Origin of the six bar lift term/design?

So, the naming/numbering of n-bar lifts has always been really confusing for me and my teams. I just found this article while digging around the AURA website, and I’m wondering

  1. Did they actually invent the term “six bar lift”?
  2. Does anyone have non-vex examples of these linkages (6, 8 bar) or is there another term used in engineering?
  3. Is there an ‘official’ definition/convention for naming these lifts?


In mechanical engineering, there are six-bar linkage mechanisms, but they look nothing like the design called that in VRC. The VRC mechanism is actually two 4-bar links tied together, but the sloppy and inaccurate term persists. When these first started showing up in VRC, some people suggested calling them extended 4-bars, but the teenagers won.


Add it to the list: DR4B, Goliath intake, choo-choo, Danny lift…even CIM (from FRC, it’s the acronym of a Chinese motor factory’s name) and “pistons” instead of pneumatic cylinders are all obnoxious terms.


Vex and other robotics programs have changed the meaning of a lot of words and mechanical terms. We could start a list, but it might be kind of pointless.

It seems like double/triple 4 bar lifts is a much more accurate name then - and it fits with the DR4B/RD4B naming scheme.

Now I really want to know what the choo-choo is… Goliath is the two sided rubber band intakes from ITZ, right? Danny lift seems to be a specific, compact, DR4B.

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Yes, a “Goliath” was the double hyperboloid-shaped intake made from sprockets and rubber bands. I have no idea who “Goliath” is, but teams from around the world were using the term last year at Worlds.

A choo-choo is a version of a radial release mechanism. The were popular on FRC robots a few years ago, and a Virus team tried using one during starstruck. It slightly resembles the drive mechanism of a steam locomotive.

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OG Choo Choo


The choo choo is just an advanced form of the crank and slider

Sigh… looks like it is time for my annual rant with all the strange naming of mechanism…

There is a proper “engineering” approach in counting the N in the N-bar mechanism, and for most students out here - no… it is not by counting the number of c-channels.

Anyway, @Rick_TYler is correct to say that AURA modified the existing concepts of 6-bar in engineering to the current 6-bar lift that we are familiar with. In the earlier years, many teams called it NZ-bot.

But as for some of the “newer” namings… sigh…
I just cannot understand goliath intake… we used to just call it “top-roller intake”.


Im fine with the names for the most part, but am vehemently against calling things “Bling” drives and “Goliath” intakes when more technical names make more sense and can be applied easier.

But in the end it seems the less technical names always win on the forums.


But, on the bright side, men’s was part of the conversation (as was I) that mostly did away with the “double catapult,” and instead replaced it with the more accurate “2-ball catapult,” or “2BC,” as I call it. It hasn’t caught on as well as I would’ve liked, but at least it’s better.

It’s hard to break tradition. “Bling drive” was mostly dead in favor of the standard “locked omnis,” until somewhat recently revived. And I still don’t understand Goliath intakes. I just call it a “roller system,” or lrubber band rollers."

And I still don’t really understand why the base tower, etc. is counted in N-bar lifts. But I just don’t argue with it because it would cause mass confusion.

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Well… at least 2BC has been pretty consistent… :slight_smile:

we have been calling it 2BC since day 1…