pic: WCD

[Aren Siekmeier]

Originally Posted by Akash Rastogi

He is concerned about losing mobility (chain popping off) when using #25 chain without bearing blocks.

I still see no difference between an indirect drive with bearing blocks and an indirect drive without, since maintaining tension on the chain from transmission to first driven wheel is as simple as a slotted transmission noun. That point of failure doesn't depend at all on an ability to move wheels to adjust tension. And beyond that, the system is identical to a direct driven WCD (w/ or w/o blocks). I see bearing blocks and direct drive as two completely independent design decisions, though if there are other details I have overlooked I would be glad to hear them.

[Chris is me]

With a direct drive live axle drivetrain (or any chain drive), you need a method to tension the chain. Since this isn't an indirect drive, moving the gearbox isn't an option. The most efficient way to do it is to move the wheels slightly outward or inward, hence bearing blocks.

[craigboez]

We had an 8WD WCD last season. The siderails were 1" x 2" x .125" rectangular tubing, and we put the bearings right into the siderails, no bearing blocks. They were designed to use exact C-to-C for #25 chain. Our thinking is that if the chain ever stretched to the point of being a problem, we'd replace it with new un-stretched chain. This served us well through two regionals. We never replaced a chain. Looking back, I think I'd have the students replace the chain at the beginning of each regional just to be safe.

See here for CAD:
http://www.chiefdelphi.com/media/papers/2752

[Adam.garcia]

Has anybody been able to find the CAD models for the WCP 2-speed Shifters? It doesn't look like it is yet available on the website.

Originally Posted by msimon785

We are actually not using this bellypan. It was designed more for the aesthetic of the rendering and would actually be useless because it does not prevent torsion in the frame much at all (because of the typography in the center).

Instead, we are using a waterjet 1/16" ABS bellypan with a few large pockets rather than the conventional diamond pattern.

As to the electronics, 1515's electronics for the past 3 years have utilized c-channel slides and either a reinforced corroplast or polycarbonate. We use WAGO X-comm modular terminal blocks to allow us to easily remove all the electronics in a matter of seconds. Is this level of modularity necessary, or perhaps even desired? No. However, it is a technique that has worked for our team in the past and we do intend to continue modularity in electronics in the future. It is something that our programmers and electrical students both very much appreciate as it allows them to work independently and free of debris.

The bearing blocks are very similar to the 973/1323 ones as Michael said, but with a different bolt pattern.

Please note that while this is a "standard" wcd frame, a much more recent iteration (except for the abs bellypan) is found here.

EDIT: Also, the WCP gearboxes are anodized black and colors in both this rendering and that of our latest revision are simply for the sake of the rendering. (I actually helped with the WCP renderings).

[MichaelBick]

Originally Posted by Adam.garcia

Has anybody been able to find the CAD models for the WCP 2-speed Shifters? It doesn't look like it is yet available on the website.

Both Mathew and I got it directly from RC himself. Try PMing him for the CAD

[DampRobot]

Originally Posted by MICHAELABICK

Both Mathew and I got it directly from RC himself. Try PMing him for the CAD

Seconded. RC's very good about answering email. I got my model directly from him too.

[josesantos]

I haven't downloaded them myself, but it appears that the CADs you're looking for are here: http://wcproducts.net/cad/

[Gary.C]

Originally Posted by josesantos

I haven't downloaded them myself, but it appears that the CADs you're looking for are here: http://wcproducts.net/cad/

Correct, working on getting the rest of the missing models up, but all the important ones are there.

Each part has its CAD model on its respective page now! (Still working on getting them all covered)

Such as WCP DS: Dual Speed

http://wcproducts.net/wcp-00100/

[rees2001]

Originally Posted by rcmolloy

How about the idea of no bearing blocks at all?

This was our approach last year also. We did do a few things to help prevent the loss of a chain. First of all our chains were all internal, placed inside the 1.5 x 2 frame rails. We changed our chains before the start of our second regional, before Championship, and again before IRI. We have had the same chains on since IRI which includes MANY hours of demos, Beta testing, drive practice, and the Ruckus.
Overall we didn't see much wear on the sprockets but the chain does stretch quite a but. We have looked at adding a chain tensioner to the system. If the chains were external I would look into a system to tension the chains.
Cutting the frame rails with exact c-c and not worrying about additional machine time for bearing blocks is nice. It gives us time to work on other aspects of the robot.

[AdamHeard]

There clearly isn't a correct bearing block design for all teams with all resource sets across the board.

I think the distinguishing factor is teams that know how to machine and commonly do it, and those that machine less or have a buddy, sponsor, etc... make stuff.

If a team has a manual mill in house and regularly uses it, the bearing block design we make is just as fast to make (or even faster the way we cut them) than most of the ideas presented in this thread that are less rigid and functional. Our blocks look big and to someone who isn't used to milling it might seem like a lot of material removal, but it really isn't. We could manufacture a season set within 2-4 hours (that's 20-40).

The most important aspect of a bearing block for a WCD is rigidity. When it is clamped to the tubing, there must be no slop or play.

[josesantos]

Originally Posted by AdamHeard

If a team has a manual mill in house and regularly uses it, the bearing block design we make is just as fast to make (or even faster the way we cut them) than most of the ideas presented in this thread that are less rigid and functional. Our blocks look big and to someone who isn't used to milling it might seem like a lot of material removal, but it really isn't. We could manufacture a season set within 2-4 hours (that's 20-40).
*emphasis mine*

Care to share?

[Adam.garcia]

Can you please explain how you are mounting your bumpers to those frame rails?

How are you attaching the bumpers to the front and the back?

[Cash4587]

Where can I get the CAD files for the WCP DS: DUAL SPEED Gearbox?? Idk how to download the ones from their site and use them in solid works..

[Akash Rastogi]

Originally Posted by Cash4587

Where can I get the CAD files for the WCP DS: DUAL SPEED Gearbox?? Idk how to download the ones from their site and use them in solid works..

Did you try right click and save as?

[Cash4587]

Yeah.. it comes up and opens as a text document and incompatible file.