functions through a turntable

[gilby]

ok im trying to make a moc attachemet for the mog and for the life of me i cant figure out how to run two functions throught the tur table any help would be apperciated.

[timslegos]

ok im trying to make a moc attachemet for the mog and for the life of me i cant figure out how to run two functions throught the tur table any help would be apperciated.

I will give you a hint, use an old style differential without any internal gears... Good luck!

tim

[laix]

Take a look at the instructions of e.g. 8043.

Booklet 1/3, Page 35

Booklet 1/3, Page 45

Edited January 23, 2012 by laix

[efferman]

[Wiseman_2]

You will need a driving ring, and possibly an extension, and two 16 tooth clutch gears (the ones that can spin on an axle without rotating it). The central axle will have one function on it, but by stacking those parts onto the axle as it goes through the turntable, you can run a second function up through it. I probably haven't explained that very well, but if you check the first instruction booklet of 8043 (here) you can see how it's done. You'll need the following parts:

http://www.bricklink.com/catalogItemPic.asp?P=32187

http://www.bricklink.com/catalogItemPic.asp?P=6539

http://www.bricklink.com/catalogItemPic.asp?P=6542

EDIT: Damn, beaten to the punch several times

Edited January 23, 2012 by Wiseman_2

[gilby]

i see how its done now thank you

[timslegos]

i see how its done now thank you

The problem with the suggestions above is that the drive that goes through the clutch gears has some play to it. With the differential, none of the drive is lost.

tim

[asielen]

In all these methods, it seems the functions that are sent through the turntable are affected by the turntable itself. I.e. When the turntable turns, they will move slightly also. (Unless I am missing something?)

Is there anyway to send functions through a turntable (even if it is just one), without it being affected by the turntable turning?

[timslegos]

Is there anyway to send functions through a turntable (even if it is just one), without it being affected by the turntable turning?

I dont think it is possible, however i am no expert.

tim

[dhc6twinotter]

I will give you a hint, use an old style differential without any internal gears... Good luck!

tim

That is probably the best way to do it, but if space is a concern, you can use the driving rings also.

In all these methods, it seems the functions that are sent through the turntable are affected by the turntable itself. I.e. When the turntable turns, they will move slightly also. (Unless I am missing something?)

Is there anyway to send functions through a turntable (even if it is just one), without it being affected by the turntable turning?

You could build a geared system using a differential for each function going through the center to compensate for the turntable turning. For example, use a setup similar to what Efferman posted, but use a differential at the bottom of the green axle, and another at the bottom of the red axle. Connect the ring gear of each differential to a set of gears that are also turned by the same shaft that turns the turntable. As the turntable turns, it also turns the ring gear on each of the differentials, and this, in turn, rotates the two axles that run through the center of the turntable. The trick is to get the gear ratios just right.

I'm not good at explaining stuff. Hopefully that makes sense.

[Mud]

In all these methods, it seems the functions that are sent through the turntable are affected by the turntable itself. I.e. When the turntable turns, they will move slightly also. (Unless I am missing something?)

Is there anyway to send functions through a turntable (even if it is just one), without it being affected by the turntable turning?

I have done it,

. I would be interested to see if anyone has a simpler solution.

[Tobbe Arnesson]

...and when you realize you want a third axle here's how to do it: http://www.eurobricks.com/forum/index.php?showtopic=51679&view=findpost&p=919869

[imajor]

I have done it,

. I would be interested to see if anyone has a simpler solution.

This is very interesting, grats!

[asielen]

I have done it,

. I would be interested to see if anyone has a simpler solution.

Wow. That gives me some ideas. I will have to try that.

[Scorpion]

I think this topic should be indexed. Many great solutions for this particular problem are collected here.

[jorgeopesi]

Very good topic, many and very good solutions there are here.

[Scorpion]

You could build a geared system using a differential for each function going through the center to compensate for the turntable turning. For example, use a setup similar to what Efferman posted, but use a differential at the bottom of the green axle, and another at the bottom of the red axle. Connect the ring gear of each differential to a set of gears that are also turned by the same shaft that turns the turntable. As the turntable turns, it also turns the ring gear on each of the differentials, and this, in turn, rotates the two axles that run through the center of the turntable. The trick is to get the gear ratios just right.

I'm planning to do this also in a MOC using the old type turntable. I'm split between what types of differential to use: do I use the older one with two gears (one 24 teeth at one end, another 16 teeth at the other) or the newer with 28 bevelled teeth?

(It'll be used to power cannon elevation in a tank turret, if that helps...)

[Mud]

I'm planning to do this also in a MOC using the old type turntable. I'm split between what types of differential to use: do I use the older one with two gears (one 24 teeth at one end, another 16 teeth at the other) or the newer with 28 bevelled teeth?

(It'll be used to power cannon elevation in a tank turret, if that helps...)

I used the 28 tooth differential because if you go from 28 teeth to a 12 toother (in my case via a 20 tooth) that's a ratio of 2.333:1. You can match that ratio with a 24 tooth gear to the 56 teeth around the outside of the turntable. I may have missed a trick though, I'd certainly be interested to see if there's an easy way to use the 24 tooth differential instead since there's the possibility of a much tidier package. I posted a video earlier in this thread.

Passing a single function through a turntable is probably pretty easy with the 24/16 tooth differential since you can use an 8 tooth gear on the inside teeth of the turntable for an easy 1:3 ratio.

[Brickthus]

In all these methods, it seems the functions that are sent through the turntable are affected by the turntable itself. I.e. When the turntable turns, they will move slightly also. (Unless I am missing something?)

Is there anyway to send functions through a turntable (even if it is just one), without it being affected by the turntable turning?

I have done it,

. I would be interested to see if anyone has a simpler solution.

I don't know about "simpler" but there is always the way I extended Parax's Chain Precession Drive

I quoted his original model as prior art for a patent.

The important difference, in moving from the prior art to my invention, is that the chain moves when it was static before.

Of course I built a model first, but I can't release the photos yet.

I used 3 new-type turntables with 24T and 16T cogs.

This is another way of putting a single drive through a turntable without the drive being affected by the rotation of the turntable. It may be used in multiple, given enough concentric shafts, hence Claim 12. This would allow the pitches of two propellers to be controlled from a static position without the pitch motor shafts having to rotate with the propellers. It is equally applicable to turret vehicles.

Mark

[dhc6twinotter]

I don't know about "simpler" but there is always the way I extended Parax's Chain Precession Drive

I quoted his original model as prior art for a patent.

The important difference, in moving from the prior art to my invention, is that the chain moves when it was static before.

Of course I built a model first, but I can't release the photos yet.

I used 3 new-type turntables with 24T and 16T cogs.

This is another way of putting a single drive through a turntable without the drive being affected by the rotation of the turntable. It may be used in multiple, given enough concentric shafts, hence Claim 12. This would allow the pitches of two propellers to be controlled from a static position without the pitch motor shafts having to rotate with the propellers. It is equally applicable to turret vehicles.

Mark

I'm not sure I understand how that works, but it would be very cool to see, especially in the propellor pitch application.

[Mud]

I don't know about "simpler" but there is always the way I extended Parax's Chain Precession Drive

I quoted his original model as prior art for a patent.

The important difference, in moving from the prior art to my invention, is that the chain moves when it was static before.

Of course I built a model first, but I can't release the photos yet.

I used 3 new-type turntables with 24T and 16T cogs.

This is another way of putting a single drive through a turntable without the drive being affected by the rotation of the turntable. It may be used in multiple, given enough concentric shafts, hence Claim 12. This would allow the pitches of two propellers to be controlled from a static position without the pitch motor shafts having to rotate with the propellers. It is equally applicable to turret vehicles.

Mark

That looks neat although I'd have to see it going to intuitively understand it. Patent-speak isn't very intelligible at the best of times...