Dumbwaiter (elevator)
Dumbwaiters are small freight elevators (or lifts) intended to carry objects rather than people. Dumbwaiters found within modern structures, including both commercial and private buildings, are often connected between two floors. When they are located in restaurants or in private homes, the lifts generally terminate in a kitchen.[1][2]
Thomas Jefferson used one of the world's first dumbwaiters in his mountain home at Monticello, Virginia, to limit the number of servants around the table to one, so that his guests could enjoy more of the view. He is credited by some as its inventor.[3]
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[edit] Description
A simple dumbwaiter is a movable frame in a shaft, dropped by a rope on a pulley, guided by rails; most dumbwaiters have a shaft, car, and capacity smaller than those of passenger elevators, usually 100 to 1000 lbs.[2] Before electric motors were added in the 1920s, dumbwaiters were controlled manually by ropes on pulleys.[1]
Early 20th-century codes sometimes required fireproof dumbwaiter walls and self-closing fireproof doors and mention features such as buttons to control movement between floors and locks on doors preventing them from opening unless the car is stopped at that floor.[4]
A legal complaint about a Manhattan restaurant's dumbwaiter in 1915, which also mentions that food orders are shouted up and down the shaft, describes its operation and limitations as follows:
[There is] ... great play between the car of the dumb-waiter and the guides on which it runs, with the result that the running of the car is accompanied by a loud noise. The rope which operates the car of the dumb-waiter runs in a wheel with a very shallow groove, so that the rope is liable to and does at times slip off. ... The car has no shock absorbers at the top, so that when it strikes the top of the shaft or wheel there is a loud report. ... [T]he ropes of the dumb-waiter strike such wall at frequent intervals with a loud report. ... [T]he dumb-waiter is often negligently operated, by running it faster than necessary, and by letting it go down with a sudden fall.[5]
More recent dumbwaiters can be more sophisticated, using electric motors, automatic control systems, and custom freight containers of other kinds of elevators.[citation needed] Recently constructed book lifts in libraries and mail or other freight transports in office towers may be larger than many dumbwaiters in public restaurants and private homes, supporting loads as heavy as 1000 pounds.
[edit] Regulations governing construction and operation
Building codes have regulated the construction and operation of dumbwaiters in parts of North America since the 19th century.[2] Modern dumbwaiters in the United States and Canada must comply with American Society of Mechanical Engineers (ASME) codes and, therefore, have features similar to those of passenger elevators.[6] The construction, operation and usage of dumbwaiters varies widely according to country.
[edit] References
[edit] Notes
- ^ a b George R. Strakosch (1998). The Vertical Transport Handbook. New York: John Wiley and Sons, 1998. ISBN 0471162914.
- ^ a b c Harry Robert Cullmer and Albert Bauer (1912). Elevator Shaft Construction. New York: W.T. Comstock Company, 1912. p. 30. http://books.google.com/?id=M6aEAAAAIAAJ&pg=PA30&dq=dumbwaiter. Limited Preview, Google Books, accessed August 26, 2008.
- ^ "Popular Science - Google Books". Books.google.com. http://books.google.com/books?id=WCEDAAAAMBAJ&pg=PA104&dq=thomas+jefferson+dumbwaiter+inventor&hl=en#v=onepage&q=dumbwaiter&f=false. Retrieved 2012-03-05.
- ^ Anthony Avillo (2002). Fireground Strategies. Tulsa: PennWell Books, 2002. ISBN 9780878148400.
- ^ System, National Reporter; Superior Court (new York), New York (State); Court Of Appeals, New York (State); Supreme Court, New York (State); Company, West Publishing (1916). "DARR V. COHEN" (print and Web). New York Supplement, National Reporter System, New York (State) Superior Court (New York: West Publishing Company, 1916) 158 (c. 3): 325. http://books.google.com/?id=4og7AAAAIAAJ&pg=PA325&dq=dumbwaiter#PPA325,M1. Retrieved 2008-08-26. "Cases argued and determined in the Court of Appeals, Supreme and lower courts of record of New York State, with key number annotations." Via Google Books. (Original from the University of California. Digitized August 3, 2007.)
- ^ See "ASME Product Catalogue". ASME. http://catalog.asme.org/home.cfm?CATEGORY=CS&TaxonomyItemID=2990&ProductFormat=DigitalBook. Retrieved 2008-08-26. ASME A17.1 covers safety for new elevators; A17.2, elevator inspection; A17.3, safety for existing elevators; and A17.4, emergency procedures, including those applying to modern dumbwaiters.
[edit] Manufacturers
[edit] Bibliography
- ASME. ASME Product Catalogue. ASME. Accessed August 26, 2008.
- Avillo, Anthony. Fireground Strategies. Tulsa: PennWell Books, 2002. ISBN 087814840X (10). ISBN 9780878148400 (13).
- Cullmer, Harry Robert, and Albert Bauer, Elevator Shaft Construction; Or, Practical Suggestions for the Installation of Electric Elevators in Buildings. New York: W.T. Comstock Company, 1912. 30. Google Books (Limited Preview). Accessed August 26, 2008.
- Stannah (The Stannah Group). "The Origins of a 'Dumb Waiter' or 'Dumbwaiter' ". What's New in Building, WNIBi.com (CMP Information Ltd), 2007. Accessed August 26, 2008. (Cites performance rev. by Brown.)
- Strakosch, George R. The Vertical Transport Handbook. New York: John Wiley and Sons, 1998. ISBN 0471162914.
