-
1 timekeeper
timekeeper ['taɪm‚ki:pə(r)]∎ this watch is a good timekeeper cette montre est toujours à l'heure(b) (supervisor) pointeau m(c) (employee, friend)∎ he's a good timekeeper il est toujours à l'heure, il est toujours très ponctuel;∎ he's a bad timekeeper il n'est jamais à l'heure -
2 timekeeper
1 Sport chronométreur m ;2 ( punctual person) he's a good timekeeper il est toujours à l'heure ;3 (watch, clock) this watch is a good timekeeper cette montre est toujours à l'heure. -
3 timekeeper
['taɪmkiːpə(r)]1) sport cronometrista m. e f.* * *timekeeper /ˈtaɪmki:pə(r)/n.1 (ind.) controllore delle ore di lavoro4 cronometro; orologio● (mus.) a good timekeeper, un tempista □ This watch is a good [a bad] timekeeper, questo orologio va bene [va male]timekeepingn. [u]1 (ind.) rilevamento dei tempi* * *['taɪmkiːpə(r)]1) sport cronometrista m. e f. -
4 timekeeper
time-keeper
1> хронометражист
2> хронометрист; счетчик времени
3> табельщик
4> часы
_Ex:
this watch is a good time-keeper эти часы отлично идут -
5 timekeeper
ˈtime·keep·ernthis watch is not an accurate \timekeeper diese Uhr geht nicht genauto be a bad/good \timekeeper person sein Zeitsoll nie/immer erfüllen* * *1. Zeitmesser m:be a good timekeeper genau gehen (Uhr)* * *n.Zeitmesser m. -
6 timekeeper
'time·keep·er n2) (clock, watch) Zeitmesser m;this watch is not an accurate \timekeeper diese Uhr geht nicht genau; -
7 Harrison, John
[br]b. 24 March 1693 Foulby, Yorkshire, Englandd. 24 March 1776 London, England[br]English horologist who constructed the first timekeeper of sufficient accuracy to determine longitude at sea and invented the gridiron pendulum for temperature compensation.[br]John Harrison was the son of a carpenter and was brought up to that trade. He was largely self-taught and learned mechanics from a copy of Nicholas Saunderson's lectures that had been lent to him. With the assistance of his younger brother, James, he built a series of unconventional clocks, mainly of wood. He was always concerned to reduce friction, without using oil, and this influenced the design of his "grasshopper" escapement. He also invented the "gridiron" compensation pendulum, which depended on the differential expansion of brass and steel. The excellent performance of his regulator clocks, which incorporated these devices, convinced him that they could also be used in a sea dock to compete for the longitude prize. In 1714 the Government had offered a prize of £20,000 for a method of determining longitude at sea to within half a degree after a voyage to the West Indies. In theory the longitude could be found by carrying an accurate timepiece that would indicate the time at a known longitude, but the requirements of the Act were very exacting. The timepiece would have to have a cumulative error of no more than two minutes after a voyage lasting six weeks.In 1730 Harrison went to London with his proposal for a sea clock, supported by examples of his grasshopper escapement and his gridiron pendulum. His proposal received sufficient encouragement and financial support, from George Graham and others, to enable him to return to Barrow and construct his first sea clock, which he completed five years later. This was a large and complicated machine that was made out of brass but retained the wooden wheelwork and the grasshopper escapement of the regulator clocks. The two balances were interlinked to counteract the rolling of the vessel and were controlled by helical springs operating in tension. It was the first timepiece with a balance to have temperature compensation. The effect of temperature change on the timekeeping of a balance is more pronounced than it is for a pendulum, as two effects are involved: the change in the size of the balance; and the change in the elasticity of the balance spring. Harrison compensated for both effects by using a gridiron arrangement to alter the tension in the springs. This timekeeper performed creditably when it was tested on a voyage to Lisbon, and the Board of Longitude agreed to finance improved models. Harrison's second timekeeper dispensed with the use of wood and had the added refinement of a remontoire, but even before it was tested he had embarked on a third machine. The balance of this machine was controlled by a spiral spring whose effective length was altered by a bimetallic strip to compensate for changes in temperature. In 1753 Harrison commissioned a London watchmaker, John Jefferys, to make a watch for his own personal use, with a similar form of temperature compensation and a modified verge escapement that was intended to compensate for the lack of isochronism of the balance spring. The time-keeping of this watch was surprisingly good and Harrison proceeded to build a larger and more sophisticated version, with a remontoire. This timekeeper was completed in 1759 and its performance was so remarkable that Harrison decided to enter it for the longitude prize in place of his third machine. It was tested on two voyages to the West Indies and on both occasions it met the requirements of the Act, but the Board of Longitude withheld half the prize money until they had proof that the timekeeper could be duplicated. Copies were made by Harrison and by Larcum Kendall, but the Board still continued to prevaricate and Harrison received the full amount of the prize in 1773 only after George III had intervened on his behalf.Although Harrison had shown that it was possible to construct a timepiece of sufficient accuracy to determine longitude at sea, his solution was too complex and costly to be produced in quantity. It had, for example, taken Larcum Kendall two years to produce his copy of Harrison's fourth timekeeper, but Harrison had overcome the psychological barrier and opened the door for others to produce chronometers in quantity at an affordable price. This was achieved before the end of the century by Arnold and Earnshaw, but they used an entirely different design that owed more to Le Roy than it did to Harrison and which only retained Harrison's maintaining power.[br]Principal Honours and DistinctionsRoyal Society Copley Medal 1749.Bibliography1767, The Principles of Mr Harrison's Time-keeper, with Plates of the Same, London. 1767, Remarks on a Pamphlet Lately Published by the Rev. Mr Maskelyne Under theAuthority of the Board of Longitude, London.1775, A Description Concerning Such Mechanisms as Will Afford a Nice or True Mensuration of Time, London.Further ReadingR.T.Gould, 1923, The Marine Chronometer: Its History and Development, London; reprinted 1960, Holland Press.—1978, John Harrison and His Timekeepers, 4th edn, London: National Maritime Museum.H.Quill, 1966, John Harrison, the Man who Found Longitude, London. A.G.Randall, 1989, "The technology of John Harrison's portable timekeepers", Antiquarian Horology 18:145–60, 261–77.J.Betts, 1993, John Harrison London (a good short account of Harrison's work). S.Smiles, 1905, Men of Invention and Industry; London: John Murray, Chapter III. Dictionary of National Biography, Vol. IX, pp. 35–6.DV -
8 Mudge, Thomas
SUBJECT AREA: Horology[br]b. 1715 Exeter, Englandd. 14 November 1794 Walworth, England[br]English clock-and watchmaker who invented the lever escapement that was ultimately used in all mechanical watches.[br]Thomas Mudge was the son of a clergyman and schoolmaster who, recognizing his son's mechanical aptitude, apprenticed him to the eminent London clock-and watchmaker George Graham. Mudge became free of the Clockmakers' Company in 1738 and set up on his own account after Graham's death in 1751. Around 1755 he formed a partnership with William Dutton, another apprentice of Graham. The firm produced conventional clocks and watches of excellent quality, but Mudge had also established a reputation for making highly innovative individual pieces. The most significant of these was the watch with a detached-lever escapement that he completed in 1770, although the idea had occurred to him as early as 1754. This watch was purchased by George III for Queen Charlotte and is still in the Royal Collection. Shortly afterwards Mudge moved to Plymouth, to devote his time to the perfection of the marine chronometer, leaving the London business in the hands of Dutton. The chronometers he produced were comparable in performance to those of John Harrison, but like them they were too complicated and expensive to be produced in quantity.Mudge's patron, Count Bruhl, recognized the potential of the detached-lever escapement, but Mudge was too involved with his marine chronometers to make a watch for him. He did, however, provide Bruhl with a large-scale model of his escapement, from which the Swiss expatriate Josiah Emery was able to make a watch in 1782. Over the next decade Emery made a limited number of similar watches for wealthy clients, and it was the performance of these watches that demonstrated the worth of the escapement. The detached-lever escapement took some time to be adopted universally, but this was facilitated in the nineteenth century by the development of a cheaper form, the pin lever.By the end of the century the detached-lever escapement was used in one form or another in practically all mechanical watches and portable clocks. If a watch is to be a good timekeeper the balance must be free to swing with as little interference as possible from the escapement. In this respect the cylinder escapement is an improvement on the verge, although it still exerts a frictional force on the balance. The lever escapement is a further improvement because it detaches itself from the balance after delivering the impulse which keeps it oscillating.[br]Principal Honours and DistinctionsClockmaker to George III 1776.Further ReadingT.Mudge, Jr, 1799, A Description with Plates of the Time-Keeper Invented by the Late Mr. Thomas Mudge, London (contains a tract written by his father and the text of his letters to Count Bruhl).C.Clutton and G.Daniels, 1986, Watches, 4th edn, London (provides further biographical information and a good account of the history of the lever watch).R.Good, 1978, Britten's Watch \& Clock Maker's Handbook Dictionary and Guide, 16th edn, London, pp. 190–200 (provides a good technical description of Mudge's lever escapement and its later development).DV
См. также в других словарях:
timekeeper — timekeeping, n. /tuym kee peuhr/, n. 1. a person or thing that keeps time. 2. an official appointed to time, regulate, and record the duration of a sports contest or its component parts, as to give the official time of a race, assure that a round … Universalium
watch — /woch/, v.i. 1. to be alertly on the lookout, look attentively, or observe, as to see what comes, is done, or happens: to watch while an experiment is performed. 2. to look or wait attentively and expectantly (usually fol. by for): to watch for a … Universalium
Swatch — a Swiss conglomerate with vertical control of the production of Swiss watches and related products. In 1982, Swatch was conceived and it was introduced on the market in Switzerland in March 1983.OriginSwatch was originally intended to re capture… … Wikipedia
Swindon Town F.C. — Football club infobox clubname = Swindon Town fullname = Swindon Town Football Club nickname = The Robins founded = 1879 ground = The County Ground Swindon | SN1 2ED capacity = 15,728 chairman = Andrew Fitton manager = flagicon|Scotland Maurice… … Wikipedia
Glossary of nautical terms — This is a glossary of nautical terms; some remain current, many date from the 17th 19th century. See also Wiktionary s nautical terms, Category:Nautical terms, and Nautical metaphors in English. Contents: A B C D E F G H I J K L M N O P Q R … Wikipedia
Pendulum — This article is about pendulums. For other uses, see Pendulum (disambiguation). Simple gravity pendulum model assumes no friction or air resistance … Wikipedia
Compass — This article is about the direction finding instrument used in navigation. For other uses, see Compass (disambiguation). A simple dry magnetic pocket compass … Wikipedia
Geologic time scale — This clock representation shows some of the major units of geological time and definitive events of Earth history. The Hadean eon represents the time before fossil record of life on Earth; its upper boundary is now regarded as 4.0 Ga.[1] Other… … Wikipedia
Time dilation — This article is about a concept in physics. For the concept in sociology, see time displacement. In the theory of relativity, time dilation is an observed difference of elapsed time between two events as measured by observers either moving… … Wikipedia
John Harrison — Infobox Scientist name = John Harrison |300px image width = 260px caption = P.L. Tassaert s half tone print of Thomas King s original 1767 portrait of John Harrison, located at the Science and Society Picture Library, London birth date = birth… … Wikipedia
Balance wheel — in a cheap 1950s alarm clock, the Apollo, by Lux Mfg. Co. showing the balance spring (1) and regulator (2) … Wikipedia
