The scale was invented by the Frenchman Jill persona de loberval.Scale, also known as electronic scale, is the alias of Weighbridge and truck scale. It is the main weighing equipment used for measuring bulk goods such as grain processing industry, factories and mines. The most primitive scale in the world was invented by the ancient Egyptians. More than 7000 years ago, ancient Egyptians used a hanging double pan scale to weigh wheat. The scale has two scales, which are hung at both ends of the scale beam.In China, the scale also appeared very early. In the middle and late spring and Autumn period, the state of Chu has made a small weighing instrument - wooden scale and copper ring weight, which is used to call gold currency. A complete set of ring weights consists of ten pieces, increasing in multiples, namely one baht, two baht, three baht, six baht, twelve baht, one or two, two, four, eight and one kilogram. The Chinese History Museum has a bronze balance pole from 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 process of gradual evolution, the boom of the scale bar 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 Roman scale are unequal, and the scale arm at the weighing end is short and the length is fixed. When weighing the weight, move the weight at the other end of the scale bar (thus changing the length of the scale arm at that end) until the scale bar reaches the horizontal state. This scale can be used to weigh objects much heavier than the scale hammer.In 1670, Gilles personne de Roberval (1602-1675), a famous French mathematician, physicist and mechanical designer, submitted his invented case scale to the Paris Academy of Sciences in 1670. This is an equal arm double disk case scale (also known as scale). The scale pan is installed at both ends of the scale beam, and a rigid guide rod is installed below it, which can move up and down in the corresponding guide hole on the scale base. In this way, when the scale beam swings around the shaft, the scale pan can move up and down under the action of the guide rod, but its horizontal state remains unchanged. Up to now, lobawal case scale is still the most widely used commercial scale in the world.