On Sat, 21 Apr 2007 21:18:29 +0100, Theo Markettos wrote:

Bit of a long shot this one, but...

I'm looking at designing a spiral staircase (for a new-build). For
various reasons it needs to be possible to separate the floors the
staircase links, so I'm thinking of having a trapdoor that fits into the
gap in the ceiling formed by the staircase. The door would be hinged and
counterweighted, on a pulley controlled by a handle somewhere, tight
fitting and fairly heavy (for sound and thermal insulation), with a bolt
to lock it. It wouldn't be moved very often (once a week maybe),
otherwise staying fixed open or fixed closed.

Obviously such a thing could be built from scratch, but does anything like
this already exist? Is there anyone who specialises in the building of
trapdoors or similar, who'd be able to give me advice on whether this is a
silly idea or not, or suppliers of components?

Thanks
Theo

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Since you're open to the idea of using ropes and pulleys it might be
easier to have a detached trap door something like a manhole cover. Such a
trap door would only need a single centrally placed hook / rope to lift
it vertically and so would not interfere with a surrounding handrail. It
could be operated by an off-the-shelf electric hoist. Look here for hoists:

http://www.machinemart.co.uk/shop/se...r/hoist/page/1

A similar arrangement is sometimes used (I think) on blast furnaces but
you may not need a 6" thick steel plate for your trap door.

Cic.

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