By the way, the history of clock development:
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 shoe device, which has been used for single pendulum wall clock.
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 was less than 0.5 seconds, and clocks entered a new era of timely integration of microelectronics technology and precision machinery.
Types of clocks and watches
Clocks and watches have a wide range of applications and many varieties, which can be classified according to vibration principle, structure and application characteristics. According to the principle of vibration, it can be divided into clocks and watches that use low-frequency mechanical vibration, such as pendulum clocks and balance clocks. Clocks and watches that use high-frequency electromagnetic oscillation and synchronous oscillation, such as synchronous clocks and synchronous clocks; According to the structural characteristics, it can be divided into mechanical watches, such as mechanical alarm clock, automatic, calendar, double calendar, clockwork, etc. Electromechanical, such as electric pendulum clock, electric balance wheel clock, etc. ; Electronic clock, such as balance wheel electronic clock, tuning fork electronic clock, pointer and digital display time electronic clock, etc.
There are many structural forms of mechanical clocks and watches, but their working principles are basically the same. They are all composed of prime mover system, transmission system, escapement governor, pointer system and winding system.
Mechanical clocks and watches take clockwork as the power system, and drive the escape governor through a transmission system composed of a group of gears; Then the speed of the transmission system is controlled by the escape governor in turn; The transmission system drives the pointer mechanism while pushing the escapement mechanism, and the rotation speed of the transmission system is controlled by the escapement mechanism, so the pointer can indicate the time on the dial according to certain rules; The winding pointer system is a mechanism for winding springs or moving pointers.
In addition, there are some additional mechanisms that can increase the functions of clocks and watches, such as automatic winding mechanism, calendar (double calendar) mechanism, alarm device, moon phase indication and timing mechanism.
The prime mover is a mechanism for storing and transmitting working energy, which usually consists of a box wheel, a box cover, a lever shaft, a spring and a spring hook. When the spring is in a free state, it is a spiral or S-shaped spring with a small hole at its inner end, which is sleeved on the hook of the rod shaft. Its outer end is hooked on the inner wall of the box wheel through the clockwork outer hook. When winding, the winding needle system rotates the winding shaft and tightly winds the spring on the winding shaft. The elastic action of the spring makes the box wheel rotate, thus driving the transmission system.
The transmission system is a set of transmission gears, which transfer the energy of the prime mover to the escapement governor. It consists of two wheels (central wheel), three wheels (passing wheel), four wheels (second wheel) and the pinion shaft of the escape wheel, wherein the blade is the driving gear and the pinion shaft is the driven gear. The tooth profile of clock transmission system is mostly modified cycloidal tooth profile based on theoretical cycloidal principle.
The escapement governor consists of escapement mechanism and vibration system. It relies on the periodic vibration of the vibration system to keep the escapement mechanism in accurate and regular intermittent motion, thus realizing speed regulation. Fork-shoe escapement is the most widely used escapement. It consists of an escape wheel, an escape fork, a double disc and a limit nail. Its function is to transfer the energy of the power system to the vibration system, so as to maintain the constant amplitude vibration of the vibration system and transfer the vibration times of the vibration system to the indicating mechanism, thus achieving the purpose of timing.
The vibration system is mainly composed of balance wheel, swing shaft, hairspring, movable outer pile ring, fast and slow needle, etc. The inner and outer ends of the hairspring are respectively fixed on the swinging shaft and the swinging splint; When the balance wheel deviates from the balance position by external force and begins to swing, the hairspring is twisted to produce potential energy, which is called recovery moment. The escapement mechanism completes the above two actions, and the vibration system swings in the opposite direction under the action of hairspring potential energy to complete the other half of the vibration period, which is the principle that the escapement governor works continuously and repeatedly when the mechanical clock is running.
The needle winding and shifting system is used for needle winding and shifting. It consists of a handle head, a handle shaft, a vertical wheel, a clutch wheel, a clutch lever, a clutch lever spring, a pull rod, a pressure spring, a needle shifting wheel, a straddle wheel, an hour wheel, a minute wheel, a large steel wheel, a small steel wheel, a pawl, a pawl spring and the like. Both winding and needle setting are realized by the handle part. When winding, the vertical wheel and the clutch wheel are engaged. When the handle head is rotated, the clutch wheel drives the vertical wheel, and the vertical wheel passes through the small steel wheel and the large steel wheel to wind the winding shaft tightly. The pawl prevents the big steel wheel from reversing. When the needle is pulled out, the handle head is pulled out, and the tooth pulling shaft rotates to push the clutch lever, so that the clutch wheel is separated from the vertical wheel and engaged with the needle pulling wheel. At this time, the rotating handle will drive the hour wheel and the minute wheel through the straddle wheel to achieve the purpose of correcting the hour hand and the minute hand.
Clocks and watches require accuracy, stability and reliability. However, some internal factors and external environmental conditions will affect the time accuracy of clocks and watches. Internal factors include structural design, working performance, material selection, processing technology and assembly quality of each component system. For example, the stability of clockwork torque, the stability of transmission system and the accuracy of escape governor all affect the travel time accuracy. External environmental conditions include temperature, magnetic field, humidity, air pressure, vibration, collision, use position, etc. For example, temperature changes will cause changes in the performance of lubricating oil and hairspring in watches and clocks, thus causing changes in driving performance; When the environmental magnetic field intensity is greater than 60 Oster, some parts will be magnetized and slow down; Humidity can cause oxidation and corrosion of some parts, etc.
The origin of clocks and watches
The ancient people lived a simple life and had nothing to do except eat, fish, hunt and make tools, so they worked at sunrise and rested at sunset, so there was no need to fight for time. Then when human beings live in groups and have transactions, it is just' Japan and China are the market, and transactions retreat'. Later, personnel became more and more complicated, especially after the rise of agriculture, and human beings gradually realized the importance of time. The concept of time varies with the degree of human civilization, from the early "immediate effect" to measuring time with a standard watch or sundial, to the invention of "missing engraving" which requires accurate time measurement, and to the invention of the water clock later, which drives the shaft or makes the gear run by increasing the weight of dripping water. It was not until the 11th century that the mechanical clock officially appeared. The mechanical clock used a heavy hammer instead of water as the power to drive the gears to run.
The legend of the invention of the watch is that the locksmith in Nuremberg (the industrial capital of northern Germany) made it as big as an egg in the16th century, so it was called "Nuremberg egg". Watch parts themselves contain power, and they are completely handmade, with the improvement of the system, so the styles of things made are different.
Swiss Watch Switzerland is known as the "kingdom of watches". Its watch industry has ruled the world for two and a half centuries, and it still maintains the first position in the world. Switzerland's watch industry originated in a small village between the valley and basin of the Gnome mountain range on the Franco-Swiss border with Geneva as the center. As early as the15th century, jewelers and goldsmiths in Geneva began to make watches. 160165438+1October 20th, the Geneva authorities formally approved the establishment of the world's first watch trade association. At that time, there were only about 300 watch technicians in Geneva, with an annual output of about 5,000. By the middle of the18th century, a large number of watchmakers had gathered in Geneva. They often opened shops on the ground floor facing the street to attract customers and made and repaired watches in a quiet place on the top floor.
Geneva's experience of relying on the prosperity of clocks and watches inspired farmers and herdsmen deep in the dwarf mountains, and they also began to make gears, springs and clockwork. Some local youths have studied in cities such as Geneva for more than ten years or even decades, and then returned to their hometowns to start their own handicraft workshops. Together with Qi Xin, they are determined to build the best parts in the world and assemble the most complicated and precise watches. /kloc-At the turn of the 20th century, the Swiss watch industry is really facing severe challenges. With the deepening of the industrial revolution, standardized mass production invented by Americans swept the world. It seems that only American-style factories can earn enough profits to survive, but Swiss watch workshops have finally found a way to adapt to modern industrial society. It is through the unified design and mass production of professional parts companies such as movement, strap and case that the expensive value of watches is reduced to the level that ordinary consumers can bear. Coupled with those skilled craftsmen and small watch factories with unique styles, the purchased parts are modified and customized into special parts, so that the Swiss watch industry can maintain harmony with those famous watches. American watches, which have always threatened mass production, became invisible in the market after World War II because of the lack of product support of various grades and prices.