What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Procurement and sales in the testing process know that the quality of screws is manufactured, not detected, but in manufacturing, we must try our best to make them as good as possible. But it is unlikely to be completely error-free and error-free. We all know that errors are unavoidable and can only be approached infinitely. Therefore, at this time, the quality inspection of the screw is required to improve the quality of the screw. At the beginning of ordering from screw wire material into the production of screw industry manufacturers, you must first check the wire diameter of the screw wire and the material of the screw. Generally, the wire diameter of the screw is measured with a caliper to measure the size of the wire diameter, whether it is suitable for self-ordering. Same size. After testing these, it is the testing in the production process, starting from the head of the screw, to determine the size of the head, the opposite side of the head, the diagonal angle, the depth of the cross groove, the tolerance range of the screw, and so on. These are checked with calipers. In the inspection of all aspects when rolling teeth, the main thing is whether the thread can pass the pass and stop gauge, and whether the screw thread can pass the gauge and stop. Next is the electroplating measurement problem. After electroplating, whether it meets the requirements of environmental protection and whether it can pass the time required by the salt spray. Tools include environmental testing machines and salt spray testing machines. In short, in the process of screw production and sales, there must be necessary tools to detect the quality of screws. The summary should be summarized as follows: calipers, hardness testers, salt spray machines, environmental testing machines, pass and stop gauges, etc. When producing and selling screws, there will be a screw specification and screw model. With the screw specification and screw model, we can understand what specification screw and what size screw the customer needs. Many screw specifications and screw models are based on national standard specifications and models. Generally, such screws are called ordinary screws, which are generally available on the market. There are some non-standard screws, which are not based on the national standard specifications, models and sizes, but are customized according to the standards required by the product materials. There is no stock in the general market at all. In this way, it is necessary to make drawings and samples.
In machine tool processing, it is often necessary to calibrate and debug the probe. The method of manually correcting the detection is inefficient and the accuracy is unstable. In addition, accidents such as collisions will occur. However, calibration tools such as ring gauges are expensive, have large working strokes and poor versatility. Technical realization elements: In view of the above content, it is necessary to provide a positioning pin for probe calibration to solve the above problems. A positioning pin is used for calibrating a probe, the positioning pin includes a connected cylinder and a cylinder, the cylinder is used to be installed on a jig in a machine tool, and the end of the cylinder away from the cylinder is provided with a measuring hole to calibrate the probe. Further, the positioning pin is also provided with a chip removal hole, one end of the chip removal hole is connected to the measuring hole, the other end of the chip removal hole penetrates the end of the cylinder away from the cylinder, and the chip removal hole is used for discharging machining chips and cutting fluid. Further, the diameter of the chip removal hole is smaller than the diameter of the measuring hole. Further, the positioning pin further includes a positioning piece, the positioning piece includes a base and a magnetic piece, one end of the base is provided with a mounting hole for installing the magnetic piece, and the other end of the base is provided with a limiting hole for mounting the column. Further, the limiting hole communicates with the mounting hole. Further, the limiting hole is a blind hole. Further, the diameter of the cylinder is larger than the diameter of the cylinder. Further, the measuring hole is a cylindrical hole. Further, the diameter of the cylindrical hole is 4 mm. Further, the end face of one end of the cylinder provided with the measuring hole is a curved surface, and the end faces the peripheral wall of the cylinder to bend and transition to connect the peripheral wall. The positioning pin of Guangdong Yueluo Hardware Industry Co., Ltd. uses the measuring hole to carry out the probe. It is easy to operate, simple in structure and highly versatile. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a positioning pin of an embodiment of Guangdong Yueluo Hardware Industry Co., Ltd. FIG. 2 is a three-dimensional schematic view of the positioning pin shown in FIG. 1 without a positioning member. FIG. 3 is an exploded schematic view of the positioning pin shown in FIG. 1 . FIG. 4 is a cross-sectional view of the positioning pin shown in FIG. 1 along the line IV-IV. Description of main components and symbols Locating pin 100 Cylinder 10 Measuring hole 11 Chip removal hole 12 Cylinder 20 Positioning piece 30 Base 32 Mounting hole 321 Limiting hole 323 Magnetic piece 34 The following specific embodiments will be further described in conjunction with the above drawings Guangdong Yueluo Hardware Industrial Co., Ltd. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The technical solutions in the embodiments of Guangdong Yueluo Hardware Industry Co., Ltd. will be clearly and completely described below with reference to the accompanying drawings in the embodiments of Guangdong Yueluo Hardware Industry Co., Ltd. Obviously, the described embodiments are only Some examples of Guangdong Yueluo Hardware Industry Co., Ltd. are not all examples. Based on the embodiments in Guangdong Yueluo Hardware Industry Co., Ltd., all other embodiments obtained by those of ordinary skill in the art without creative work belong to the protection scope of Guangdong Yueluo Hardware Industry Co., Ltd. It should be noted that when an element is referred to as being connected to another element, it can be directly connected to the other element or intervening elements may also be present. When an element is referred to as being disposed on another element, it can be directly disposed on the other element or intervening elements may also be present. Unless otherwise defined, all technical and scientific terms used herein are related to those of Guangdong Yueluo Hardware Industry Co., Ltd.
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.
Blind rivets are a type of rivets for single-sided riveting, but they must be riveted with a special tool - a rivet gun (manual, electric, and moving). This type of rivet is especially suitable for riveting occasions where it is inconvenient to use ordinary rivets (which must be riveted from both sides), so it is widely used in construction, automobiles, ships, aircraft, machinery, electrical appliances, furniture and other products. Among them, the open type oblate head blind rivets are the most widely used, the countersunk head blind rivets are suitable for riveting occasions that require smooth performance, and the closed blind rivets are suitable for riveting occasions that require higher load and certain sealing performance.
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