I was wondering, where do teams go to get pulleys for cable-actuated elevator systems?
It seems like most of the stuff out there is pretty generic, and either overkill heavy-duty and huge, or too weak to be useful. I’ve seen teams in the past that used very small pulleys that look like they were actually meant for use with the size cable you would use in FRC.
Any ideas? In particular, I’m interested in bottom-mounted and side-mounted pulleys (and preferably designed in such a way that the cable can’t fall off of the pulley/track).
Probably not exactly what you are looking for but last year we used these. They weighed very little and seemed to work very well. We just mounted them using a 10-32 and never had an issue.
This year we made our own pulleys using UHMW. We had some donated by a sponsor so we turned them down similar to these but with slight changes (flanges and shaft diameter change).
If you do go the DIY route with UHMW, it’s really easy to do so using a wood lathe if you don’t have other options. If there is an Alro Metals Plus location near you, they usually have a large supply of fairly cheap drops/remnants in various sizes.
5660 went to DIY route and printed ours out of ABS. The pulleys were designed with a pocket to press a VexPro 3/16" ID 1/2" OD bearing into.
I’ve used these before with elevators and they have worked well in rope pulley applications - https://www.mcmaster.com/#pulleys/=ee8500ea5a664e1fad917476b8047a55jrqb1qf5
We used these from mcmaster-carr. We had one of the pins fail that hold the pulley in the building, so we replaced it with a bolt.
We used these last year for Spectra and polycord.
Boats figured all of this out pretty well. And, while expensive, they offer many different ways to attach and manage pulleys.
We got grooved sliding glass door bearings made from POM on Amazon. They seem robust enough for most elevators and are much cheaper than McMaster.
I would not use either of those. The first ones are for horizontal pulling, not vertical on an elevator. The second ones are not rated for any load.
We use those pulleys can #10 harware doesn’t fit through the .188in ID.
We are using those pulleys. We were able to get a 10-32 bolt thru the hole by filing down the major thread diameter. We used a lathe and a file, but the same can be done with a drill and a file. We found out that it did not take much to get them to fit.
We also used those pulleys with 10-32s last year, and I believe we sanded the bolts in a drill to fit them (pulley was sitting on the threaded portion of the bolt, so it’s quick). We are using the same pulleys this year too.
Are you looking for just pulley’s or were you wondering about the Drum as well. The drum is a little trickier than the pulleys which the users above have posted some great ideas about.
Last year we used the wire rope from McMaster and they were great!
We have found that when you are lifting very little weight (4 lbs for final stage, roughly 1 or 2 lbs for 2nd stage), you don’t need to use something that is industry standard and rated. From what I’ve seen, things that are actually rated for the correct load are more expensive and heavier.
Unless you were using this elevator to lift other robots, I wouldn’t be worried about ratings personally.
If your final stage only weighs 4 lbs and your second stage only weights 2 lbs, I am very very jealous!!!
In our initial engineering estimates at the start of the season I was guessing 15 pounds for the two combined when we were brainstorming different designs.