it is drawn now, if your shoulder bolt bottoms out in the axle before it is tight against the side rail, the axle will be loose.

I love the idea of adding the sprockets without major fabrication/modification to the wheel/hub. Your idea is doable by many less equipped teams.

Also, is this drawn in SolidWorks? Where did you get the model for the wheel?

General question for everyone: The idea of a 6WD with drop center is to enable easier turning, but then aren't you effectively only pushing with 4 wheels when shoving someone?

For the 3/4" axle, the shoulder bolts on the axles could be replaced with bolts. The intent is for the shoulder bolt NOT to bottom out in the axle hole, but rather to mount the axle tightly to the frame. If we do traditional wheels with 1/2" axles on the corners, then a 3/8" shoulder bolt with 5/16-18 threads would be used. This would allow a common frame hole (3/8") and permit interchangeability of axle types.

One of our CAD mentors modeled the hub using AutoCAD. He may have gotten some of the data from the OEM (Wagner ?), but the detailed dimensions on the hub were reverse engineered from the one we bought. The Grainger catalog isn't too specific. This is Grainger p/n 1ZPE1.