I will feel dumb if someone has thought of this before, but instead of placing a plug that you have to connect and disconnect each time you use a liftout section (usually for access purposes), has anyone tried using simple brass contacts at the bottom of the liftout section where it joins the permanent sections. The weight of the liftout section would simply rest on contacts and automatically form a circuit each time the liftout section is inserted.
dav
You can find contacts like those in your minvan sliding door electrical wiring.
In the Caravans there are contacts like you describe that should work for what you need.
Gordon
Gordon,
The reason i brought this up is because I’ve visited several layouts that need to be plugged in; and I’ve always thought about the contact idea but didn’t want to say anything that might appear critical.
You don’t appear critical to me.
You’ve only brought up a great idea, one that I’ve thought about doing, probably on my next layout.
The catch would have to be that one on the contacts would have to be spring loaded so that there would be constant contact at all times with little worry about the contacts separating.
Gordon
Gordon,
Yes, a prime example would be the spring in the old D cell flashlight batteries that keeps a firm connection. Hadn’t thought about the spring because was figuring the weight itself would do the trick. However, a ‘spring’ could be made simply by folding over the brass contact; sort of like Lionel has done in the past with its train-activited crossing gate. Might break over time, however?
Good idea but wrong material. Brass oxide will not conduct current as those of us old enough to have had brass track are aware. I would use something else for the material such as Phosphore bronze or silverplated contacts and a pin that could be polished. I would also make the strips spring loaded so there is a set distance that the modules slide together but a shorter distance for the pin to make contact with the metal strip. That way it self adjusts rather than be a fixed distance. One thing to watch for is the amount of contact area between the two. Making the pin come to a point would be the equivalent of a fine wire which could severely limit power distribution. If the strips were supported like a diving board and could flex down it could be feasible and you could have as many side by side as you needed.
good “points” ndbprr.
Something else just occurred to me. The same principal could be used in making fast connections between modules; esp. time saving if setting up for train meets. Standard way to do it now is by plugs.
dav
But,keep in mind, that you need sufficient weight on your liftout- to keep the rail-heads lined up[:D].
Yes it can be done. One of the guys in our round robin group does it that way. I’m not sure if they are store bought contacts or home made. They work just as well as any plug type connection. Try it and let us know how it works.
I span a 5 1/2’ opening across two doors.The " bridge" is a simple L girder,reinforced with aluminmum angle strips.The contacts are old brass,flat door striker plates (with the varnish removed)I’ve been useing it for around 5 years with no problems. The weight of the bridge is enough to keep good electrical contact.
Theoretically, you could use these contact strips to also automatically cut power to the track leading to the lift-out section in order to keep trains from running over the edge of the “cliff”.
This is an idea I came up with but have not tested. I don’t see any reason why it wouldn’t work :
At each end of the opening, on the permanent structure, place two (2) pin-like contacts – one wired to your power source, the other to one rail of the approach track. On the bottom of your bridge section, place a metal strip so that it will make contact with both pins, and connect this to the corresponding rail of the track on the bridge. Do this for each rail at both ends of the opening.
Be sure to cut through both rails of the approach tracks to isolate them from the rest of the layout. This isolated section should be at least 4-5" (10-12cm) longer than your longest trains to give a reversing train time to stop before pushing any cars over the “cliff”.
When the bridge is in place, the metal strip makes contact with the pins, closing the circuit and allowing power to be fed to the approach tracks as well as the bridge section. When the bridge is removed, the circuit is broken and no power goes to the approach tracks. An approaching train will stop before it falls over the “cliff”.
Rather than using flat strips, you can simply build the plug INTO the liftout. The plug itself will serve as an alignment device.
Go to your nearest pick and pull and find an old suv or minivan. They typically have four to six contacts that are spring loaded and can be had cheap.
Jesse
Not dumb at all!
I’m going to have to make a lift out section on the layout I’ll be building. The idea of using solid electrical contacts seems to make good sense.
Plugs and Pins can be a hassle while fixed plates of solid brass or silver would seem not to require as much maintenance other than making sure that the surfaces are clean and make solid contact.
Idea with potential? [8D][8)]
Hers a link to spring loaded contact pins we use in the electrical test industry. I have used thousands of these in my time building test fixtures. A style with a wide head would handle current and give good contact.
http://dkc3.digikey.com/PDF/T062/0340.pdf?bcsi_scan_FD9165EEE0F12B09=0&bcsi_scan_filename=0340.pdf
ed9008 would be a good choice.
How about snap fastners like the kind used in boat and truck bed covers? The button end attached to the liftout and the stud attached to the layout. Wires can be soldered between the snaps and the bus wires.
Firebirds and Camaros used spring loaded contacts as well. You could also use the spring and contact from round fuse holders.
How about banana pins? Female afixed to the benchwork vertically, males facing down from the bottom of your lift out. This would also serve as a line up method.
I’ve only seen that contact idea used twice. The first time was on a club layout where the liftout portion would be set into place and aligned by 4 nails that fit into index holes. The nails and holes were so arranged that it could only fit one way. On the bottom left edge of the liftout piece were two metal contacts that would contact two matching contacts on the benchwork. As long as these were kept clean, they worked well.
The second time was when I built my last layout. I made a contact system that didn’t need cleaning all the time. This is a simple system. The dropout that needs power for lights has three barrel locks that hold it in place. Since it’s essential the locks be in place to keep gravity from doing it’s thing, it works well. It goes like this. The + wire is connected to on of the barrel locks on the underside of the layout. The - wire is connected to the barrel lock across from on the other side of the hole. The wires going to the structures on the dropout are connected to the retainers that the locks slide into to secure the dropout, thereby being ‘cleaned’ everytime the dropout is removed. Works for me.
Dave, it’s not a dumb idea. I’ll be building a lift up bridge and have been pondering the best method of providing electricity to both approach tracks plus the bridge. Thanks for starting this informational session. It has given me much food for thought.