Sprinkle the excess standard spring washer 7 on the positioning plate 12-1 on the spring washer positioning plate 2, and shake the spring washer positioning plate 2 by hand. After a short time, the spring washer 7 will be positioned and arranged on the upper positioning plate 12-1. In the upper spring washer hole 2-7, since the width of the opening groove 12-32 of the baffle plate 12-3 is smaller than the diameter of the spring washer hole 2-7, and the thickness of the upper positioning plate 12-1 is designed according to the thickness of the spring washer 7, Only one spring washer 7 can be accommodated in the spring washer hole 2-7 of each upper positioning plate 12-1, and the excess spring washer 7 is cleaned with a brush.
screw suitable for a variety of tools is a single-structure threaded part, including a screw body and a screw head. The outer surface of the screw body is processed with an external thread 1, and the outer side of the screw head is formed by six screw heads. Prismatic, the top surface of each edge of the outer hexagonal prism is a boss, between each boss is an end face groove 4, and the middle of each boss is provided with an end face hole 3; the inner side of the screw head is formed by six screw heads. The side surface 5 forms an inner hexagonal prism hole, and the bottom of the inner hexagonal prism hole is processed with a cross groove 12 .
The existing method of tightening large screws is generally 1. After the nut is screwed to the connected piece by hammering + nut angle method, use a casing to connect the lever arm of the wrench, or use a free hammer to hammer the plate handle, Rotate the nut an additional angle to obtain the required preload. This is not only a primitive and labor-intensive fastening method, but also has great limitations, such as limited space, or the screw itself is a rotating shaft and so on, it is difficult to use this method.
The earliest rivets were small pegs made of wood or bone, and the earliest metal variants may be the ancestors of what we know as rivets. They are without a doubt the oldest known method of joining metals, dating back as far as the earliest use of malleable metals, eg: Bronze Age Egyptians riveted the six wooden sectors of the outer lines of a slotted wheel with rivets Fastened together, after the Greeks had succeeded in casting large statues in bronze, the parts were riveted together with rivets.
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.
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