What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The technical solution of Guangdong Yueluo Hardware Industry Co., Ltd. is: Guangdong Yueluo Hardware Industry Co., Ltd. discloses an anti-dropping nut, which includes a lock, a lock plate, a nut body, a lock ring and a lock claw. The lock ring and the nut body When used together, the lock ring is a circular ring, the inner diameter of the lock ring is larger than the inner diameter of the circumscribed circle of the nut body, the outer diameter of the lock ring is smaller than the inner diameter of the lock buckle, the lock disk is an arc-shaped metal plate, and the number of lock disks is greater than or equal to three. One short side end of the lock plate is connected to the nut body, and the other end of the lock plate is connected to the lock pawl, the lock plate is inclined to the outside of the nut body, and the lock catch is arranged on the outer side of the connection end between the lock pawl and the lock plate. On the side, the lock is a concave arc.
At present, the stopping method of the pin shaft stop pin of the general hydraulic excavator is mainly by using a long bolt to pass through the pin shaft stop sleeve pin hole and the pin shaft pin hole, and then use a double nut on the other end of the bolt to force it away from the pin shaft. The outer circle of the stop sleeve is about 2 3mm away to prevent the bolts and nuts from falling off. Due to the structure in which the double nuts are pressed against each other, the disassembly and assembly efficiency of this pin shaft stop method is not high, and two wrenches are required for each assembly and disassembly, which is extremely troublesome.
Standards are norms, and each country and sector has its own standards. The most commonly used standards in our daily business are as follows: GB—China National Standard (National Standard) ANSI—American National Standard (American Standard) DIN—German National Standard (German Standard) ASME—American Society of Mechanical Engineers Standard JIS - Japanese National Standard (Japanese Standard) BSW - British National Standard GB - National Standard is one of many standards in my country, as well as industry standards, professional standards and department standards. National standards are divided into: GB (mandatory standards) and GB/T (recommended standards) and GBn (national internal standards) and so on. We usually see GB30, GB5783, etc. are mandatory standards. In addition to some basic dimensions such as head-to-side, head thickness, etc., the above standards are mainly different in the threaded part. The threads of GB, DIN, JIS, etc. are all in MM (millimeters), which are collectively referred to as metric threads. Another thread like ANSI, ASME, etc. is called American standard thread in inches. In addition to metric threads and American threads, there is also a BSW-imperial standard, whose threads are also in inches, commonly known as Wyeth threads.
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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