Mechanized Portcullis? (Help!?)

J1A3L5 · Post by **J1A3L5** » Tue Aug 24, 2004 2:11 am

Hello all,

As I may have mentioned in the last MOC I posted, and many of you know I'm working on a fairly large-scale gate.

I'm trying to make the portcullis raise and lower, and I've seen it done many times before with strings. Even a piece you pull up or something, which is a very simple design.

I already have sliders at each edge with work perfectly, and a way to attach a mechanism.

What my goal is to have it so you can turn a certain feature on the front (Or a gear or something on the back) and have it bring the portcullis up or down. I had a half-working one basically by running steering racks up the edge of the gate, and then having a gear against it on a straight axel. There's several reasons I could state, but suffice it to say it didn't work.

I have a few more ideas yet, but I'm interested if anyone else has ever done this. I want something more than string to make it move.

So please, if anyone has any tips they could share, I'd be very interested in hearing.

Post by **davee123** » Tue Aug 24, 2004 3:01 am

A long time ago (in like 2000 or so) I built a gatehouse with a pretty neat portcullis:

http://www.suave.net/~dave/gatehouse.html

That little T-shaped dealy on the top wound the chain for the portcullis, and the little technic piece on a 36-cog gear racheted it pretty well, actually. That way, you'd wind it up, and it'd sit there until you flipped the little lever, when it would come crashing down.

DaveE

J1A3L5 · Post by **J1A3L5** » Tue Aug 24, 2004 5:21 pm

Wow, that is a completely different approach than what I was trying. I might have to try it, if it's okay with you. The only problem is I don't want whatever you turn to be at the top of the MOC, really. I might have to somehow make the chains go around a bend, or add gears and a chain, if that's possible.

Thanks, Dave.

lemon_squeezer2 · Post by **lemon_squeezer2** » Tue Aug 24, 2004 8:19 pm

This is kind of ironic. The truth be told, I was inspired by your tower and I've built a wall system of my own. Then, I started work on a gatehouse and I was tackling the same problem. Now you are doing a gatehouse

As far as a portcullis goes, mine is position between two sets of doors and I am using the prefabricated piece. Attaching two 17 L chains to it, I was independently thing of a plan somewhat similar to what "davee" suggested, though I had not thought of a turnstyle. Good luck on your project! If it is on the same scale as your wall, I do believe mine will be dwarfed - It is only four stories tall at the projected height of the towers.

J1A3L5 · Post by **J1A3L5** » Tue Aug 24, 2004 8:31 pm

Thanks for responding, and I'm glad you were inspired by mine. And yes, mine is the same scale as my tower. I like the scale, it isn't hugely oversize, but it isn't so small that a fig could stand on another fig's shoulders and see over the wall.

My towers are just over 30 bricks tall, plus landscaping, if you're interested. I'm doing exteriors only, so it isn't really in floors. Each tower does have 4 windows, though.

Thanks for the info on what you're doing with your portcullis, I'm having a bit of trouble imagining it exactly, but I think I know how mine will work.

I'm glad I inspired you to build your own - I was inspired to build a gate in the same scale after the response I got. (I really wasn't sure if I would get much of a good reaction)

Thanks.

Post by **rogue27** » Tue Aug 24, 2004 8:32 pm

I started working on a mechanical portcullis a while ago, but that project has been on hold for the better part of a year now. I mean to get back to it soon.

Anyway, if I ever get it to work well, I'll post it here and tell everybody how I did it.

Buford · Post by **Buford** » Wed Aug 25, 2004 11:52 am

I tried a rack & screw drive portcullis with poor results.

I can see why simple gravity/ pulley portcullis are so popular.

J1A3L5 · Post by **J1A3L5** » Wed Aug 25, 2004 4:38 pm

rogue27 wrote:I started working on a mechanical portcullis a while ago, but that project has been on hold for the better part of a year now. I mean to get back to it soon.

Anyway, if I ever get it to work well, I'll post it here and tell everybody how I did it.

Awesome, can't wait to see it if it does work out.

Buford wrote:I tried a rack & screw drive portcullis with poor results.
I can see why simple gravity/ pulley portcullis are so popular.

Indeed. But that's exactly why I want to avoid that - It's very simple, isn't something new, and has been done all the time.

I sort of attemtped a rack & screw drive and didn't have very good results either - I wanted it to move faster. With how I had it set up you had to be turning and turning and turning to get it all the way up. I could gear it to be faster, but I have a very limited size I'm trying to work within.