The general term for clocks and watches. Clock and watch are both precise instruments for measuring and indicating time.
Clocks are usually distinguished by the size of the internal machine. According to international practice, clocks and watches with movement diameter greater than 50 mm and thickness greater than 12 mm; A pocket watch with a diameter of 37 ~ 50 mm and a thickness of 4 ~ 6 mm is called a pocket watch; Watches with a diameter less than 37 mm; A watch whose diameter does not exceed 20mm or whose movement area does not exceed 3 14m2 is called a women's watch. The watch is one of the smallest, strongest and most sophisticated machines invented by human beings.
The power of modern clocks and watches includes mechanical force and electricity. Mechanical clock is a kind of timer which uses the energy released by heavy hammer or spring as power to drive a series of gears to run, adjusts the speed of gear train with the help of escape governor, and indicates time and metering time with hands. Electronic clock is a kind of timer which is powered by electric energy, and liquid crystal displays numbers and timely hands.
[Edit this paragraph] clock history
Primitive people judged time according to the change of sky color and the brightness of the sun. Ancient Egypt discovered that the shadow length would change with time and invented the sundial to measure time in the morning. They also found that the time needed for water to flow was fixed, so they invented the water clock. In ancient China, people also used water to time-dripping water from a copper pot, and burning incense to time. Put the incense horizontally and put a rope with steel balls on it, which can tell the time.
1283, the first mechanical clock driven by weight appeared in English monasteries.
Monks in northern Italy began to build bell towers (or bell towers) in the third century A.D./Kloc-to remind people of the time of prayer.
/kloc-in the middle of the 0/6th century, Germany began to have clocks on the table. Those clocks have only one hand, and the clock face is divided into four parts, which makes the time accurate to the nearest 15 minutes.
1657, huygens discovered that the frequency of pendulum can calculate time, and made the first pendulum clock. 1670, an Englishman William Clement invented the anchor escapement.
1797, Eli Terry, an American, obtained the patent right of clocks and watches. He is regarded as the originator of American watch industry.
[Edit this paragraph] Observe the development
Before 1300 years ago, human beings mainly used the continuous movement of time by astronomical phenomena and flowing materials. For example, the sundial is timed according to the orientation of the sun's shadow; When clepsydra and hourglass are flow meters that use water and sand.
In the Eastern Han Dynasty, Zhang Heng made a leak-turning armillary sphere, and connected the elephant with a timed leak kettle by a gear system. The leaky kettle drips water to push the elephant to rotate evenly, once a day. This is the earliest mechanical clock. Su Ge and Han Honglian, etc. In the third year of the Northern Song Dynasty (1088), the water transport instrument platform was created and the escapement mechanism was used.
1350, Danti, an Italian, made the first mechanical clock with simple structure, with a daily difference of 15 ~ 30 minutes, and the indicating mechanism was only an hour hand; 1500 ~ 15 10, Henleith of Germany first replaced the heavy hammer with a steel spring and created a small mechanical clock with a crown wheel escapement mechanism. 1582 or so, Galileo of Italy invented the gravity pendulum; 1657, huygens of the Netherlands introduced the gravity pendulum into the mechanical clock and founded the pendulum clock.
1660, Hook of England invented the hairspring, and replaced the crown wheel escapement with the backward escapement. 1673, Huygens applied the governor composed of hairspring to portable clocks and watches; 1675, Clemente of England made the simplest anchor escapement with fork-hoof device, which has been used for single pendulum wall clocks.
1695, Tom ping of Britain invented the I-wheel escapement; 17 15, Graham of England invented the static escapement, which made up for the deficiency of the backward escapement and laid the foundation for the development of precision mechanical clocks and watches. 1765, March of England invented the free anchor escapement, which is the predecessor of modern fork-hoofed escapement. From 1728 to 1759, Harrison in Britain made high-precision standard navigation clocks; From 1775 to 1780, Arnold of England created the escapement mechanism of precision watches.
From 18 to 19 century, the watch manufacturing industry gradually realized industrial production and reached a fairly high level. In the 20th century, with the rapid development of electronic industry, battery-driven clocks, AC clocks, electromechanical watches, analog electronic clocks and digital electronic clocks came out one after another. The daily difference of clocks and watches has been less than 0.5 seconds, and clocks and watches have entered a new era of the integration of timely microelectronics technology and precision machinery.
[Edit this paragraph] About the evolution of clocks and watches
Can be roughly divided into three stages of evolution, namely:
First, the evolution from the Big Clock to Jason Chung.
Second, the transition from small clock to pocket watch.
Third, the development from pocket watch to wrist watch. The development of each stage is inseparable from the technological invention at that time.
1088, Su Song and Han Gonglian, scientists of the Song Dynasty, made an image platform of water transport instrument, which is a device that combines an armillary sphere, an elephant and a mechanical timer. It is driven by hydraulic power and has a scientific escapement mechanism. It is about 12 meters high and 7 meters square, and is divided into three layers: the upper layer is equipped with an armillary sphere for astronomical observation; The middle layer can simulate celestial bodies for synchronous demonstration; The lower layer is the heart of the instrument, and the formation and output of timing, time telling, power supply are all on this layer. Although it was destroyed by war decades later, it is of great significance in the history of world watches. Therefore, Mr. Jiao Da Yu, a famous master of clocks and watches in China and a collector of ancient clocks and watches, put forward the viewpoint that "China people created the history of clocks and watches".