What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Blind rivets are a type of rivets for single-sided riveting, but they must be riveted with a special tool - a rivet gun (manual, electric, and moving). This type of rivet is especially suitable for riveting occasions where it is inconvenient to use ordinary rivets (which must be riveted from both sides), so it is widely used in construction, automobiles, ships, aircraft, machinery, electrical appliances, furniture and other products. Among them, the open type oblate head blind rivets are the most widely used, the countersunk head blind rivets are suitable for riveting occasions that require smooth performance, and the closed blind rivets are suitable for riveting occasions that require higher load and certain sealing performance.
rivet with a simple structure includes a rivet cap, a rivet main rod, a rivet limit rod and a limit hole. The rivet main rod is provided with a limit hole inside, the rivet limit rod is located below the rivet main rod, the upper end side of the rivet limit rod is provided with a limit groove, the limit groove is connected with the lower end of the rivet main rod, and the groove surface of the limit groove is round. arc-shaped, the lower end side of the rivet limit rod is provided with four limit grooves, the cross section of the limit groove is in the shape of a right-angled trapezoid, the limit hole passes through the interior of the rivet limit rod and the rivet main rod, and one end of the limit hole The hole surface and the lower end surface of the rivet limit rod are on the same plane.
In the past production, gaskets were generally obtained from two channels: first, standard gaskets were mostly purchased from the market, and the cost was high; non-standard gaskets, due to the small demand, required separate tooling and molds, which were expensive and long production cycle. It is difficult to purchase; Second, the plate is purchased by the enterprise, and then the washer is formed by the automatic cutting machine. Because the cut nodules and cut marks produced by flame cutting do not meet the requirements for use, the inner and outer diameters need to be reserved 2 ～3mm machining allowance, and then finish the outer diameter and inner diameter by lathe.
Generally, 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.
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