Domestic clocks: 15th century
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After the success of the clocks in Europe's cathedrals in the 14th century, and the introduction of the clock face in places such as walls, kings and nobles naturally want this impressive technology at home. The first domestic clocks, in the 15th century, are smaller and simpler versions of the cathedral clocks which are powered by hanging weights. It shows the time to the great man's family and household by a single hand working its way round a 12-hour circuit on the clock's face. But before the middle of the 15th century a development of great significance occurs. The earliest surviving spring-driven clock dates from about 1450. By that time clock makers have not only found out how to transmit power to the mechanism from a coiled spring. They have also devised a simple solution to the problem inherent in a coiled spring which steadily loses power as it uncoils. The solution to this is the fusee. The fusee is a cone, bearing a spiral of grooves on its surface, forming part of the axle driving the wheels of the clock mechanism. The length of gut linking the drum of the spring to the axle is wound round the fusee. It lies on the thinnest part of the cone when the spring is fully wound and reaches its broadest circumference by the time the spring is weak. Increased leverage counteracts decreasing strength. These two devices make possible clocks which stand on tables, clocks which can be taken from room to room, even clocks to accompany a traveler in a carriage. Eventually, they make possible the pocket watch as well.
After the success of the clocks in Europe's cathedrals in the 14th century, and the introduction of the clock face in places such as walls, kings and nobles naturally want this impressive technology at home. The first domestic clocks, in the 15th century, are smaller and simpler versions of the cathedral clocks which are powered by hanging weights. It shows the time to the great man's family and household by a single hand working its way round a 12-hour circuit on the clock's face. But before the middle of the 15th century a development of great significance occurs. The earliest surviving spring-driven clock dates from about 1450. By that time clock makers have not only found out how to transmit power to the mechanism from a coiled spring. They have also devised a simple solution to the problem inherent in a coiled spring which steadily loses power as it uncoils. The solution to this is the fusee. The fusee is a cone, bearing a spiral of grooves on its surface, forming part of the axle driving the wheels of the clock mechanism. The length of gut linking the drum of the spring to the axle is wound round the fusee. It lies on the thinnest part of the cone when the spring is fully wound and reaches its broadest circumference by the time the spring is weak. Increased leverage counteracts decreasing strength. These two devices make possible clocks which stand on tables, clocks which can be taken from room to room, even clocks to accompany a traveler in a carriage. Eventually, they make possible the pocket watch as well.
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