pic: 296's Tri-Star Wheel

2004
frc296
#21

That is machined very well. Im not sure what that guy is thinking.:slight_smile: Anway have you tested the wheels yet? Also, why did you guys go for the gears instead of chains? The weight probably would have been cut down and it would have simplified the whole process.

#22

I don’t see where we could have used chains… seems like it would be a pain to tension them.

We did test the wheels, and they are performing beautifully, except that we haven’t yet put delrin sliders or something else on the bottom of the 'bot, and so we can’t get more than halfway up the step for now.

#23

I don’t see where we could have used chains… seems like it would be a pain to tension them.

The chains would serve the same purpose as the gears. The only reason what I could think of using them is the weight.

#24

It lookes to me like the “bumps” are to provide what we here in the aircraft biz call ED or edge distance. That is the distance from the center of a hole to the nearest edge of the part. If a hole is too near an edge it lowers the strength of the part tremendously. In general, we use a minimum ED of 1.5 times the hole diameter, though I’ve been noticing lately that EDs of 1 are common in commercial products. If the bumps weren’t there, the shafts supporting the small gears would be hanging out in space, either that or the wheel would be even heavier.

I think the design has been nicely optimized and well executed. If there were big ugly burrs hanging off the edge or chatter marks or the edges wandered like they had been cut with a hack saw then pras870 might have a point, but as it is I don’t think so. It seems pretty obvious to me that those bumps were planned and needed to be just where they are. It is a professional looking job, good work 296!