Mk. II Frame take offs - with microswitch/interlocking?

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William A
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Mk. II Frame take offs - with microswitch/interlocking?

Postby William A » Tue Jul 19, 2022 9:12 am

I'm looking to use the society lever frames to handle signal and turnout actuation mechanically on my layout. I would like to use the built-in microswitch option and lastly, I would like to fit a locking frame at a later date.

Base
The instructions for the lever frame point to a 55mm square wooden base. Instructions for the locking say that a wooden base is required and details will be 'in the notes' but doesn't say any more about it. Is the 55mm square base sufficient for the locking frame to mount to the front with clearance?

Take-offs
Reading the instructions for the frame, it suggests that the upper take-off clevis supplied with the lever frame kit is superseded if you employ the locking frame. The suggested construction is to solder the take-off to the pin in the lever, so what is the process if one wants to add the locking frame at a later date?

It looks like the use of the microswitches precludes the use of the lower take-off clevis.

My assumption is I can use a 55mm base and it should provide clearance to the frame at a later date, and that I should use a soldered pin on the lever's top take-off, which the basic clevis is sprung over. When the time comes to fit the interlocking frame, this clevis is removed and the locking connection sprung over in its place. Is that correct?

Last question - can anyone tell me the relative heights of the take-offs from the base of the lever frame? I need to make sure i'll have clearance under the surface of my baseboards! :)

Thank you!

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Julian Roberts
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Re: Mk. II Frame take offs - with microswitch/interlocking?

Postby Julian Roberts » Wed Jul 20, 2022 2:59 pm

Hi William I'm watching your thread with interest as I will also be making mine, hopefully this year, and will give my answers to your questions if no one else has. Meanwhile Martin Wynne posted this useful video by James Walters a few weeks ago though I haven't checked how far it answers your specific points.

viewtopic.php?t=8081#p91211

JFS
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Re: Mk. II Frame take offs - with microswitch/interlocking?

Postby JFS » Wed Jul 20, 2022 4:55 pm

Hello William,

Horse's Mouth here!

(edited to remove incorrect reference to video in Julians post)

In answer to your question, the 55mm square timber suits both the locking and the frame with switches - the reference to "in the notes" should really say "in the notes for the lever frame"

This dagram shows the arrangement and from it you can see that there is a fair latitude in the size. In this case, the timber is 50mm wide but only 35mm deep - you can see that the bracket supporting the locking extends slightly below the bottom of the timber. However, you can see that a piece 50mm x 40mm would actually suffice. The important thing is to find a piece which is well seasoned, straight and knot free - not as easy as it used to be and secondhand timber is usually best!

Dimensioned sketch.jpg
Dimensioned sketch.jpg (154.97 KiB) Viewed 1128 times


I supose I also should do a video - the only one I can offer so far is this one - intended to show just how easy it is to roll the quadrant plate!



Hope that helps and please continue to post - it will encourage others to have a go!

(also etided for spilling mistooks ;) )

Best Wishes,
Last edited by JFS on Wed Jul 20, 2022 5:42 pm, edited 2 times in total.

James Walters
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Re: Mk. II Frame take offs - with microswitch/interlocking?

Postby James Walters » Wed Jul 20, 2022 5:35 pm

Hi Wiliam,

For clarity, my video which you reference above does show a Mk 2 frame.

In an attempt to answer your questions, I've just measured mine and the centre-line of the top take-off from the base is approximately 37mm.
Lever Frame.jpg


The lower take-off is approximately 3mm up from the base. (I couldn't measure it accurately how I have it set-up at the moment)

If I have understood the instructions correctly, then the Drive Cam of the locking kit provides for a lead-off to a mechanically controlled point/signal.
I should imagine that in practice, if you were to retrofit the locking at a later stage it would be a simple matter to swap these parts over.
I would add that it might be best to incorporate some means of adjustment in the length of your control wire should the Upper clevis and Drive Cam have different geometries. I hope that makes sense.
Better still might be to fit the Drive Cams for the locking at this stage and then fit the locking later, although that's harder to budget for. Ask me how I know. I will shortly be starting a 55 lever frame. :shock:

I don't think you would be able to use the lower clevis and microswitches together, and I can't immediately think why one would need to. Can you elaborate please?

I hope that's helpful,

James

JFS
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Re: Mk. II Frame take offs - with microswitch/interlocking?

Postby JFS » Wed Jul 20, 2022 6:18 pm

James, Many thanks for correcting my mis-information regarding your video - please accept my apologies and I have ammended my post to remove the offending untruth.

William, I agree with James that in principle, it should be possible to remove an upper clevis and substitute the locking drive cams - there should not be any real impact on the external geometry in so much as the stoke is the same, though there might be a minor impact since the clevis (in theory) will follow a slight arc whereas the drive cam follows a straight line.
However, I have never actually tried this process so you are somewhat on your own. The vital thing is that the locking drive pins (piano wire) must be fitted right from the start: it should then be possible to fit a clevis to this drive pin (without of course, trying to solder it!!). However, if these drive pins are not fitted right from the start, it is a lot of work remove all the levers to retrofit them.

You do seem to be wanting to keep all your options open and having all three methods in use on the same frame might be over complicating things. I would echo James' request for further details - in particular to amplify the point about "clearance under the surface of my baseboards" - could you provide a drawing of the issue please?

I suppose it might be possible to contrive some kind of stirrup to take a bottom lead-off each side of the microswitches, but I struggle to envisage any situation where such hard work was unavoidable. I have built half a dozen or so of these frames up to 70 levers long and I have never actually ever used the bottom take offs - in truth they were only provided for compatibility with the MkI frame. Equally, all the frames I have built have included locking - so the top drive take-off comes "for free" without the use of the stirrup.

My suggestion would be to try to plan everything out before you get too far in - that should enable you to close down a few degrees of freedom.

James suggests fitting the mechanics of the locking right from the start - even if you do not actually fit any of the locks. Although I appreciate that this is a lot of extra work and intial expense, James is correct that this is the best way if there is any likelyhood that you will subsequently lock the frame - and why would you not do so after all ... :D

Hope that helps ...

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Julian Roberts
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Re: Mk. II Frame take offs - with microswitch/interlocking?

Postby Julian Roberts » Thu Jul 21, 2022 2:53 pm

Thanks so much to both Howard and James, this will help me tremendously I'm sure.

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William A
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Re: Mk. II Frame take offs - with microswitch/interlocking?

Postby William A » Tue Jul 26, 2022 10:57 am

Thank you all!

To repeat what i've understood, the upper-take off is 37mm above the base of the frame, and the lever frame itself should be elevated 40mm to support the locking frame. Therefore, from the base of the support to the upper take off centreline should be 77mm, and to the top of the levers 175mm.

In my case I'm using 100m deep baseboards out of 6mm ply, so if the bottom of the frame support is in line with the bottom of the baseboard, this will leave 16mm between the upper take-off and the underside of the baseboard*, and the top of the levers will protrude above baseboard level by 75mm.

* This is what I meant about clearance under the baseboards.

I understand that with the piano-wire lugs soldered in the levers for the top take off, I should be able to remove the clevis and fit the locking cam at a later date - but it is recommended to fit the locking cams first. Since I can potentially retrofit the cam at a later date, the use of lower take-off and microswitch at the same time is moot.

Is there any way to obtain the locking cam etches without the rest of the frame? The lever layout itself is unlikely to change, but with 30+ levers that's a rather hefty chunk of change to spend upfront particularly since I have no idea how to set up the locking table and design the tappets and dog layout!

davebradwell
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Re: Mk. II Frame take offs - with microswitch/interlocking?

Postby davebradwell » Tue Jul 26, 2022 1:47 pm

Why not just drill some new hoes in the levers an appropriate distance above the pivots for your own convenience and arrange your own take-off? No point in getting tied up with other bits of the mechanism.

DaveB

JFS
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Re: Mk. II Frame take offs - with microswitch/interlocking?

Postby JFS » Tue Jul 26, 2022 6:37 pm

William A wrote:Is there any way to obtain the locking cam etches without the rest of the frame?


Unfortunately not as there is a degree of filing and fitting needed to get them working smoothly with the crossheads and guides - this can be done after the frame itself is complete, but the cams, crossheads and their guides must be built at the same time.

William A wrote:In my case I'm using 100m deep baseboards ... so if the bottom of the frame support is in line with the bottom of the baseboard, ...
* This is what I meant about clearance under the baseboards.


Not sure why the bottom of the frame support must be in line with the bottom of the baseboard? Most people who build the frame into the baseboards arrange for the top of the quadrant to be level with the top of the baseboard, or arrange things so that their mechanical drive take-off aligns with the underside of the baseboard surface. The wooden frame support does not need to stand on anything - it can be simply screwed to a vertical baseboard support member or facia.

Dave (Bradwell) is quite right that you are free to drill the levers to give you any needed flexibility in locating the take-off, and, although the rear guides would not line-up, this is by no means important as it would be easy to arrange an alternative. Doing it that way means that you do not need to muck about too much when you add the locking later. By the same token, you do not need to mount the micro switches as designed - on my own (25 lever) frame, they are mounted below the bottom of the levers driven off the locking tappets.

Still not sure I understand why you want micro switches and mechanical take-off? (I have both on my layout but that is for exhibition pruposes with very strange constraints!) Given that you will changing things when you add the locking, by far the easiest way would be to use microswitches and servos or similar to provide the mechanical motion for points and signals - that way you can position the frame anywhere you like - even in the next room given a suitable multi-way connection. It is very useful to be able to just unplug the frame for maintenance etc and this is what we do on John Elliott's Leeds City North layout with a total of 135 levers.

On my layout everything is done mechanically, which is very satisfying, but it involves a LOT of skilled work to make it all work with absolute dependability and unless you are very confident in your mechanical capabilities, an electrical transmission is much easier to make reliable.

I am not sure how far you are on with building your layout or if you have yet started with the lever frame, but if have not got very far yet, one thought might be to buy a fret of five levers and build it up - once you have a good idea of what the thing looks and feels like in real life, I am sure a lot of ideas will come to mind.

It might be for example, that if you have not yet fixed your basboard depth, a small change to the design may help. Equally, if the baseboards are all finished, being able to hold the finished frame against the baseboard will thow up solutions I am sure.

Best Wishes,


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