What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
When the tightening effect is achieved by the nut, it is often necessary to use a wrench to fix the nut or turn the nut to achieve the fixing effect. During the use process, the size of the nut is fixed, so it is necessary to use the corresponding type of wrench and the corresponding nut. In the tightening operation, during the installation process, the size of the wrench is large, that is, the nut cannot be manipulated, and it takes time to find a suitable wrench, which is inefficient.
An elastic cylindrical pin loading and unloading tool, comprising a rectangular base on which a hollow cylindrical tooling station is arranged for fixing a tooling and installing a cylindrical pin on the tooling for shear force testing, the The tooling includes an outer cylinder and an inner cylinder that are assembled together, the outer cylinder and the inner cylinder are in clearance fit, and the base is further provided with a counterbore for taking out the inner cylinder after the tooling test is completed.
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 3 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 is an anti-theft screw, which can prevent the use of any disassembly tool for disassembly, and effectively plays the role of anti-theft. Its structure is that the anti-theft screw is composed of two parts; the upper part is a hexagonal part, and the lower part is a threaded part; the hexagonal part and the threaded part are connected in rotation; The core shell is formed with the lock core; the lock core is rotatably connected with the lock core shell. The shell of the lock cylinder is fixedly connected with the hexagonal piece, and the starting structure is as follows: a pin hole is arranged on the hexagonal piece; The lower part of the hexagonal part is provided with a polygonal hole, which is connected with the polygonal hole on the threaded part; the lower part of the lock cylinder is a threaded rod; the threaded rod is located in the polygonal hole; The edge block moves up and down in the polygonal hole. When working, slowly twist the hexagonal piece from left to right and turn the key at the same time to achieve the alignment of the upper and lower polygonal holes.
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