Trapdoor

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A trapdoor is a sliding or hinged door, flush with the surface of a floor, roof, or ceiling, or in the stage of a theatre. A hatch, an opening which may also be in a wall and need not be flush with the surface, is similar; in some cases either name is applicable. A small door in a wall, floor or ceiling used to gain access to equipment is called an access hatch or access door.

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History

Originally, trapdoors were sack traps in mills, and allowed the sacks to pass up through the mill while naturally falling back to a closed position.

Many buildings with flat roofs have hatches that provide access to the roof; on ships, hatches--usually not flush, and never called trapdoors--provide access to the deck. Cargo ships, including bulk carriers, have large hatches for access to the holds.

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Gallows

Most 19th- and early 20th-century gallows featured a trapdoor, usually with two flaps. The victim was placed at the join. The edge of a trapdoor farthest from the hinge accelerates faster than gravity, so that the prisoner does not hit the flaps but falls freely.

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Railways

The term trapdoor also refers to a plate in the entry vestibule of a passenger railcar that permits access to high-level platforms when lying flat against the floor of the car, and which can be flipped open to expose steps for accessing ground-level platforms. Many American commuter railroads which operate the Comet railcars made by Bombardier have trapdoors to accommodate passengers boarding and alighting on both high-level and ground-level platforms. Amtrak's Viewliner, Amfleet, and Horizon railcar fleets all have trapdoors.

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Biology

Trapdoor spiders hide in an underground nest they line with their silk, and then conceal it with a hinged silk lid, the trapdoor.

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Star traps in theatre

In theatrical use, "star traps" allowed explosively fast appearances on stage, such as Jinn appearing in a puff of smoke. Unfortunately these devices were also dangerous if the mechanism operated too slowly, causing the actor to fall back through the hole or onto the jagged teeth; thus their use was banned and surpassed by the older hand-cranked elevators.

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Fiction

Hidden trapdoors occasionally appear in fiction, as entrances to secret passageways, or to secret tunnels. They also appear as literal traps into which a hapless pedestrian may fall if he or she happens to step on one.

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See also

• Trap (disambiguation)

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References

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External links

Media related to Trapdoors at Wikimedia Commons

Source of article : Wikipedia