What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Embedding of fasteners, especially screws. The main point of the structure is that it includes an annular base, one at the base and a plurality of cylindrical tubes on the base, and the cylindrical tubes and the cylindrical tubes on the base are connected by ribs. Cylindrical tubes are used as fixing holes and fastener pre-embedded holes respectively. The product is fixed on the formwork that needs to use screw points through the fixing holes. After the concrete is poured into the floor, the embedded screw parts are pre-embedded, and the floor has embedded screw holes for hanging the installation objects with screws. . Avoid future re-drilling damage to the wall and floor. Guangdong Yueluo Hardware Industry Co., Ltd. has a simple and scientific structure, easy pre-embedding, strong tensile strength and firmness.
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 11 the result is that the material cut out when screwing in the screw can be discharged without any accumulation, the dependent claims reflecting many advantages of further embodiments.
The capped nut can prevent the bolt connection from directly contacting with the outside world, which is corroded and makes it difficult to disassemble later. Nuts with caps in the prior art are mostly of one-piece structure, and the surface is not treated with anti-oxidation, which is easy to be corroded. In addition to the protective effect, the fastening method is the same as that of ordinary nuts, so it is easy to loosen when subjected to severe vibration. .
Guangdong Yueluo Hardware Industry Co., Ltd. is a kind of locking nut, which includes a nut, the bottom of which is circular, the middle is hexagonal, the top is circular, there is a bolt hole in the center, the side wall of the bolt hole is threaded, and the top of the nut is Set up several squash notches. According to the locking nut of the preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the number of flattening notches is three. The three flattening gaps can be used as the focal point of the tightening tool and the clamping place of the anti-loose gasket bayonet, and the structure is simple and can be formed by die stamping at one time.
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