What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Swimming self-locking nut GJB 125.1～125.6-86 The double-ear sealing swimming self-locking nut is composed of four parts: sealing cover, self-locking nut, pressure ring and sealing ring. It has compact structure and reliable sealing, and is suitable for products whose working pressure is not more than 2atm, working medium is gasoline, kerosene, water or air, and the operating temperature is -50～100℃. However, it has certain difficulties in the manufacturing process and air tightness test.
Ordinary snap-type retaining rings have ears on their structure, which cause interference with the inner parts. If the ears are not provided, it is very troublesome to disassemble. For the very demanding aerospace field, ordinary snap rings cannot meet their requirements.
kind of screw provided by Yueluo, the rod body of the screw rod has a thread segment, one end of the thread segment is provided with an annular convex ring on the outer peripheral surface of the rod body, and the distance between the convex ring at the front end of the screw threading direction and the rod core Smaller than the nominal size of the threaded section or the distance from the rear end of the bead to the rod core in the screwing direction is greater than the nominal size of the threaded section.
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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