pic: Super Light Chassis System

[ajlapp]

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[Cyberphil]

Very interesting. Looks like it could be extremely useful, and it does look extremely light! A few questions:

How much does it weigh?

What are the dimensions?

[ajlapp]

How much does it weigh?

What are the dimensions?

9.2 lbs as pictured.

The narrow bot configuration is 37" by 22.5". The wide bot configuration is 27" by 32.5".

Super Light product page.

[billbo911]

It looks very simple and straight forward. I like that it is reconfigurable into a variety of configurations with little effort.

My only concern is it's ability to resist racking during the rigors of competition. Might I suggest that once it is assembled in it's final configuration and aligned and squared that the joints be welded. A bit of the hardware could then be removed and a bit of weight could be saved.

[Cyberphil]

Very impressive. I have seen many of your systems before, and the more I look into them, the more I am impressed. Does your team design make all of these products? And have you ever configured this system so it was completely gear-driven? It would add a little weight, but I think you would save on the hassles of chain.

Great design, and excellent work.

[Josh Fox]

I'm assuming the "hassles of chain" you're referring to would be proper tensioning and alignment, which are more or less resolved with by the super light chassis system.

[ajlapp]

Does your team design make all of these products?

Most of our products that are geared towards competitive robotics are developed with the help of FIRST teams.....this product was developed by Team RUSH, frc27.

Disclaimer: Our company is independent of FIRST Robotics and is not associated with any team.

And have you ever configured this system so it was completely gear-driven? It would add a little weight, but I think you would save on the hassles of chain.

No. In my opinion, #25 chain, when properly aligned and tensioned is almost foolproof. Any hassles I've ever encountered with chain have come from master links, poor shaft support or improper tensioning......ever product we create attempts to solve this problem. Which is why we feature #25 chain!

[BJC]

Very nice. The 1 by 2 bar kind of reminds me of the Poof's chassis. With some welds and a bellypan I bet it would be really stiff too.

[Josh Fox]

It's definitely drawn a lot of inspiration from the classic west coast drive of teams like 254/60/968.

[Cyberphil]

Originally Posted by Josh Fox

I'm assuming the "hassles of chain" you're referring to would be proper tensioning and alignment, which are more or less resolved with by the super light chassis system.

Yes, these are exactly what I am referring to. Our team went away from chains many years ago due to many complications and failures. These could very well be from un-proper tensioning and alignment. I do understand how these problems are solved with this system, but I was just more or less wondering you had ever considered it.

In my opinion, #25 chain, when properly aligned and tensioned is almost foolproof. Any hassles I've ever encountered with chain have come from master links, poor shaft support or improper tensioning......ever product we create attempts to solve this problem. Which is why we feature #25 chain!

I completely agree. The only reasons we use a directly gear-driven DT is because of the failures in these places. The less room for problems, the less problems in general is our view. And, yes, I understand that there are complications with a direct gear-driven DT also.

Our company is independent of FIRST Robotics and is not associated with any team.

Very interesting. Then I have one more question. Why did you name it Team 221 Robotic Systems?

[ajlapp]

We have never tried direct drive, though Andymark has a system that works well....and I have admired team 25 for years. Every design choice has it's merits!

The name Team 221 LLC. has turned out to be a poor choice. It was supposed to be a reference to our inolvement with FIRST and to the fact that I once was the leader of FRC221, the number was retiredin 2001.

At the time it seemed a fitting moniker for a company that got it's start developing products for competitive robotics teams.

We now refer to ourselves as 221 Robotics Systems.

This naming confusion is only a problem when we participate in FIRST events.

[Cyberphil]

Originally Posted by ajlapp

We have never tried direct drive, though Andymark has a system that works well....and I have admired team 25 for years. Every design choice has it's merits!

The name Team 221 LLC. has turned out to be a poor choice. It was supposed to be a reference to our inolvement with FIRST and to the fact that I once was the leader of FRC221, the number was retiredin 2001.

At the time it seemed a fitting moniker for a company that got it's start developing products for competitive robotics teams.

We now refer to ourselves as 221 Robotics Systems.

This naming confusion is only a problem when we participate in FIRST events.

Interesting. Thank you very much! I appreciate the information!

[AdamHeard]

Originally Posted by Cyberphil

Yes, these are exactly what I am referring to. Our team went away from chains many years ago due to many complications and failures. These could very well be from un-proper tensioning and alignment. I do understand how these problems are solved with this system, but I was just more or less wondering you had ever considered it.



I completely agree. The only reasons we use a directly gear-driven DT is because of the failures in these places. The less room for problems, the less problems in general is our view. And, yes, I understand that there are complications with a direct gear-driven DT also.



Very interesting. Then I have one more question. Why did you name it Team 221 Robotic Systems?

The advantage of this style chain system is that it allows you to run a single frame rail, which saves a good deal of weight alone. The sliding bearing blocks also makes it so machining the rails is far easier, with lower tolerance. A geared system is both heavier and requires more precision.

With proper alignment and tensioning, which is pretty easy, chain failure in #25 chain is a complete non-issue.

[Cyberphil]

Originally Posted by AdamHeard

The advantage of this style chain system is that it allows you to run a single frame rail, which saves a good deal of weight alone. The sliding bearing blocks also makes it so machining the rails is far easier, with lower tolerance. A geared system is both heavier and requires more precision.

With proper alignment and tensioning, which is pretty easy, chain failure in #25 chain is a complete non-issue.

And thats why I ask questions! Do you really need two frame rails to create a geared system? I would imagine that if you created it well enough you could modify this very system so it could be a geared system. If I am wrong please let me know. I am very curious, and obviously ignorant.

[Chris is me]

Ground clearance and low wheel size is another big thing with chained systems.

With a gear drive, you want as few gears as possible or else your weight and efficiency really starts to add up. To accomplish this, you'll need big gears (several inches in diameter), which brings the gears rather low to the ground unless you also use very large wheels (8" or more). Here's a diagram of team 25's drive (probably similar to 103's):



The design works because of the very large wheels to accompany the large gears. While great for climbing, large wheels inherently weigh more than small ones and combined with the multiple gears and drive shafts adds to the weight considerably.

With a sprocket drive, you can run relatively small sprockets on relatively smaller wheels.


Here the sprockets for 6 inch wheels are only about 2.5 inches in diameter. This keeps the chain clear of the floor while reducing sprocket weight. The 6 inch wheels in turn are much smaller, lowering weight further.