[FRC Blog] Questions That Need Answering

The rope does not need to be constructed of a uniform material. The material used do not need to be the full length of the rope.

If you don’t want to make the argument that sewing isn’t a form of weaving, can you not think of a way to braid or weave or knot it into/onto a strap?

The Velcro website uses the word woven in their product description… https://www.velcro.com/business/products/textile-hook-and-loop My team is going to use this as justification if necessary.

So am I the only one who even after this blog post and Team Update 2 still cannot tell if and under what circumstances velcro is legal to use on a rope? :confused:

  • It must be loop side
  • It must not have adhesive on the back
  • It must follow the rest of rope rules

Would it be legal to sew some Velcro onto the rope that is hook on the inside and loop on the outside? Might we have to file off the hooks?

Hooks might be ok, too. According to this, the hooks on 3M’s hook and loop with a plain back (no adhesive) are made from woven nylon or woven polyester. Product numbers SJ3401, SJ3402, SJ3476, SJ3477.

Snap shot attached if you don’t want to go to the pdf.





Why wouldn’t you just buy plain-backed? Pretty cheap on McMaster: https://www.mcmaster.com/#hook-and-loop-fasteners

Because I couldn’t find any :slight_smile: Didn’t even think to check McMaster. Ordering now.

In our rookie team last year we wondered around kickoff why everyone was making jokes about the McMaster catalog.

We get it now. :smiley:

We spent some significant time prototyping weaving velcro into our rope today. Our best results came with using string to tie the velcro, however we have concerns that it may be interpreted as “whipping,” which is specifically only allowed for preventing fray.

Before sewing Velcro onto your ropes, double-check Q6’s answer. Emphasis mine:

Non-adhesive-backed hook and loop fastener may be part of, or the entirety of, a legal ROPE, provided that the ROPE is entirely made of “flexible, non-metallic fibers twisted, tied, woven, or braided together” per I04 (e.g. something stuck to or wrapped around the outside of the ROPE does not satisfy this requirement unless it’s whipping as permitted per I04 part D).

Cue debate on whether sewing Velcro onto the rope counts as sticking it on or weaving it in.

Drat. If you can’t wrap velcro around a rope, why would sewing it be any more legal?

The question is, are sewing and weaving the same thing?

Ask any craftsperson, and likely the answer will be No. You sew woven things together.

From Dictionary.com

Sew:

to join or attach by stitches.
2.
to make, repair, etc., (a garment) by such means.
3.
to enclose or secure with stitches:
to sew flour in a bag.
4.
to close (a hole, wound, etc.) by means of stitches (usually followed by up).
5.
to work with a needle and thread or with a sewing machine.

Weave:

to interlace (threads, yarns, strips, fibrous material, etc.) so as to form a fabric or material.
2.
to form by interlacing threads, yarns, strands, or strips of some material:
to weave a basket; to weave cloth.
3.
to form by combining various elements or details into a connected whole:
to weave a tale; to weave a plan.
4.
to introduce as an element or detail into a connected whole (usually followed by in or into):
She wove an old folk melody into her latest musical composition.
5.
to direct or move along in a winding or zigzag course; move from side to side, especially to avoid obstructions:
to weave one’s way through traffic.
6.
to form or construct something, as fabric, by interlacing threads, yarns, strips, etc.
7.
to compose a connected whole by combining various elements or details.
8.
to be or become formed or composed from the interlacing of materials or the combining of various elements:
The yarn wove into a beautiful fabric.
9.
to move or proceed in a winding course or from side to side:
dancers weaving in time to the music.

(several of those definitions are abstractions of the original meaning of making fabric)

The OP stated this

Answer: Please see Team Update 02. Non-adhesive-backed hook and loop fastener may be part of, or the entirety of, a legal ROPE, provided that the ROPE is entirely made of “flexible, non-metallic fibers twisted, tied, woven, or braided together” per I04 (e.g. something stuck to or wrapped around the outside of the ROPE does not satisfy this requirement unless it’s whipping as permitted per I04 part

I would argue that sewing is just a former of tieing

People. Do we really want to put together a plan in which one of the major objectives of the game will rely on our ability to debate the meaning of words with an inspector? When we still have five weeks to design, prototype, and test? When there are dozens of viable alternatives? For instance, have we tried combing fibers out of something else that is, inarguably, rope, and tested them against the hook side of Velcro for adhesion? Just one of many options.

I implore you to not spend your mental energy on preparing your argument for the inspectors. We all have better things to be thinking about and working on.

I’ll second this. There are plenty of excellent ropes and excellent climber ideas that don’t need to involve velcro in any way. I think that if you’re using semantics to pass inspection you’re trying hard to be lazy (Trust me I’m really good at doing it). I personally think it will be more interesting if everyone’s robot isn’t the same. (Cue joke about 2015 robot design here.)

Arguably that’s half my job as an engineer.

Good question. But, team 4466 asked about sewing directly, https://frc-qa.firstinspires.org/qa/156. We’ll see how that turns out.

Oh god. This is a tricky one.

Non-metallic is easy.

The loop side has fibers twisted an/or woven in, just loosely. So I guess that counts.

The hook side, well, if the hooks are made of heavy fibers, it depends all on how they are attached to the backing. If they are woven in, then it’s all good.

Either, way, you’ll need to find double-sided Velcro or sew two strips back-to-back.