# Rotary couplers



## Burl (Jan 2, 2008)

I have been pondering how to do these. Where I'm stumped is that if I make it fit a Kadee #1 scale box, then I don't have the height to make the shank as thick as it seems like it should be - and hence, not as round as the prototype. 


There's also not much room to fit a screw in to hold the shank together. I guess I'd try to solder it together, but I don't know that doing so would not fix the head at the same time.



Just thinking out loud for now I guess.


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## Dick413 (Jan 7, 2008)

keep thinking out loud


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## SD90WLMT (Feb 16, 2010)

Would it help alignment during assembly of the paired shank halves to have some vertically displaced keyed points..
Say.. little rectangular male / female tab n slots .. kinda thing-ies..

Geez. Sometimes it's hard thining out load!
.... and ya have'ta spell too!!

Does a real rotary still fit a standard draft gear box?

... getting good with couplers Burl !!

;-)


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## Burl (Jan 2, 2008)

I've never been able to get up close to a 1:1 rotary coupler to see what all is in there. The drawings I'm finding show a different yolk and a carrier spring.


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## Burl (Jan 2, 2008)

If I made my own draft gear box, and got away from the Kadee design, I could do whatever I want with it. But making the gear box in resin wouldn't be an option anymore (I don't think it would be strong enough). That would make me have to go to brass, which would get expensive.


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## krs (Feb 29, 2008)

Couldn't you scale up an O-scale Lionel rotary coupler design up to 1 or G-scale?

Knut


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## Garratt (Sep 15, 2012)

I take it that this is for rotary dumping of hoppers. An ideal coupler would right itself the normal way when not coupled. Making things even more tricky to design. 

Andrew


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## bnsfconductor (Jan 3, 2008)

Garratt said:


> I take it that this is for rotary dumping of hoppers. An ideal coupler would right itself the normal way when not coupled. Making things even more tricky to design.
> 
> Andrew


Actually, on the real ones they have this problem every once in awhile. A coupler will come uncoupled during the dumping process, and result in an inside down coupler.


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## krs (Feb 29, 2008)

I came across an article here how to convert a Kadee G coupler to a rotary one.

Half way down the page on the left:
http://www.houstonagg.com/issue-134-july-august-2014/

Knut


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## Burl (Jan 2, 2008)

I tried searching last night for Lionel rotary couplers, but never could find anything that showed me how they work. Do you have any photos?


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## SD90WLMT (Feb 16, 2010)

Andrew, while it would be fun to have self-righting couplers.... we are faced with a disadvantage in our models.
Be they model aircraft, or model trains - they lack the mass of their full size copies!!

Lacking this.. it would be really difficult to have enough weight offset to cause a coupler to rotate around the pivot on its own .... then it probably would not look the same as Burl's beautiful couplers are turning out now!

Don't stop 'sperimenting tho... keep trying!!

Working together... we can all explore new frontiers in our miniature world!

D


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## Garratt (Sep 15, 2012)

Ah!... but one could use a fine short spring that was wound a number of times to give tension in a radial fashion. One that is a little bigger, sitting around the coupler shaft to not impede it's swivel motion but to give it tension each way. It could be bent at each end poking in fine holes to secure. Getting the spring right by hand would be a precision job but if these were manufactured in quantity it would be simple enough to replace them if they went out of whack a little.

Andrew


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## Scott (Jan 29, 2008)

Hmmmmm Burl another interesting modelling task. Maybe use the ball bearing in the cup trick. Some power tools come with a sprung internal ball bearing, it lets you rotate while maintaining use. Some let the shank rotate, but the action comes to a stop when the ball hits the groove and locks in place. Sort of like a rachet and socket set up.


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## krs (Feb 29, 2008)

Maybe I missed the beginning of this 'rotary coupler' discussion within another thread.

But it seems to me that the design and manufacture of the rotary coupler is relatively simple compared to the other item that is needed for operation - the rotary dumper.

Here is the O-gauge version of that - this would look pretty impressive in G-gauge
https://www.youtube.com/watch?feature=player_detailpage&v=IKykBIWyHb8

And here is the real McCoy
https://www.youtube.com/watch?feature=player_detailpage&v=lPiY_m3i3Ns

Knut


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## John J (Dec 29, 2007)

I started from the wrong end. My thought was the rotary dumper. I was trying to figure out a dumper that would rotate the car on the Coupler Axis.

I never did get the  mechanism figured out. I put it on the back Burner and turned the flame off. 

JJ


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## CliffyJ (Apr 29, 2009)

Burl, here are a few patents (with drawings) that may shed some light.

http://www.google.com/patents/US4230228

http://www.google.com/patents/US8496128

http://www.google.com/patents/US3157291


Cliff


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## KD Rail (Feb 27, 2011)

Keith 'KD Rail' Stratton here. I'm the guy who wrote the article in the HAGG Newsletter #134 that Knut referred to earlier. If you go to our site the article should be under the 'Build/Bash/Repair' drop down but for some reason the article hasn't been posted yet. So, go to the 'Club Newsletter' drop down and you'll be able to get to #134 from there. The HAGG Website address is http://www.houstonagg.com/ottosmagazine/

I have converted two of these so far and run them regularly with no issues whatsoever. They can rotate 360 degrees but in actuality only need to rotate 180 degrees when being used in a rotary dumper. I have them mounted on AML Bethgon's. They are quite robust but I haven't done any pull tests to the point of failure yet. I have tested 830's and mine failed at a 55 lb straight line pull, so I estimate the rotary conversions will do 30lbs, but only a test will tell.

I just converted my entire fleet from Kadee 830/930's to the new rust colored Type E 906's. The shank on the 830/930's is square and the same width along it's length which made my conversion relatively easy, whereas the shank on the type E couplers is rectangular and tapered along it's length, which will make for a more challenging conversion, but not impossible.

I used two regular couplers to make one, as you'll see in the article, but the good news is that I have a 6" x 6" x 4" box full of 830 couplers to create lots of rotary couplers from. I'll leave the 906 rust colored type E couplers on the non-rotating end, and on the other end will be a modified 930 coupler. I really like your design Burt, but wonder if the rounded internal shaft of reduced diameter could be a weak point, unless its cast from metal.

Once it gets too hot to be outside (I live in Houston) I'll return to my indoor experiments!

Keith


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## Dick413 (Jan 7, 2008)

Keith good job on the couplers. i see you did this in 2013 so how is the rotatory coming a long?


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## KD Rail (Feb 27, 2011)

Thanks Dick.
Unfortunately the rotary dumper hasn't made it out of my head yet!! But it will be a very cool project. Will probably start with a plywood mockup and then make something out of Styrene and/or aluminium? I currently have about 50 coal hoppers and will eventually have a flood loading facility and a rotary dumper, but that's a little ways off yet. First lets see what kind of magic Burl can weave!

Keith


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## Burl (Jan 2, 2008)

The patterns came in today:


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## Scott (Jan 29, 2008)

Looking good mate.


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