pic: 2011 Drive Prototype

[Cory]

Originally Posted by Chris is me

There's a belly pan spanning the width of the robot. Generally such pans are used as structural members of the chassis (see 233/254's frames)

We put cross members even when using the "belly pan" design.

For the original poster: How do you intend to manufacture your gears? I'm guessing our 2007 robot was the inspiration for this design based on some of the aspects you've chosen to incorporate. If you've read much about that robot you'll have seen that everyone involved with the robot agrees that it's simply not worth the time and cost to make aluminum gears, for the ~2-2.5 lb weight savings.

Additionally we have moved away from delrin in the past two years. It flexes too much and isn't as durable as aluminum. If you have access to a waterjet it becomes very easy to make pocketed .250" aluminum gearbox plates which will be comparable in weight to .250 delrin but much more rigid. If you have access to a CNC mill, which I assume you do based on your design, it's a little more work, but still fairly simple.

Originally Posted by MWB

They slide inside of of a square cutout, ask somebody from 254, who might know more about the subject.

If you intend to make this as a prototype, you should probably understand the basics of how the design actually works. If you're just copying it and drawing it in CAD with no understanding of why things are done the way they are, then what value is that bringing to your team?

[MWB]

Originally Posted by Cory

We put cross members even when using the "belly pan" design.

For the original poster: How do you intend to manufacture your gears? I'm guessing our 2007 robot was the inspiration for this design based on some of the aspects you've chosen to incorporate. If you've read much about that robot you'll have seen that everyone involved with the robot agrees that it's simply not worth the time and cost to make aluminum gears, for the ~2-2.5 lb weight savings.

Additionally we have moved away from delrin in the past two years. It flexes too much and isn't as durable as aluminum. If you have access to a waterjet it becomes very easy to make pocketed .250" aluminum gearbox plates which will be comparable in weight to .250 delrin but much more rigid. If you have access to a CNC mill, which I assume you do based on your design, it's a little more work, but still fairly simple.



If you intend to make this as a prototype, you should probably understand the basics of how the design actually works. If you're just copying it and drawing it in CAD with no understanding of why things are done the way they are, then what value is that bringing to your team?

Well i just thought that it would be cool to lighten our shifters, then i saw yours and incorporated some of those features into my design.

Delrin is an easier material for us to mill because we do not have access to a vmc yet, just a prototrak machine.

I do understand how the design works, just i did not want to give him wrong information so that i do not confuse him. PM me so that i can explain.

[Travis Covington]

Why the secrecy with the tensioning method? I have to assume that most all of your design inspiration exists because of a lack of secrecy and the willingness of others to share ideas and to develop understanding.

[MWB]

Originally Posted by Travis Covington

Why the secrecy with the tensioning method? I have to assume that most all of your design inspiration exists because of a lack of secrecy and the willingness of others to share ideas and to develop understanding.

Well we are happy to share it during the build season, but not before. And anyways its only a prototype or a design. So we might not even end up doing the design.

[Brandon Holley]

Originally Posted by MWB

Delrin is an easier material for us to mill because we do not have access to a vmc yet, just a prototrak machine.
.

We make 100% of all our CNC milled parts on a ProtoTrak. We have absolutely no problems cutting any kind of aluminum. What sort of problems are you having?


Also, about the tensioning system...it seems extremely similar to 254s, why are you keeping it secret?

-Brando

[MWB]

Originally Posted by Brandon Holley

We make 100% of all our CNC milled parts on a ProtoTrak. We have absolutely no problems cutting any kind of aluminum. What sort of problems are you having?


Also, about the tensioning system...it seems extremely similar to 254s, why are you keeping it secret?

-Brando

Its the programming of pocketing that is hard, not the actual cutting.

Well its the way the cams are turned, not the actual system.

[MWB]

Originally Posted by ttldomination

That's some smexy stuff.

Just a quick question about how the bearing blocks are mounted? I'm not exactly sure how that works.

- Sunny

They slide inside of of a square cutout, while a cam (involute of a circle) with lots of tiny ridges sort of ratchets into place. the ridges fit onto the radius of the bearing block. PM Cory if you want to get the total lowdown.

[JamesCH95]

How are you putting the frame together? Bolts and brackets? Welding? The concept is good (though you should have some additional triangulation as some have mentioned). You just need a little more detailing for it to be 100%.

[MWB]

Originally Posted by Chris is me

A few questions:

1. Are the cam tensioners any different than the standard 254/968 style? Based on their mount location it doesn't look any different, in which case there's not much point to keeping them "a secret".

2. Did you remember to set material properties on the compressor and CIMs? Right now you have 11 pounds in CIMs and 4.3 pounds in the compressor, which means everything else shown weighs only ~18 pounds?

3. What are your transmissions made of that you get them down to 1 pound? I'm curious. I've basically found through CAD that the only way to get a shifter in a similar application down to 1.01 pound would be to switch to suboptimal (as I've been told) parts, or like 1/8th delrin or something ridiculous like that. How'd you get this transmission to 1 pound?

If everything's as it seems and you made a 34 pound chassis that does all that, good job!

Well the cams method of turning are different, not the actual block.

Yes all the materials are set. The reason that it is so light is because the upper-structure is made of 1/16in aluminum

They are made of 1/4in Delrin and 7075 Aluminum