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Heures sautantes = springende uren… Jumphour…
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43 mm., CHF 5.100,00
Ze verzinnen toch werkelijk van alles! Een soort digitaal horloge dus …
haha is al een heel oud principe hoor, in de jaren rond 1790-1800 waren er al dergelijke zakhorloges…
1790 - 1800 is historisch gezien een uiterst belangrijke periode geweest. Maar niet voor horloges …
? ow ?
In deze periode werden wel, imho, de grondslagen gelegd voor de moderne horologie…
1760 Temperature compensation and chronometers
Diagram of Earnshaw’s standard chronometer detent escapement
The Enlightenment view of watches as scientific instruments brought rapid advances to their mechanisms. The development during this period of accurate marine chronometers to determine longitude during sea voyages produced many technological advances that were later used in watches. It was found that a major cause of error in balance wheel timepieces was changes in elasticity of the balance spring with temperature changes. This problem was solved by the bimetallic temperature compensated balance wheel invented in 1765 by Pierre Le Roy and improved by Thomas Earnshaw. This type of balance wheel had two semicircular arms made of a bimetallic construction. If the temperature rose, the arms bent inward slightly, causing the balance wheel to rotate faster back and forth, compensating for the slowing due to the weaker balance spring. This system, which could reduce temperature induced error to a few seconds per day, gradually began to be used in watches over the next hundred years.
The going barrel invented in 1760 by Jean-Antoine Lépine provided a more constant drive force over the watch’s running period, and its adoption in the 19th century made the fusee obsolete. Complicated pocket chronometers and astronomical watches with many hands and functions were made during this period.
1800 Lever escapement
Thomas Mudge, inventor of the lever escapement
The lever escapement, invented by Thomas Mudge in 1759 and improved by Josiah Emery in 1785, gradually came into use from about 1800 onwards, chiefly in Britain; it was also adopted by Abraham-Louis Breguet, but Swiss watchmakers (who by now were the chief suppliers of watches to most of Europe) mostly adhered to the cylinder until the 1860s. By about 1900, however, the lever was used in almost every watch made. In this escapement the escape wheel pushed on a T shaped ‘lever’, which was unlocked as the balance wheel swung through its centre position and gave the wheel a brief push before releasing it. The advantages of the lever was that it allowed the balance wheel to swing completely free during most of its cycle; due to ‘locking’ and ‘draw’ its action was very precise; and it was self-starting, so if the balance wheel was stopped by a jar it would start again.
Jewel bearings, introduced in England in 1702 by the Swiss mathematician Nicolas Fatio de Duillier, also came into use for quality watches during this period. Watches of this period are characterised by their thinness. New innovations, such as the cylinder and lever escapements, allowed watches to become much thinner than they had previously been. This caused a change in style. The thick pocketwatches based on the verge movement went out of fashion and were only worn by the poor, and were derisively referred to as “onions” and “turnips”.
Mooi hoor,
Ik denk nog wel eens om een mooie jumphour aan te schaffen maar dan voor een redelijke prijs van rond de twee of drie honderd euro om te proberen, maar nog steeds niets moois gevonden .
groetjes Lenno