Couplings - a different take

Do you have a problem? Here is the place to appeal for help
Post Reply
User avatar
philipy
Moderator
Moderator
Posts: 5033
Joined: Sun Jan 30, 2011 3:00 pm
Location: South Northants

Couplings - a different take

Post by philipy » Thu Aug 23, 2018 2:25 pm

Inspired by Rik's Couplings' thread and influenced by Tom's work on the subject of magnetically operated ones, I decided to experiment with combining the two idea's.

I started by making and fitting brass 'loops' and then attaching P/B hooks, as per the diagram on Riks thread, and all that worked fine.
DSC_0001.JPG
DSC_0001.JPG (225.73 KiB) Viewed 1462 times
I then tried fixing soft iron droppers to the hooks for magnetic uncoupling, similar to Tom's system. However the Accucraft choppers are hinged and working under gravity and less sensitive to the position and weight of the dropper once the actual shape/position was sorted out. I found it next to impossible to get the P/B springy hook to pull down properly. Position the dropper too high and it doesn't move, too low and it gets stuck on the magnet. I should say at this point that I have N50 grade, 60x8x5mm Neodymium bar magnets.

Thinking again about the Accucraft version, I dispensed with the loops and soldered to the hook to a short piece of brass tub, running on an axle in a piece of ali channel fixed to the u/s of the wagon. The weight of the dropper pulls the hook down, so this is counterbalanced by a small weight at the other end to return the hook to its 'normal' position.
DSC_0002.JPG
DSC_0002.JPG (210.33 KiB) Viewed 1462 times
I kind of went for broke and formed the hooks as Alex Jackson hooks, but slightly larger. This all more or less works, to my surprise, but there are 2 drawbacks at present: (1) Its all a bit fiddly and labour intensive to manufacture(2) Again the magnets pull the hooks down every time they pass ( I always used under track solenoids with 4mm AJ's in the past, and you only energise the one you want, for as long as you want).

I then tried another experiment, going back the Riks original hook & loop system. I remembered my previous comment that Rik's picture looked a bit like an AJ hook I so I shaped my hooks like reversed AJ's, with the top section pointing backwards like Riks and the bottom section pointing forward ( A true AJ has the top section pointing forward and the bottom pointing backwards), but with the two sections angled 45deg and 30deg sideways respectively. This means that they will still couple to Rik's loops, but at the same time will function as automatic coupling/delayed uncoupling, when paired.
Please ignore the orange wire! It's just there to create a restraining loop to stop the dropper gluing itself to the magnet. Seems to work OK and a decent version might solve the other similar problems I had.
DSC_0004.JPG
DSC_0004.JPG (214.12 KiB) Viewed 1462 times
DSC_0007.JPG
DSC_0007.JPG (229.36 KiB) Viewed 1462 times
Having done all this, like Rik, I don't really think its worth progressing much further. It might be if solenoids were viable, but outdoors I don't think the potential electrical problems are worth it.
Philip

User avatar
tom_tom_go
Driver
Driver
Posts: 4824
Joined: Wed Feb 23, 2011 3:08 am
Location: Kent, UK
Contact:

Re: Couplings - a different take

Post by tom_tom_go » Thu Aug 23, 2018 4:47 pm

Like Rik's efforts I appreciate the time spent on this.

I also debated using powered magnets but neodymium magnets are so strong I didn't see the point.

Post Reply

Who is online

Users browsing this forum: No registered users and 5 guests