View Single Post
  #12   Spotlight this post!  
Unread 12-09-2015, 11:53
Monochron's Avatar
Monochron Monochron is online now
Engineering Mentor
AKA: Brian O'Sullivan
FRC #4561 (TerrorBytes)
Team Role: Engineer
 
Join Date: Feb 2007
Rookie Year: 2002
Location: Research Triangle Park, NC
Posts: 898
Monochron has a reputation beyond reputeMonochron has a reputation beyond reputeMonochron has a reputation beyond reputeMonochron has a reputation beyond reputeMonochron has a reputation beyond reputeMonochron has a reputation beyond reputeMonochron has a reputation beyond reputeMonochron has a reputation beyond reputeMonochron has a reputation beyond reputeMonochron has a reputation beyond reputeMonochron has a reputation beyond repute
Re: Bearings vs Bearing Blocks

Quote:
Originally Posted by Cory View Post
I don't know what you'd have to even be doing to see chain ratchet on a FRC drive.

I'm not saying it can be flopping all over the place. But chain stretch isn't going to cause your chains to derail if you do exact c-c with Paul's added distance.
To echo other comments, I too have seen ratcheting multiple times, twice on my high school team's early drive trains. We were using the 2004 and 2005 kitbot back then and I believe the issue was that we mounted our gearboxes on sliding rails in order to allow us to adjust tension. Unfortunately the gearboxes would slip during matches leaving slightly looser chain. As a result we ratched in multiple matches.

On our 2015 robot we have a chain run of around 3 feet with 12 tooth sprockets on either side. It encounters no issues unless the load of the elevator increases dramatically. The chain is tensioned so as to give a nice twang if plucked but it still ratches when under a lot of load. I can check how well aligned the sprockets are. I feel like the answer is "well aligned" but I have no idea of the tolerance off the top of my head.