pic: 57's Tape Measure Scaler

[Kevin Sevcik]

Originally Posted by trumpthero786

Wow. That's a fantastic product. My team tried something very similar, but it unfortunately never got integrated to the final design. I have a couple of questions. So there's one Bag motor to extend, and then the WCP DS kicks in and winches it all up, right? I'm assuming it's the PTO. What gear ratio will you use on the robot for the winch? And I love the servo by the way. Also, how is the hook attached to the tape? We had tons of issues finding a good and secure way to do that. Finally, (lots of questions, sorry ) did you put the whole tape measure, with its casing, or did you create your own solution to housing the tape around the winch?

Excellent work, this is very awesome!

That IS a lot of questions. Answers, in an order that makes more sense:
1. Tape is completely removed from the original FatMax tape measure. It's wrapped around a 42 tooth Versapulley with a lot of extra slices. We attach it with high strength double sided tape on the bottom side of the tape. So our tape is wrapped "backwards" from how it's wrapped inside a tape measure. We have zero worries about this attachment system, since we've actually spooled out too far before and doubled the tape over without pulling off the double-sided tape.
2. The BAG+VP+Banebots wheel is right next to the tape spool. It's crucial to have something that pushes the tape out/pulls the tape off the spool. Turning the spool backwards without that just unwinds things and makes a mess. When the tape is wrapped on the spool, the BB wheel is tightly squished against it. It doesn't HAVE to push against it that hard, but this makes sure we have push down to the bottom of the spool without spring loading something.
3. The WCP DS low gear ratio is 11:42 and 14:60. We don't use the high gear because our deploy speed is limited by the speed of the BAG currently. If we HAD to have a faster deploy, I'd swap a 775pro in for the BAG, then maybe switch in high gear on the WCP DS. Also, this is a completely self-contained system, not a PTO.
4. The hook attachment is just a curved piece of PVC acting as a washer on the underside of the tape, and a curved surface sanded onto the hook, with two socket head screws through the mess. We DID discover that the hook has to be question mark shaped so the tape doesn't kink or bend when under tension. Our original hook was lots smaller, but the tape wasn't pulling in line with the center of the bar, so it kinked under tension. That snapped it off instantly as soon as the weight of the robot hit it at the start of the lift.