ideas on 3 axle functions going though turntable?

[rgbrown]

Technically the rope is a third function Should be good for cranes. The 3,2 mm tube can carry some torque, it depends on the gears used.

Yes, as I said earlier . Except I had a rotating flex cable up the middle, instead of a rope. Not my idea though, I've seen clocks built this way.

[Oerieth]

yeah kinda'

Here's how to do it:

get as many freely spinning axles through the turntable, then one ofter another get into the centre then lead them away to their functions:

hope you understand

Very genius sollution. I'm just wondering if the "get into the centre and lead them away" is required on both sides. I think it would be sufficient and probably more efficient to do it only on one side.

Correct me if I'm wrong.

Edited February 7, 2011 by Oerieth

[blueShinyApple]

Very genius sollution. I'm just wondering if the "get into the centre and lead them away" is required on both sides. I think it would be sufficient and probably more efficient to do it only on one side.

Correct me if I'm wrong.

No, it's not needed, but it would take just as lot of space as it takes now; only difference is that everything would be on one side of the turntable, instead of 50/50 as it is now.

[CP5670]

Doing it on both sides actually provides an advantage here since it allows the blue geartrain (36t gears) to move independently of the other two geartrains. The gears inside the gray liftarms would behave like planetary gears. That's what I especially like about his idea. The other solutions I've seen for doing this involve quite a bit of dependency and backlash between the different geartrains, which make them useless in practice.

All the geartrains will still be affected by the movements of the main turntable, but that seems to be harder to avoid and happens in the usual method for two geartrains too (8258/8043).

[fmmjqtft]

Here is the animation. I finished it a week ago but only uploaded it today.

I saved the frames to separate .pngs and then converted them to a video using gimp. For some reason this messed up the colors and the first upload had a 'black crush' (although this didn't happen when I opened it in VLC ). I fixed this by reducing the contrast on each image using imagemagick but now lbg and dbg look too similar.

[blueShinyApple]

I saved the frames to separate .pngs and then converted them to a video using gimp. For some reason this messed up the colors and the first upload had a 'black crush' (although this didn't happen when I opened it in VLC ). I fixed this by reducing the contrast on each image using imagemagick but now lbg and dbg look too similar.

huh?

Awesome anyways!

[fmmjqtft]

huh?

Basically the colors in this video are slightly distorted.

[blueShinyApple]

Basically the colors in this video are slightly distorted.

OK.. didn't notice

[Bricktrain]

hmm, I was rather thinking to make a GIGANTIC 8270(mini terrain crane), like 5 times as big! that would just be mighty!

edit: I really dont think it would fit in the 8053, but it's absolutely worth a try

I tried with 8421 and ended up with this http://www.brickshelf.com/cgi-bin/gallery.cgi?i=3909612

[blueShinyApple]

Yay, I'm on technicBRICKs!!

[Alasdair Ryan]

Yay, I'm on technicBRICKs!!

I have not seen you on here for a long time.

Edited November 29, 2011 by Alasdair Ryan

[blueShinyApple]

I have not seen you on here for a long time.

Yeah, i know.. I'm in the 9th grade (=11th US grade, i think), so i have quite a bit of homework to do, tests to practice for, and papers to write :/

have anything special happened/been built?

[Alasdair Ryan]

Well apart from the loader i finished today i am working on a harvester and my big skip truck.

Edited November 29, 2011 by Alasdair Ryan

[timslegos]

And i making some pretty awesome machines to . Anyway, i have just read the whole thread and i am amazed! i never thought that 3 functions through a turntable would be possible. Is there any way that it can be built smaller?

tim

[blueShinyApple]

And i'm making some pretty awesome machines to . Anyway, i have just read the whole thread and i am amazed! i never thought that 3 functions through a turntable would be possible. Is there any way that it can be built smaller?

tim

I don't think so, but perhaps the new small turntable could be used somehow. Do you know when the 1h2012 sets will come?

[timslegos]

I don't think so, but perhaps the new small turntable could be used somehow. Do you know when the 1h2012 sets will come?

I dont know when they come out, i cant wait until they do.

tim

[le60head]

I just read trough this topic and i'm seriously amazed!

blueShinyApples, your solutions is incredible. i couldnt't understand how it worked until i saw the video.

Congratulations on your idea :)

[SNIPE]

I would imagine since the 8 tooth gears mesh with the inner gear of the geat ring it would be hard to fix the axles of the 8 tooth gears because they are offset.

Note that a 24 tooth concrate/crown gear can fit inside of the inner gear and if im not mistaken I think a LEGO 24 tooth clutch gear should be able tp aswell which allows for bi rotational movement but only slips when used on one direction, the other one meshes

Since the outer gear of the gear 'ring' is bi rirectional you can have 4 'speeds' with one gear ring so one can be for one function of the midel ,and the other one can be for 'such and such'

Just have two gear rings beside each other but on counter rotating axles that are still put 'end to end' in this configurationand that is 8 functions.

You can put two 8L axles with stops back to back (yes the stops are back to back) and then lock something over the stops so that it is harder to pulll them apart but still allows for counter-rotation which means having the hole for the axle a 'pin' hole not an axle hole.

Edited December 1, 2011 by SNIPE

[Alasdair Ryan]

I counted three functions plus rotation,but feel free to count them your self.

Hopefully you can see the video alright....

The design above will not work,to make it work it requires one height retractable drive shaft to power the turntables.

Edited December 7, 2012 by Alasdair Ryan

[Alasdair Ryan]

I just came up with a very easy solution to a well known problem,it's not perfect but it will allow more functions though a turntable.

The pink drive shaft is connected to a cam which in turn lifts the whole middle axle,this then powers the third function.

Both blue and yellow gears are for your main functions which are still powered independently of one another.

The red gear is for the extra function.

Edited May 26, 2013 by Alasdair Ryan

[JLiu15]

Not sure if this is practical, but here's what I'm thinking of: do the standard two functions through a turntable (central axle + driving ring/gears or old diff), but then use the turntable itself as a function provider (for example, drive the turntable from the bottom and use the turntable's rotation for the third function). As for the actual turntable then, use the ring pieces from the 42055 and reinforce it a bit. The upcoming 42082 Rough Terrain Crane seems to use the ring gears as part of its turntable, so maybe this could potentially work for large-scale models like the 42082?

In other words, the turntable becomes the third of the concentric axles, through a larger turntable made of ring gears from the 42055.

Edited June 29, 2018 by JLiu15

[JLiu15]

On 2/3/2011 at 4:55 PM, Blakbird said:

The only way to run mechanical functions through a rotating turntable is to have them be coaxial. With present LEGO parts, you can only manage 2 coaxial functions using an axle as the central function and a series of driving rings as the annular function. There is no space inside the turntable ring gear for anything else. However, the ring gear itself could theoretically also be used to power a function, though that function would be slaved to the rotation of the ring gear.

There is a way to get an unlimited number of mechanical functions above a turntable. Use the central axis for driven power. Use the drive rings to power a second function which is a switching function for a transmission which is above the turntable. As long as the transmission is above, you can shift it from below and drive as many functions as the transmission has gears. This means you'll need quite a bit of space available above your turntable, but at least it can be done. You'll need a sequential transmission to really be able to shift more than 2 functions though. I'd love to see someone do it!

With the new rotary changeover catches from the Bugatti this could potentially become a lot easier: get one of the axles to drive a single rotary catch with several driving rings placed around it. This way when it turns the driving rings will be shifted at different intervals, allowing for many functions to just come off of that single catch. You could easily add another one of those modules if you want more functions. Compared to the lever-type changeover catches, this should take up a lot less space.

Note: I do not have the new rotary catch so I'm not sure about the exact properties of it, but I do think it will make your solution a lot easier to incorporate.