What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
In the existing industrial technology field, screws are mostly used for the connection between components. For many electronic products, because the products are more and more thin and light, the connection between the shell and the shell is often affected by the thickness of the shell. , usually need to use screw column structure for connection. Take the existing outdoor three-proof mobile phone as an example: the screw column structure includes a shell, a shell and a screw, the shell is provided with a plurality of screw columns, and the nuts in the screw columns are injected through the in-mold injection process. Directly integrated with the housing. Due to the special use environment and use requirements of outdoor three-proof mobile phones, they need to have good high-strength anti-drop performance, while the three-proof mobile phones in the prior art are subjected to high-strength drop tests due to the fundamental stress concentration of the screw column. During the process, problems such as cracking of the screw column or breaking from the root occur.
According to the process, the wing nut can be divided into cold heading wing nut, casting wing nut and stamping wing nut. According to the shape, it can be divided into two basic shapes: square wing and round wing. According to the national standard number, it can be divided into GB/T62.2-2004 Square Wing Wing Nut Wing Nut Round Wing Wing Nut Round Wing GB/T62.1-2004 Round Wing Wing Nut
R-type plastic rivets, also known as expansion rivets, are composed of plastic sub-nails and female buckles. It is not necessary to use installation tools during installation, place the installation base in the smooth hole, and then press the head, the specially designed feet expand and stretch after being stressed, and are firmly locked on the installation surface. It is often used to connect plastic shells, lightweight boards, insulating materials, circuit boards, or any other thin, light-weight materials. It is beautiful, practical, and easy 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.
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