Chain drive vs. cogged belt drive(timing belts)

[LordBritten]

Has anyone tried cogged belts (timing belts) instead of chain?
Any ideas?
Any comments about the idea?

[Rob2713g]

Originally Posted by LordBritten

Has anyone tried togged belts instead of chain?
Any ideas?
Any comments about the idea?

Do you mean cogged belts?

If so then according to Goodyear "Because of their higher coefficient of friction, cogged belts tend to be more sensitive to alignment. While envelope belts can tolerate some misalignment, cogged belts are more likely to turn over under the same conditions. Cogged belts should not be used in clutching drives, drives with severe shock loads, and drives that have changing center distances, such as shaker screens. In these applications, the aggressive nature and flexibility of cogged belts can cause vibration, belt turnover, and belt breakage. Cogged belts should also be avoided in drives that require slippage during frequent stops and starts."

[Qbranch]

I've never used timing belts (cog belts) on a first machine before, but use em a lot around work. They work very well for high transmission energy, minimal backlash, high accuracy situations. Have a linear positioning table using a large timing belt drive (4 leadscrews driven by 1 step motor), whole system is accurate to +/-0.0005" with up to 600lbs on it

cog belts work awesome for high precision/high torque applications, just make sure you do your math right and line everything up, and keep at least a few teeth engaged in each pulley to prevent skipping teeth.

if any ?'s hit me up.

-Q

[Billfred]

1293 used timing belt on their elevator lift in 2005. The lift was smooth as anything--it was beautiful stuff.

[Dan Petrovic]

We don't use timing belts for the drive because of slippage that might occur. Plus there's the fact that there is no way to alter the length of a belt and they are a hassle to put on.

[Cody Carey]

We hope to use them next year, At least from the motor to the first drive wheel. They have been more reliable for us than chain, and I still love taper-lock But we'll really just have to wait and take a look at next years game to see ...

[efoote868]

we used 2 for our ball collector this year... it seemed like a good idea at the time.

What it really amounted to was frustration everytime we took the darn thing apart, and now in the offseason, (probably because we 'over-tweaked' the robot) when we go to give demonstrations, and we pick up balls, the collector actually stops once the ball gets in it , then the ball slowly crawls up and in. (not saying it will happen to you, but be wary)

[LordBritten]

well we used the timing belts for our ball collector and it worked fine but the chain for our drive train would break all of the time and we thought that we might want to use the cogged belts next year.

[Gabe]

This year probably saw more teams using timing belts for the synchronous belt pulley on the large CIM. They are a whole lot quieter, but for adjustability in length I'll use chains.

[Jeff K.]

Both of them have their pros and cons
Cogged belts can beat chain in lighter weight, and chain can beat it in high torque transfer such as in a really torquey drivetrain. A timing belt is pretty reliable for transferring lots of torque, but there is the chance you could rip it in a worst case scenario, which could be avoided by a good design. Though like Gabe said, you have to get your design down first before ordering belts, because you can't change its length quickly like you can with chain by just popping out a link or two.

If you design it well, it will perform well.

Also, both chain and belts will stretch, so you need someway to tension it. If you just keep it static, then as it stretches, problems will arise of the belt or chain popping off and it failing.

Good luck with your designs though.

Also Lord Britten, what pitch of chain did you use? #25 or #35?

[ewankoff]

for our shooter we hooked up the large sime via a small cogged belt. it worked beautifully and we had only one problem. the belt semi wore out through the course of 1.5 competitions and needed to be replaced. we expected this so we were able to easily disassemble and replace the belt no prob.

[Tom Bottiglieri]

When half of your robot gets bashed in during a match, you'll be happy you used #35 chain.

[RyanN]

Okay, with the 2003 robot, "The Raging Squid," Team Fusion used belt drive. The advantages to belt drives are weight and responsiveness (lack of slack like with chains). However... the belt drive slips so much that there is no way that it could compete with our 2005 or 2006 robot in a pushing contest. As with chain, you usually don't have to worry about slippage or it snapping like with belts, but of course with chain, you must use metal sprockets and the metal chain weight quite a bit. We use #25 chain for our robots to cut the weight and we have not had any of our chains break in the past 2 year.

[LordBritten]

Originally Posted by Stonefan5271138

Both of them have their pros and cons
Cogged belts can beat chain in lighter weight, and chain can beat it in high torque transfer such as in a really torquey drivetrain. A timing belt is pretty reliable for transferring lots of torque, but there is the chance you could rip it in a worst case scenario, which could be avoided by a good design. Though like Gabe said, you have to get your design down first before ordering belts, because you can't change its length quickly like you can with chain by just popping out a link or two.

If you design it well, it will perform well.

Also, both chain and belts will stretch, so you need someway to tension it. If you just keep it static, then as it stretches, problems will arise of the belt or chain popping off and it failing.

Good luck with your designs though.

Also Lord Britten, what pitch of chain did you use? #25 or #35?

#25

[LordBritten]

Originally Posted by RyanN

Okay, with the 2003 robot, "The Raging Squid," Team Fusion used belt drive. The advantages to belt drives are weight and responsiveness (lack of slack like with chains). However... the belt drive slips so much that there is no way that it could compete with our 2005 or 2006 robot in a pushing contest. As with chain, you usually don't have to worry about slippage or it snapping like with belts, but of course with chain, you must use metal sprockets and the metal chain weight quite a bit. We use #25 chain for our robots to cut the weight and we have not had any of our chains break in the past 2 year.

Mt team used #25 chain last year and our chains would break all of the time. that is why lost in the semi-finals at the Portland regional we did not have time to fix the chain.