operating doors

About 25 years ago I used am HO slow motion switch machine to make a large door open. I attached a long rod to the hinge side, ran it through the table and rigged it to be turned by the machine hooked to the bottom of the rod which I bent to form a right angle lever.

 

It worked okay but I didn't make it to last and it wasn't pretty.  You could do better.

 

The hard part was getting the arm under the table the right length so the short throw on the machine would male the larger arc on the door work.  Trial and error.

First I'd provide as much detail of what you want.  How fast does it swing, how far, how often, what triggers it, how much clearance do you have.  Then see if someone can suggest an off-the-shelf toy or gadget that does that with minor modification.

 

Otherwise, use a surplus DC gearmotor in the $5 range to swing something the size of a fence door at realistic scale speeds.  Reverse the voltage and it swings the other way. If you are not one for DIY electrical component assembly you can adapt a trolley back-and-forth system (for example) that rotates the motor one direction until a sensor indicates end-of-travel and then waits and reverse the motor until a different sensor indicates end-of-travel the other way...and repeats. The motor would directly drive the pivot point of the gate/door so the beneath-the-layout clearance is around that axis.

 

And with any custom project, there's the old adage: fast, cheap, good...you get to pick two.

Looking at operating Korber roundhouse doors:

90+ deg. swing

relatively slow moving.

controlled by a panel switch.

My solution would work but would probably use two motors per bay... one for each side...  and could get pricey.

 

You might look at some of the slow motor chain drive items from Walthers.

There was an article in one of the magazines at some point not to long ago. My best guess would be Model Railroader. It was in regards to Steel Gates across a siding if memory serves me correctly. I would try thier web site and search or ask on thier forum.

OK, so it's a roundhouse.  Limited space between hinge pivot axis of one stall to next stall...challenge to use single drive to turn both doors at once via gears/pulleys.   So two gearmotors per stall.  Surplus DC gearmotor drive...a few bucks a piece. 

 

Each mechanism drives inner rod.  Each door on outer telescoping tube.  Enough "friction" in telescoping tubes to rotate door at same speed as inner rod.  Put mechanical stop when door opens to limit swing to 90 deg.  Motor can safely continue spinning as rods "slip".  Roundhouse frame stops door when closing; motor can safely continue spinning as rods "slip".  Switch reverses polarity of DC motor to control direction.  Very little power required (less than 1 Watt).  Motors may not swing exactly same speed but I'd think that's actually prototypical and more interesting to watch anyway.

 

 

I occasionally troll All Electronics motors and Electronic Goldmine motors for their sales or clearance specials.  For something like a slowly swinging door, I'd be thinking, say, $5 for a worm-gear style that can run at a few RPMs or so.

 

For example, the Goldmine link above is something I might pick up on principle to mess with - that is, a worm type gearmotor assembly for $1.50.  Obviously it's hit and miss with surplus stuff and when you want to get another one they are probably gone.

 

For non-surplus, I'd look at the Tamiya line of gearboxes and motors made for hobby applications.  Pololu is one distributor.

I just ordered some of them dc motors...

 

Thanks!