The offseason project for team 1719 using VexPro and REV components to make a compact multi-stage elevator.
This is an offseason project that team 1719 undertook to get new students up to speed, and to figure out a nice compact multi-stage elevator design. This design uses a mix of VexPro and REV components. While the linear slide kit has been around for a few years, our design is unique because it uses a special low-profile bolt and corresponding stackup to let the rolling stages pass each other. This allows us to maintain the longest overlap distance between the first two stages. We used the REV eccentric bearings to account for the tolerance with the VexPro linear slide gussets. We chronicled our work on our team wiki here.
A quick note on our wiki, some of the pages are unfinished. Our wiki is the vehicle our team has chosen to document work and transfer some detailed lessons learned from one generation to the next.
The elevator is driven by a VersaPlanetary gearbox and a 775Pro motor. We chose a chain drive to simplify the attachment using the VexPro chain gussets. We omitted the chain tensions in this design due to time constraints, but obviously a competition design would have them. We’re interested in the aviation cable attachment strategy used by 254 and some other teams and the turnbuckle tensioner system.
A competition implementation of this design would need constant force springs, an improved inner stage to make mounting mechanisms easier, cable/chain tensioners, and more robust sensors.
We’d be happy to answer any questions or look at any suggestions you have. In particular, we’d appreciate any advice on tensioning. We also have the CAD files on GrabCAD, and we can share those with anyone who wants a copy.
I love this.
Amazing you were able to do this with what looks like pure cots.
Thanks Adam!
This is an offseason project that team 1719 undertook to get new students up to speed, and to figure out a nice compact multi-stage elevator design. This design uses a mix of VexPro and REV components. While the linear slide kit has been around for a few years, our design is unique because it uses a special low-profile bolt and corresponding stackup to let the rolling stages pass each other. This allows us to maintain the longest overlap distance between the first two stages. We used the REV eccentric bearings to account for the tolerance with the VexPro linear slide gussets. We chronicled our work on our team wiki here.
A quick note on our wiki, some of the pages are unfinished. Our wiki is the vehicle our team has chosen to document work and transfer some detailed lessons learned from one generation to the next.
The elevator is driven by a VersaPlanetary gearbox and a 775Pro motor. We chose a chain drive to simplify the attachment using the VexPro chain gussets. We omitted the chain tensions in this design due to time constraints, but obviously a competition design would have them. We’re interested in the aviation cable attachment strategy used by 254 and some other teams and the turnbuckle tensioner system.
A competition implementation of this design would need constant force springs, an improved inner stage to make mounting mechanisms easier, cable/chain tensioners, and more robust sensors.
We’d be happy to answer any questions or look at any suggestions you have. In particular, we’d appreciate any advice on tensioning. We also have the CAD files on GrabCAD, and we can share those with anyone who wants a copy.
How much slop is in the VEX linear motion gusset setup without the eccentric bearings?
There wasn’t a huge amount, maybe on the order of .020", probably only as much as the tolerance 1/4" holes and 1/4-20 bolts had. By eye, it’s not enough slop to worry me, but we had a really bad experience with our custom elevator in 2015, so we wanted a way to tighten the slides up if we needed. We’re working on ways to mount a mechanism on that inner carrier that could have one last adjustment to keep the mechanism level, just in case.
As a side note, we drilled and mounted the gussets by hand which I argue is a good sign that a reasonably tight elevator is possible for teams with limited machining resources.
Very cool! Do you have a CAD you can share?
Awesome job, this is a very cool use of COTS parts. The document looks excellent, thanks for sharing this.
Will definitely be referencing this if the game calls for an elevator! This is the COTs elevator we have all dreamed of!
Thanks for the nice feedback everyone!
The CAD files in Inventor format can be found here and a STEP file is here
http://104.131.160.86/images/d/d0/1719ElevatorCAD.JPG
Hi, I was wondering if you guys had issues using the 775pro to hold it in position, given their low tolerance to stalling. Or if you used a special mechanism to hold it in place to take the load off of the motor.
Thank You!
We didn’t see any issues, but we didn’t have it highly loaded. Based on the greenhorns videos I don’t imagine it would be an issue. We recommend adding a constant force spring if you are really concerned.