Lever Frames

[The_Prisoner]

I need to carry out a small survey:

How many of you are using the lever frames from Ambis Engineering, MSE, Modratec, or SHAG?

Are you using any form of mechanical interlocking?

Finally, does anyone else market a similar product?

(I have also asked this on E4um)

Peter

[grovenor-2685]

The SHAG version is now the Scalefour Stores version.
Mike Clark also offers a lever frame on his Masokits label.
Older, maybe not similar enough, is the GEM lever frame, which I am still using for yard points, without interlocking.
Regards
Keith

[Tim V]

Scratchbuilt mine, with mechanical locking, and electric release on two levers.

Over 20 years old, no sign of wear.

[Russ Elliott]

Peter - may we ask why you "need to carry out" this survey"?

[Tim V]

Something Number 2 dreamt up.

[Alan Turner]

AMBIS do one as well.

Alan

[Pannier Tank]

Brassmasters also do a lever frame.

[AUllyott]

Have a S4 (SHAG) one on Wheal Elizabeth. No problems in building and has done 20 odd shows with no problems. Mechanically linked to DPDT slide switches to change feed polarity for tortoise motors.

[barhamd]

Using a SHAG frame on my layout, 20 levers with electric interlocking via servos.

Only issue is getting a decent joint between the steel handles and the nickel silver levers, every now and again I seem to have to resolder the joint.

David Barham

[Pannier Tank]

Only issue is getting a decent joint between the steel handles and the nickel silver levers, every now and again I seem to have to resolder the joint.

David Barham

Could you Braze / silver solder the joint?

[The_Prisoner]

To answer the "why are you asking/" question:

I'm developing a small electronic circuit board to link directly to the bottom of the levers and produce the necessary pulses to drive cheap radio-control servos to operate points and signals. I'm trying to find out which lever frames are the most popular, then follow up with some dimensional questions on lever pitch and throw (the manufacturers don't always seem to know the answers).

I hope to be able to sell bare circuit boards and assembled units, but I doubt I'll ever get rich on it.

I was hoping for a "one size fits all" but I already know that the Modratec lever pitch is less than MSE's so that may not be possible. For the record, I know of the Ambis and SHAG versions also.

So, if you have a lever frame, please answer the following:

1. What make?
2. What is the lever pitch?
3. What extra space is required if you put two banks of levers side-by-sise?
4. What is the maximum throw (i.e. last hole out) of the levers as supplied?

The original interlocking question was just to find out the level of interest in that - definitely non-commercial.

Off to investigate the others - GEM discounted.

[Mark Tatlow]

For my part I am a user of the SHAG/Scalefour Society levers and like them a lot. Except early on, I do not have a problem with the heads of the levers coming off but I solder these on with 245 degree solder and a lot of heat right at the outset of the build so that they are really well secured.

I also have a 13 lever MSE version which I extended to 14 levers. I have to say it is a bit sloppy and when I tried to use it with microswitches they sometimes slipped between the levers. I solved this by using slide DPDT switches but if you were considering coming up with something that was compatible with the MSE version then you may need to accommodate this trait. It is a lot less of a problem with the Society version.

I might well be interested in a servo driver that was added to be integral with the lever frame, subject to it being sufficiently simple and robust as well as having the right features (programmability for bouncing signals being one).

I have seen David Barham's article on his interlocking frame in MERG's mag and had thought about doing soemthing similar but then thought it was probably a complication beyond my inclinations! I take it you have seen this? The point of his approach is that it used with a further set of servos to lock the levers so not only did they not work the turnout/signal, they were physically held until released.

[newport_rod]

I intend to build an interlocked frame for our club's 7mm (spit) layout and have purchased a SHAG kit as a start point. I too had seen the article in the MERG but was still thinking in terms of mechanical interlocking.
Rod

[Russ Elliott]

The point of his approach is that it used with a further set of servos to lock the levers so not only did they not work the turnout/signal, they were physically held until released.

Yep. My thoughts were about some kind of wedge-shaped actuator (solenoid-driven?) that could do the mechanical locking, whilst external configurable logic (cheap diodes and gates) could do the decision-making process according to the locking chart. It's not the Tim V 'full-monty' of course, but an approach that recognises that most people's track plans will evolve and change.

lever-locker.png (2.99 KiB) Viewed 1752 times

[nigelcliffe]

The point of his approach is that it used with a further set of servos to lock the levers so not only did they not work the turnout/signal, they were physically held until released.

Yep. My thoughts were about some kind of wedge-shaped actuator (solenoid-driven?) that could do the mechanical locking, whilst external configurable logic (cheap diodes and gates) could do the decision-making process according to the locking chart. It's not the Tim V 'full-monty' of course, but an approach that recognises that most people's track plans will evolve and change.

lever-locker.png

I originally started with a method similar to the one you have drawn.

David's method uses the top of a narrow (2.5g) servo, fitted with a tube with a slot cut in it. This is fitted directly below the base of the lever (slightly extended in his design). The servo rotates the tube through about 90 degrees. With the two slots in line with the bottom of the turnout lever, the lever can pass through the slots. With the tube rotated, the slots become "walls" and stop the lever moving.

The "logic" can be done with whatever method you find most convinient. I'm quite happy with a computer running software. But one does not need "big computers" to do the relatively simple interlocking logic, and a small microprocessor (eg. PIC) or descrete logic gates (AND, OR, NOT, etc), or some diodes and relays could do the job.


- Nigel

[paultownsend]

1. What make?
2. What is the lever pitch?
3. What extra space is required if you put two banks of levers side-by-sise?
4. What is the maximum throw (i.e. last hole out) of the levers as supplied?

The original interlocking question was just to find out the level of interest in that - definitely non-commercial.

1. Shag/ S4
2. 10mm
3. none
4. approx 5mm. I can measure more precisely if you need it but will need to unmount it to do so.

I would be interested in your PCB for a 15 way assembly.

[grovenor-2685]

Peter,
I don't see where this PCB fits in, to operate servos and provide simple adjustment of speed, end positions, bounce etc you are going to need a PIC or similar. MERG already has cheap boards designed, proven and available as kits that will do exactly this and can be controlled by the microswitches that many of the lever frames, certainly the SHAG one, already have designed in provision for.
But of coure, if designing PCBs is what you want to do, go for it.
Russ,
DavidB's rotating servos do exactly what your proposed solenoid would do, but IMHO are simpler to assemble and easier to control with available electronics and software.
Regards
Keith

[Pannier Tank]

I intend to build an interlocked frame for our club's 7mm (spit) layout and have purchased a SHAG kit as a start point. I too had seen the article in the MERG but was still thinking in terms of mechanical interlocking.
Rod

I thoroughly recommend http://www.noodlebooks.co.uk/product/view/2050 it covers mechanical interlocking and makes interesting reading.

[John Bateson]

Amazon - £12.25 - 3 left only
John

[andrew jukes]

I'm planning (eventually) to have a lever frame at Welwyn North as a local alternative to the screen-based whole-layout control of my layout. The idea is to have (probably) a SHAG frame fitted with microswitches giving simple normal/reversed one bit inputs to the Merg RPC bus used for everything on the layout, and then to have one bit outputs from the RPC bus for locking each lever. I have so far been picturing using low current solenoids and some clever mechanical lock (perhaps like Russ's drawing). It would mean having quite a few solenoids normally 'on' but provided the solenoids only involve 20mA or so (the sort of current that would allow direct connection to an RPC output), that would seem to be OK.

Going to servos for this use sounds like quite a lot more complication for little gain (always assuming I can make my approach work!).

The Merg article on a locking lever frame, so far as I can recall, seemed to involve locking and unlocking the whole frame, which didn't feel right at all.

My locking is all in software - I can't imagine doing it any other way on a large and evolving layout.

Andrew

[grovenor-2685]

The Merg article on a locking lever frame, so far as I can recall, seemed to involve locking and unlocking the whole frame, which didn't feel right at all.

That was another one, look for the recent article by David Barham, Winter 2011 Journal.

Also discussed here for those not in MERG.
Keith

[barhamd]

A better description of the servo based locking system which locks individual levers is in a more recent blog entry http://www.rmweb.co.uk/community/index.php?/blog/186/entry-6813-fun-with-servo-based-interlocked-lever-frame/

David

[Pannier Tank]

Scale Signal Supply also do a Lever Frame.

[Easterner]

I have looked at many types and I feel the SHAG one is the best around - Does anybody know when it is due back in stock?

[paultownsend]

I have looked at many types and I feel the SHAG one is the best around - Does anybody know when it is due back in stock?

I asked about restock time a few days ago and was informed that Jeremy is awaiting the springs, and we should watch the S4 website for an announcement.

Perhaps the bod who sees it first could copy to here!