What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
3. Friction coefficient The friction angle is an important factor affecting the torque, and the existence of friction is the basis for the normal operation of the lock nut. When the lock nut is working, the contact surface has pressure and friction under the action of the elastic restoring force of the thread piece. During the repeated use, the rough position and edges and corners of the contact surface are ground and smoothed under the action of cyclic friction. The coefficient of friction becomes smaller, which in turn reduces the maximum unscrewing torque of the nut.
In view of the deficiencies in the prior art, the purpose of Guangdong Yueluo Hardware Industry Co., Ltd. is to provide a detachable rivet to solve the problems raised in the above-mentioned background technology. Guangdong Yueluo Hardware Industry Co., Ltd. is easy to use, easy to operate, and has good stability. , high reliability.
At present, when using the existing screwdriver to install the screw, it is necessary to fix the screw with the left hand and turn the screwdriver with the right hand. However, in some places where the installation space is small and the installation is difficult, there are many areas that cannot be accessed by hands, and the installation is very difficult. For example, on an airplane, when installing with a common screwdriver, it is very difficult to install the screws and the installation efficiency is low because the screws cannot be positioned; in addition, when installing screws on the aircraft wing or fuselage, the combination between the screwdriver and the screw is easy to slip, The blade of the screwdriver slipped out and could easily bruise the hand and damage the aluminum skin of the aircraft.
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.
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