Bulk Run of Tank Track by Feb 1st

[TankChain]

Originally Posted by tgraham_533

Can you provide the weight of this track system, either by link or by length?

The assembled track weighs 1.17 pounds per foot of track. One foot of track is 16 links.

I hope this helps. I know the competition has some weight limits. We have thought about investing in some plastic roller chain for a light weight option as well. But it would obviously not be as strong as the steel chain.

Josh

[TankChain]

All,

I received some video and pictures from one of our previous customers. The Dalton School in NY designed and built a robot for the FIRST FTC competition. They were kind enough to share these with me and gave me permission to publish them. They said they would try to make a video about how they combined the track system with the Tetrix Robotics Kits.

I hope this helps some teams get an idea of how our track system works.

Here is a link to the video first. It is not very long but I think it shows the tracks working very well.
https://youtu.be/iuOcrR4hvzw

I have to upload the pictures to another site so that I can link them on here. So I will make another post in a little bit after that is done.

Josh

[TankChain]

And here are the pictures I promised. The Dalton Team did an amazing job on this robot.

[thatprogrammer]

Originally Posted by TankChain

The assembled track weighs 1.17 pounds per foot of track. One foot of track is 16 links.

I hope this helps. I know the competition has some weight limits. We have thought about investing in some plastic roller chain for a light weight option as well. But it would obviously not be as strong as the steel chain.

Josh

Perhaps you could look into aluminum as a middle ground? My team isn't considering these for this season, but might for future seasons. Are you familiar with the CoF on carpet of these treads?

[cglrcng]

While the Bulldozer configuration (using those 2 large sets of sprockets does use less track per side - as seen on that FTC bot pictured and videoed), I personally believe a regular tank tread configuration, while using more track length & equaling more final weight on the robot equaling a lower CG also (four sets of much smaller sprockets, 2 high & long, 2 low and short and a center low drop idler wheel set in the middle of the lower run of tread, to make turning on the carpet - mounted both inner & outer but inside the chain contacting the inner rubber portion of the tread,), would make a much better use of track footprint and give you the WC Drivetrain feel of driving it much faster and over anything you wish to drive over.

It would also spread out that weight end to end on the bot, and be much less apt to flip over easily even on steeper climbs like a real tank. It would raise the tread height on both front and rear of the bot making getting over obstacles easier driving the bot in either direction making turning around unnecessary to cross the Defenses in Stronghold.

_________
\_______/
{}Drop center Idler wheel, 2 speed shifter, 2 or 3 CIM'S per side, 8 sprockets & 2 lower drop center idler wheels per tread side. You can mount gearboxes & drive center / center, or on each opposing end to even the weight out so no end is heavier than the other and spread that LOW CG out over the entire kitbot frame.

Positioning the tread runs under a long/narrow kitbot frame wouldn't be that difficult concerning the additional fabrication necessary to support / drive the chain treads (if you just adjust the inner rails), and still allow easy bumper addition to the outside of the frame perimeter as opposed to adding bumpers to that belt driven tread addition avail. on AndyMark. Just a personal opinion there as that other one seems to be a nightmare to add legal bumpers to that don't also defeat the treads that only rise on one end.

[TankChain]

cglrcng has a good point. There are quite a lot of different configurations of tracked vehicles. When I designed this track system I wanted it to be modular and highly configurable. So you could easily change your design.

One of my other customers is a University building a robot like what cglrcng mentioned. They ordered a set of Tank Chain and are in the process of upgrading their robot. They had problems with the conveyor belt they were using for track because it didn't have grip.

https://sites.google.com/a/vt.edu/am...-vehicle-mk-iv

[TankChain]

I just wanted to give a small update. The mold is being machined right now and should be completed shortly. Our other parts have shipped from China and should also arrive in a few days. I talked with the injection molder today and we are on schedule to have 7500 parts molded on Feb 1st and 2nd. We plan to be packaging parts that evening and putting them in them mail the next day. So everything is on track to mail out parts the first week of February.

Josh

[TankChain]

Talked with the injection molding company and it sounds like they will be able to run the parts in two days. I am planning on being onsite the first day and we should be able to ship most of the orders out from the first batch of parts. So most orders will ship out Feb 2nd.

We increased our order of injection molded parts, so there is still plenty of parts for other teams.

Josh

[TankChain]

Originally Posted by thatprogrammer

Perhaps you could look into aluminum as a middle ground? My team isn't considering these for this season, but might for future seasons. Are you familiar with the CoF on carpet of these treads?

I have never seen aluminum roller chain. I have seen mild steel, stainless steel and plastic chain. We have a partnership with a manufacturer which sends up parts before they get assembled into full chain. Because these chains are made in bulk the price for chain components is reasonable. Custom aluminum chain might be significantly more expensive. But we will look into it.

They do sell aluminum sprockets which would really help save weight on a robot.

As for the coefficient of friction on carpet; That is not really a simple thing to answer because there are thousands of types of carpet. I assume that people here only care about the regulation carpet for FIRST. Which I don't have access to. What I can tell you is that the treads are made from Shore 70 A Urethane rubber currently and the injection molded parts are almost the same material. This is very similar to the rubber in your car tires.

If you would be interested in doing some tests I can send you some samples. I would ask that you share your method and results. I also would like to be allowed to post the details on my website.

Josh

[Billfred]

Originally Posted by TankChain

I have never seen aluminum roller chain. I have seen mild steel, stainless steel and plastic chain. We have a partnership with a manufacturer which sends up parts before they get assembled into full chain. Because these chains are made in bulk the price for chain components is reasonable. Custom aluminum chain might be significantly more expensive. But we will look into it.

They do sell aluminum sprockets which would really help save weight on a robot.

As for the coefficient of friction on carpet; That is not really a simple thing to answer because there are thousands of types of carpet. I assume that people here only care about the regulation carpet for FIRST. Which I don't have access to. What I can tell you is that the treads are made from Shore 70 A Urethane rubber currently and the injection molded parts are almost the same material. This is very similar to the rubber in your car tires.

If you would be interested in doing some tests I can send you some samples. I would ask that you share your method and results. I also would like to be allowed to post the details on my website.

Josh

Josh,

My team isn't in a position to test ourselves, but I'll share that FIRST uses cheap commercial carpet that is replaced every 1-2 events. The robots top out around 130-150 pounds wet, with the battery and mandated bumpers on. That might help guide your testing if you optimize for the FRC market.

Even if plastic chain isn't the best look for one of our drive systems, there are many years that call for conveyor systems inside the robot. This year could even see some action for that.

Hope this helps--welcome to our strange little world.