A low-carbon steel rivet nut fastener composed of a brim, a deformed skirt and a threaded wire hole is characterized in that there are fish teeth below the brim; the outer side of the lower end of the threaded wire hole has a chamfer; the inner wall of the threaded wire hole The cross section of the thread is an isosceles trapezoid, and the upper bottom of the trapezoid is a concave arc.
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.
There are many types of rivets, including dome head, flat head, blind rivet and so on. When riveting parts, they will have uneven force and affect the quality of riveting. Some rivet caps are too thin to easily affect the quality of riveting. Some rivets have poor tightness of riveted parts when riveting. Therefore, both the structure of the rivet and the tightness of the riveting need to be considered, so as to enhance the quality of the rivet fastening.
The common riveting techniques of non-blind rivets are divided into cold riveting and hot riveting. Cold riveting is a riveting method that uses a rivet rod to partially pressurize the rivet, and continuously swings around the center or the rivet is forced to expand until the rivet is formed. The common cold riveting methods are the pendulum riveting method and the radial riveting method. The pendulum rolling riveting method is easy to understand, and the rivet head only swings and rolls in the circumferential direction.
Nuts cooperate with screws to achieve the fixing and connection of components. SMD nuts are generally used in the circuit board industry to fix electronic components. That is, the chip nut is soldered on the circuit board by solder, and the electronic components are fixed by turning the screw. However, when the current chip nut is soldered on the circuit board, there may be uneven soldering, which makes the soldering untidy. At the same time, during soldering, the excess solder overflows from the periphery of the nut, which affects the appearance and may affect its appearance. electrical properties. In addition, the nut is only welded with the circuit board on one end face, and its firmness and reliability after welding are low.
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