Those of you that have been around for years (especially in 2007) - what are some of the best lift designs you’ve seen? Lets focus this thread specifically on forklift style mechanisms that could be used to elevate the game pieces from floor level to scoring level. I was able to find several threads with examples of lifts but not much anecdotal evidence on how successful each was. If we could summarize the best of the best in this thread, I think that would help a lot of teams out this season. Close up pictures, drawings, etc would be great to post in support of your comments.
Good video of it in action:
Pay attention to:
0:36 - removing the blue trackball on the far side of the field. You can get a good idea of how long it takes to lower the tower.
1:45 - a great shot of raising the tower to place a trackball. Again, it’s all about how long it takes to get it up there.
We were worried about the relatively high CG with this design. To help counter that, there was a 10lb steel plate bolted to the bottom of the robot, and we had the maximum speed of the robot limited once the tower was raised above a certain point. That said, we never tipped over - although there were a few times where everyone in the audience held their breath.
Our team hasn’t decided yet on our design for this year, but I can tell you that we’re considering two designs - this one (modified to pick up tubes instead of trackballs, of course), and something similar in concept to what team 148 did in 2007 - That was our rookie year, and our pit was right next to them in St. Louis.
If we go with this one, there will be quite a few design modifications: built-in stopping points for each level of the rack, a grabber that can fetch them from the ground, and modified for an appropriate maximum height come to mind… So in the end, we can’t just attach our claw from 2007 to our 2008 robot and call it a day!
That looks very nice. Did you use the same size rectangular tubing for all stages of the lift? It looks that way but I can’t quite tell from the picture. Is there any additional detail you can give on how the rails slide past each other and how the cabling was strung?
Yes, we used identical tubing for all stages. Each of the rails fits a little loosely inside of each other - too tight and it’ll bind and not move.We have small roller assemblies that hold the stages together - you can see some of them in the close up pictures, or at the top of this picture. The roller assembly is essentially a small aluminum plate that is bolted to one of the stages, and sticks out both in front and behind the stages. Attached to it are small rollers that hold the adjacent stage in place.
If you look at the outer most stage, there is a roller bolted near the top. The middle stage (the first stage that actually moves) slides up between those rollers. Near the bottom of the middle stage, a roller is bolted on that sticks out around the outer stage - this way as the middle stage goes up, these two sets of rollers get closer together, eventually meeting at the top (if we didn’t have a physical stop before then).
The inner most stage is relatively small, and has rollers bolted both to the top and the bottom of it, sticking out around the middle stage. As it goes up, there’s a physical stop to keep it from leaving the middle stage at all.
We had to run a few wires with this - you can see the rollers and motors in the first picture, and they had to be powered. All the wires went up one of the tubes of the outer stage, then hung down the back through some energy chain (available in the KoP!), where they attached to the inner most stage - you can see the energy chain in the close up pictures. The wires were long enough to accommodate the entire extended height of the elevator, while the energy chain ensured they moved in a controlled fashion.
the whole contraption was built pretty well… the elevator still moves freely, and aside from cannibalized parts, the whole thing would still be working. The elevator still slides up and down extremely easily (as it must - the battery on that robot was right below it, so we have to life the whole thing up just to get it powered!).