What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
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.
A rivet is a nail-shaped object with a cap on one end: in riveting, the parts being riveted are joined by their own deformation or by interference. There are many types of rivets, and they are informal. However, the two ends of conventional rivets are concentric, which is not suitable for special occasions.
flat washer, an annular groove is formed on the outer side of the upper surface of the flat washer, and a sealing ring is embedded in the annular groove, at least five circularly equidistantly arranged cylinders are fixed on the upper surface of the flat washer, and the The upper surface of the flat washer is provided with a circular hole that communicates with its bottom, a collar is arranged in the circular hole, an upper circular ring is fixed above the collar, a lower circular ring is fixed below the collar, and the upper circular The diameter of the ring is the same as the diameter of the lower ring, the diameter of the collar is smaller than the diameter of the upper ring, the diameter of the collar is consistent with the diameter of the circular hole, and there are at least three equally spaced holes in the middle of the outer wall of the flat washer. A circular groove, the outer wall of the flat washer is fixed with at least three reinforcing blocks staggered with the circular groove, and the reinforcing blocks and the flat washer are welded into one piece.
The quality of the combination screw should start with the screw wire of the combination screw manufacturer. The wire of the screw is the first hurdle to determine the quality of the combination screw. Even if the wire is not good, even if the production equipment is advanced and the staff is skilled, it is impossible to produce high-quality combination screws. In the second look at the quality of the combination screw products, from the overall aesthetics of the combination screw. A combined screw is formed, the size of the screw head, the superior appearance of the flat washer, whether the screw thread can pass the stop gauge, etc. These are all things that need to be detected. A good combination screw, its overall standard can meet the national standard requirements, or customer requirements. Finally, the quality of the combination screw product is seen from the color of the plating. Of course, the iron combination screw needs to be plated, but the stainless steel combination screw does not need it. Some of them are passivation at most, in order to increase the salt spray resistance of stainless steel combination screws. In the electroplating color of the combination screw, some of them are not well controlled, which will produce a great color difference. That doesn't look good.
The above content is uploaded by Yueluo or the Internet. If there is any copyright issue, please contact [email protected].
