Service HotlineThere is a standard for the outer hexagon bolt standard, which is a grade standard, which is divided into grade 4.8 and grade 8.8. These two levels are used a lot in the market. Especially grade 4.8 hex head bolts. Because it is much cheaper than 8.8 hex bolts. Of course it is more widely used. But for demanding products. Because of its high requirements in various aspects such as hardness. This requires the use of 8.8 hex bolts. Grade 8.8 hex bolts are harder in terms of hardness and screw torque. It is safer to use the product. Tighter and more stable.
In automobiles, wheel nuts are a widely used component. According to the actual use requirements of the wheel nut, there are often spacers on the wheel nut. In this way, the wheel nut and spacer form a wheel nut assembly. However, in the prior art, since the washer is only movably fitted on the wheel nut, when the wheel nut is removed or a large number of wheel nuts are placed, the wheel nut and the washer will be separated. When in use, they need to be assembled one by one, and when they are disassembled or placed again after use, they need to be assembled again, which not only increases the unnecessary workload, but also affects the use effect of the wheel nut in actual use.
Dowels are made on the steering seat on the ball head of the car, and the rollers are assembled to the steering seat through the dowels. The prior art is manual driving of the pins, and the position of the pins is inaccurate when driving the pins, the labor intensity is high, the efficiency is low, and the quality of the steering seat is also affected. Therefore, it is necessary to design an automatic pin-driving mechanism to drive the pins into the steering seat. .
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.
In the process of our transformation and upgrading from big manufacturing to strong manufacturing, the talents of the main body of innovation play an important catalytic role, including a large number of engineers, and drawings are a necessary expression tool for their practical innovation. Engineering drawing courses, as the basic courses of engineering colleges, play an important role in students' ability to read and output engineering drawings, and are directly related to the innovation ability in future work practice.
We have many years of experience in the production and sales of screws, nuts, flat washers, etc. The main products are: H59 injection molded copper nuts, semi-circular head internal screws, self-locking screws, plastic support studs and other products, we can provide you with suitable fastening for you. piece solution.
