What is this lift called?

so i built this sort of dr4b with an extra joint but im not sure if i can exactly call it that in the notebook. is this a six bar perhaps? terminology is not my strong suit but i dont want to keep calling it a “modified reverse four bar” in the notebook if it has a proper name. does anyone know what to call this?

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Yes, you are correct that you can call it a “DR4B with a second stage implemented as a 6-bar”.

However, I believe, there is no industry term “double reverse four bar” or DR4B. If you google it - all the links will point back to vexforum, chiefdelphi, or closely related sites.

If you just call it a DR4B that should make it much easier to understand and not confuse volunteer judges who are not that much versed in VRC/FRC/FTC specific terminology. But then, you can have a small print in the notebook and, if you talk during an interview to somebody with more experience, you can add that it has a 6-bar linkage on the top stage, to get some extra bonus pedantic points. :slight_smile:

But you have to be careful, because, once judges sense the smell of the correct engineering terms in the water, they will question you even more aggressively on the merits of the screw joints, gear ratios, and friction mitigation strategies. :smile:

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unfortunately i dont think i can avoid addressing the extra joint in the notebook as this is v2 of our lift, the original was a standard four bar lift, and i will eventually add an entry talking about the reasoning behind the change. thank you for your answer !!

https://wiki.purduesigbots.com/hardware/lifts/dr4b#the-double-reverse-design

Here’s a way you can talk about the general “double reverse” design concept.

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You can call it a DR4-6B
Double Reverse Four-Six Bar

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I am going rogue here - but for judging purposes, who cares what you call it (yup, says the guy who really stopped listening to teams calling a mechanism a “pooper” or whatever).

From a design point of view while judging and reviewing notebooks - what problem are your trying to solve? what solutions you think would remedy it? Which is best approach for your team with level of skill to design, build, test the solution? Once you have decided approach, you need to identify art / technique to solve it. This may entail identifying common industry accepted terms - four bar, scissor lift, etc. When you use jargon, reference primary source for the term ( vexForum might not be the best first reference for terms if it is a common mechanism :slight_smile: ).

pretty sure Leonardo Da Vinci Leonardo da Vinci - Wikipedia
anticipated any cool mechanism you might think of - even water games :slight_smile:

Judges could care less if you use jargon found on VEXforum than if you use industry terminology, but they will focus on the problem you are trying to solve. Best to have drawings, photos, etc and test results about how this mechanism performed in competition.

Good luck this season! Great questions - sometimes a picture is worth a thousand words vs finding precise name for a mechanism.

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Yup.
In fact, I don’t really see any actual industrial implementation of dr4b or even 6-bar.

The industrial application of bar linkages are pretty different from VRC.

And if I am not wrong, AURA was the 1st to apply 6-bar linkage into VRC context. And of course, it was popularised by the NZ teams.

And in that same year, 8059 (ahem… ) adapted from the concept of 6-bar and made a dr4b for worlds.
And the rest are history.

So if one is to look at the origin of dr4b, etc… all these mechanisms are very specific to VRC. So I am not surprise not to see any industrial term for such mechanisms,

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it is a fun web quest to search linkages - lots of complex motion examples, it is pretty wild the animations on wikipedia and elsewhere.

thank you !! he inspects every part for quality control

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