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Author Topic: New coupler development (was Coupling survey)  (Read 30513 times)

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Offline Newportnobby

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Re: Coupling survey
« Reply #225 on: March 23, 2018, 09:52:40 AM »
Soldering would present a problem for me as I'm just so useless at it. I'd have a go but am more likely to melt the bungalow myself and the layout are housed in :-[

Offline Black Sheep

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Re: Coupling survey
« Reply #226 on: March 23, 2018, 11:09:38 AM »
The issue I've been having with DG couplings is getting a robust soldered joint between the wire dropper and brass loop, it simply breaks apart so a solder free production would be preferable for me but brass on brass soldering I should be able to achieve.

is it the bar for the NEM mount that's going to be soldered?


I had been attempting to use DG couplings, slipping the bit of brass into the coupling pocket and wedging it in there with a bit of plasticard, allowing an NEM to go back in at a later date, could that be an option, a friction fit?

Offline SheldonC

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Re: Coupling survey
« Reply #227 on: March 23, 2018, 09:57:39 PM »
I now have a nice simple design for NEM plug-in coupler hooks with easy height adjustment.  The only problem is that it will require soldering - a length of wire soldered at right angles to the coupler, and then the ends snipped off short.  It needs to be soldered to accommodate all the different lengths of coupler that will be needed for NEM equipped locos. Do people think this will be a problem?  I have tried to keep the design soldering-free but I can't see a way around this one. I suppose the pin could be glued, but a round wire on a flat surface doesn't give a lot of contact area, so I am not sure it would really be strong enough, depends on the glue I suppose.  I might try it with thick cyano.

I only have two unmodified locos with NEM coupler pockets, Dapol B1 and Farish A2.  So I made up a rough prototype of my new design and tried fitting it.  To equip these two locos with new couplers front and back I need three different lengths of coupler at two different heights, with two different pin diameters.  So much for the "standard" NEM coupler pocket.
Personally, I'm not a confident or competent solderer of small things.  As for the "standard" nature of NEM pockets, etc., I've found it quite difficult to fit Farish NEM coupler arms into Dapol NEM coupler pockets.  Examination of the respective suppliers' NEM coupler arms shows they are different.

Offline belstone

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Re: Coupling survey
« Reply #228 on: March 23, 2018, 11:37:45 PM »
Thanks for the feedback.  I may have a solution.  I have some square section wire which I bought for an earlier experiment.  This would give a nice flat surface for adhesive bonding.  The wire I have is stainless steel which is not especially easy to glue, but I made a quick test piece and it clipped nicely into an NEM coupler pocket.  The square section wire is available in brass or nickel silver in various sizes, 21 gauge looks about right, the stainless stuff I have is 22 gauge and fractionally small.  I would probably use a slow-setting cyano adhesive so the bar can be accurately positioned, it needs to be square to the shank.

@Black Sheep I don't much fancy trying to solder steel wire to anything.  It is possible but I have never found it easy to get consistently good joints.  The B&B version of the DG coupler uses several turns of fine iron wire wrapped round the drop arm and secured with a dab of cyano, which is the method I have used for my design.

Offline belstone

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Re: Coupling survey
« Reply #229 on: March 24, 2018, 08:16:05 PM »
As for the "standard" nature of NEM pockets, etc., I've found it quite difficult to fit Farish NEM coupler arms into Dapol NEM coupler pockets.  Examination of the respective suppliers' NEM coupler arms shows they are different.

So they are.  I just tried to fit a Dapol coupler into a Farish pocket and it is totally solid, will not lift at all.  It also droops downwards.  I get the impression that couplers are a bit of an afterthought for manufacturers.

Offline JasonBz

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Re: Coupling survey
« Reply #230 on: March 24, 2018, 09:27:43 PM »
Intersting tales of a heroic struggle here :)

As and aside
you can make the loop and dropper for DG couplings out of a single piece of wire :)

Offline belstone

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Re: Coupling survey
« Reply #231 on: March 27, 2018, 08:39:45 AM »
Some XXX rated shunting action for a Tuesday morning.  Poor quality video, I really need to get a proper video camera, but you can just about see what is going on.  I fitted a flap-type uncoupler using a heavy brass hinge, but have not yet motorised it as the servo supplied with the control board was rubbish, and I have now dismantled it to see if it was fixable so I can't send it back.  Servos are cheap so I ordered a couple of hopefully better quality ones instead. As @Black Sheep pointed out to me I could mount the magnet direct on the end of the servo arm: the flap was originally intended to work with a solenoid.  It does have the advantage that if a coupler sticks and will not uncouple you can tap the underside of the baseboard with the flap to free it.  Pretty good reliability here, I had a 30 minute session last night with similar results.  That box van needs looking at, I suspect the angle on one of the droppers is wrong, hence the difficulty uncoupling it.

Richard


Offline belstone

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Re: Coupling survey
« Reply #232 on: March 31, 2018, 05:07:02 PM »
The first prototype servo-powered uncoupler is now installed and works beautifully even if it looks a bit crude.  The top of the magnet (10 x 10 x 5 N52 Neodymium) sits around 6mm below the rail tops, so even with Peco Code 80 it can be completely hidden.  The same basic principle can be used for other magnetic uncoupling systems (Dapol, Micro Trains etc).  I'm so excited I have even managed to stir myself to complete the design for the latest revised coupler etches...

Richard




Offline Newportnobby

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Re: Coupling survey
« Reply #233 on: March 31, 2018, 05:28:12 PM »
That's my brain cell blown, then :dunce:

Offline Izzy

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Re: Coupling survey
« Reply #234 on: March 31, 2018, 07:14:40 PM »
Intersting tales of a heroic struggle here :)

As and aside
you can make the loop and dropper for DG couplings out of a single piece of wire :)

The only problem I found with that is after a while the wire/loop becomes magnetized and they then stick to each other when coupling up, i.e. won't slide along against each other, and coupling doesn't happen. I now make the whole loop with drop wire in one piece - out of PB wire - and wind a few turns of soft-iron wire on it, which I solder in place.

Izzy

Offline belstone

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Re: Coupling survey
« Reply #235 on: April 01, 2018, 10:07:37 AM »


A new addition to the test fleet.  I'm on the lookout for more "awkward" vehicles which might cause problems, and a long wheelbase van was high on the list.  This Dapol "Fruit D" turned up unboxed at a fair price. It is the first successful conversion I have done of a wagon with NEM coupler pockets.  The chassis has some very clever spring-loaded pivoting devices to allow for sharp curves but these flapped about all over the place and I couldn't get a consistent height for the couplers, so in the end I put a small nut and bolt through them to lock them up solid.  I also moved them inwards on their mounts for closer coupling. It works fine although the Impossible Siding (Setrack no 2 reverse curve) proved too much for it, buffer locked with the loco and derailed. 

Next on the awkward list is a four wheeled parcels van with long overhangs, either a CCT or PMV.  They seem a bit hard to find at the moment.

Richard

Offline belstone

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Re: New coupler development (was Coupling survey)
« Reply #236 on: April 01, 2018, 12:27:57 PM »
I changed the thread title as it seemed a bit out of date, and I thought I would do a quick photo sequence as it may not be entirely clear to readers what the Magpie coupler looks like in its current form, or how it works.  So here goes, hope people will find this useful...



The "standard" coupler with lifting loop.  The bar sticking forwards above the coupler is the "delay bar" whose purpose will become clear shortly.  The loop has a drop arm underneath with a few turns of soft iron wire wound round the lower end: when the coupler is positioned over a magnet the iron wire is attracted to the magnet which pulls down the drop arm and lifts the loop.  There is a central buffer bar with a simple flat hook above it bent back at about 30 degrees.



The couplers are not "handed", coaches and wagons have lifting loops at both ends.  This means locos can have a plain hook and buffer bar without the loop, which makes fitting much easier especially on diesels, and the bogies / pony trucks of steam locos where it would be very difficult to find enough room for the drop arm. This photo shows the delay bar very clearly.



To couple up the vehicles are simply pushed together.  One loop rides up above the other, the lower loop drops over the hook.  Because the loops are quite large diameter (0.7mm) and heavy the couplers do not suffer as badly as some other designs from "loop clash" where the two loops just ride up against each other.  Usually if these couplers have loop clash it is because one of the loops is not horizontal as it should be.



To uncouple, the two vehicles are positioned over the magnet which is activated (electromagnets) or lifted up (permanent magnets) pulling the drop arms downwards.  The vehicles are then drawn slightly apart (maybe 2mm) so that both loops are pulled fully upwards.



Still with the magnet activated, the vehicles are pushed back together.  The loops sit on top of the delay bars, preventing the two vehicles from recoupling.  They can now be propelled to wherever is needed and then will uncouple automatically. So you can shunt a whole fan of sidings with just a single uncoupling magnet at the throat.

These aren't as neat or clever as the DG / B&B finescale couplers with their lifting latches, but they are a lot less fiddly to set up.  The uncoupling "shuffle" will be familiar to anyone who has used knuckle couplers (MicroTrains or Dapol Easishunts).

Richard

Offline Newportnobby

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Re: New coupler development (was Coupling survey)
« Reply #237 on: April 01, 2018, 12:38:35 PM »
The loop has a drop arm underneath with a few turns of soft iron wire wound round the lower end

Thanks, Richard. In the first couple of pics I thought " ??? Where's that then?" but in the last 3 pics all became much clearer.

Online kirky

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Re: New coupler development (was Coupling survey)
« Reply #238 on: April 01, 2018, 05:43:31 PM »


A new addition to the test fleet.  I'm on the lookout for more "awkward" vehicles which might cause problems, and a long wheelbase van was high on the list.  This Dapol "Fruit D" turned up unboxed at a fair price. It is the first successful conversion I have done of a wagon with NEM coupler pockets.  The chassis has some very clever spring-loaded pivoting devices to allow for sharp curves but these flapped about all over the place and I couldn't get a consistent height for the couplers, so in the end I put a small nut and bolt through them to lock them up solid.  I also moved them inwards on their mounts for closer coupling. It works fine although the Impossible Siding (Setrack no 2 reverse curve) proved too much for it, buffer locked with the loco and derailed. 

Next on the awkward list is a four wheeled parcels van with long overhangs, either a CCT or PMV.  They seem a bit hard to find at the moment.

Richard

Hi Richard
Thanks for the explanation of how things work. Its all looking very exciting.
Just a question about using the NEM pocket. I think elsewhere you said it was possible to revert back to standard Elsie Rapido couplings after using your Magpie coupler. Just to confirm, this was a 'plug n play' fitting? ie it can be removed and the original coupling used? Just wondering if having to secure the Dapol swinging pocket has made the conversion permanent?
Thanks
Kirky
« Last Edit: April 01, 2018, 05:47:24 PM by kirky »
Northallerton is in the August 2018 edition of Raiway Modeller

and in real life at the Normanton and Pontefract exhibition. New College, Park Lane, Pontefract. 26/27th January 2019



Layout: Northallerton: http://www.ngaugeforum.co.uk/SMFN/index.php?topic=1671.msg16930#msg16930

www.northallertonngauge.co.uk

Cleveland Model Railway club website: www.clevelandmrc.club

Offline belstone

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Re: New coupler development (was Coupling survey)
« Reply #239 on: April 01, 2018, 06:30:50 PM »

Just a question about using the NEM pocket. I think elsewhere you said it was possible to revert back to standard Elsie Rapido couplings after using your Magpie coupler. Just to confirm, this was a 'plug n play' fitting? ie it can be removed and the original coupling used? Just wondering if having to secure the Dapol swinging pocket has made the conversion permanent?
Thanks
Kirky

In this case, yes.  The nuts and bolts can be removed leaving just a small hole in the underframe behind the coupler pocket.  However, the implementation of NEM coupler standards by Farish and Dapol is frankly disgraceful, and there will be many vehicles where the only solution is to remove the NEM pockets altogether.  In some cases these just clip on and can be retained for refitting.  Locos tend to actually be easier as there is no lifting loop to worry about and the pockets are not generally designed to move around, I should think most of them will be plug-in conversion with no problems.

Richard

 

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