Brief introduction of steelyard
The steelyard is a kind of scale, and it is a simple weighing instrument that uses the principle of lever balance to weigh the weight. It consists of a wooden weighing beam with a weighing star, a metal weighing hammer and a hanging rope.
A small weighing instrument, with a wooden or metal rod with star point and taper as the main body, is equipped with a weight, a weight rope and a weighing pan (or hook). According to the scope of use and the size of the scale, it can be divided into shovel scale, pot scale and hook scale.
The steelyard consists of the first lever, and its center of gravity is at the outer end of the fulcrum. When weighing, according to the weight of the weighed object, move the weight and the weighting rope on the balance beam to keep the balance. According to the star point on the balance beam corresponding to the counterweight rope during balance, the quality indication value of the weighed object can be read out. The scale is simple in structure and manufacturing process, light and compact, easy to carry and use, low in cost, but low in accuracy.
The steelyard is the oldest weighing instrument invented by human beings. There are various refined weights, scales, scales, silk threads, hanging ropes, etc. among the cultural relics unearthed from the Chu Tomb in the eastern suburb of Changsha, Hunan, China before 700 BC. Among the cultural relics unearthed from the Han tombs in China before 200 BC, there have been various specifications of pole weights. 1989, a complete relic of wooden pole scale was found in a brick tomb of Han Dynasty in Yaoshang Village, Changxing Town, Meixian County, Shaanxi Province, China, and it was made about BC 1 ~ AD 1 century. The development of ancient steelyard has long been based on the use of rope buckles, non-quantitative weights and wooden, bamboo and bone scales. It was not until the 20th century that the steelyard gradually changed from the traditional rope buckle structure to the outer knife buckle plus knife bearing structure or the inner knife buckle plus knife bearing structure. After 1949, in order to strengthen the legal management of measurement, China has formulated the verification procedures and national standards for steelyard. From 1985 to 1987, the structure of steelyard in China has been greatly reformed, and the original wooden pole has been changed into metal pole, which has solved the shortcoming that the measurement accuracy of wooden pole is affected by the region and weather, and met the needs of semi-mechanization, standardization, generalization and mass production. However, the steelyard has been gradually eliminated because of its low measurement accuracy.
Scale culture
For thousands of years, hand scales have been regarded as China's "national quintessence". Lightweight, classic and easy to use. As the main measurement tool of commodity circulation, it is active in the north and south of the river and passed down from generation to generation. There is a steelyard between heaven and earth. People constantly endow the steelyard with cultural connotation, a symbol of fairness and justice, and a yardstick of heaven and earth conscience. One transaction after another is completed between the weight and the scale. ?
With the development of the times, some things will also withdraw from our daily life. The popularity of electronic scales indicates that the steelyard will withdraw from the historical stage and become a symbol of a country. ?
The technology of making a steelyard is passed down from mouth to mouth. Making a scale is a delicate craft. There is no room for carelessness in the procedures of selecting materials, planing, soaking in alkaline water, polishing and nailing the scale, and the scale will be biased. Weighers are extremely sacred and pious to their profession, and never let the scales be short because of operational mistakes. ?
The wooden poles used in the scale are picky, requiring delicate lines and hard wood. Oak, mahogany and so on. Are excellent materials. In order to ensure that the wooden poles do not crack, the selected materials should be stored in a dry place for two days before they can be used. After the wood is shaved and planed, it becomes a straight and slender oval cylinder, and then it is polished and smoothed with fine sand cloth, and some of it is wiped back and forth with Polygonum beads. From this point of view, the weigher can definitely be called an excellent carpenter. After both ends of the wooden pole are covered with metal skin, the steelyard is formed. ?
The next step is to elaborate and make weighing scale. The producer of the scale also needs to know physics and mathematics, otherwise it is quite laborious to scale. It is a very detailed process to hang the polished weighing beam on the scale, fix the fulcrum and check it with weights. The maker of the scale gently pulls the weight with the index finger of his left hand. When the wooden pole was in balance, he drew a mark on the back of the wooden pole with a foot gauge. This mark is called the fixed disk star, and the rest can be inferred from it. ?
There are too many marks on the steelyard for others to understand. The manufacturer of the scale punched holes in the mark with a very delicate seal. As many stars as there are on a scale, so many eyes are needed. A scale bearing 15 kg needs to drill nearly 300 holes. This process requires patience, and if you are not careful, you will puncture the wooden pole and scrap it. Most steel workers have sunken eyes, which are mostly caused by excessive use of eyes when drilling. ?
Insert the thin aluminum wire into the eye, break it and file it flat, leaving the stars. The arrangement structure of stars has also become a symbol for each scale to identify its own products. Hundreds of eyes, of course, have to be inserted hundreds of times, broken hundreds of times and filed hundreds of times. In order to save time, some scales put mercury in their eyes, and the eyes become stars. ?
The last process of the scale is coloring. If a scale is needed, it should be crushed with gallnut and soap alum and smeared with water. Like reddish brown, polished with soaked black tea residue and lime ... The color of the scale depends entirely on the customer's preference. ?
Nowadays, it is an indisputable fact that fewer and fewer people know and do this business. ?
Polishing the steelyard, the years also passed away in polishing, and the craftsmanship also disappeared in polishing.
manufacturing method
(1) Choose disposable chopsticks and polish them with a knife and sandpaper; ?
(2) Cut the iron sheet into a circle to make a weighing pan, tie it on the disk surface with a string, and lift it; ?
(3) drilling a hole at one end of the polished balance beam and hanging a disc; ?
(4) Tie a rope with a nut of about 5g to make it heavier; ?
(5) Hang the balance beam, disc and nut, find out the center of gravity of the whole system, drill a small hole on the center of gravity, and hang a rope as a lifting buckle; ?
(6) Don't put objects to balance the steelyard, find out the position of the zero scale line and mark it; ?
(7) Put a 20g object and find out the position of the weight when the 20g object is balanced, which is the position of the 20g object here; ?
(8) Draw an average of 20 scales between the zero scale line and the 20g position, and each scale is1g..