Reversing weapon belts

Last year we used a belt driven weapon with the teeth of the belt inward. I heard about people flipping the belt inside out and putting the teeth on the outside (smooth side against the pulleys) to reduce the amount of backlash (and motor stress) when hitting an opponent. Thoughts and/or experiences with either option?

Flip your weapon belts. With proper tension they can slip just a little on hard hits, when the weapon is jammed, and on hard startup, saving your motors, ESCs, shafts, supports, etc.

The tricky part is figuring out the center distance.

yah definitely flip the belt

you could destroy your motors of your belts with the teeth down and thats never good in a bout

it might slip a little but not much if the tension is correct

its the way to go

Thanks for the reply. Is it better to use pulleys with a smooth finish or with some texture (such as those designed to mesh with belt teeth)?

im not really sure we have done both so i would say it doesn't matter at least i couldn't tell the difference

from my teams past experience flipping our belts did allow for slip, however it is a major pain to tension them just right. We also noticed a major speed difference going from a slip setup, to a toothed setup. (the toothed being faster). my best advice is if you do go with flipping the belt then use some type of belt dressing to help maintain some grip

best of luck

One of the reasons we were thinking about flipping the belts is because we have a lathe and can make our own spindles. If the tension is too much or too little, we can just alter or make a new spindle.

fogdog wrote:

One of the reasons we were thinking about flipping the belts is because we have a lathe and can make our own spindles. If the tension is too much or too little, we can just alter or make a new spindle.

smooth pulleys have less surface area so less contact patch than a toothed pulley however a smooth pulley with traction compound can give higher rpm and less shock if it is tensioned properly i find that toothed pulleys start to create alot of friction if they have high deflection or break 20k rpm.

I think that we kind of pioneered the inverted timing belt idea.....

If you have an adjustable motor bracket, it goes a long way to getting tension correct and NO speed loss compared to teeth down. Also, the cheap neoprene belts grip better than the more expensive ones.

MLEC might have lost last years BotsIq nat's due to bad choice of belt material. We switched from neoprene to another material and belts wouldn;t stay on the pullies. My bad idea and not taking away from Green Mojito....they deserved the win

Matt gahlager has been doing it on humdingers for awhile, we tried it and didn't see any differences.

An upside down timing belt is just a flat belt, and they have been around since the dawn of time (almost).

I saw Hummdinger in 2008 and it'ss belt wasn't upside down then...or was it? I haven't been keeping tabs on how people wear thier belts....

Hello, I know this is an extremely late reply but, oh well... Back in the fall of 2006 during Humdinger's very first competition we realized that we were going to need to do something different with our timing belt. Every time we had a big hit the belt would break. We ended up reversing the belt to prevent breakage. Actually, for Humdinger's fisrt competition, we were not smart enough to bring a spare belt. We had to duct tape the belt back together. It would last only one hit. Since then we have always reversed the belt for fights, except Humdinger 2 sometimes did run teeth down for printer destruction demos. I tried flipping Chucker's belt teeth down once and the belt snapped also. But when Humdinger 2 and Chucker were designed, they were designed with belt tensioners. Matt didn't seem to need his tensioner. I know he had to use belt dressing. Chucker really didn't need dressing.

But yah, we did bring Humdinger to Bots IQ 2007 that way. Unfortunately for us, our beater broke the very first fight. It must have developed cracks from all the fights at home. We had to weld our beater almost every fight. Hardened S7 doesn't seem to be too great for welding. Somehow we still managed to get 3rd. Amazing.

Humdinger 2 got to do some destruction demos at Mecha Mayhem 2012. I uploaded some videos to the BooyahRobotics youtube channel. I did some slight changes to the design, nothing major. It's setup just for demos. Matt likes to refer to it as Humdinger 1.5...lol