Cranks to operate level crossing gates under baseboard

[Captain Kernow]

I'd be grateful if anyone could point me in the right direction for some metal or plastic cranks, to which I could attach linkages to operate a 4mm level crossing, all installed under the baseboard, please?

 

Many thanks.

 

[31A]

Might these help?

 

https://www.wizardmodels.ltd/shop/tools/sm8/

 

[kevinlms]

Depends on how the gates work, most have 4 gates that operate at once. Others have 2 gates, where one moves, completes it's journey, then the 2nd gate moves!

[Michael Hodgson]

46 minutes ago, kevinlms said:

Depends on how the gates work, most have 4 gates that operate at once. Others have 2 gates, where one moves, completes it's journey, then the 2nd gate moves!

That's easy if you use two servos.  If you are looking on ebay for servos to operate it, note that they sometimes come with a coupld of cranks thrown in.  The easiest way to operate a gate from a servo is to extend the gate post through the baseboard and rotate that. 

Note that it means the gate post will rotate (unlike the prototype).  If you want the post to remain fixed, you need a crank under the post connect to the gate near its pivot.

 

4-gate crossings were often were worked from the signalbox using a gatewheel, these had complex linkages including cranks under the boarding. The mechanism was expensive both in capital cost and maintenance, so was only justified where road or rail traffic was frequent enough to warrant it.

 

The more common 2-gate crossings were usually hand-operated (two gates typically foul each other so have to be worked independently, whereas 4 gates usually don't), but of course you have the problem that you can't model a working crossing keeper pushing first one then the other.

[stewartingram]

How to make a crank?

Get bsome sheet material (plasticard or brass)

Cut in to suares, then halve them to make triangles.

Drill 3 holes.

 

Isn't modelling easier and cheaper if you do it yourself.....

[melmoth]

7 minutes ago, stewartingram said:

Isn't modelling easier and cheaper if you do it yourself.....

 

You were doing so well until what seems like the gratuitous sarcasm here. 

[GrumpyPenguin]

21 minutes ago, stewartingram said:

How to make a crank?

Get bsome sheet material (plasticard or brass)

Cut in to suares, then halve them to make triangles.

Drill 3 holes.

 

Isn't modelling easier and cheaper if you do it yourself.....

At the price of the cranks (available from any model stop that sell R/C models) it really is not worth the saving, especially as the ready made cranks come with bearings.

[Izzy]

2 hours ago, Captain Kernow said:

I'd be grateful if anyone could point me in the right direction for some metal or plastic cranks, to which I could attach linkages to operate a 4mm level crossing, all installed under the baseboard, please?

 

Many thanks.

 

Could I ask if this is for a pair of gates, and whether you already have a design to work them. It’s just that I think you will need cranks with a large throw to get reasonable speed movement, not too fast, and especially if they are to be worked mechanically and/or by hand rather than servos. The late John Watson’s design is a good one to use, which I have in 2mm. Just involves a fair bit of DIY.

 

Bob

[Captain Kernow]

Just to summarise and thanks for the suggestions, this is for a 4 gate, double track level crossing, operated from the adjacent signal box.

 

They will be servo operated, provided I can understand how to set up and wire up the things. I've never been able to understand servos, despite many patient explanations from many learned people. 

 

And finally, a polite warning - anyone who tells me, 'it's easy', will be struck off my Christmas card list!!

 

Edited March 10 by Captain Kernow

[ikcdab]

This is how I did it. Just four servos connected directly though the baseboard to the gates.  You don't need cranks. All connected to a merg servo4 board.  Programmed to give me bounce too. If you would like some of the servo mounts, I am happy to send you some foc.

 

Ian

[Michael Hodgson]

57 minutes ago, Captain Kernow said:

And finally, a polite warning - anyone who tells me, 'it's easy', will be struck off my Christmas card list!!

 

Actually there was a mechanism on the market that did make it easy but unfortunately it no longer seems to be available.  From memory I think the supplier was Frizinghall Model Railways, though I could be mistaken about that - it was a long time ago. 

 

Essentially it's a flat square box that sits below the baseboard, containing a number of contra-rotating gears arranged so that a square post could be stuck into the 4 square holes for extended gate posts, and all you had to do was rotate one and the other three would follow via these gears.  You glued an Airfix crossing gate to each of these posts.

 

I can see no reason in principle why a copy of this should be beyond the abilities of those who know how to use 3d printers, and the whole thing worked by  a single servo.

 

But until somebody does, I agree with the recommendation of 4 servos controlled by the MERG servo4 board (available to MERG members only, as kit 75a for £7.58)

[Michael Hodgson]

3 hours ago, melmoth said:

 

You were doing so well until what seems like the gratuitous sarcasm here. 

 

Railway modelling has something of a reputation for attracting cranks ! 😄

[Captain Kernow]

3 hours ago, ikcdab said:

This is how I did it. Just four servos connected directly though the baseboard to the gates.  You don't need cranks. All connected to a merg servo4 board.  Programmed to give me bounce too. If you would like some of the servo mounts, I am happy to send you some foc.

 

 

3 hours ago, Michael Hodgson said:

But until somebody does, I agree with the recommendation of 4 servos controlled by the MERG servo4 board (available to MERG members only, as kit 75a for £7.58)

Thank you both.

 

The gates in question are MSE whitemetal onces, to which a piece of brass rod (approx 2mm diameter) has been attached at the base and it is this brass rod which will descend through matching brass tubes to the underside of the baseboard, where the servo activity is to take place.

 

Thanks for the kind offer to send me some servo mounts, Ian. I do have the necessary servos, mounts and other alchemy, bought at a show a couple of years ago, so hopefully these will suffice, but I am struggling to see how the servo can be directly attached to my brass rods?...

 

[ikcdab]

8 minutes ago, Captain Kernow said:

 

 

Thank you both.

 

The gates in question are MSE whitemetal onces, to which a piece of brass rod (approx 2mm diameter) has been attached at the base and it is this brass rod which will descend through matching brass tubes to the underside of the baseboard, where the servo activity is to take place.

 

Thanks for the kind offer to send me some servo mounts, Ian. I do have the necessary servos, mounts and other alchemy, bought at a show a couple of years ago, so hopefully these will suffice, but I am struggling to see how the servo can be directly attached to my brass rods?...

 

Hi Tim, does the attached photo help. My gates are also the MSE whitemetal ones and I also attached brass rod to the gate and through a tube in the baseboard. Though i think my brass rod was probably 1mm or 1.5mm. 

I then made the brass fittings seen in the pic. 

I epoxied a piece of brass tube into the recess in the top of the servo horn. The rod from the gate simply slides into that brass tube. The collar at the top is there so that i could drill and tap for a grub screw to hold the gate rod.

It needed a bit of space to accommodate the fitting, hence i made the servo mounts which you can see.

Here is a better pic and below is a diagram.

Hope that helps. I'm not sure where you are, but if you're passing through Taunton, pop in and have a look.

Ian

 

 

 

[ikcdab]

here is a better diagram that I have just found.....

 

[Mainlinefreighter58]

5 hours ago, ikcdab said:

This is how I did it. Just four servos connected directly though the baseboard to the gates.  You don't need cranks. All connected to a merg servo4 board.  Programmed to give me bounce too. If you would like some of the servo mounts, I am happy to send you some foc.

 

Ian

could this eventually be programmed to operate automatically when the train approaches?

[ikcdab]

6 minutes ago, Mainlinefreighter58 said:

could this eventually be programmed to operate automatically when the train approaches?

yes of course, but i don't know how to do it. I guess you could use a reed switch or infra red sensor of some sort fairly easily.

However, even on my fairly lengthy continuous run, the gates would be constantly on the move. What is more important to me is a section that is dead when the gates are across the line such that the trains stop and don't crash into them. I have the facility to do this, I just havent implemented it yet.

[BroadLeaves]

3 hours ago, Captain Kernow said:

it is this brass rod which will descend through matching brass tubes to the underside of the baseboard, where the servo activity is to take place.

Similar to @ikcdab 's solution, assuming you can mount the servo so that the servo axle is pointing up and you can mount it directly under the brass rod, you can cut the plastic away from a mains screw terminal connector block leaving just the brass insert and glue one end of that insert either to the servo's horn or to the axle itself, so that the "tube" of the insert is vertical, and then feed the brass rod from the gate down into the tube, (i.e. where the wire would go if you were using the connector as an electrical connector) and secure it with the screw that would secure the wire.

That means you can slacken off the screw, reposition the gate slightly and tighten the screw again, which will be much easier than repositioning the servo mount or messing around programming limit angles on the servo controller.

[nick_bastable]

may give a few ideas

 

 

[Captain Kernow]

11 hours ago, BroadLeaves said:

you can cut the plastic away from a mains screw terminal connector block leaving just the brass insert 

Interestingly, my plans featured just this very thing, although I hadn't got so far as to work out exactly where it would be positioned.

 

[Captain Kernow]

Upon reflection, I honestly don't really know why I am motorising these gates in the first place. It would be operationally much easier to just leave them closed to road traffic, as they are located right where the double track emerges from the fiddle yard...

 

On Bleakhouse Road, I have two sets of manually operated gates (both operated by linkages under the board) and completely non-interlocked with anything else. In other words, the operator has to check the position of the gates each time.

 

Once, at a show, one of my operators forgot to check and ran the train straight into the gates. These feature MSE whitemetal frames and scratchbuilt Evergreen strip 'innards', which took a Saturday morning to rebuild...

 

But I will motorise the double gates (on Callow Lane), so thanks for the continuing suggestions and information!

 

[Compound2632]

On 11/03/2024 at 09:43, Captain Kernow said:

Upon reflection, I honestly don't really know why I am motorising these gates in the first place. It would be operationally much easier to just leave them closed to road traffic, as they are located right where the double track emerges from the fiddle yard...

 

With you there! Wasn't closed to the road the default position of level crossing gates from the earliest times until the triumph of the infernal combustion engine?

 

On 11/03/2024 at 09:43, Captain Kernow said:

Once, at a show, one of my operators forgot to check and ran the train straight into the gates. These feature MSE whitemetal frames and scratchbuilt Evergreen strip 'innards', which took a Saturday morning to rebuild...

 

Isn't that a piece of entirely prototypical operation? The real thing had spare gates ready to hand to cover such incidents...