Need some help with forklifts

[Smaug]

team 675 used #25 chain and # 15 chain to lift our two stage lift

[RyanN]

I don't remember the exact name of what we used, but I know it's some sailboat rope. I think like 1/8". We never had any problems with it. It didn't stretch much either. If you have a local West Marine, that's where we bought ours from. I tried finding it on their website, but I didn't find it.

This is probably pretty close: http://www.westmarine.com/webapp/wcs...$@#$@#$@# Num=11452

Our's is blue though, so it may be a different brand. Look at the breaking strength... 530lbs. That's a lot of trackballs.

[Tom Line]

We used size 25 chain to drive our first stage, with spectra pulling the second up and down.

We used bungee cord to counterbalance the stages the motors didn't have to lift the weight of the them.

One thing to note about using any time of spectra or other line - tieing a knot in it will reduce the strength on the order of 40%. So, for instance, if you had a piece of line with a breaking strength of 500 pounds, and tied a knot in it, the break strength at the point of the knot will only be around 250 pounds. That sounds like a lot, but we managed to break a piece of spectra line with a break strength of over 1000 pounds when we were lifting a trackball and then got hit from the side by another robot (hard). If you can find a local rigger or a West Marine, they can splice the rope for you and eliminate the sharp bends that you'll create by tieing a knot. Or if you can "wrap" the spectra around whatever you're tieing it to several times then tie a couple half hitches, you'll eliminate that problem.

Shock loads are killer. Forces in a 10 mph collision have been measured at over 8 g's in the auto industry. We go a lot faster than that.

Another thing to note is that most spectra will not have a cover on it like your standard "West Marine" line, and that it is very susceptible to chafe. Vectran less so but you will certainly pay through the nose for vectran or any other high-tech line.

[camtunkpa]

222 has used 1/8" steel cable, 3/32" steel cable, 1/8" spectra cable, #25 chain and timing belts for extension devices. Out of everything we used I would say that I liked the chain and timing belt the best. You can't get much simpler. We used steel cable for years and that worked out well for us but many of us got tired of the frays on the steel cable making us bleed. So we eventually moved onto Spectra cable. I will utter the woes of the spectra cable creep. It gets very annoying. #25 chain is bullet proof for most FIRST lifts and can be as simple as a sprocket on a motor and a sprocket on a fixed member and an attachment block to the piece you want to extend. Timing belts can be used the same way the chain can, they are lighter and if tensioned correctly almost as strong. We used the timing belts for extension in our arm this year and we were impressed with how smooth the motion was. As far as chains and timing belts go your can find tons of sources. The timing belt and pulleys we used were supplied in the kit this year and they held up great! As far as a source for cables or other types of rope, here's a source I found that's got a little bit of everything.http://www.us-rope-cable.com/?gclid=...FQWAHgodgjYNWw

Hope this helps

[Dick Linn]

We've used 1/4" nylon rope before. It just happened to fit the groove in those ball-bearing sliding door rollers that are available at Home Depot: http://www.homedepot.com/webapp/wcs/...ctId=100200036

One team used some 1" wide nylon web strap, like you find on tie-down straps. That was nice because it would feed nicely on and off the winch mechanism. Plastic strapping used for shipping might work.