What's the history of Weighing Scales

What's the history of Weighing Scales

Weighing scales are also called "weighment ",Weighing apparatus. Or the weighing instruments with unequal arms are called scales, or refers to the lifting and tie bar scales that measure the weight of things by looking at the scales, or refers to the scale bars. During the Warring States period, there were unequal arm weighing apparatus. It has not been decided when the domestic steelyard started. The unearthed king of Chu bronze balance pole has a scale of ten equal parts. It is speculated that it is a sign of hanging weight and weight in different parts when weighing. It is likely to be a kind of weighing instrument in the transition from equal arm balance to pole scale. After the Eastern Han Dynasty, it evolved into a scale to see the weight from the scale star.

 

Steelyard:

It is a small weighing instrument with wooden or metal rod with star point and taper as the main body, and equipped with mound (weight), mound rope and scale plate (or hook). According to the scope of use and the size of the scale, it can be divided into three kinds, i.e. chain, pan scale and hook scale. The steelyard is a first-class lever. It is a simple weighing instrument that uses the principle of lever balance to weigh. It is composed of a wooden steelyard with a steelyard star, a metal steelyard hammer and a lifting rope.

 

The steelyard scale consists of the first kind of lever, which focuses on the outer end of the fulcrum. When weighing, according to the weight of the object to be weighed, the weight and the weight rope move on the scale pole to maintain balance. According to the star point on the scale pole corresponding to the weight rope during balance, the mass indication of the weighed object can be read out. The structure and manufacturing process of the scale are simple, light and small, easy to carry and use, low cost, but low accuracy.

 

The steelyard scale is one of the most long-standing scales invented by human beings. Among the artifacts unearthed from the Chu tomb in the eastern suburb of Changsha, Hunan Province, China, there are various refined weights, scales, scales, silk threads and lifting ropes.

 

Among the relics unearthed from the Han Tombs in China 200 BC, there are various sizes of pole weights. In 1984, a complete wooden steelyard was found in a single kiln brick Tomb of Han Dynasty in Yaoshang village, Changxing Town, Meixian County, Shaanxi Province, China. It was made in the first century B.C. - A.D.

 

Weighing Scale:

For a long time, the development of ancient steelyard was based on the use of rope knobs, non quantitative weights and wooden, bamboo and bone steelyards, which were made by hand. It was not until the 20th century that the traditional structure of rope button was gradually changed into the structure of outer knife button and knife bearing or inner knife button and knife bearing. After 1949, in order to strengthen the legal management of metrology, China has formulated the verification regulations and national standards of pole scales. From 1985 to 1987, China made a major reform on the structure of the pole scale, replacing the original wooden pole with metal pole, thus solving the problem that the accuracy of the measurement of the wooden pole is affected by the region and weather, and meeting the needs of semi mechanization, standardization, generalization and mass production. However, due to its low measurement accuracy, the steelyard scale has been gradually eliminated.

 

Bench Scale:

Lever type mechanical scale weighing 50kg to 1000kg. The load-bearing device is a small weighing instrument with rectangular table, which is usually used on the ground. According to the structure principle, it can be divided into mechanical platform scale and electronic platform scale.

 

Mechanical Platform Scale:

The principle of unequal arm lever is used. It is composed of bearing device, reading device, base lever and scale body.

 

The reading device includes adding weight, hanging weight, measuring lever, etc. The basic lever is connected by a long lever and a short lever in parallel. When weighing, the force transmission system is: the four components of the force when placing the weighed object on the bearing plate act on the key knife of the long and short lever, and the force is transmitted to the key knife of the measuring lever by the force point knife of the long lever and the connecting hook. By manually adding, subtracting, adding and moving the weight, the measuring lever is balanced, and the weight indication of the weighed object can be obtained.

 

The mechanical platform scale has simple structure and accurate measurement. It can be placed and used as long as there is a flat and solid scale frame or ground.

 

The model of Chinese platform scale is composed of tgt3 Chinese Pinyin letters and a group of Arabic numerals. The letters T, G and t represent platform scale, lever structure and weight increasing type respectively, and the Arabic numerals represent the maximum weight (kg).

 

The main models are tgt-50, tgt-300, tgt-500 and tgt-1000. Electronic platform scale: a small electronic weighing instrument based on the principle of non electric measurement. It is composed of load-bearing table, scale body, weighing sensor, weighing display and regulated power supply.

 

When weighing, the weight of the measured object is converted into an electrical signal by the weighing sensor. After being amplified by an operational amplifier and processed by a single-chip microprocessor, the weighing value is displayed in digital form. The electronic platform scale can be placed on the hard ground or installed in the foundation pit.

 

The utility model has the advantages of light weight, convenient movement, multiple functions, cable connection between the display and the scale body, and can be placed according to the needs when using. In addition to weighing, peeling weight, cumulative weight and other functions, it can also be connected with the actuator and set the upper and lower limits to control the speed of feeding. It can be used as small package batching scale or quantitative scale.

 

Counter Scales:

Lever type mechanical scale weighing below 50kg (excluding 50kg). According to the structure and function, it can be divided into ordinary case scale and electronic pricing scale.

 

Common case scale: it is composed of base, bracket, connecting rod, knife rest, adjusting weight, bearing plate, floating weight, scale piece and increasing weight. The structure is simple.

 

The common scale is designed and manufactured by using the principle of unequal arm lever and half side robertwell mechanism. The load-bearing plate is located above the measuring lever, which is unstable because the center of gravity is higher than the support. Therefore, the robertwell mechanism is composed of connecting rod, pulling plate and adjusting plate, and the double fulcrum and double point composite lever is used to increase the bearing area, so as to ensure that the load-bearing plate only swings up and down during weighing, and does not topple forward, backward, left and right. This mechanism overcomes the disadvantages of hanging weighing tools that need to be carried by hand and the balance of the scale is affected by the shaking of the scale.

 

The advantages of ordinary scale are as follows: ①The load-bearing plate can be made into flat plate type or movable disc type, which is easy to be taken down when weighing and used as container. ② The relationship between the weight of the added weight P, the weight of the weighed object W and the length of the lever arm is as follows: when an object with a mass of 5kg is placed on the bearing plate, only the added weight with a mass of 1kg needs to be placed on the added weight plate to make the scale in a balanced state. There are four kinds of the maximum weight of the table scale, which are 1kg, 3kg, 6kg and 15kg. The corresponding models are agt-1, agt-3, agt-6 and agt-15. This scale is accurate, durable, easy to use and maintain, so it is widely used.

 

Electronic pricing scale:

It is composed of high-precision resistance strain type weighing sensor, load-bearing device and weighing display.

 

The analog voltage output by the weighing sensor, which is proportional to the weight of the object, is filtered out by the filter and converted into digital quantity by the analog-to-digital converter. Then, it is displayed by the digital display in the form of quality and amount through pulse counting and digital display technology. Electronic pricing scale can set the unit price in advance, and automatically display the amount of the weighed items at the same time. It is a commercial scale integrating weighing, pricing, display, peeling and printing.

 

It has the characteristics of high measurement accuracy, convenient and fast keyboard operation, and has the function of digital memory.

 

When the key cannot be pressed, the key can be locked to avoid misoperation. There are three kinds of the maximum weighing / minimum dividing value of the electronic scale: 3kg/1g, 6kg/2g and 15kg/5g.

 

Spring Scale:

A weighing instrument for measuring the weight of an object by using the deformation of a spring under the action of gravity. Its scale can be from 1 mg to dozens of tons. There are two kinds of scales, one is single-sided display and the other is double-sided display. Spring scale, also known as spring dynamometer, is a device to measure the force made of the relationship between the deformation of the spring and the external force. In different latitudes of the earth, the mass of the same object measured by the same spring scale will be different.

 

Spring scale is divided into two types: pressure and tension. The pressure on the tray of the pressure spring scale is equal to the gravity of the object. The rotation angle of the pointer of the scale plate indicates the value of the pressure. The lower end of the tension spring scale is connected with a hook (the hook is connected with the lower end of the spring), and the upper end of the spring scale is fixed on the ring on the top of the shell. When the object to be measured is hung on the hook, the spring is extended, and the pointer fixed on the spring is lowered. Because the extension of the spring is proportional to the external force within the elastic limit, the magnitude of the force or the gravity of the object can be read directly from the scale value on the shell indicated by the pointer of the spring scale. When using, it should be noted that the measured gravity or force should not exceed the measuring range of the spring scale. It should also be checked whether the pointer points to the zero scale when the spring scale is not hung. If not, it can be corrected. Before hanging objects, it is better to gently pull the hook back and forth several times to prevent the spring pointer from sticking on the shell. In addition, attention should be paid not to make the spring and pointer with the shell friction, in order to avoid excessive error.

 

Electronic Platform Scale:

The weight of the items on the platform, plate and hook of the scale is balanced by the creep reaction of the sensor, and the scale displayed by the digital instrument is an electronic scale. Electronic scale integrates machine, electricity and instrument. It has the characteristics of multi-function, high precision, fast and dynamic measurement, stable and reliable. It represents the development direction of weighing instrument products.

 

Tray Balance:

Commonly used balances with low accuracy. It is composed of a tray, a beam, a balance nut, a scale, a pointer, a knife edge, a base, an index ruler, a running weight, a weight, etc. The accuracy is generally 0.1 or 0.2 grams. The balance beam is supported by the fulcrum (axle) in the center of the beam to form two arms. Each arm hangs or holds a plate, and one of the plates (usually the right plate) holds an object of known weight (weight) ), another pan (usually the left pan) puts the scale to be weighed;

The object and the slider slide on the scale. When the pointer fixed on the beam does not swing and points to the center scale, or when the swing amplitude is small and equal, the sum of the weight of the weight and the indication of the weight position indicates the weight of the object to be weighed. Note:

1:Place it horizontally.

2:Adjust the balance nut in advance to balance the balance.

3:Put weights on the right and objects on the left.

4:The weight can't be held by hand, it should be clamped with tweezers. You can't move it by hand.

 

Electronic Balance:

The electronic scale is an automatic weighing equipment used to weigh the goods. The measurement of the goods is completed by the power-to-electric conversion of the sensor and processed by the weighing instrument. It is suitable for the measurement of various bulk goods. Working principle: The weighing object converts gravity into an analog signal of voltage or current through a weight sensor installed on the mechanism. After amplification and filtering, it is converted into a digital signal by the A/D processor. The digital signal is processed by the central processing unit ( CPU) arithmetic processing, and peripheral required functions and various interface circuits are also connected to the CPU for application, and finally displayed in digital form on the display screen.

 

Loader scale:

The electronic scale of loader is a kind of measuring equipment for weighing the loaded bulk materials according to the actual application needs of users, which can be used for vehicle loading measurement, load limiting measurement and earthwork measurement. It is composed of sensor and weighing display instrument, which can measure dynamically or statically. Weighing instrument can print date, time, display peeling, zero, store weight data and information and other functions, working principle: loader electronic scale is a kind of loader weighing equipment, which is integrated with the mechanical control part of loader to realize weighing during the progress of loader. It uses a proximity switch to monitor the pre-determined weighing position, and converts the hydraulic pressure into the weight of the load in the bucket to realize weighing. It has two different working modes: target mode and accumulation mode. According to the operator's choice, it can automatically accumulate the load or deduct it from the target set value.

 

Main components: a weighing instrument, two oil pressure sensors, a position sensor, four installation modules.

 

Development History:

The most primitive scale in the world, its physical evidence (stone weight) was found in the Indus River civilization site (about 2400-1800 B.C.) in Pakistan, with a history of 3000-4000 years. The ancient Egyptians also mentioned it in the records of the same time (about 1878b. C.), but no real object has been found so far. In China, scale appeared very early. In the middle and late spring and Autumn period, the state of Chu had made a small weighing instrument - wooden scale and copper ring power, which was used to call gold currency. A complete set of ten ring weights, roughly increasing by multiple, are one baht, two baht, three baht, six baht, twelve baht, one or two, two or two, four baht, eight baht and one jin. There is a bronze balance pole in the Museum of Chinese history during the Warring States period. This kind of scale is different from the balance and the later scale pole, but it is similar to the unequal arm balance. Through the gradual evolution process, the heavy arm of the scale pole is shortened, and the force arm is lengthened, which has become a modern scale still in use. Before the birth of Jesus, the scale was introduced into the west by the nomadic ministry and was named Roman scale. This scale is recorded in the works of many Latin writers. The two arms of the Roman scale are not equal, and the arm at the end of the scale is short, and the length is fixed. When weighing the weight, move the scale hammer at the other end of the scale bar (this changes the length of the scale arm at that end) until the scale bar reaches the horizontal state. The scale can be used to weigh objects much heavier than the scale hammer.

 

The most primitive scale in the world, its physical evidence (stone weight) was found in the Indus River civilization site (about 2400-1800 B.C.) in Pakistan, with a history of 3000-4000 years. The ancient Egyptians also mentioned it in the records of the same time (about 1878b. C.), but no real object has been found so far. In China, scale appeared very early. In the middle and late spring and Autumn period, the state of Chu had made a small weighing instrument - wooden scale and copper ring power, which was used to call gold currency. A complete set of ten ring weights, roughly increasing by multiple, are one baht, two baht, three baht, six baht, twelve baht, one or two, two or two, four baht, eight baht and one jin. There is a bronze balance pole in the Museum of Chinese history during the Warring States period. This kind of scale is different from the balance and the later scale pole, but it is similar to the unequal arm balance. Through the gradual evolution process, the heavy arm of the scale pole is shortened, and the force arm is lengthened, which has become a modern scale still in use. Before the birth of Jesus, the scale was introduced into the west by the nomadic ministry and was named Roman scale. This scale is recorded in the works of many Latin writers. The two arms of the Roman scale are not equal, and the arm at the end of the scale is short, and the length is fixed. When weighing the weight, move the scale hammer at the other end of the scale bar (this changes the length of the scale arm at that end) until the scale bar reaches the horizontal state. The scale can be used to weigh objects much heavier than the scale hammer.

 

Legend of invention:

It is said that Fan Li found in his business that people always use their eyes to evaluate things in the market, so it is difficult to achieve fair trade. So he came up with the idea of creating a tool to measure the weight of goods. One day, on his way home from business, Fan Li happened to see a farmer drawing water from a well. The method was very ingenious: a high wooden stake was erected beside the well, and then a horizontal wood was tied to the top of the stake; One end of the crossbar is hung with a wooden bucket, and the other end is tied with stones. It is light and light from top to bottom

 

Save effort. Inspired by this, Fan Li Dun rushed home to imitate: he drilled a small hole with a thin and straight stick, tied a hemp rope on the hole, and weighed it with his hand; One end of the thin wood is tied with a hanging plate to hold goods, and the other end is tied with a pebble as a mound; The farther the pebbles are moved from the rope, the more cargo they can lift. So he thought: how many goods to hang on one end and how far to move the pebbles on the other end in order to keep balance, it is necessary to carve a mark on the fine wood. But what's a good way to mark it? Fan Li pondered for several months, but he still had no idea. One night, Fan Li went out to take a walk. As soon as he looked up and saw the stars in the sky, he had a whim and decided to use the six stars of the South and the seven stars of the north as marks. One star represents one or two weights, and thirteen stars represent one kilogram. Since then, the market will have a unified measurement tool - weighing scale.

 

However, after a long time, Fan Li found that some unscrupulous businessmen were short of weight when they were selling things, and they cut off the common people. He thought, how to improve the scale and put an end to the evil deeds of unscrupulous merchants? Finally, he came up with the idea of changing the black star carved in white wood into a metal star inlaid in mahogany, and adding three stars of fortune, fortune and longevity to the six stars of the southern and the seven stars of the northern dipper, with 16 Liang as a Jin. The purpose is to warn peers: as a businessman, you must be aboveboard, not to make dirty money. He said: "if a businessman deceives others for one or two years, he will lose his fortune and happiness; If you cheat others, you will never be able to get a salary; If you deceive others, you will lose your "Yang Shou" (short life)! "

 

In this way, the weighing tool has been handed down from generation to generation, and has been followed for more than 2000 years, until today.

 

Steelyard Culture:

For thousands of years, hand scale can also be regarded as the "quintessence" of China. It is light, classic and convenient to use. As the main measurement tool of commodity circulation, it is active in the north and south of the country and handed down from generation to generation. There is a scale between heaven and earth, people constantly give the cultural connotation of scale, the symbol of fairness and justice, the ruler of conscience of heaven and earth, a pile of transactions are completed between the weight and the scale. With the development of the times, some things will also withdraw from our daily life, and the popularity of electronic scales indicates that the scale will withdraw from the stage of history and become a national symbol.

 

The technology of steelyard maker is handed down from mouth to mouth. Weighing is a fine craft, from material selection, planing, to soaking in alkaline water, polishing, nail scale flower and other procedures, the road can not tolerate a little careless, a little careless, the scale will have deviation. The steelmaker is very sacred and devout to his profession. He never makes the steelyard short because of operational mistakes.

 

The wood used to make the scale is more picky. It needs fine grain and hard wood. Oak and mahogany are all superior materials. In order to ensure that the wooden pole does not crack, the selected materials should be stacked in a dry place for two days before use. After being chiseled and planed, the wood becomes a straight, long and thin elliptical cylinder, which is polished smooth and smooth with fine abrasive cloth and water, and some are wiped back and forth with Polygonum beads. From this point of view, the weigher can definitely be called an excellent carpenter. After the two ends of the wooden pole are covered with metal skin, the steelyard will appear its rudiment.

 

The next step is to work out the weight scale. The weigher also needs to know physics and mathematics, otherwise it will take a lot of effort to set the scale. It is a very detailed process to fix the fulcrum of the polished scale pole after hanging it on the scale plate and check it with weights. The steelmaker's left index finger keeps gently moving the weight. When the wooden pole is in balance, he uses the foot gauge to mark a mark on the back of the wooden pole. This mark is called dingpan star, and the rest infers the weight according to this mark. There are various marks on the scale, which others can't understand. The steelmaker punched the mark with a very delicate stamp. As many stars as there are on a steelyard, he needed as many eyes. A 15kg scale needs to drill nearly 300 holes. This procedure is very patient. If you don't pay attention to it, the wooden pole will be punctured and scrapped. Most steelmakers have sunken eyes, which is mostly caused by excessive use of eyes when drilling.

 

Insert a section of thin aluminum wire into the eye, break it, file it flat, then leave a star. The arrangement structure of the stars has also become the identification of their products among the weighers. Hundreds of eyes, of course, hundreds of times to insert, break, file. In order to save time, some weighers put mercury into their eyes and become stars.

 

The last procedure of the steelyard is coloring. If the steelyard needs to be black and blue, it should be crushed with gallnut and alum and smeared with water; I like the reddish brown ones. I rub and polish them with soaked red tea residue and lime. The color of the scale depends on the preference of customers.

 

Nowadays, it is an indisputable fact that there are fewer and fewer people who understand and do this business. The years of grinding the steelyard are also passing away, and the craftsmanship is also disappearing.

 

Production Method:

(1) Select a disposable chopstick and polish it with knife and sandpaper;

(2) Cut the iron sheet into a circle and make it into a scale plate, which is tied and hoisted around the plate with string;

(3) Drill a hole in one end of the polished scale rod and hang the disc;

(4) Tie a rope with a nut about 5g to make a weight;

(5) Hang up the beam, disc and nut, find out the center of gravity of the whole system, drill a small hole in the center of gravity, and hang a rope as the lifting button;

(6) Do not put objects to balance the scale, find out the position of the zero scale line and mark it;

(7) Put on the 20g object and find out the position of the weight when the 20g object is balanced. Here is the position of the 20g object;

(8) Draw an average of 20 graduations between the zero mark and the 20 gram position, and each scale is 1 gram.

 

Weighing instrument development:

The ten types of weighing instruments (table scale, platform scale, ground scale, ground scale, hanging scale, belt scale, hopper scale, inspection scale, track scale and special scale) listed in China's product standards have all been electronic. According to statistics, electronic products in industrial weighing instruments (according to sales volume statistics) have accounted for about two-thirds of the total. The measurement range of static weighing instruments with relatively mature technology can be from 1 μ G to 800t, some non automatic weighing instruments (such as electronic pricing scale, electronic platform scale, electronic ground scale, electronic belt scale, electronic hanging scale and electronic track scale, etc.).