Forklift Dilemma

[Kevin Ray]

We have done fork lift on two previous bots and are very comfortable wth the results of the second year's bot, 2008. We used 3/32 cable and you can see in the first pic that we designed our own pullies because of the problem we had in the first forklift model. We made a recess to accommodate a bearing with a 1/4 in. bore in a small block of acetal (Delrin) and wrapped it in sheet metal. We then drilled an entry and exit hole in the Delrin for the cable and a 1/4 in hole through the side for a bolt for the bearing to ride on.
For the winch we used two FP's with a drum. Please note that you will ABSOLUTELY need a tension take up on the cable between the first pulley and the drum. If the slides are lubricated enough, you shouldn't need to close the loop (which just adds to the weight and headaches), gravity worked well enough for us.



If you'd like more detailed support, feel free to send a private message and I'll send you detailed pics if you'd like.

BTW, that forklift went to 11.5' in under 5 seconds

[dduran]

How do you prevent the motor from back driving when you want the elevator to lock in a particular position? Then how do you release to allow it to come down again?

[Bob Steele]

To prevent backdriving you are going to need some sort of brake. Our lift has a ratcheting system that is controlled by a small pneumatic.to stop it from backdriving the motors..

You could also make some sort of brake disk with a pad operated by a pneumatic.

Oh by the way, don't believe what everyone says about spectra... we use it...and it works great BUT it DOES stretch initially... so you have to pre-stretch it...after that you should be fine..

We have quite a few sailors out here that use it all the time and they have shown us how to splice it to make secure connections... you might want to learn that...or figure out some good knots...

[sdcantrell56]

We are using belt this year and so far it is working very well. It is much nicer to deal with than cable or chain and very light. Also belt essentially does not stretch. The belt we are using has a kevlar tension member.

My team this year is doing something similar, we're using super strong Spiderline fishing line (50lb test, no stretch), but we have issues with stops for the slides. Does anyone know of anything that works for stops on the standard KOP slides?

[joek]

you can get pre-stretched polypropylene rope, that has almost all of the stretch eliminated

No, I meant something that works well for slide stops, I already have some fishing line that appears to be indestructible.