Bar Design?

Hey everyone! May someone explain to me how this bar design works? Is it a 4 bar or is it technically a 3 bar? And if someone has any ideas on how to use it for Toss Up that would be much appreciated :smiley:

Thanks guys!


That would be a chain bar with a tilting sprocket ratio and pneumatic assist. Hmm looks familiar…

Oh Cool! So the Spur Flys do have a vex forum account :smiley:
Now Aaron could you explain to me how the chain and sprocket idea actually works? I’ve seen the articles on the Aura website about them but I don’t fully understand how that is efficient…It just seems like it creates more stress on the chain :confused: I do see the pneumatic piston in the back but does that “L” shabed elbow give it support like a regular bar design lift?

IT’S THE SPUR FLYS. It’s Caleb from 918 Pantherbots from Middle School. We went against you… and lost. The thing with the pneumatic assists on continuous flow was really smart.

And clabrador96 the chain bar is basically one sprocket at the tower that does not pivot attached to another sprocket at the end of the bar which does pivot. I’m not sure if I explained right.

Jesse323Z has a nice tutorial explaining the concept.

What do you mean by “efficient”? And “more stress on the chain” compared to what?

Every different mechanism has its advantages and disadvantages. A chain linkage can rotate further than a 4-bar in many applications. (example - see how the arm goes completely vertical?). And if you want your intake to tilt while you lift (always by the same amount) then a chain linkage allows you to do this using different sprocket sizes, similar to using an unequal 4-bar, but different tilting geometry and rates.

I don’t like chain linkages where you have something reasonably heavy on the end of the arm, or where you need very precise movement, I prefer 4-bar linkages in those situations.

And who is Aurora? :smiley:

yeah the “4 bar” looking part of the arm is just a way to have all four motors power the top two bars and is convenient for pneumatic assist.

Yes we did experience some issues early on with precision, especially when scoring on the high goal. Due to the chain the basket had some “slop” in it, meaning it would rotate a bit back and forth around the pivot point. We found that you can remove a lot of the slop by using lock bearings on the sprockets.

Hope this helped.

Sorry I was comparing it to a 4 bar or a 6 bar but looking at the design now it looks better than a 4 bar or 6 bar idea but what’s cool about it is that incorporaties the 4 bar “mechanics” while at the same time it uses pneumatics and the chain and sprocket lift :slight_smile:

You guys definitely helped thanks again to Chris at *Aura :slight_smile: and Aaron whose team originally created the fantastic robot :smiley:

Good Job Spur Flys!