Has anyone tried cogged belts (timing belts) instead of chain?
Any ideas?
Any comments about the idea?
Do you mean cogged belts?
If so then according to Goodyear âBecause 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.â
Iâve 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 :ahh:
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
1293 used timing belt on their elevator lift in 2005. The lift was smooth as anythingâit was beautiful stuff.
We donât use timing belts for the drive because of slippage that might occur. Plus thereâs the fact that there is no way to alter the length of a belt and they are a hassle to put on.
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 weâll really just have to wait and take a look at next years game to see âŚ
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 âover-tweakedâ 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)
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.
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 Iâll use chains.
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 canât 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?
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.
When half of your robot gets bashed in during a match, youâll be happy you used #35 chain.
Okay, with the 2003 robot, âThe Raging Squid,â 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 donât 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.
Were you a high traction pushing robot? If so then you might want to go with #35 chain.
Our team has used #25 chain every year except 2004 and havenât had problems breaking them that Iâve ever known of (I know we havenât the past 2 years; donât know about before). Weâve never been a robot with high traction wheels that does a bunch of pushing either though, so I doubt we put as much stress on them as other teams do.
we have used them for the past 3 years
2004 the arm that hooked the bar- worked well
2005 the arm for picking up tetras- we use timing belts on the secant pivot but when we put it together and tryed to move it with no load and it riped the cogs off so we change 35# chain
2006 the upper Harv that moved balls to the shooter we used double sided timing belt
but after seeing 1503âs robot i like chain
Weâve used #35 chain for 5 years. We have never had a drivetrain malfunction and only need to adjust chain tension once during a regional. That is probably because we donât get much practice time in ahead of time and things are just getting seated
One thing I like about chain is that itâs easy to add or remove links to get the right length. When we can do it, we position the gearbox between the front and rear drive wheels (4 wheel drive). This keeps the chains short, which helps with weight and reduces the effect of chain wear. Chain tensioning is done by placing shims (washers) under the gearbox where it mounts to the frame. Very simple, very sturdy.
We used cogged belts on mech wheels last year and we broken normal timing belts and stripped Kevlar ones.
We ended up using gears for reliable operation. We also tried chain but couldnât find a robust 8 tooth sprocket the fit the dewalts.
If you design the drive train correctly, you should never have any problems. (use large sprockets, dont have any slack, have chain guides)
We have been a high traction robot for two years with our 6WD system. The secret is the larger sprockets, it allows for more chain to go over a single sprocket than a smaller sprocket, which would give you more torque. Think of it as a bicycle, if you put your bike on the highest speed, it causes you to push harder (which also puts more tension on the chain), if you put it on a low speed, there isnât as much tension on the chain. The same applies with using 2 large sprockets or 2 small sprockets. The weight cost to go to larger sprockets is minimal, and will save you at competition.