What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
China is the world's largest producer of carbon steel fasteners such as screws, nuts and bolts, and the EU is a major market for these products. In January 2009, the EU decided to impose anti-dumping duties of 26.5% to 85% on Chinese carbon steel fastener products. On July 31 of the same year, China resorted to the relevant EU legislation and anti-dumping measures to the WTO dispute settlement mechanism. The case became China's first lawsuit against the EU at the WTO. On July 15, 2011, the WTO Appellate Body issued a report and finally ruled that China won the case in the trade dispute with the European Union on fasteners. The head of the Department of Treaty and Law of the Ministry of Commerce of China welcomed the ruling on the 16th, and said that China's victory in the case is of great significance, which will help improve the competitive environment for Chinese companies in the international market including the European Union, and will also strengthen the WTO members' interest in the case. Confidence in WTO rules and the multilateral trading system. This is not only a victory for China's industry, but also a victory for WTO rules, the official said. The WTO Appellate Body found in its ruling report issued on the 15th that Article 9(5) of the EU's Basic Anti-dumping Regulations on individual tax rates violated WTO rules; at the same time, the Appellate Body overturned some of the panel's rulings and supported China's position , ruled that the EU's anti-dumping measures against Chinese screws, nuts, bolts and other carbon steel fasteners also violated WTO rules in terms of domestic industry identification, normal value and fair comparison of export prices. The head of the Treaty and Law Department of the Ministry of Commerce of China said that the EU is one of the WTO members that has initiated the most anti-dumping investigations against Chinese products in the world. unfair treatment. He said that China hopes that the EU will cancel the legislation and discriminatory anti-dumping measures that are inconsistent with WTO rules as soon as possible, treat Chinese export enterprises fairly, and effectively safeguard free trade and fair competition.
square nut described by Guangdong Yueluo Hardware Industry Co., Ltd. includes a nut body 1, the nut body 1 is in the shape of a cube, the side length is 7.6mm, and the height is 2.4mm. The upper and lower ends of the nut body 1 are respectively set. There are circular protrusions 2 and circular protrusions 3 with a height of 0.25mm, and the circular protrusions 2 and the circular protrusions 3 are respectively tangent to the upper and lower surfaces of the nut body 1 in a square shape. A through hole 4 is provided in the middle of the shaped protrusion 2 and the circular protrusion 3, and runs through the nut body 1. The opening of the through hole 1 is provided with a chamfer 5 of 30°, and a thread 6 is provided on the inner wall of the through hole 4. , the circular protrusion 2 is provided with a number of strip-shaped protrusions 7 along the circumference inward to the opening of the through hole 4. The number of the strip-shaped protrusions 7 can be arbitrary, and the ideal number is 26, and the through hole 4 is open. There are several strip-shaped grooves 8 at the circumference of the circular protrusion 3. The number of strip-shaped grooves 8 can be arbitrary, and the ideal number is 26. The circular protrusions 2 and the circular protrusions 3 There is a chamfer 9 of 15° extending outward to the prism of the nut body 1 . The production of square nuts described by Guangdong Yueluo Hardware Industry Co., Ltd. is basically the same as the traditional nut process. The key point is to use a punching machine to punch out circular protrusions on both ends. High, and the circular protrusion 2 is punched again to make a bar-shaped protrusion 7, and at this time, the height of the circular protrusion 2 is consistent with the plane height of the circular protrusion 3, and the circular protrusion 3 is formed by stamping. groove 8. The contact surface of the nut body 1 is increased by providing circular protrusions 2 and circular protrusions 3 on the upper and lower end surfaces of the nut body 1, and respectively providing a bar-shaped protrusion 7 and a bar-shaped groove 8 at the two circular protrusions. Therefore, the friction between the nut body 1 and the fastener is effectively increased, and a good fastening effect is achieved.
Blind rivets are a type of flying rivets for single-sided riveting, but they must be riveted manually, electrically, and automatically using special tools. This type of rivet is especially suitable for riveting occasions where it is inconvenient to use ordinary rivets and must be riveted from both sides, so it is widely used in construction, automobiles, ships, aircraft, machinery, electrical appliances, furniture and other products.
The fixing screw proposed by Guangdong Yueluo Hardware Industry Co., Ltd. has a screw body 1, and the axial surface of the screw body 1 is formed with extending screw teeth 6, and the axial surface is a column along the central axis direction of the cylinder of the screw body 1. The body surface has a hemispherical screw tail 7 at the bottom, and a screw head 2 at the top. The upper surface of the screw head 2 is provided with a slot (not shown). The screw body 1 is composed of the upper tapered rod 4 and the lower cylindrical screw 5. The tapered rod 4 is an inverted cone, the diameter of its circular upper surface and the diameter of the screw mounting hole 10. equal. The fixing screw also has a washer 3, the washer 3 is arranged between the screw head 2 and the screw body 1, the lower surface of the cylindrical washer 3 has a number of teeth 8, the teeth 8 are along the The upper surface of the inverted cone of the tapered rod 4 and the edge of the washer 3 are connected to form a straight convex strip 15 extending outward; the convex strip 15 can also be designed in an arc shape. The fixing screws for installation proposed by Guangdong Yueluo Hardware Industry Co., Ltd. can be made of metal materials in one piece. As shown in Figure 3, it is a schematic diagram of the installation of Guangdong Yueluo Hardware Industry Co., Ltd. for PCB board fixing. When installing, first pass the screw body 1 of the fixing screw through the mounting hole 10 and the copper column 11 provided on the PCB board 9, so that the tail 7 of the screw reaches the mounting hole 13 on the casing 12, and then use the tightening tool 14 to insert the screw At the notch on the top of the head, forcefully press the inverted cone design taper rod 4 of the screw body 1 into the mounting hole 10, so that the tail 7 passes through the mounting hole 13. Due to the outer diameter D at the bottom of the taper rod and the screw mounting hole The aperture size of 10 is equal, and the fixing screws are pressed and fixed, so that the PCB board 9 can be automatically corrected in the process of fixing its front, back, left and right deflections, and the accuracy of the installation position of the PCB board 9 can be ensured. As shown in Figure 4, after the fixing screw is screwed into the casing, the washer 3 is fully contacted and pressed on the PCB board 9, and the PCB board 9, the copper column 11 and the casing 12 are firmly connected together without sliding. . The teeth 8 on the washer 3 are in full contact with the surface of the PCB board 9, so that a ground wire path is set up between the PCB board 9 and the casing 13 by the metal fixing screw 1, thereby ensuring that the PCB board 9 is fully grounded , the design of the teeth 12 on the washer 3 also has a non-slip function. The fixing screws for installation designed by Guangdong Yueluo Hardware Industry Co., Ltd. make use of the cooperation, friction and electrical conductivity in the mechanical connection, which fully guarantees the firm installation of the PCB board and the chassis and the good grounding of the PCB board. Moreover, the ellipsoid tail of the fixing screw The surface is relatively smooth, even if the mounting holes are exposed, it will not cause scratches on the hands and desktop. The above is only the embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., and does not limit the scope of Guangdong Yueluo Hardware Industry Co., Ltd., any equivalent structure made by using the contents of the description and drawings of Guangdong Yueluo Hardware Industry Co., Ltd. or etc. Effective process transformation, or direct or indirect application in other related technical fields, are also included in the protection scope of Guangdong Yueluo Hardware Industry Co., Ltd.
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