be a good timekeeper

tr['taɪmkiːpə^SMALLr/SMALL]

noun

1 cronometrador,-ra

timekeeper ['taɪm.ki:pər] n

: cronometrador m, -dora f

• cronometrador, -ora s.m.,f.

• cronómetro s.m.

• reloj s.m.

a) ( Sport) cronometrador, -dora m,f

b) ( worker) (BrE)

['taɪmˌkiːpǝ(r)]

1) (=watch) reloj m, cronómetro m

2) (=official) cronometrador(a) m / f

3)

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a) ( Sport) cronometrador, -dora m,f

b) ( worker) (BrE)

timekeeper ['taɪm‚ki:pə(r)]

noun

(a) (watch) montre f; (clock) horloge f; (stopwatch) chronomètre m;

∎ 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

(d) Sport (official) chronométreur(euse) m,f officiel(elle)

timekeeper [ˈtaɪmki:pə^r]

( = official) chronométreur m, - euse f officiel(le)

• to be a good timekeeper [person] être toujours à l'heure

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noun Sport chronométreur m; gen

timekeeper n

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.

1) sport cronometrista m. e f.

2) (punctual person)

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1 (ind.) controllore delle ore di lavoro

2 (mus.) chi batte il tempo ( per una banda, ecc.)

3 ( sport) cronometrista

4 cronometro; orologio

● (mus.) a good timekeeper, un tempista □ This watch is a good [a bad] timekeeper, questo orologio va bene [va male]

n. [u]

1 (ind.) rilevamento dei tempi

2 ( sport) cronometraggio.

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1) sport cronometrista m. e f.

2) (punctual person)

1. (in sports) Zeitnehmer m

2. (clock, watch) Zeitmesser m

this watch is not an accurate \timekeeper diese Uhr geht nicht genau

to be a bad/good \timekeeper person sein Zeitsoll nie/immer erfüllen

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timekeeper s

1. Zeitmesser m:

be a good timekeeper genau gehen (Uhr)

2. SPORT Zeitnehmer(in)

3. WIRTSCH Arbeitszeitkontrolleur(in)

* * *

Zeitmesser m.

Sport cronometrista m/f

n. scheidsrechter bij sportwedstrijden; noteert aanwezigheid van personeel

1  uurwerk

2  tijdwaarnemer ⇒ tijdopnemer

♦voorbeelden:

1   my watch is a good timekeeper • mijn horloge loopt altijd op tijd

'time·keep·er n

1) ( in sports) Zeitnehmer m

2) (clock, watch) Zeitmesser m;

this watch is not an accurate \timekeeper diese Uhr geht nicht genau;

to be a bad/good \timekeeper person sein Zeitsoll nie/immer erfüllen

(a) (supervisor) pointeau m

(b) (employee)

∎ 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

subst. \/ˈtaɪmˌkiːpə\/

1) ( sport) tidtaker

2) tidtaker(ur), stemplingsur (på arbeidsplass)

3) timeskriver (på arbeidsplass)

4) person som er punktlig

• Susan is a good timekeeper

5) ( gammeldags) klokke

SUBJECT AREA: Horology

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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.

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SUBJECT AREA: Horology, Ports and shipping

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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.

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See also: Burgi, Jost; Huygens, Christiaan