Service HotlineGenerally, the countersunk head is used in places where the surface is required to be smooth without protrusions, because the countersunk head can be screwed into the part. Round heads can also be screwed into parts. The tightening force of the square head can be larger, but the size is large. In addition, in order to meet the needs of locking after installation, there are holes in the head and holes in the rod. These holes can prevent the bolts from loosening when they are vibrated. Some bolts without threads should be made thin, called thin-waisted bolts. This kind of bolt is beneficial to the connection under variable force. There are special high-strength bolts on the steel structure, the head will be larger, and the size will also change. In addition, there are special uses: for T-slot bolts, which are most used on machine tool fixtures, with special shapes, and both sides of the head should be cut off. Anchor bolts, used for machine and ground connection and fixing, come in many shapes. U-bolts, as previously described. and many more. There are also special studs for welding. One end has a thread and the other end is not. It can be welded to the part, and the other side can directly screw the nut.
At present, the commonly used shaft retaining rings in the market usually include elastic retaining rings and screw locking retaining rings, but they all require tools to be installed and disassembled, which is relatively inconvenient to use.
Yueluo relates to a self-tapping screw according to the preamble of claim 1. A self-tapping screw is known from EP0623759B1, the ratio of the outer diameter to the smaller diameter of the self-tapping screw is about 1.25-1.5, the ratio of the outer diameter to the pitch lead is about 1.5-1.6 and the thread The flank angles of , are < 50° and ≥ 35°. EP0433484B1 proposes a self-tapping screw whose thread is provided with cutting teeth of approximately arcuate design, and the cutting edge and the thread crest are at the same horizontal position and are set in opposite directions. One purpose of Yueluo is to realize a general type of self-tapping screw so that it can be screwed particularly easily into holes drilled in concrete or other materials such as bricks and the like. According to Yueluo, this object is achieved by the features in the characterizing part of claim 1, and surprisingly, it has been found that the parallel arrangement of the flanks, ie with a flank angle of about 0°, will make screwing particularly easy when screwing in , especially if the diameter of the hole varies within an allowable tolerance. One reason may be due to the fact that there is no lateral pressure on the material screwed into the thread, even if threads of different depths are cut in concrete or other materials such as brick, chipped plywood, or hardwood. The thread cuts into the material over its entire width by cutting grooves. In particular according to the embodiment of claim 4 the material cut out when screwing in the screw can be discharged without any accumulation, the dependent claims reflecting many advantages of further embodiments.
Usually, the car wheel is fixed on the axle sleeve with positioning pins and pins, and the tire hub and the sleeve are fastened on the axle with locking nuts, lock washers, and adjusting nuts. This structure can operate normally within a certain period of time when the vehicle speed is low and the vibration is small. However, when the car runs for a long time, especially when the road surface is uneven and the load changes sharply, the axle sleeve bears a great impact. Once the shear force generated is too large, the pin will break, and the nut will be loosened. Affected, the wheel and hub will be loose. If the maintenance is not timely, or the driver is inexperienced, the car will have an accident in which the tire falls off with the wheel hub. This is extremely dangerous. So people are looking for ways to prevent wheels and hubs from falling off
Round head three-combination screw The screw size in the round-head three-combination screw is GB818, and the main technical requirements of various types are: iron and stainless steel material requirements, iron low, medium, high carbon steel, stainless steel combination The materials of the screws are stainless steel 201, stainless steel 304 and stainless steel 316. The thread tolerance is 6G, and the mechanical properties of the iron combination screws are 4.8 and 8.8. The 4.8-level combination screws are ordinary steel, and the maximum allowable hardness is 255HV. The 8.8-level combination screws are generally made of wire rod 10B21. , and then undergo hardening treatment, and then dehydrogenation after hardening treatment. Hydrogen removal is to prevent hydrogen embrittlement of the spring washer in the combination screw. Prevent the spring pad from breaking. The tolerance class of the combination screws is A. The cross groove is H-shaped. The surface treatment of the combination screw has environmental protection and non-environmental protection. Such as, environmental protection blue zinc, environmental protection color zinc, black zinc, color zinc, white nickel and so on. The technical requirement of the combination screw for the spring washer is that the washer should be able to rotate automatically without falling off.
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