# A Mechanical design issue for comments



## gunrunnerjohn (Nov 10, 2010)

I have an interesting project I'm considering. I have this Lionel Tie-Jector (the remake with the DC motor).

As you know (or will know), the unit uses track-side trips to turn on and off the tie ejection action. I'd like to convert it to TMCC, and I also want to switch the ejection mechanism remotely as well and not use the lame trips.

In the first picture, you can see the mechanism that actually turns on and off the ejector, it's the little over-center lever with the switch. In truth, the actual switching takes almost no energy, the major part of the switching force is because of the over-center switch. I'm thinking of removing that and extending the socket it plugs into with a small metal axle or the like. On the end, I'd have a loop and use a very small gear motor to toggle the position. I could also use a pair of solenoids if I could find them small enough.

The end you see loose has a pivot that mounts to the two posts here, it doesn't flop free. 










The upper right hand corner in the picture below is the place that I have to mount a motor or other actuator. It's about 1/2" x 1/2" and over 1" high. I'm trying to come up with something that can toggle the lever back and forth under command control.


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## tjcruiser (Jan 10, 2010)

Sounds like a great, creative bash project. That said, I'm not sure I understand the mechanics from your pics. Maybe post a short vid, if that's possible? Gizmo as-found in action?

Thanks!

TJ


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## gunrunnerjohn (Nov 10, 2010)

Well, the mechanical issue that I'm trying to solve is just to move a small lever about 3/4" of an inch, basically it's that thing you see with the spring. I'm going to take the spring off and secure the lever in the socket that's out of sight and move it back and forth with "something". 

As far as the actual operation, I was looking for a video of one in operation. The ties sit on the top and that red lever feeds them down near the track and drops them out as the unit rolls along the track. It's geared to the drive motor.


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## 93firebird (Dec 25, 2011)

What about an rc helicopter micro servo?


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## gunrunnerjohn (Nov 10, 2010)

Hmm... If I could drive it without the logic, that might do the trick. I know just the guy to ask, my brother! He does a ton of that stuff.


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## tjcruiser (Jan 10, 2010)

John,

I repaired an old, outdated VCR player a while back. If I recall, there were all sorts of linear actuators in the guts. Perhaps something in a cheap, garage-sale VCR that would work well for you?

TJ


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## Ed Gerken (Jan 23, 2012)

I stripped down a car CD player for the motors. The laser carriage is positioned by a small geared motor driving a coarse-threaded screw. The motor is about an inch long and the threaded portion has about 1.5 inches of travel. The carriage has a simple lever that rides the threads. This limits torque as the lever will simply jump a thread when the carriage is held back by a finger. This might be enough force if the lever you wish to drive moves easily.

The entire mechanism is kinda large, but maybe just the driven portion could be lifted and adapted to work using a normally-threaded screw and nut instead of the flimsy lever and it would apply a lot more driving force. 

It would take some fabrication, but can be driven with plain ol' DC. I just tried it on my Tyco power pack and it travels the full stroke in a second or less at any throttle position. That's with the coarse-threaded screw, it would be slower using a normal screw.

Maybe not perfect for your project, but it oughta be useful for something on a layout. I thought it could be used to make a working elevator or maybe a functioning hoist in a workshop or auto-repair shop.


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## gunrunnerjohn (Nov 10, 2010)

That looks too large. I'm pursuing the model plane servo idea, that looks like it'll be the size I need.


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## NIMT (Jan 6, 2011)

How about this or I have even smaller solenoids too?


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## gunrunnerjohn (Nov 10, 2010)

The space available: _1/2" x 1/2" and over 1" high_. That one is probably too big.


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## NIMT (Jan 6, 2011)

Does it have to be mounted right there or could it be mounted somewhere else and move the switch remotely with a cable. I do it with my Tortoise switch machines.


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## gunrunnerjohn (Nov 10, 2010)

There is nowhere else in the unit to mount it. The platform on the other end is consumed mostly by the TMCC board.

I might be able to find a skinny area a couple inches long next to the logic board if I move it to one side, I'll have to check. What are all the contacts on that, looks more like a relay? That looks to be at least an inch in diameter, I'm guessing that sucks quite a bit of juice when it is actuated. I don't need that kind of power.


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## gunrunnerjohn (Nov 10, 2010)

Well, the mechanical issue is solved.  I ended up going with a model airplane servo. I started by running it bare without the logic, but the control got away from me and the first one ate it's gears! Clearly, that isn't the answer. I picked up another one and mounted it inside. My brother supplied some bits and pieces like the swivel links and the sheathed cable.

I have a design figured out and breadboarded for the PWM servo control, a relay will be activated to switch between the two positions required. I have two selectable resistors that will be installed to allow the proper servo travel.

*Here's where I started.*











*Chopped away some extra plastic and mounted the servo.*











*I built a control arm extension from a screw, flattened the end and drilled it for the actuator cable.*











*The completed serve installation. Works like a champ.*


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## gunrunnerjohn (Nov 10, 2010)

Here's the PWM circuit. The relay is driven from an output on the TMCC logic board and simply shorts out the one resistor to run the servo to the position to start the tie-ejector mechanism.


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## Gansett (Apr 8, 2011)

My interpretation of GRJ's schematic,










At least I spelled schematic right,,,didn't I?


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## gunrunnerjohn (Nov 10, 2010)

That was my starting design, but I simplified it.


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## gunrunnerjohn (Nov 10, 2010)

If you're going to put all that gear inside, the thing's got to have lights, so that was this afternoon's project. 

Next I have to build the PWM board and get ready for the TMCC stuff, it still hasn't arrived...


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## NIMT (Jan 6, 2011)

Jackc, 
OH MY I'M DYING HERE!!!!:laugh::laugh::laugh::laugh::laugh::laugh: Love it!:thumbsup::thumbsup::thumbsup: Made my day

GRJ,
Glad to see you got it working:thumbsup::thumbsup: ...Humm who said cable drive ...What lights but not a working horn!:laugh:


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## gunrunnerjohn (Nov 10, 2010)

The jury is still out on the horn, but I don't think I can fit it in. I'm using almost all the space under that flat platform for the TMCC board, the PWM board, and the servo. There is no usable space in the rear, the ejector takes up pretty much all of it. Lights don't really take any space, and I already have an output from the TMCC control board for them, so I might as well have them.

My brother came up with the cable parts, I didn't have any of that stuff. Yep, Sean, it was a good idea, and it works.  I wish I had thought it through the first time, I could have saved buying another servo, my brother gave me the first one I destroyed.  Since I was paying shipping, I bought a spare, now that I know how to do the PWM, I can think about using the servo in another creative project.


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## tjcruiser (Jan 10, 2010)

Hey John,

Nice Frankencreatin' on the servo install. I'll echo Jack's comprehension on my end on all of circuitry logic, but the end result is pretty cool.

Well done!

TJ


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## gunrunnerjohn (Nov 10, 2010)

The project marches on. I did my bench testing of the module, and made a few circuit alterations, so here's what is actually going into the unit.


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## gunrunnerjohn (Nov 10, 2010)

Here's some progress pictures, we're closing in on the home stretch. The board has been finalized and tested. I added a strobe light to the top of the cab, you can see the connector at the bottom. I have the two boards installed, and the antenna run around in the shell. I'm waiting on some large capacitors to better filter the DC, turns out the servo doesn't like much ripple on it's power supply. Once they're in, I'll put them in the empty spot next to the board with a bridge rectifier and a small resistor.

I'm also waiting on the programming instructions for the TMCC module, I need to know which outputs I can program to do the lights and the trigger for the ejector servo. The sheet was supposed to come with the TMCC boards, but I didn't get it.


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## Gansett (Apr 8, 2011)

ooohhhhh


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## tjcruiser (Jan 10, 2010)

gunrunnerjohn said:


> The project marches on. I did my bench testing of the module, and made a few circuit alterations, so here's what is actually going into the unit.


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## gunrunnerjohn (Nov 10, 2010)

I can't believe you're comparing my masterpiece to Frankenstein!


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## gunrunnerjohn (Nov 10, 2010)

Well, the project has reached it Zenith! Just buttoned it up for the "final" time (I hope) and ran a test, take a look. 

It now has directional headlights, front and rear. Taillights on the rear, and a strobe light that runs when the tie-ejection mechanism is running.

Add one to my TMCC locomotive count.


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## tjcruiser (Jan 10, 2010)

Looks great ... but it keeps dropping something over the side 

So are you remotely triggering each ejection individually, or do you remotely toggle it "on", and it ejects and ejects until you toggle it "off"?

Just curious. Nice work!

TJ


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## gunrunnerjohn (Nov 10, 2010)

I just toggle the ejection on or off using the smoke controls on the TMCC remote. The model airplane servo that you see in previous shots in the thread turns it on/off. That was one of the more challenging parts of the project, I was coming up blank on how to move that lever. I removed the track trip stuff from the bottom and put that in to trigger the ejection mechanism.

The strobe on the top was an afterthought, I thought it would be nice to signal that the ties were being ejected.


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