Chain Lift Experience

Can anyone tell me a bit about their experience with chain lifts (such as difficulties they faced, solutions to them, disadvantages, surprises, tricks)?

I’m trying to make a chain lift which makes the intake steeper as the lift raises. The sprockets i’m planning on using are the 24 teeth and 18 teeth.

I’ve already read these threads

http://www.aura.org.nz/archives/991
https://vexforum.com/t/chain-lift-pictures/21843/1&highlight=chain+lift

cough chain bar cough

I actually have spent the last month experimenting with them lol and i found that the best way to make it extremely compact is by using the green inner piece on the high strength gears so that you can have a fully supported axle and have the bar be directly next to the screwed in sprocket so it is constructed

tower gear bar sprocket tower
with the gear screwed into the bar and powered from below
Just something I found useful.
I did this because the one aura shows in the page on them is extremely large.

If you have any specific questions I can answer them but it actually was really useful and easy to build.

https://vexforum.com/t/chain-lift-pictures/21843/1&highlight=chain+lift

We have started referring to this style of lift as a chain arm, so as not to confuse the term with chain elevator lifts.

The best ways to learn about this style of lift would be to look at robots in the Robot Showcase with chain lifts and see if they offer any pointers, and then build one yourself (nothing beats firsthand experience).

haha you guys saved me from posting about chain elevator lifts.

Yeah the phrase “chain lift” sounds like the mechanism that often used sliders vertically powered by a chain loop. Chain arm or Chain bar or even rotating chain lift would work in my eyes. Just my $0.02

-Nick

Sorry about the chain bar and chain lift confusion. After reading that thread i got too use to calling it a chain lift:p

But i’ve always wondered why people call those chain lifts. Considering that vex calls the pieces linear slides, the name linear lift or multi-stage linear lift always comes to mind.

so… is it called chain arm or chain bar lol

We could always start a poll to decide, as long as everyone agrees to stick with the result (I personally thought we were all using chain bar already :/.)

Not all chain elevators use linear slides, though. For example, our Round Up robot had a forklift that was connected directly to the chain using zip-ties.

I prefer the term chain arm over chain bar, but either works I guess. Like StimpNZ said, we could post a poll.

They can’t call them all just linear slide lift because that might confused with rack and pinion lifts.

Are you guys ignoring the other half of what stimpnz said everyone already calls it chain bar because it makes the most sense. A 4 or 6 bar are name so because 4 arms are able to get an affect which is somehow named bar so when chain gets this affect it should be called a chain bar.

If someone ever gets around to making a poll CALL IT A CHAIN BAR.

I don’t know if this will help you, but in this video, red interaction uses a chain lift quite effectively http://www.youtube.com/watch?v=GNIB8JonOWc&list=UU-9Tpfltm-lRPHS7fjC0hVA&index=3&feature=plcp

Back to the original question…

Two things I’ll mention, one is that there is inevitably some “slop” in the chain allowing the ramp to rotate slightly in either direction, obviously you can minimise it with good chain tensioning but not eliminate it, so design the intake etc accordingly. You can also try things with weight distribution and elastics to get what you want…

The second is that it is even more important than with a 4-bar to minimise weight lifted, because chain isn’t as strong as a 4-bar and the heavier the weight, the worse the slop problem will be.

I also recommend some kind of protection to stop the chain being accidentally knocked off the sprockets.

All of my tests were in a more or less controlled environment and while I did test with weight I never encountered this problem was this common?

Ah that makes sense; that i should of saw that coming. Can you give me an estimate of how bad the slop is?

Also, if chain is shorter, less slop should occur right?

Jesse323Z pmed me asking for pictures of what I was talking about so i just made this youtube video explaining it.

This was kinda thrown together so it may not be perfect; I am happy to answer any quesitons anyone may have.

Wow i really like that:) It seems very secure and compact. I don’t have high strength gears but are the holes(without inserts) the same size as the holes in pillow blocks? Also, is it possible to reduce the size of the sprocket to the 6 tooth and run zip ties throughout most of the chain?

I used the smallest sprocket that has screw holes. You could use smaller sprockets if you used the metal bar locks.
The inserts I used have the same sized hole as a pillow block without an insert it would be a larger square hole.
You should be able to drill a whole in normal gears to get the affect but I very highly recommend buying high strength gears.

Edit Yes you should be able to use zip ties throughout most of the chain also seems likes a very good tension system; I would be scared that this might cause problems though.

I don’t know how many times I’ve said this, but using metal bar locks (on shafts) to hold any kind of weight is VERY BAD. Shafts are not meant to hold very much weight at all and will twist severely if apply weight to them. I strongly recommend that you use a larger sprocket with screw holes so that the shaft doesn’t have to hold any weight.

I have never used them for fear of that very thing happening and I wasn’t sure if it would be an issue because the only weight it would be holding is what ever was on the end of the arm.

Well, usually there’s an intake on the end of the arm. That can be pretty heavy.

Really depends on design and loading, could typically be in the region of 10-20 degrees. Like I said it can be minimised with clever design.

Yes

Yeah, I’m talking about in matches. I have seen robots where it never happened and also those where it occurred all the time. I guess slight changes in design can make a fair difference.

It happened to Green Eggs in the Math semifinals. Thankfully it didn’t affect the match because they spent the entire time blocking 1437X.