Generally speaking, combination screws are widely used in electrical, electric, mechanical, electronic, household appliances, furniture, ships and so on. But the above said that different combination screws have different functions. For example, Phillips pan head combination screws are generally used in small electronic products. Larger cross hexagon combination screws are used in larger electrical products, such as frequency converters, and some larger frequency converters use many cross hexagon combination screws. Hit the inverter case. To loosen the tightening effect. For example, two combination screws with flower teeth, which are used on the inverter, are used to break the paint, so that all the two combination screws on the surface of the casing are powered on. There is also a two-combination screw with a square pressure line, which itself is a two-combination screw with a pan head screw and a square pad. It is generally used on the surface of the terminal block. The function is for wiring and for crimping.
T-bolts for channel steel usually include a head and a shank. The shank is provided with threads. Traditional T-bolts for channel steel are used for channel steel, and both channel steel and bolts are made of steel. , the two are prone to thermal expansion and contraction due to changes in the external ambient temperature, and are prone to loosening, resulting in unstable connections.
The first person to describe the spiral was the Greek scientist Archimedes (c. 287 BC - 212 BC). An Archimedes screw is a huge spiral contained in a wooden cylinder that is used to irrigate fields by raising water from one level to another. The real inventor may not be Archimedes himself. Maybe he was just describing something that already existed. It may have been designed by the skilled craftsmen of ancient Egypt for irrigation on both sides of the Nile. In the Middle Ages, carpenters used wooden or metal nails to attach furniture to wooden structures. In the 16th century, nail makers began producing nails with a helical thread, which were used to connect things more securely. That's a small step from these kinds of nails to screws. Around 1550 AD, the metal nuts and bolts that first appeared in Europe as fasteners were all made by hand on a simple wooden lathe. Screwdrivers (screw chisels) appeared in London around 1780. Carpenters have found that tightening a screw with a screwdriver holds things in place better than hitting with a hammer, especially with fine-grained screws. In 1797, Maudsley invented the all-metal precision screw lathe in London. The following year, Wilkinson built a nut and bolt making machine in the United States. Both machines produce universal nuts and bolts. Screws were quite popular as fixings because an inexpensive method of production had been found at that time. In 1836, Henry M. Philips applied for a patent for a screw with a cross recessed head, which marked a major advance in screw base technology. Unlike traditional slotted head screws, Phillips head screws have the edge of the head of the Phillips head screw. This design makes the screwdriver self-centered and not easy to slip out, so it is very popular. Universal nuts and bolts can connect metal parts together, so by the 19th century, the wood used to make machines to build houses could be replaced by metal bolts and nuts. Now the function of the screw is mainly to connect the two workpieces together and play the role of fastening. The screw is used in general equipment, such as mobile phones, computers, automobiles, bicycles, various machine tools and equipment, and almost all machines. need to use screws. Screws are indispensable industrial necessities in daily life: extremely small screws used in cameras, glasses, clocks, electronics, etc.; general screws for televisions, electrical products, musical instruments, furniture, etc.
The electroplating of cross recessed screws generally refers to the electroplating of iron cross recessed screws. Stainless steel cross recessed screws are rarely electroplated. The electroplating colors of cross recessed screws are divided into environmental protection and non-environmental protection. Environmental protection blue zinc, environmental protection color zinc, environmental protection black zinc, environmental protection white nickel, etc., non-environmental protection includes white nickel, white zinc, color zinc, black zinc, black nickel, black cladding, blue zinc.
At present, with the continuous growth of the demand for communication products, higher and higher requirements are put forward for the production capacity of equipment manufacturers, and at the same time, the requirements for the cost, weight and reliability of communication products are also more and more stringent. In order to facilitate the positioning of the equipment, pins are often used to complete the equipment, and a certain cost is incurred for its manufacture and assembly. In the past, such parts have been assembled in the form of threads. In order to ensure that the assembly height is within the specified range and to prevent loosening, bar turning is often used to form threads and positioning steps, and thread pinning glue is used in the assembly, and the cost of machining is relatively high. Large, more material waste. Based on the above drawbacks, in order to better solve this problem, some existing manufacturers use the interference fit riveting method, which solves the problem of material waste and anti-loosening, but the inner diameter of the pin hole and the outer diameter of the pin are matched. The machining accuracy of the machine is relatively high. Once the matching size is out of tolerance, a second matching is required, which wastes working hours and increases the slack time.
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