Not directly related to what gets discussed on here, but does anyone have any ideas for a powered trapdoor to provide access to a celler?

Either ideas to build or a commercially available product are acceptable.

cheers.

Don't quite understand what you mean. Are we talking like a beer keg lift sort of thing?

where's this trapdoor located - Tracy Island?

but seriously, do you mean automatically opening doors, or an elevator? for serious engineering of this type, you could try delstar - don't have any contact details to hand, I'm sure they have a website.

Delstar Engineering

Cheers,
Piers

Cheers all.

It's only a domestic cellar trapdoor which is going to be covered over in heavy stone and the customer (thinks) they want it powered to make access easy.

It's a mates father in law who has seen us install automated gates and seems to think the principle is the same, which it is to a point execpt this is lifting rather than pushing/pulling.

Read these forums now and again and thought I'd post on here as I know weird stuff crops up now and again, but I am looking for a commercial product really as I can someone like delstar being very expensive. We do electrical installs and steel fabs so the aim isn't really to pass the job over anyway.

A lot of places use gas rams to assist a manual door, a la car hatchback. I am not sure how you would go about the calculations but I am sure if you can find a manufacturer they may be able to help.

We've got some "power assisted" (I.e spring loaded) bombdoors installed in the floor of our upper dock to cater for the long thin things over 5.5m we can't get in our scenery lift - these were an "off the shelf" solution - I'll talk to my colleague who has the "who what where" information and report back. Our doors drop down into the void below, (I think - I've not seen them work yet, we're still building the place...), but I imagine you could specify which direction you need the doors to move.

(the problem about drop-down doors being you would need to allow clearance for the thickness of cladding material which I don't imagine would be allowed for in the design of the basic product)

Cool.

The only things I have found on line are;

linear actuators:

http://www.actuators-electric.co.uk/item.php?cat=0

And this:

http://freespace.virgin.net/j.markham/trapdoor.html

As regarding calcs- not sure how we will get round this or what the bulding regs might require. I just hope the thing can open upwards or there will be some issues with safety.

Ps- anyone had any experience using 'working model' software? looks really impressive but hard to get to grips with.

Never thought of gas springs.

Sort of jumped to looking for an electrical solution because that's my thing.

Does it really have to be powered?
It was said earlier that the mechanism was to make opening the doors easier.
Hi Tech is generally expensive to install and expensive to fix.
Plus this sounds like a one off so there's got to be a hefty design fee

How about going low tech?
What about having the doors opening upwards and fitting an arm of some kind to the underside with a counterweight on the end?
The counterweightweight would assist in opening the doors and whilst would dangle when the door was open would be tight up to the ceiling when the door was shut.
Design time short
Installation costs 2 bits of steel / wood battern, some string, some screws/bolts and a few heavy things.
Repair costs next to zero

Brixton's idea is a pretty nice engineering solution - this is how Tower Bridge works after all. Only snag is you need a bit of space for the counterweights to move in, (yellow lines on floor, sign saying "Do Not Store Chateau Petrus Here" but apart from that, lovely - low maintenance, easy build, works in a power cut....

The reference I was looking for for trapdoors and spring-assisted stuff is Bilco. I've no idea about budget, I'm afraid, but specialist things seem to be pricey in the construction industry because (quote) "they are the only people who do this...."(unquote). (we've just had a quote for nearly 3 grand to install two bits of steel wire rope catenary....)

If the weights were fixed to the arms which weren't made too long then they would only decend the height of the length of the arms!? Urrm yes

God I'm getting defensive over my baby and I haven't even made it.

Exit Brixton looking for valium, vodka and a place to lie down

No need to be , mate - I'm a fan of the idea. it was only a tiny snag and easy to solve - to get short arms, you just increase the size of counterweight required - fulcrums and moments and stuff like that.

hope the vodka hit the spot.