Need some help with forklifts

[R.C.]

Jon Jack, do you have any pics??? Thanks guys for all the help and more ideas and pics would be helpful to team 1323 and a lot of rookie teams. So if you could post some pics of your robot here along with an explanation of how it works, it would be really helpful.

[kajeevan]

i know this is a lift tread but just on thing i want to bring up is that always consider arm before lift, always. proof of this is beachbot time and time again that simplicity kills all else. are team is finally making the transition and we already prototyped a strong fast arm for 09.

but to answer your question on materials we've been doing elevators every year expect for 06 and we've done custom lift frames to bosch (very expensive if your doing two). we've tried both spectra and steel cable. 1/8in steel cable uncoated works fine but the coated versions were a problem in terms of flexibility. spectra on the other hand is good if you take a lot of care in tensioning the it so it doesn't get cut up in anything. but my choice between the two would be steel cable. we used spectra on our lift this year and went through i believe 200f of the stuff. first spool had a breaking force of over a 100lbs and the other had breaking force of over 1500lbs. it was a bosch elevator forklift pulling up and gravity drop using 2 light senors for bottom and top limits so the spectra wouldn't come off the pulley. but the major problem would be spectra getting caught up every minute in the elevator because the string wouldn't tension at the same time that the elevator would drop. to keep string from getting caught in other areas we ended up using those key chain/card zippy things that act like tape measures pulling in. that had solved the problem most of the time. but if u want proof of elevator failer in action just watch some of our matches at waterloo you'll see the elevator go up and then get stuck either because it came of the pulley or getting caught.

but please please consider arm before elevator one because it'll take much less time to build second because its simple beyond belief and third its proven by 330.

[R.C.]

Yes, we have making arms for the last 6 years and we just wanted to test out the forklifts, thatz all. But we will be probably going for an arm. We loved the beachbots robot this year and last. Very nice bot guys. Congrats on winning IRI.

[kajeevan]

sry bout the rant type thing i didnt realize the situation

[R.C.]

don't worry about it, it was a good thing.

[EricH]

kajeevan, what you might not realize is that the BeachBots built lifts on most of their robots between 1999 and 2004, with the exception of 2003's 4-bar linkage. We've proved lifts, too. Go do a search for 330 in CD-Media, and you just might find our 2001 robot and our 2004 robot. The blue structure is a lift.

If we need to, we can do a lift again. It's better for certain applications. For others, it isn't.

[kajeevan]

never realized i've only seen 330s 05-08 i guess i shouldnt have assumed

[Jon Jack]

There are pictures of all of our robots on our team gallery.

[Mark Pendergast]

1760 had a very nice lift with #25 chain on the lower stage and 3/32 steel cable on the top. (We get our chain at McMaster-Carr and our cable from Lowes.)

The lower stage had dual chains on sprockets between 2 - 1/2 inch steel rods. (The rods were held in place by brass bushings.) The motor then drove the lower rod through a third sprocket. Power up and down.

The upper stage had a single 3/32 inch cable that was fastened in such a way that the upper stage lifted automagically when the lower stage lifted. Power up (indirectly) and gravity down. We used PVC pipe over an alluminum tube at the top of the lower stage as the pully.

One trick I have not seen mentioned is that we used cable clamps to fasten the cable. (U-shaped bolts with a cast wedge to hold the wire loop together. Also from Lowes). I believe these are much superior to knots. We never had a problem with them.

We did have some issues with the cable jumping the sprockets on one side, but it was managable. We also used zip ties as a floating cable tensioner. (You would think it would bind up or get stuck, but it has worked for us for two years now. )