Introduction to the development of Worksite power tools
Cutting machine In 1895, Germany manufactured the world's first DC electric drill. The shell is made of cast iron and can drill 4mm holes in the steel plate. Then appeared a three-phase power frequency (50Hz) electric drill, but the motor speed failed to break 3000r/min. In 1914, a Worksite electric tool driven by a single-phase series motor appeared, and the motor speed reached more than 10000r/min. In 1927, an intermediate frequency Worksite power tool with a power supply frequency of 150 to 200 Hz appeared. It not only has the benefit of a single-phase series motor with high speed, but also has the benefit of a simple and reliable three-phase power frequency motor. However, it needs intermediate frequency current. Power supply, use is restricted. In the 1960s, following the development of battery manufacturing skills, battery-type Worksite power tools without power cords using nickel-cadmium batteries as power sources appeared. However, the expansion was slow due to the high price. In the 1960s, thermoplastic engineering plastics were used in Worksite power tools and completed the two-layer insulation of Worksite power tools, ensuring the safety of the use of Worksite power tools. Due to the development of electronic skills, electronic speed-controlled Worksite power tools also appeared in the 1960s. This kind of Worksite power tools use thyristors and other components to form an electronic circuit, and adjust the speed by the depth of the switch button being pressed, so that the Worksite power tools can be processed according to the different processing principles (such as different materials, Drilling diameter size, etc.), choose a different speed. In the mid-to-late 1970s, due to the decline in battery quotations, the charging time was also shortened. This kind of Worksite power tools were widely used in Europe, America and Japan. Worksite power tools started out with cast iron as the outer shell, and later switched to aluminum alloy as the outer shell.