Balancing a Pneumatic wheel

[Thad House]

Something that seems a little odd to me is that alot of teams used very similar shooter designs last year, and I don't remember seeing as many worries as I have seen this year. Would the wheels being horizontal vs vertical make that much of a difference?

BTW both last year and this year we used 2008 KOP Grey wheels, and we had no trouble running them at 5k rpms either year.

[Shu]

The discussion is centered on the pneumatic tire/wheel which I don't think was widely used on last year's robots as part of the shooter.

[jimwick]

We found that the valve stem was being pushed outward by centrifugal force.

So we put a zip tie around the valve stem and the bolts holding everything together. Seems to work well. Has been reliable.

We are only running about 3000 rpm. We are not trying for real long shots.

[Brandon_L]

Originally Posted by jimwick

We found that the valve stem was being pushed outward by centrifugal force.

So we put a zip tie around the valve stem and the bolts holding everything together. Seems to work well. Has been reliable.

We are only running about 3000 rpm. We are not trying for real long shots.

We did the same but with a few wraps of a fishing line

[z_beeblebrox]

Originally Posted by jimwick

We found that the valve stem was being pushed outward by centrifugal force.

Had same issue. Elegantly solved with strategically placed duct tape toroid.

[FrankJ]

After some thoughtful offline conversations.....

Al is more likely to inspect your robot than I am. Take heed of his words.

Regards of who inspects your robot. It is your job to make sure it is safe. This means:

1. making sure anything attached to the rotating bits is well attached and is not going to come off.
2. making sure your shooter is not going to come apart from rotational forces or having your frisbee jammed into it.
3. Making sure the shooter is well attached and the shafting and bearings are adequate for the job.

Apologies in advance if this sounds the least bit preachy. I am looking forward to seeing amazing things this year.

[Ether]

Originally Posted by FrankJ

Regards of who inspects your robot. It is your job to make sure it is safe. This means:

1. making sure anything attached to the rotating bits is well attached and is not going to come off.
2. making sure your shooter is not going to come apart from rotational forces or having your frisbee jammed into it.
3. Making sure the shooter is well attached and the shafting and bearings are adequate for the job.

^^^This^^^

A couple of years ago, I leaned over my lawn tractor with the engine running and slipped and caught myself by placing my hand squarely on the spinning debris mesh on the top of the engine. Not fun. I was "single handed" for several weeks after that.

So I would add #4:

4. put some sort of guard over the spinning wheel to protect wayward hands and contain pieces that might come flying off due to failures.

[FrankJ]

Originally Posted by Ether

^^^This^^^


So I would add #4:

4. put some sort of guard over the spinning wheel to protect wayward hands and contain pieces that might come flying off due to failures.

Good add.

A major concern of mine regarding high speed rotating wheels that I stricktly enforced with the 4134 kids was loose clothing and long hair. Hanging untucked shirts, hoodie strings and espesially long hair pose significant saftey issues. Most of time the kids know where there hands are, but not the strings on their hoodie.

[Ether]

Originally Posted by DMike

A major concern of mine regarding high speed rotating wheels that I stricktly enforced with the 4134 kids was loose clothing and long hair. Hanging untucked shirts, hoodie strings and espesially long hair pose significant saftey issues. Most of time the kids know where there hands are, but not the strings on their hoodie.

Yikes. Great point.

[Al Skierkiewicz]

Dangling chains, bracelets and chums, too.

[FrankJ]

Basic rules of our build site. If you are in the build area
closed toe shoes
safety glasses
hair pulled back
No danglies
hoodie strings tucked in.

[Andrew Schreiber]

Originally Posted by Al Skierkiewicz

Dangling chains, bracelets and chums, too.

Watches too. I usually have my watch and a band that tracks my activity over the day on my left wrist. When I'm anywhere near that shooter both of those are put in my computer bag. Neither of those are even loose but they are things attached to my person that increase risk and, again, I'm rather fond of my limbs.

[Jon Stratis]

Originally Posted by DMike

A major concern of mine regarding high speed rotating wheels that I stricktly enforced with the 4134 kids was loose clothing and long hair. Hanging untucked shirts, hoodie strings and espesially long hair pose significant saftey issues. Most of time the kids know where there hands are, but not the strings on their hoodie.

This isn't only an issue with fast spinning wheels. A drill press will run at 1000 RPMs, if not faster... get a string or hair caught in that, and the students head will be pulled in before you can blink.

[FrankJ]

This is why my wedding ring stays in my dresser. I regularly work with rotating equipment & hot circuits (which you should never to begin with). I am paranoid that I will leave it some place.