What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The rivet nut is a kind of nut applied to thin plate or sheet metal. The principle is to press the embossed teeth into the preset holes of the sheet metal. Generally, the diameter of the square preset holes is slightly smaller than the embossed teeth of the pressure riveting nut. The periphery of the hole is plastically deformed, and the deformed object is squeezed into the guide groove, thereby producing a locking effect. The pressure riveting nut is divided into free-cutting steel pressure riveting nut S type, stainless steel pressure riveting nut type CLS, stainless iron pressure riveting nut SP type and copper and aluminum pressure riveting nut CLA type, which should be used in different environments. . Generally speaking, the national standard domestic products without rivet nuts from M2 to M12 are PEM specifications, which are usually produced in chassis cabinets and sheet metal industries.
Fan rivets are specially designed for manual installation. They can be pulled in through the holes of the panel or the bottom frame. They are made of elastomer material with good toughness and can be installed quickly even in interference assembly. The design is clever and has elastic function. It is not easy to slide out after being pulled in with the corresponding aperture. The fan rivets are mainly used in the fixing of electronic computer case fans, heat sinks and chips, with anti-vibration and noise reduction.
The existing spring screw includes a screw rod, a spring connecting sleeve, a spring, a fixed connecting sleeve, a nut and a nut sleeve, wherein the screw rod includes a screw cap, a connecting section without threads and a threaded connecting section with threads, and the connecting section is located in the screw cap and the thread. A shaft shoulder is arranged between the connecting sections and between the connecting section and the threaded connecting section, the connecting section of the screw is sleeved with a spring connecting sleeve, a spring and a fixed connecting sleeve, the spring connecting sleeve is close to the screw cap, and the connecting sleeve is connected between the spring connecting sleeve and the fixed connecting sleeve The connection spring is connected with a threaded nut on the threaded connection section of the screw, and the nut sleeve is connected to the nut sleeve. The fixed connection sleeve is fixedly connected to the upper die of the steel mold through bolts, and the nut sleeve is welded to the lower mold of the steel mold. When clamping the mold, a professional is required to turn the screw from the lower mold to the upper mold or hook it to the upper mold with a foot and then tighten it with the wind, which is inconvenient to install, has low work efficiency, and has potential safety hazards. Contents of the utility model Yueluo Guangdong Yueluo Hardware Industry Co., Ltd. aims to provide a spring screw that is easy to operate. In order to solve the problems existing in the background technology, Guangdong Yueluo Hardware Industry Co., Ltd. adopts the following technical scheme: a spring screw, including a screw rod, an upper compression spring washer, a spring, a fixed sleeve, a lower compression spring washer, Base and fixing nut. The screw rod includes a screw cap, a connecting section without threads and a threaded connecting section with threads, the connecting section is located between the screw cap and the threaded connecting section, and a shaft shoulder is arranged between the connecting section and the threaded connecting section. The connecting section of the screw rod is sleeved with an upper compression spring washer, a spring, a fixing sleeve, a lower compression spring washer and a base, and the threaded connection section is connected with a fixing nut. A fixed sleeve is sleeved between the connection section and the threaded connection section, and the fixed sleeve is sleeved with a lower pressure spring washer and a base. The upper compression spring washer is close to the screw cap, the lower compression spring washer is fixed on the base by four screws, the spring is placed between the upper compression spring washer and the lower compression spring washer, and one end of the spring is sleeved with the upper compression spring washer , and the other end is sleeved with a fixed sleeve. For Yueluo, the diameter of the spring screw is between T20-T27. In this preferred solution, the use performance of the spring is high, which is beneficial to prolong the service life of the spring screw. For Yueluo, preferably, the thread connecting section of the screw adopts T-shaped thread. In this preferred solution, the fixing nut is tightly matched with the threaded connection section, so that the steel mold is clamped tightly. Yueluo is preferably made of 40Cr material for the fixing nut and screw. In this preferred solution, the rigidity of the fixing nut and the screw rod is high, which is beneficial to improve the usability of the spring screw. Yueluo is preferred, the spring screw parts except the fixing nut and the screw rod are made of 47# steel material. In this preferred solution, the production cost is low. In summary, Guangdong Yueluo Hardware Industry Co., Ltd. brings the beneficial effects: when the spring screw is used, it is only necessary to use a wrench to move the fixed nut, which is convenient for installation, disassembly and replacement, improving work efficiency and reducing production costs.
The embedded nut is made of copper nuts made of various embossed wires (usually lead brass, such as H59, 3604, 3602). The embedded knurled copper nuts that we come into contact with on a daily basis are processed by precision automatic lathes. The reference standard for embedded knurled copper nuts comes from the national standard GB/T809. The main operation method of the anti-loose nut is to inject the embedded knurled copper nut. After heating, it is embedded into the plastic part or directly injected into the mold. If the mold is injection-molded, the melting point of PA/NYLOY/PET is above 200°C , After the embedded nut is hot melted into the plastic part, the temperature rises rapidly. After injection molding, the plastic body rapidly cools and crystallizes and becomes hard. If the embedded nut temperature is still at a high temperature, it may fall to the place where the copper nut contacts the plastic part. Start to loosen or crack. Therefore, copper nuts are used instead of carbon steel nuts in the injection molding of embedded nuts. There are two ways to form the external knurling of the embedded copper nut. One is to use copper raw material to draw the knurl and then to produce it on the upper equipment. Generally, the pattern of this method is straight, and the other is to use The round copper material is directly embossed while tapping during the production process. This processing method can produce some non-standard size knurled copper nuts. The embossed shape of the embedded copper nut can be selected by the user, such as mesh, Character embossing, herringbone embossing and other knurling patterns.
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