What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Process equipment for aircraft production (hereinafter referred to as tooling) is directly used for part forming and component assembly. In order to satisfy the loading and unloading of aircraft parts and components during the use of the tooling, the tooling generally adopts a structural form that is easy to disassemble as a whole. In the field of aircraft process equipment manufacturing, positioning pins are usually used to connect and position the detachable parts of the tooling. At present, this kind of locating pin is divided into two types: direct pull-out locating pin and tie-suspended locating pin.
With the continuous improvement of automation technology, human participation in the production process is gradually decreasing, especially in the processing of some small parts, the manual processing efficiency and accuracy are low. Whether the screws can be stably picked up and installed automatically is of great help to improve automated production.
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.
The technical scheme adopted by Guangdong Yueluo Hardware Industry Co., Ltd. is: a pin pressure riveting structure, including a pin, a cavity and a pressure riveting fixture, the pin is a columnar structure, an annular groove is arranged on the surface of the pin, and the cavity is The body is provided with a light hole, the depth of the light hole is greater than the height of the annular groove relative to the bottom of the pin, the lower end of the pin is inserted into the light hole, the pressure riveting fixture includes a pressure riveting part and a pressure-bearing part located on the top of the pressure riveting part, so The riveting part and the pressure-bearing part are provided with coaxial and penetrating connecting holes, and the upper ends of the pins are sleeved in the connecting holes.
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