Does anybody know of a COTS multi-stage telescoping pneumatic cylinder that is under $500? So far, the only ones I’ve been able to find have been too expensive to be legal, but I was wondering if anyone else has had better luck.
I’m not sure such a thing is legal period, but if you find one cool. (Didn’t even know they existed)
On what basis?
Not sure. Like I said, didn’t know these things existed. They might be legal, and I might not be imagining what you are looking for correctly. Generally if teams don’t really use them there’s a good reason, either cost or legality or usefulness. So don’t quote me but that was just my initial thought. IANTM (not the manual).
Edit: did go look at them, see
Or awareness. (See: Fairlane wheels, press-in tube connecting nuts, and if we’re talking deep cuts then wedgetop and roughtop tread).
Commenting on legality without a solid understanding of the rules and the part in question can cause teams to waste time and resources barking up the wrong tree.
Sorry. I’ll stop.
Usually when we think of a neat way to do something on the robot, but it turns out there is some reason we can’t do it, such as the cost of the part, etc., we “go back to the drawing board” and find another half dozen ways to do the job, using stuff that we can actually get, and build.
It’s all part of the design process.
Sorry I can’t be more help.
Do you mean something like this?
Often we will use two cylinders back end to end to make a multistage cylinder. Sometimes being flipped side-by-side with a custom bracket. It is what we used for 4 positions on the 2016 roller arm, and I’ve known team to do that for a pneumatic launcher to have multi-distance shots.
Also from Bimba, a 2 stage cylinder
WOW! I just can’t make those fit the BOM.
I think the real question here is: Do we need a drivetrain, or a super cool telescoping piston?
I think the biggest problem you’re going to find with telescoping cylinders is that you won’t get one with enough force to actually lift your robot, so you’ll spend lots of money to get the hook up there, but still need a winch to do the lifting.
The reason I think the force is less is because bore is compromised because there’s another cylinder in the middle of your first one–so active “pushing” or “pulling” area is the annular ring around the inside cylinder. But presumably the lower stages of the cylinder have more push area than the higher ones…not sure.
But they do exist and I’d love to see one on a robot just the same.
The Bimba one looks great, but here’s a funny video that I just ‘googled up’ that has multi-stage telescoping. Looks cool. Great music too.
That video is better than the “dancing fountains” that one finds in front of some of the big casinos in Vegas.
The issue with that one is it’s over $500 (in the default configuration, not sure if there is a configuration that makes it cheaper).
If you have access to a 3D printer and can do simple CAD, then you can make one for way, way under $500 — but you’ll still have to winch it back down.
Aren’t custom-made pneumatic components illegal?
Seems like this is a COTS piston (gray part on the left side) attached to a cascading telescoping elevator. No problem there
Yeah, its a nested PVC cascade system. Pretty simple and effective.
The challenge I see with PVC cascade elevators is figuring out how to effectively manage the cabling without compromising the stability or smoothness of the system. That said, I’ve never built one before, so perhaps this isn’t as difficult as I’m expecting.
Right, it’s a COTS piston with a cascade PVC lift.
We used tie-down strap for cabling and 3D printed brackets to mount and guide them. Came together really fast–we printed fast and dirty PLA prototypes on a mini delta, made sure we were happy with them, modified where needed, then printed the real things on a MarkForged–which is almost definitely overkill in this application.