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A dumbwaiter is a small freight elevator (or lift) intended to carry objects rather than people. Dumbwaiters found within modern structures, including both commercial, public and private buildings, are often connected between multiple floors. When installed in restaurants, schools, kindergartens, hospitals, retirement homes or in private homes, the lifts generally terminate in a kitchen.〔 Limited Preview, ''Google Books'', accessed August 26, 2008.〕 The term seems to have been popularized in the United States in the 1840s, after the model of earlier "dumbwaiters" now known as serving trays and lazy Susans.〔Quinion, Michael. ''World Wide Words'': "(Lazy Susan )". 24 Apr 2010. Accessed 11 Aug 2013.〕 The mechanical dumbwaiter was invented by George W. Cannon, a New York inventor. Cannon first filed for the patent of a brake system (US Patent no. 260776) that could be used for a dumbwaiter on January 6, 1883.〔 Limited Preview, ''Google Books'', accessed October 30, 2012.〕 Cannon later filed for the patent on the mechanical dumbwaiter (US Patent No. 361268) on February 17, 1887.〔 Limited Preview, ''Google Books'', accessed October 30, 2012.〕 Cannon reportedly generated a vast amount of royalties from the dumbwaiter patents until his death in 1897.〔, retrieved October 30, 2012.〕 ==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, cart, and capacity smaller than those of passenger elevators, usually 45 to 450 kg (100 to 1000 lbs.)〔 Before electric motors were added in the 1920s, dumbwaiters were controlled manually by ropes on pulleys.〔 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 cart is stopped at that floor. Dumbwaiter Lifts in London were extremely popular in the houses of the rich and privileged. Maids would use them to deliver laundry to the laundry room from different rooms in the house. They negated the need to carry handfuls of dirty washing through the house, saving time and preventing injury. 〔http://www.tower-lifts.co.uk/goods-lifts/dumbwaiter-lifts/〕 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: (is ) ... great play between the cart of the dumb-waiter and the guides on which it runs, with the result that the running of the cart is accompanied by a loud noise. The rope which operates the cart 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 cart has no shock absorbers at the top, so that when it strikes the top of the shaft or wheel there is a loud report. ... ()he ropes of the dumb-waiter strike such wall at frequent intervals with a loud report. ... ()he dumb-waiter is often negligently operated, by running it faster than necessary, and by letting it go down with a sudden fall.〔 Via Google Books. (Original from the University of California. Digitized August 3, 2007.)〕 More recent dumbwaiters can be more sophisticated, using electric motors, automatic control systems, and custom freight containers of other kinds of elevators.〔http://acelifts.com/dumbwaiter-lifts/〕 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 450 kg (990 lbs). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Dumbwaiter」の詳細全文を読む スポンサード リンク
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