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Author Topic: New coupler development (was Coupling survey)  (Read 30462 times)

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Offline Howlin`baz

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Re: Coupling survey
« Reply #75 on: June 16, 2014, 05:07:46 PM »
Yes - that looks very good.   Are the pockrts flexible enough to accept the strain of curves?   If so, I will be putting an order in . . .

Offline Karhedron

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Re: Coupling survey
« Reply #76 on: June 16, 2014, 06:57:37 PM »
For bogie mounted stock there is no strain as the bogies pivot around the curves. I haven't tried it on fixed wheelbase stock but I can't imagine it having a problem.
Well, that's just not good enough. Some fount of all knowledge you are!  :no:  ;)

Offline belstone

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Re: Coupling survey
« Reply #77 on: June 22, 2014, 02:01:02 PM »
Short update: I have spent most of the morning trying to teach myself how to use a CAD program to design coupling hooks.  I'm a slow learner, but now I've got the hang of it I should be able to get a design ready for etching shortly.  Currently having lots of fun plotting the arcs of the moving bits and checking there is enough clearance for it all to work properly.

I'm also getting a better understanding of why the design works so well, which was a bit of a mystery to me when I built the first couple.  It looks like accurate positioning over the uncoupling magnet will be important, and the shorter and more powerful the magnet, the better.  It will be interesting to try it with an under-track electromagnet.

Hoping to have the first test etch done and testing under way in the next couple of weeks - then I'll know whether this is ever going to be a viable product.

Offline Caz

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Re: Coupling survey
« Reply #78 on: June 22, 2014, 04:20:29 PM »
More and more intriguing, really looking forward to see what you have come up with.   :)

Offline Newportnobby

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Re: Coupling survey
« Reply #79 on: June 22, 2014, 05:41:02 PM »
Me too - sounds like a most exciting development and I hope all goes well during testing :thumbsup:

Offline DodgerB

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Re: Coupling survey
« Reply #80 on: July 21, 2014, 04:27:55 PM »
any update?! I'm currently struggling through with starting on MBDs, and can certainly see the potential.

however, it would be a pain fitting each one, and involve a lot of butchering.

Not something I really want to get involved with for new 100+ farish steamers :S

Plus with the flat-plate attachement to the wagon/loco getting each height the same isn't ideal :S.

If your couplers fitted in the standard nem/hole pockets that would be great.
I would personally be happy to glue "filler" bits in the bottom of some pockets if they were the wrong height. I would also be happy to glue it in place - provided no other big butchering was required.
 
A big annoyance with the MBDs is that they decided to put a hole in the middle of the wagon-attachment plate. If they had just left it solid it would give me the option of filing the edge away instead, if it happens to be better to joing it with a long thing piece in the middle.
But you can't join much with a long thin hole!

So if your system had a bit of flexibility in it that would be fab!
Without being so adaptable it looks like a duckbilled platypus of course.
« Last Edit: July 21, 2014, 04:34:39 PM by DodgerB »

Offline belstone

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Re: Coupling survey
« Reply #81 on: July 21, 2014, 06:23:52 PM »
any update?! I'm currently struggling through with starting on MBDs, and can certainly see the potential.


The coupler project has run into a couple of snags.  Firstly, teaching myself CAD via the internet has proved a bit more difficult than I thought. It took me three days to work out how to draw a straight line of a given length. I'm nearly there but still a couple of glitches to sort out in the drawing before it can be turned into an etched fret.

The second snag? Boris.



Nearly thirteen years since I last had a puppy and I had forgotten how much time they take up. Hopefully I'll be able to get the drawing finished this week, after that things should start moving again.

Richard

Offline Jerry Howlett

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Re: Coupling survey
« Reply #82 on: July 30, 2014, 09:21:43 AM »
Thats a "play with me daddy" face, chap or chappess ?

Jerry
Some days its just not worth gnawing through the straps.

Offline belstone

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Re: Coupling survey
« Reply #83 on: August 04, 2014, 10:30:26 AM »
First test etches arrived this morning and look exactly like what I thought I had drawn on the computer which is a promising start.  If the basset puppy gives me a few minutes of peace this evening I'll try building up a few couplings and see what happens. He woke me up at 1.30am in the hope of playing some biting games.

Offline Caz

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Re: Coupling survey
« Reply #84 on: August 04, 2014, 01:54:24 PM »
The suspense is killing, dying to see what you've come up with.   :)

Offline belstone

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Re: Coupling survey
« Reply #85 on: August 11, 2014, 10:02:17 AM »
Progress report....

Yesterday I finally got round to building up a handful of couplers and fitting them to vehicles.  They go together pretty much exactly as I hoped and the NEM-pattern ones clip into the coupler boxes with a little bit of fettling.  I'm getting down to around 15 minutes per pair to build, fit and adjust. Then the problems started.

I only had one loco with unmodified NEM pockets, a Farish Ivatt 2MT which I hadn't run for any length of time.  It turned out to have pickup issues making slow speed control impossible. I also had problems with the couplers failing to uncouple reliably which I am still working on.  The length and angle of the drop arm are critical as is the length of the under-track bar magnet, which needs to be very short so that it pulls the drop arms towards each other with the vehicles positioned centrally over the magnet.  And I screwed up the dimensions of the bar bending jig on the etched fret but that is easy enough to fix. I also had problems with the coupler bars getting snarled up with each other, but I think I have a simple fix for that.

I'm now building up a few more couplers so I can fit them to one of my reliable locos (a J39) and a couple of coaches. I also need to play around with magnets of various kinds - under track magnets are all very well, but not so good if you have already laid and ballasted your track. I bought a Peco electromagnetic uncoupler but it doesn't seem very powerful. I don't seem to have had much luck so far finding a supplier of magnets in various sizes at a sensible price - I am using B&Q cupboard catch magnets cut in half at the moment but I really need something that fits between the rails and sits level with the top of the sleepers.

I didn't have my camera with me at home so no photos yet, but I'll try to take a few this evening. Some of you may be disappointed when I do - there is nothing exotic or sophisticated about this coupler, it is just a boring old tension-lock with a fixed hook, Sprat and Winkle style delay post and a single-sided lifting loop operated by a dropper arm with a bit of steel tube stuck on the end.  The phrase "tension-lock" will probably put off about half of you but they are going to be pretty inexpensive - target price is 15 for 10 pairs. I know the B&B / DG couplers are a lot cheaper than that, but ever tried assembling one? Watchmaking is easy in comparison.

More to follow when I have some pictures.

Offline Malc

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Re: Coupling survey
« Reply #86 on: August 11, 2014, 10:08:47 AM »
I'm not sure if life is passing me by, or trying to run me over.

Offline belstone

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Re: Coupling survey
« Reply #87 on: August 11, 2014, 10:41:48 AM »
If you want a small powerful magnet, try a rare earth one .ie http://www.ebay.co.uk/itm/20-x-Strong-Round-Magnet-5mm-x-2mm-Disc-Rare-Earth-Neodymium-N35-Grade-/370846166861?pt=LH_DefaultDomain_3&hash=item5658276f4d


Thanks for that. I quickly found a UK supplier and have now ordered disc and bar magnets in several sizes. 

Offline belstone

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Re: Coupling survey
« Reply #88 on: August 12, 2014, 11:12:57 AM »
As promised a few photos.  Please remember this is still very much a work in progress and I am a fair way off being able to say whether this is a viable design, but a lot of you have been very helpful with your input and views and it seems only fair that I should keep everyone up to date.



Raw materials - the etched fret, some plastic strip, copper jewellery pins and a handful of hooks bent up and attached to shanks.  The fixed plastic shank makes them easy to fit whether you have Rapido pockets, NEM pockets or (scratch and kit built vehicles) no pockets at all.



Completed (but unpainted) NEM clip-fit coupler, cruelly enlarged. The bar on this one is the wrong shape - I have since added a short bend at the end to stop the bars getting tangled up.





Coupler fitted to a Farish horsebox.  You'll have to take my word that it looks less ugly and obtrusive in reality than in the photos. Any N gauge coupler is going to be a compromise between appearance, reliability and ease of assembly/fitting.  This particular design is very much biased towards operation at the expense of appearance - which is what the survey suggested most people wanted. I'm going to look into having the etches chemically blackened which should help. I might also rework the design a little and slim down the delay bar - it doesn't need to be as thick as it is. And I think I'll have to redesign the hook slightly to reduce the risk of self-uncoupling over the magnets - it isn't quite 'hooky' enough on this first version.  Good thing I only had two frets made...

Magnets should be here tomorrow - then I can start to play properly on a real layout.

Offline Caz

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Re: Coupling survey
« Reply #89 on: August 12, 2014, 02:24:41 PM »
Interesting, looking forward to seeing the live tests and how well the delayed action works.   :thumbsup:

 

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