Mk2 Lever Frame , Dimensions

Discussions of the prototypes and how to model them. Show us how you do it.
junctionmad
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Joined: Tue Dec 08, 2015 3:38 pm

Re: Mk2 Lever Frame , Dimensions

Postby junctionmad » Thu Jun 21, 2018 9:45 am

PS: can the catch handles be electrically detected ?

JFS
Posts: 561
Joined: Wed Dec 16, 2009 3:47 pm

Re: Mk2 Lever Frame , Dimensions

Postby JFS » Thu Jun 21, 2018 4:13 pm

junctionmad wrote:PS: can the catch handles be electrically detected ?


Hi Dave,

There is no provision in the kit for doing this (needless to say!), however, I did have a look at it, and the easiest way is to mount a microswitch on the lever itself and connect it via extra flexible instrument wire. To do that would require a small bracket making which would be an easy enough scratch build job, though I could look into getting some etched - bearing in mind of course that one-off etching is not cheap!

An alternative would be to design a cam to attach to the microswitch arm to follow the swing of the lever and detect the position of the catch rod. This would allow the switch to be rigidly mounted but is a bit more of a design challenge.

The bottom line might be that either of the above solutions would be more trouble than they are worth.

I would mention that when I first looked into designs for lever frames I did consider catch-handle locking and worked out a design for it. But the job foundered on the difficulty of making a catch handle robust enough to resist a full-sized finger when locked

Best wishes,

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Colin Parks
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Re: Mk2 Lever Frame , Dimensions

Postby Colin Parks » Thu Jun 21, 2018 5:45 pm

Re, locking the lever catches, what about just using a scale version of those metal 'egg cup' thingies that can be slipped over the lever handles, thus preventing the catch handle from being moved? It is not very hi-tech perhaps, but they use this method on the local preserved line, the Gwili Railway, in their ex - GWR signal box.

Colin

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grovenor-2685
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Re: Mk2 Lever Frame , Dimensions

Postby grovenor-2685 » Thu Jun 21, 2018 7:05 pm

Colin Parks wrote:Re, locking the lever catches, what about just using a scale version of those metal 'egg cup' thingies that can be slipped over the lever handles, thus preventing the catch handle from being moved? It is not very hi-tech perhaps, but they use this method on the local preserved line, the Gwili Railway, in their ex - GWR signal box.

Colin

You can have those (lever collars) Colin, but they serve a completely different purpose, ie to allow a block or possession to be applied. Nothing to do with the interlocking.
Regards

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Colin Parks
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Re: Mk2 Lever Frame , Dimensions

Postby Colin Parks » Thu Jun 21, 2018 7:29 pm

Ah Keith, it just had to be too simple to be true! I must go back to the Gwili and have another lesson from the bobby there.


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