Chain Tensioner
 

We were debating whether a floating tensioner (leaning to toward one manufactured by McMaster-Carr Model #5973K2) would work on a chain with a slight angle...we called the customer service and they didnt know so we wondered if anyone ever used on a chain path not parallel to the ground...if so how efective

Love, Peace, and Robot Grease
Team 2582 PantherBots

Re: Chain Tensioner
 

Buy the floating tensioner from Andymark. It is much cheaper and will probably work better.

Re: Chain Tensioner
 

how well do they work on an angled chain path?

Re: Chain Tensioner
 

I've seen those work on two sprockets of very different size when they chain is intentionally looser, so that tensioner pulls the chain very close together, a distance apart that is less than the pitch diameter of the sprocket I imagine.

Re: Chain Tensioner
 

i think they should work the same because the tensioner angles the chain anyway besides if its taught the chain will have the same tension everywhere

just like a pulley

Re: Chain Tensioner
 

I would use something similiar to what we used last year. It worked very well and cost about $6-$10 per tensioner. It was a skateboard wheel with a bolt going through it pulled back by two stiff springs. Just fingue out a way to mount it at the angle you want. (trust me. I do this for racing motor cycles quite a bit)

Srpings are from Ace
Long bolts we had
Got a $10 kiddie skateboard from Walmart and too the wheels off.

Re: Chain Tensioner
 

You can cut/file/turn a slight groove in the skateboard wheel to provided a little lateral support if things get sloppy.

Chains work on a slight angle - watch a motocross race where they whip around a tight turn. :D

Re: Chain Tensioner
 

We have used these for several years and they work AWESOME!!!!

Re: Chain Tensioner
 

These what? Skateboard wheel tensioners or AndyMark tensioners or the McMaster-Carr part? Do be terse.

And are they awesome, or do they work awesomely?

Re: Chain Tensioner
 

We're using this tensioner from AndyMark:

http://www.andymark.biz/am-0286.html

Re: Chain Tensioner
 

Wonderful! Things don't have to be really high-tech to work well, eh? The point of a conventional chain tensioner is not really to "tension" a chain, so much as to prevent slack from derailing it. A rigid tensioner on a bi-directional drive system does help eliminate lash...

Re: Chain Tensioner
 

who needs chain tensioners?
we are leavin them out again this year, less weight.
mike d

Re: Chain Tensioner
 

Amen.

Re: Chain Tensioner
 

They will work on a slight angle, but I would try to keep them as strait as possible. It works better. These work very well.

Re: Chain Tensioner
 

wow thats cutting it close...the drive train/ tension was our biggest problem last year and hence our biggest concern this year

Re: Chain Tensioner
 

If you have the resources to machine to close tolerances and you space your wheels by an integer number, you will not need tensioners until the chain stretches and then you can just replace it. I would personally not run without tensioners but it can be done. I would rather tension then replace but some teams are ok replacing chain more frequently for the weight savings.

Re: Chain Tensioner
 

Assuming you have the capabilities to make either, it is simpler to make as well.

Re: Chain Tensioner
 

we are closing in on 11 months without replacing our chains on our 2008 robot. and not one problem. also as Adam stated it saved us from making all other tensioner associated parts. I predict the drive chains lasting at least 5 years on this year robot.
mike d

Re: Chain Tensioner
 

Wow that is incredible. So are the chains loose now? How did you figure out the spacing to get it so perfect?

Re: Chain Tensioner
 

they were loose to begin with and they are even more loose than when we started but with 180 degrees of wrap they are still working fine. as for the spacing, we use #25 chain so the axle spacing is just a dimension divisible by .250 or 1/4".
mike d

Re: Chain Tensioner
 

Thats what I thought you guys did. I guess since you weren't using a super high force drivetrain the shock load on the chain wasn't great enough to break it. I always thought the reason for chain tensioning on #25 chain was so that it stays taught and doesn't snap when a shock is introduced. This year would be perfect to try going without a tensioner since the forces are so low on the drivetrain.

Re: Chain Tensioner
 

Last year we used a floating sprocket on our launcher. here's a pic.

Re: Chain Tensioner
 

I used to get all the drive train components about where I wanted them, mount the chain, then drill the holes in the right places. No real precision is required, though a good eye helps. Don't over complicate things. It's only rocket science if your robot is chosen for the next mission. You can probably find several good books about chain drives on Google books that were published from 1890 to 1915 or so.

Re: Chain Tensioner
 

We made some UHMW & Ziptie chain tensioners which resembled those of Andymark. They were on 4 chains that were all at a 5-10 degree angle and they worked fine.

You can guarantee they'll work fine so long as the spacing between the chain through the tensioners is smaller than the diameter of your smallest sprocket. That may not be easy to do though.