pic: Linear bearing rails: the Cheesy RAWC way

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

I like the colors, blue and black

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

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.:wink:

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.

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?

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. :wink:

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.

Nicely put

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.

I’ve always looked at the 254 and 968 elevators and wondered how’d they do that. IMO it looks like the best way to do an elevator if you can machine the bearing blocks and if you can weld the aluminum. We used 80/20 the is year an it worked great for use but I noticed that the pads had a tendency to sag at full extension towards the end of the season. Also 80/20 is some heavy stuff (and that’s putting it nicely:D ). Did you notice that the teflon pads wore down on your old elevators after a lot of use? I’d really like to experiment with an elevator like this and it seems like the teflon pads are a more feasible option for us.

Thanks a lot for discussing your designs here as well, I know 254 and 968 and even 60? when they were with 254 back in the day have inspired more robots then you’ll ever be able to count.

I think the key word here is “professional welder,” I could best be described as a “professional n00b” seeing how all I weld are the team robots… :wink:

Thanks for the tips though. We’ll keep that in mind if we ever do it again.

Were the bearings attached with simple bolts or shoulder bolt? If you just used plain bolts then it would be much cheaper.

Regular screws with nylon washers so the outer races could spin freely.

I was hoping regular bolts was the answer. That will make things much simpler.