Elevators/ Forklifts

[Choi9111]

I think that fork lifts are a great idea!...but how would it be possible to lift more than 1 robot? what do u guys think?

[USAF Capt. Sean]

As for team 1675 a scissor lift is becoming a better concept. We have figured out that when it is collapsed it should take up 6"-7" inches, but once opened it could reach upto a height of 88" inches. I personally think this is HUGE payoff. We have the machines to build one and hope to be testing it soon (Within the next week or so...) But we are still talking about drive types. So it might not be done at that point.

[xur2007]

Does anyone else have quick visual aid of a forklift system?? I think i'll be making a trip to a local Home Depot get acquainted to one.

[AndrewRibeiro]

Originally Posted by xur2007

Does anyone else have quick visual aid of a forklift system?? I think i'll be making a trip to a local Home Depot get acquainted to one.

You may want to ask you school Maintenance Shop. Ours has one and let us give it a look over to help with our design.

[Jesterofkings]

Originally Posted by Choi9111

I think that fork lifts are a great idea!...but how would it be possible to lift more than 1 robot? what do u guys think?

Our team come up with an to your answer your question there is 2 ways to lift 2 robots off the ground at the same time. One have a forklift on each side of ur bot and lift bots at the same team and hope they weigh the same and ur Center Of Gravity is to much to one side or the other. The other way is wat we are going to try. Have a lift strong enough to lift a bot on the front and kind of like a roll back ramp on the back. get one team to drive up on the bak and use them as a counter balance to lifting the other. The only bad things about these ideas is that you are relying on your teammates to be able to finish the round and that they will be strong enough to climb the ramps. If we figure out how to solve these problems or if u guys and gals got any ideas we will be welcome to hear them.


~Jester~

[Rick TYler]

Originally Posted by Jesterofkings

One have a forklift on each side of ur bot and lift bots at the same team and hope they weigh the same and ur Center Of Gravity is to much to one side or the other.

You are making an assumption here of which you are probably unaware.

FIRST koan: Why must the two robots have the same weight?

[Scion13]

If your center of mass is outside of the wheels then gravity will apply a torque which will cause your robot to tip over

[Rick TYler]

Originally Posted by Scion13

If your center of mass is outside of the wheels then gravity will apply a torque which will cause your robot to tip over

You are making an assumption here of which you are probably unaware.

FIRST koan: Why must the two robots have the same weight?

Second FIRST koan: Does the robot tilt the Earth, or does the Earth tilt the robot?

[razor95kds]

Thanks for all the photos and links for the elevators!

Our team is edging closer to our decsion of whether to use an arm or elevator, but one thing that is limiting the elevator from becoming the design choice is the linear slides. Our team has found some slides, but they are too weak. We want a single tack elevator with a beefy slide that won't weaken if robot to elevator occurs by accident. We like the size of team 64's in 2005 but cannot find a slide of their size. Any help with this would be greatly appreciated.

[abroerman]

We're at this stage as well, and as I've been home sick I figured I could try to come up with ideas of my own. The consensus is that my plan would be rather heavy, but it's possible I just embellished it too much.

Minimized (click either for a larger version)


Maximized


Anyone have more experience with extruded aluminum? How much does the stuff weigh? Would the sliders breaking be a problem? I don't know enough to make truly informed decisions regarding this plan, so I'm off to research I guess.

[Ianworld]

That looks fantastic but you're right its going to be heavy. One thing to keep in mind this year is that the ringers only weigh about a pound. That device there could probably, based on my wildly inaccurate guess, support about 150 pounds just as a point of context. The first thing to do is think about your material. Aluminum square tube extrusion or 80/20 is probably a good place to start. With 80/20 you can purchase linear slides. I'm not exactly sure what they're rated for, but considering what teams have used them for in the past you can probably get away with a very lightweight design(one 80/20 strut, if properly designed).

As for the weight of a set up a good number to remember is that aluminum weighs .1 pounds per cubic inch. So a foot long piece of square aluminum tube 1" x 1" with a 1/8" wall weighs a little over half a pound. So an elevator that is 8 feet high could easily have about 20 feet of extrusion and weigh about 10 pounds but at the same time that would probably be overkill.

[Jeremiah H]

The discussion thus far is great, but I have two questions:
-How will these forks grab the bot to be lifted?
-What will prevent the lifted bot from falling off?
Just curious.

On another note, we are planning on using a forklift-inspired tube lifter that will grip the tubes with two sets of froks, one on top and one underneath, with each prong roughly 8" off of vertical center. We plan to be able to get two bots off the ground at the end of the match, but not by sheer force. We intend to make our lift on a pivot where it connects to the bot, and at the end of the match we will be able to rotate it downwards until it is level with the top of our bot. At this point the prongs that hold the tube will be resting on the floor to give the support for that end. A ramp will be deployed out the back, and two robots will be able to run up onto the long track resulting. We also will have a ramp out the side for that occasional bot that has a wide & short configuration rather than narrow & long as ours will be.

Any thoughts, anyone? JH

[Tatsu]

Originally Posted by razor95kds

Thanks for all the photos and links for the elevators!

Our team is edging closer to our decsion of whether to use an arm or elevator, but one thing that is limiting the elevator from becoming the design choice is the linear slides. Our team has found some slides, but they are too weak. We want a single tack elevator with a beefy slide that won't weaken if robot to elevator occurs by accident. We like the size of team 64's in 2005 but cannot find a slide of their size. Any help with this would be greatly appreciated.

We did elevators in 2005 using Igus drylin linear bearings.. You're welcome to come visit and we'll show you how we did it and such (we always like to talk to other teams)
here's some things I found were good and bad.

Good-
linear tracks are strong.. we cheeseholed the heck out of ours and we didnt have a problem. It did sway a little at the top but then again, we did go extremely high.

Much less programming involved, we could get the thing up and running with just dead reckon code.. good arms require good control code, dunno if thats a problem with you guys.

The things are robust.. theres not much that can go wrong with a good pulley system.

Bad-
Binding.. binding binding binding, makes it pretty hard to drag up the linear bearings (even with no load) we used 2 fisher-price motors in their plastic gearboxes attached to a spool.

Cables are annoying.. I can't stress this enough. cables have to be tensioned, there has to be a return cable.. its just annoying and unless you think it thorugh its full of surprises.

Good luck with whatever you choose

[GeoffP]

Here is a basic scissor style fork lift which is quite doable.

[Molly Stieber]

We have had lots of success with forklift style elevators, we used a system with cables, pulleys and bearings on our 2005 robot and it worked really well. It was pretty fast too. We have some pictures on our website, cooneyrobotics.com under the media part if you want to take a look.