Re: Tape measure climber club
 

This is a pretty cool club. Are you accepting applications? We might be ready to file ours around Week 7.

Just curious - how many of you are actually using the tape measure as the device supporting the weight of your robot, versus using it just as a hook deployer? My gut says the latter is better.

Re: Tape measure climber club
 

We're not doing anything like this for FRC, so I can't speak to these cases, but this fall our two FTC teams discovered that the former does not work well, even for smaller robots. The metal 'tape' ended up breaking off from the spools they were attached to, and the teams switched to a different material after their first two events.

Our two MidKnight Magic teams broke so many tape measures that the Inventors didn't have any left in our shop by the time build season came around. I think they ended up replacing the tapes at least 2 or 3 times an event.

Re: Tape measure climber club
 

What width and brand of tape measures were they using? Were the loads purely in tension, or was there significant torsion or shear?

Re: Tape measure climber club
 

My team uses the tape measures to support the weight of the robot. While we had an issue with this at the WPI event (a chain of events led to one tape measure twisting and snapping), it has worked just fine. I like using the tape measures as the lifting mechanism because it packaged very well into our robot and only required one CIM for the entire system.

So the tapes actually tore away from the spool they were wound around? After my team's testing during build and first event, we only had one tape measure tear right near the hooks, and never had any issues regarding the spool. I also echo Mr. Lavery's questions.

Re: Tape measure climber club
 

Yes indeed. I'll see if I can dig some pictures of the breaks out of their Engineering Notebook folder, but they would break right before their attachment points on our spools. A pretty clean break straight across the tape measure.

They used Stanley FatMax measures - the widest we could find.

Almost entirely tension. We tried to keep them as free of torsion as we could, but the robot would twist a little bit when it hit the upper churros (FTC field). For our uses it was worth switching to another climber - I'm now a little bit wary of tape measures as pure weight-bearing, but love them as hook-delivery systems.

Re: Tape measure climber club
 

We use the tape measures together to lift the robot. We had one tape tear at the hook once (other held and we did not fall), and both broke at the same time once (we fell :ahh: , but no damage ). Then we redesigned the hook to grab from the back of the bar. This puts a lot less stress at the hook. Did not have any other issues or failure after that change. The trick is making sure the hook does not kink the tape measure.

Re: Tape measure climber club
 

How was the tape attached? Did the break occur at the beginning of the lift when the tape was the most unspooled? Were there any extra wraps left on the spool when you started lifting?

We snapped a tape at the hook in testing, but that was thanks a programming error that ran the retract at full power without any voltage ramping. Hook hit the bar at free speed and the shock snapped the tape clean off. Haven't done much more testing, that'll come tomorrow, since I got busy with being sick and work. Should have a good bit of data on our system tomorrow afternoon, though.

Re: Tape measure climber club
 

got a new member for yall
2471