Re: A Simple Elevator
 

How was the durability of the pads on this? Did you notice that the tower was swaying when all the way up high?

When we made our lift with 8020, it was fast and came together nicely. However, it was heavy. One issue that was critical was that when the tower was at its maximum height, the tower would sway. We found that this was because of the play that would develop in the plastic slides (in all fairness, those slides are meant for compression loads). In short, would not do again.

One solution that I found nice was use the iGus products. If I had to do it again, I'd have to track down exactly the types to use, but IIRC, 1771 simply used some super-light c-channel lined with the iGus products. Worked like a charm.

- Sunny G.

Re: A Simple Elevator
 

For the elevator, you could probably even use PVC pipes and just stack them inside each other, like a telescoping device on each side. Or you could get the special c-channel PVC, which I think you can get on mcmaster.com, and make something similar to Wildstang's design. This would probably be strong and save weight (since it's not metal) but our team has never actually made a forklifting device before so I'm not that aware if there would be any major problems of the design.

Re: A Simple Elevator
 

We did an 80-20 lift in 2008, and in many regards, it was our best robot in recent memory. (We almost made it to division finals, I believe.)

The first stage was 2x1 80-20 with the standard nylon slides. It was slightly lightened (the back half of the 80-20 was replaced with welded on c-channel), but very similar to a system you could put together in an afternoon from regular 80-20. The second stage used v-shaped rollers that fitted into the grooves in the back of the 80-20.

While that system was fairly simple to design and execute, I wouldn't go with it again. First, it was very heavy, even with the lightening on the first stage. Second, it was poorly counter weighted. And third, the nylon sliders introduced a lot of friction into the system. You really have to pull on it to get it to lift up, and it took two CIMs to raise. I never noticed any sway, but then again, we haven't competed with it in a while.

For the OP: 80-20 is a good solution if you don't want to do bearings riding on the outside of 2x1 tubing (like 254 did in 2007 and 2011). However, don't count yourself out of that design too soon. Almost any design can be modified to fit your machining abilities, so take a look at 973's CAD to see how much machining is really required.

Re: A Simple Elevator
 

Team 841 built an elevator system with a drill press and chop saw in 2011. The elevator uses 2x1 square tubing as the outer section, 2x1 c-channel for the center and a rolling device in the center (consisting of 2x1 square tubing connected with flat bars).This elevator design worked very well for us and will definitely use it again if the need arises.

Everything was measured with a tape measure, center punched by hand and then drilled with a 1/4 drill bit.
We noticed that there needs to be enough room for the parts to move within the system, make sure that the bearings do not apply too much tension to the moving components.

Here is a link of our design with 254 and 973.
http://www.chiefdelphi.com/forums/sh...77#post1085150

Re: A Simple Elevator
 

The ecoslide pads are beastly, and hold together very, very well -- I had forgotten that we didn't even use the carriages on Shiela, just the pads (screwed into the second stage of the lift, inserted into the first stage, which was the Bosch stuff). The elevator we made consisted of two rails spaced almost to the sides of the robot, stiffened with a few small crossbeams made of 1/2" L aluminum. It didn't sway.

http://www.team1551.org/Sheila2_400x600.jpg

Our robot lift in Breakaway used the ecoslide carriage and lifted our whole robot no problem over and over again -- it didn't sway because it had little weight up top: it was just used to lift a hook, and then drew down to lift the whole robot.

Re: A Simple Elevator
 

Thank you everyone for their input. Our team used 80/20 sliders for our minibot deployment in 2011, and we swore them off after that. So I have tried to mock up a lift I think we could build image below:

Specs:

• Two stage Lift with the primary towers built out of 1x2 1/16 wall Aluminum
• Second stage uses 1x2 1/8th wall C stock
• First stage uses bearings in bearing blocks designed to be shimmed out in order to get a precise fit to control front to back motion and the side to side motion is controlled by Delrin slides riveted to the top of the towers and bottom of the first stage.
• The second Stage slides are milled Delrin inserts. These can be milled and sanded until they slides cleanly in a test piece of C channel.
• All of the gusset plates are .050 Aluminum sheet with 3/16 Rivets
• Top black brace is made of 1/4in plywood.
• Since this is a mock up the tower is not adequately braced, but for now im interested in critique of overall design.

Re: A Simple Elevator
 

I am still learning the design of the elevator system myself, but I think you need, built onto the top of that second stage, a mount for a pulley which will route the steel cable (or other means of wire) throughout your assembly. Also, that black plate in the back is going to be secured to the cable, so make sure that it is adequately strong, as it is going to be taking a lot of force.

Re: A Simple Elevator
 

There's multiple ways to rig an elevator. Pulley and cable is only one. If you do cascaded rigging you can actually run wire rope, chain, belt, or a rack and pinion. Look at the discussion here: http://www.chiefdelphi.com/forums/sh...d.php?t=110011

Re: A Simple Elevator
 

Slightly skewing off the main conversation here, but I have another question pertaining to building a minimalist and robust elevator system:

I know the elevator is not taking a lot of horizontal load, but how do you ensure that there is enough support to prevent the elevator from leaning forward/backward? I see that Adam Heard of 973 has what looks like a minimal amount of support on Emporer Swerve, and I was wondering how our team should go about determining how much support is needed.

Re: A Simple Elevator
 

The actual elevator frame needs to be just as rigid as a regular frame. Nothing special there. Putting bearing blocks on the top of the frame and the bottom of the 2nd stage adequately prevents the elevator from swaying.

Re: A Simple Elevator
 

How about the connection between the complete elevator assembly and the drive train. As seen in 254's 2011 design, the elevator system was nicely supported with gussets that served as their minibot deployment system. But, looking at 973's Emporer Swerve, they have very small plates keeping the elevator upright.

Do you have any advice on how much support is necessary on this connection?

Re: A Simple Elevator
 

You can see we actually had quite substantial support in the form of turnbuckles.

This must not be in the .step we posted?

It's hard to quantity exactly what framing needs to be there, which is the same for most FRC frames. A decent, solid triangle is usually never a bad choice though.

Re: A Simple Elevator
 

1/16" steel cable is extremely light, really annoying to work with, and excellent at stabilizing elevators.