pic: Linear bearing rails: the Cheesy RAWC way

[roboticWanderor]

Originally Posted by billbo911

I was viewing the CAD drawing and not realizing it was rotated 90°.

yep, this model is of the demo sliders they had in their pit. They even have "slide me" sharpied on! i am working on figuring out the entire lifter mechanism, coming soon.

[billbo911]

Originally Posted by roboticWanderor

I am working on figuring out the entire lifter mechanism, coming soon.

Excellent! I have seen multiple posts from people looking for lift design ideas. This will definitely be a great addition.

[=Martin=Taylor=]

Tolerances...

The Poof frame is welded, heat-treated, and then powder coated. And yet when it all goes together the bearings rest perfectly on either side of tubing. Amazing? I think so...

They probably took into acount how much the frame would expand and contract after each process to get it that perfect. Having welded an elevator myself this season, I fully appreciate that kind of craftsmanship.

[ejSabathia]

I am working on packing the entire 2008 robot cad, when I have the elevator done I'll post a .stp file for everyone.

[Jeff Waegelin]

Cory,

What kind of bearings did you use for the lift, and where did you get them?

[R.C.]

Congrats Poofs, you guys probably have the smoothest forklift made in the past few years.

I like the colors, blue and black

[roboticWanderor]

Originally Posted by p0iZeN-254

I am working on packing the entire 2008 robot cad, when I have the elevator done I'll post a .stp file for everyone.

wait what? sweeet! now i can figure out how you guys fit everything underneath your lifter!n

[ejSabathia]

Originally Posted by Jeff Waegelin

Cory,

What kind of bearings did you use for the lift, and where did you get them?

http://www.chiefdelphi.com/forums/sh...05&postcount=4

[waialua359]

thanks EJ and Cory for sharing. Pictures, CAD and explanations like these does wonders in inspiring others to either do something similar or kickstart other offshoots.
No wonder our machinist asked me to order a whole lot of channel aluminum. He's been taking "classes" in your pit area getting more ideas.

[sdcantrell56]

How big of an improvement was the switch to bearings over the teflon pads. It seems like it wouldn't make much of a difference for relatively light gamepieces and manipulators but for the trackball might have had a bigger effect.

[Cory]

Originally Posted by sdcantrell56

How big of an improvement was the switch to bearings over the teflon pads. It seems like it wouldn't make much of a difference for relatively light gamepieces and manipulators but for the trackball might have had a bigger effect.

That was the reason we did it.

We never had any problems with the teflon pads. Nor did we have any with the bearings. I'd say there was a little less play this year than last.

[sdcantrell56]

Thanks cory. Also how much play did you factor into the spacing for the teflon pads and the channel or did you have it exact?

[Travis Covington]

This design isn't much different from your average forklift. The original design used last year was inspired by a walk-behind forklift that was at my previous place of work. If you look at one you will notice they are almost identical in both form and function, bearing placement and all.

The comment about heat-treating and precision tolerances should be noted. We did not heat treat any of the welded aluminum components of the frame or the elevator. Also, the precision and fit that we were able to attain was also due to the quantity of assemblies that were made. When making four complete sets for both teams, we started out with each set labeled as a part of a complete assembly. After welding, the assemblies no longer fit together as desired (somewhat expected). Luckily, we were able to mix and match sets and ended up with 2 sets that were super smooth (competition robots) and 2 sets that were acceptable (practice robots). With more than 5 pieces per robot, with 4 robots, the mixing and matching process took almost 4 hours one evening to get things to the way we wanted. Not as much preparation and precision as some give us credit for. We wish we were that good.

I also feel the need to mention that this elevator and the previous years robots are as much 968's babies as they are 254's. Students from both teams put a lot of time and energy (and heart) in designing and making such competitive robots, and it’s hard to see those efforts ignored. I think most people who know the specifics of the collaboration would agree that both teams contributed equally. Without certain aspects from each team, neither would be as competitive, engaging, or rewarding to the students as they are when they are working together.

[R.C.]

Nicely put

[JesseK]

I think it's actually alot easier than most people think to keep things square and precise while welding. The biggest success we had this year was the fact that we had a perfectly square and flat frame on the first try. Our student build team captain took a bit of time to consider everything that was needed before welding and came up with a plan for manufacturing the frame. We didn't start welding until I and (more importantly) the professional welder at our sponsor approved the plan.

When we welded our drive train frame together, we also brought in threaded rods that matched the axle holes and a bunch of nuts to fit the rod. We then spaced out the frame on the rods and welded the outer rails to the rear cross support. Then we used precisely-cut wooden blocks as spacers, and clamped the inner rail to the outer rail with the spacers in between. We measured diagonals as well as across the gaps before we welded, then after we spot-welded, then again after the final welds. Since the rods and spacers were firmly in place, the frame could not bend/warp.