Point control wiring 'a la TedP'

[Doug Dickson]

In 2012, TedP posted his method of point control using a bicycle spoke to operate the point and a pair of contacts for frog switching.  No problem with the operating, as I have done that before, but with  microswitches to change frog polarities.  I just can't get my thick head around where exactly the wires in his drawing will go go.

I think I understand that the spoke itself is 'live'?

I was forever having to readjust the M'switches and would dearly love to do without them.

If you read this, Ted, please could you [or anyone else...]  un-fuddle me?

Doug

[gtmspyder]

Hello Doug.
Whilst I have never used the operating spoke to deliver the track current to the frog, I can envisage a way that it could be done, but as I don't know how to add a drawing to this reply, I will have to explain it the long winded way with words.

Attach a flexible wire permanently to the operating spoke at one end, and the other end to the frog.

Make two springy contacts that will touch the spoke as it is slid back and forth, and connect each contact to a rail.

Slide a piece of heat shrink onto the spoke and carefully adjust it's position such that when one spring contact is touching the spoke in one of the point blades position, the other spring contact is on the insulating heat shrink sleeving.

When the spoke is moved to operate the point switch blade against the opposite stock rail, the heat shrink sleeving will momentarily be slid under and insulate both contacts from the spoke before the continued movement of the spoke pushes the bare uninsulated length of spoke into contact with the opposite spring again.

Thus swopping the polarity of the frog, and if required, the switch blades, to suit the direction of travel for the loco.

The heat shrink sleeving needs to be a tight fit on the spoke by heating it to shrink it, and the contact fingers should have a half round shape formed on there contact tips by careful bending so that they do not catch on the edge of the sleeving as the sleeving is moved back and forth under them.

It would be worth doing a simple lash up on a scrap piece of timber to work out the optimum length and distances  between the two contacts, and the length of sleeving required to achieve the insulation of one switching position from the other whilst allowing both switch rails to touch there respective stock rails.

I hope that helps Doug, and apologies to Ted if I have got it wrong ;D

Kind regards,

BrianT.

[Graeme Dunbar]

A popular way of switching contacts is to use a slide switch as the point lever, drill a hole through the plastic switch dolly and put the bicycle spoke or equivalent through the hole.

http://www.009society.com/forum/index.php?topic=851.msg5226#msg5226

I think I've seen a variation on this where the hole is drilled at 90 degrees (parallel to the switch motion) and two adjustable stops (e.g. the metal innards of a chocolate block electrical connector) are used to set the throw.

If reliability of electrical switching is of concern then starting with a 'proper' switch is a good way to go. Switches often have 'wiping contacts' meaning the metal contacts scrape over each other cleaning off any contaminants.

[Doug Dickson]

Brian,
Thank you for that.... as soon as you said the spoke wire is connected to the frig, the veil lifted.....  :-[

Graeme,
Again, thank you for taking the time and interest to post that, I had hoped to be able to make do with the stuff I have to hand, I have already faffed so much with switches I feel determined to avoid them!  :(

I think this drawing below has got me thinking in the right direction, or has it? :-\

[gtmspyder]

Hello again Doug.

Your attached sketch shows what my long winded written explanation was trying to explain when using the spoke as a part of the circuitry, I must say that this method, to my way of thinking, has only one saving grace, it's cheap, but will entail a lot of work setting each switch assembly up.

GraemeD's method is a well proven method,  (which I have used in the past,)  for changing frog polarity while operating the point, it is very positive, and practically fool proof, and with the cost of the slide action double pole changeover switches so cheap nowadays, is really the way to go for your use, and I would heartily recommend this option over the alternative method I espoused in my long winded explanation of the el-cheapo exercise in switch making. But I was trying to answer the specific question you posed.

Good luck with which ever method you adopt, and if you look at my Glen Ogle layout's control panel which I have described on the forum, you will find that my methods are a lot more complicated to achieve the same results. ::)

Kind regards,

BrianT.

[Frank]

I have used a method similar to that described above, but using a slide switch instead of the open contacts.     The switch is mounted near the point and moved by the rod which runs to the baseboard edge.

The switch blade is then moved by the rod via a bell crank which allows some choice of the movement to match the point throw independent of the movement required to throw the switch.  It also means the rod does not have to line up with the point tie bar.

I also used pieces of wire coathanger instead of spokes which may be easier to work with (and also cheaper).

Frank

[B.Meldon]

Here are some examples of using switches and rods.

The first uses rail on its side secured to the baseboard with track pins with brass wires soldered at each end. One going to the switch:



The other going to the tie rod on the point:



The 00 rail was second hand and the 1a slide switches cost about 20p each on e-bay.

The next uses a toggle switch and a short wire:



Here is a diagram of the wiring:



(Originating web page: http://www.pls-layouts.co.uk/html/frog_types.htm)

Brian Meldon

[Doug Dickson]

Thanks  for  taking the time to post those  interesting pictures, Brian, it's  true what they say about cats and skinning!

Doug