Breco?

For anyone who has used brecoflex for treads,
is there certian model that you perfered or
had more sucess with? My team is looking
at useing treads this year, and with our
rookie year being last year and any info
would be appreciated.

Plenty of teams have used brecoflex in the past 365,48,180 1114, and many others. They work well and the main weapon of choice depends on how much friction you want on the carpet or not. Teams have used diffrent types with diffrent games. Brecoflex has great information on there website and pamphlets they will send out if you ask. Gates is another great belt company. They are quite pricey though. Hopefully Travis,Karthink,Eric or someone who did MOE’s 05 drivesystem can chip in on this.

Just a few thoughts,
Drew

The main consistent thing I’ve heard about Brecoflex is that it takes a very long time (weeks) to get some of their products sometimes.

If you are looking to create a tank drive, I invite you to present a good argument as to what is wrong with wheels. :slight_smile:

It can also be extremely expensive. I’ve heard of certain types of belts that are $200-300 EACH.

Any model made by Gates-Mectrol

Our team had plenty of success using treads in 2006, however we had terrible issues with our first batch of belts from Brecoflex. (Which eventually earned the nickname “Break-o-flex”) That being said, if you have the budget go with the truly endless belts that have the steel cabling. These are least likely to snap during a match.

Still, there’s no way I could refer anyone to Brecoflex without warning you that the three Niagara Triplets of 2006 snapped at least 15 belts. Once we switched to Gates-Mectrol, I believe we snapped no more than 2.

There are plenty of good threads discussing different belt types on these forums. A search of the archives should turn up many results.

Look up Outback Manufacturing, and their tank track drive system. Only one snapped belt across many teams using it, and that was due to driver error. They use the steel cabled red linatex. It has a wonderful life, is strong, and grips amazingly well on just about all surfaces.

When a driver error results in serious (game costing) malfunction I would worry about the system’s durability. Can you explain in more detail what happened?

Team 48 has an excellent power-point presentation on how to design a Berco belt drive system.

But IMO, solid attachment chains are the way to go. They’re a lot cheaper and stronger. Plus, you can adjust their length yourself.

Here are some designs I’ve seen:
1293
885
45 (no longer legal, but still very cool)

Are these available for sale? I check their website periodically and there’s no mention of the system there.

Also, as I recall, there aren’t many pictures here on CD that show the track drive in any sort of detail. There are a handful of pictures that give a look at the system, but nothing with any insight into how it’s designed or assembled.

I’m sorry, I should have said derailing. No belt has snapped.
They were being heavily pushed from the side. If you drive when being side loaded, you have an issue of derailing, but ONLY if you drive. Their driver knew this, and chose to move anyway. It was the only belt lost. Also, if I’m correct, they’ve fixed this issue in the next revision.

They are available for sale, but on a semi-sponsorship basis. They’re not listed on the website, as it’s not a primary function of Outback. Your best bet is to call Sam Shawe, and express your interest. He’s not the snappiest on email…

Of course there’s no details on how it’s assembled. The lack of tensioning device is created by a shape in the side, which tensions the entire system through rigidity. Here is probably the best bet you’ll have in a detail shot. The system is based around 2 plates, bolted together with standoffs specifically shaped to give maximum strength (stronger than bot a triangle and a circle!)

I’m actually available via AIM if you have any more questions, M Krass. It’s a wonderful system.

Although we had quite a few problems with tread breakage in 2004, our first year attempting a tank tread design using Brecoflex belts, we’ve had a lot more luck with Brecoflex in 2006-2007. We broke one tread in 2006 due to overtensioning by an exuberant student. We had a few tears in 2007 and a tendency for our tread modules to wear away the edges of belts (didn’t affect performance), but nothing that could be characterized as a chronic problem. We’ve used a swappable tread module design in both years which saves us downtime in the event of a jam or break.

Our experience has been that our tank-tread robots have excellent straight ahead pushing force, but we haven’t solved the smooth zero-radius turning design challenge many tank tread drivetrain designers face. Proper robot weight distribution and setting the correct “bogey” wheel depression are crucial to smooth zero-radius turning. In addition, the relatively heavy weight of a tank tread drivetrain sucks away weight budget which could be allocated elsewhere.

I agree that the red linatex backing is a very robust and hardy belt material regardless of the tread supplier. I prefer it to Brecoflex’s Supergrip Blue and Green.

Team 379, the Girard Robocats, used the same set of red linatex treads THE ENTIRE SEASON last year, and I believe they were Brecoflex. The treads were still in great shape after 3 regionals, Atlanta, and Kettering. They also had better maneuverability than we did. I’m sure those guys would have some advice for you.

I’ve asked Mike Mellott, our lead mechanical designer, to post more detailed information on our Brecoflex experiences.

Here’s a pic of the side view of our 2007 robot. It doesn’t show much but gives you the general idea of our design:

http://www.chiefdelphi.com/media/photos/27491

FYI, we’re currently experimenting with various “half-track” module designs which use much shorter (and therefore cheaper) belts. We ran with these at IRI and Kettering Kickoff with much success and much improved maneuverability, at the expense of pushing oomph. They were also much, much lighter than our full-length tread modules.

Finally, we have no experience with the Gates belts, but there’s no reason not to trust the endorsements of the others who have advocated their products in this thread.

We used the outback track system on our 2006 I believe they were the key to our success. They allowed us to push almost all of the robots we faced around or to a stand still. Even though pushing a robot half way across the field is not the best way to play defence in my opinion.

The track system is designed to use a TK10 50 mm wide brecoflex belt with red linatex backing which we had the edges chamfered so that it would reduce wear on the edge of the tread.

The sytem was degined by Sam Shawe of outback Manfuacturing so get in contact with him if you want details on pricing and availablity.

The track system is also designed so that it doesn’t need to be tensioned. when assembled the belts will not skip teeth or move out of track/derail.

We have sheared a couple of belts. They were due to driver error and abuse of the tracks. The driver drove while being pushed sideways as 114ManualLabor said and the belts sheared then they sheared because in the off season the drivers decided to abuse them and not replace them with the fresh set that we had on hand before we went to an important off season event. The belts can’t derail if they start to derail they will shear either partially or completely.

I noticed you were from Newport. If you would like to make a trip over to Corvallis some time to look at the track system and talk about the design send me a message via email(click on my profile and send message via email). We have work sessions almost every tuesday and thursday and would be more than happy to answer any questions.

If that is driver error, that means you can’t drive while being pushed on from the side. Doesn’t that seem kind of bad? The only way to escape from that position is to drive and hope you break free (kind of roll off them) or wait for the other team to stop.

We used a defend and lift strategy in 2006 so if the person that we are defending is busy pushing us rather than scoring then work accomplished. I believe that it’s only a problem if you drive full speed back or forward while being HEAVILY pushed from the side.

As Travis mentioned above, our team has used Brecoflex treads for 3 of the last 4 years. We opted for 50mm wide belts with the TK10-K13 self-tracking belt profile in order to use pulley wheels that did not have metal flanges on the outer edges. Depending on the backing you choose, belts that are spliced together for a continuous loop for a half-track design (900-1000mm) run $120-170, while belts used for a systems where they run the full length of the robot (1800-2000mm) can run up to $250. We used 32-tooth wheels for the primary drive wheels and 20-tooth wheels for the support (i.e bogey) wheels, where the wheels will run $38-50 each. We developed a bolt-on modular tread system that allowed us to remove and replace one whole tread side (wheels and all) in case of damage or belt breakage. We bought 6 belts for the '07 season (4+ events) because of manufacturing lead times (2 to 4+ weeks), tread wear (we opted for the cheaper SuperGrip tread), and potential breakage, as well as enough wheels for 4 modules. As mentioned by others, this system is not cheap compared to a wheeled drivetrain. BTW, from our experience, I will also put in my vote for the red Linatex backing–more expensive, but more than worth it with higher CoF and tread material duability.

Weight is also a major issue with this system. The wheels come as solid aluminum billets, with the 32-tooth wheels weighing 4 lb. each, so a lot of custom machining is necessary to save weight. Also, the treads need a lot of support with plates and spacers keeping the wheels from torquing due to belt tension and lateral impact forces from other robots.

Much has been said above about Brecoflex belts derailing or even snapping due to being pushed from the side. The main concern with tread breaking comes from the length of the tread and how it’s supported. With tread belts that run the full length of a robot, it’s easier for the belt to twist along the carpet due to a lateral force, which can cause derailing or breakage if the driver isn’t careful. In order to keep it from twisting, many go to a much higher tension level on the belts, putting a lot of strain on the steel chords running the length of the belts, which can cause those chords to fatigue from the high tension and break that way. A better solution is to add smaller bogey wheels or Delrin sliders to support the lateral stresses on the belts (you typically need one in the center anyway that’s lower than the outer wheels to ease turning). Of course, this extra support means extra weight. Another solution we are developing is a half-track system that uses much shorter belts, which we’ve found not only resists twisting due to the shorter length, but also requires less tension on the belt. The only issue we found at our live testing at IRI and Kettering was treadwear (we used the SuperGrip material at IRI, which wore away quickly, and used Linatex at Kettering which worked much better). I suppose another option might be looking at using tread belts with Kevlar or Stainless steel cords, but I’ve been too afraid to price them or be willing to purchase some for testing.

In the end, it’s a matter of deciding which direction you want the development of your robot to go. With Brecoflex, you can develop a strong drivetrain (assuming you also have beefy transmissions to power those treads), but it’s a heavy and often expensive system that takes away weight that could be utilized for other functionality.

I’m hoping to write up a white paper sometime soon on this, but I hope this helps until then. Feel free to contact me directly if you have any questions.