Another version of dual-wire gantry

You know how on the drawing of the dual-wire gantry people often post on the internet the gantry has one end attached to the "going" part of the belt, and the other end attached to the "coming" part?



Turns out... if you use the same kind of belt path as on a h-bot, but with fixed ends, then you get a much simpler mechanism, with no need for belt twists and whatnot. Has anyone ever implemented this scheme? I've seen it in a cnc router, thought it was really smart.

... I've "copied" this setup from a "harbour crane" around 1992 and used it for my first CO2-lasercutters

Sketched it then for a patent application in 1995:

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Quote
VDX
... I've "copied" this setup from a "harbour crane" around 1992 and used it for my first CO2-lasercutters

Yours is the "standard" dual wire gantry path implementation, with the second wire changing planes and the gantry being attached to it. My high precision ms paint technical drawing is the same as the y-axis of this:

[www.youtube.com]


In this version, the belt is only attached to the frame itself.

... there are countless "variants" out there - every application needs a slightly different setup, so the people search or develop a better fitting version

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

I've thought of this as well since I saw the DWG/Slid3r to make both axes behave the same, and get the 2:1 benefit on the Y axis as well. Unfortunately I think it might suffer from racking issues and binding as a result. Technically it would be self squaring since any racking would stretch the belt/cable which would result in it trying to pull itself back into square, but for small angles out of square the stretch causes by racking would be minimal, so the restoring force would also be minimal.

This thread mentions making a X style gantry setup with a similar belt/cable setup and one person who did a mockup mentioned binding issues. I think I remember seeing lkcl saying he abandoned it due to racking/binding issues but I can't find that comment/thread. The second thread he mentioned abandoning a similar concept due to binding issues. That being said the arrangement you've drawn is a bit different to both of the setups in the threads, and I think will pull more "symetrically" and be less prone to racking and binding.
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I'm planning to try the same arrangement as what you've drawn on a large CNC plasma I'm building for work, and I'll report back on how well/if it works. If racking is an issue I do have a few ideas to try and fix that.