What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The main technical problem solved by Guangdong Yueluo Hardware Industry Co., Ltd. is to provide a fixing screw for installation, so as to provide a PCB fixing method with convenient operation, reliable connection and low production cost. In order to solve the above-mentioned technical problems, a technical solution adopted by Guangdong Yueluo Hardware Industry Co., Ltd. is to provide a fixing screw for installation, which includes a screw body, the axial surface of the screw body is formed with extended screw teeth, and the screw body is The bottom has a hemispherical screw tail, the top of the screw body is provided with a screw head, and the upper surface of the screw head is provided with a slot. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the screw body is composed of an upper tapered rod and a lower cylindrical screw rod, and the tapered rod is an inverted cone. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the diameter of the circular upper surface of the inverted cone of the taper rod is equal to the diameter of the screw mounting hole. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the screw further has a washer, the washer is arranged between the screw head and the screw body, and the washer is a cylinder. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the lower surface of the cylindrical washer has a plurality of teeth, and the teeth are along the edge of the connection between the upper surface of the inverted cone of the tapered rod and the washer Ribs formed by extending outwards. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the teeth of the washer are in contact with and pressed against the PCB board. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the protruding strip is an arc-shaped or straight-shaped structure. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the notch opened on the upper surface of the screw head is a slot. [0018] According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the notch provided on the upper surface of the screw head is a cross groove. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the fixing screw is integrally formed with conductive material. Compared with the existing technology, the fixing screws for installation designed by Guangdong Yueluo Hardware Industry Co., Ltd. can not only ensure the accuracy of the PCB installation position, but also can be installed easily and reliably, which greatly reduces the manufacturing cost and waste of metal materials.
Screw (pinyin: luógǎn, English: screw): a cylinder with a spiral groove cut on the outer surface or a cone cut with a tapered spiral groove. The screw has a different head, the head is called an external hexagon screw. There are others, such as large flat screws, socket head screws and so on.
The main part of the pin screw is an ordinary screw, and the pin can be arranged in the melting section of the screw or the drop groove of the metering section or the smooth cylindrical surface without screw grooves at the end of the metering section. The pins are arranged in a certain arrangement, with varying degrees of density and quantity. Cylindrical pins are formed by fitting the pins into the holes of the threaded rod; square or diamond-shaped pins are formed by milling directly on the threaded rod. If these pins are set in the melting zone, the pins can break up the solid bed, destroy the two-phase flow, stir the solid and liquid phases together, increase the contact area between the undissolved solid phase fragments and the contained material, and promote molten. If the pin is set in the melt conveying area, its main function is to divide the material flow, increase the interface, change the direction of the material flow, and rearrange the flow beam. Divide and merge multiple times, change the flow direction, and homogenize the melt composition and temperature. The mixing section is an inwardly slotted structure arranged at the end of the common screw homogenizing section, and its outer diameter is equal to the outer diameter of the screw. The grooves are divided into several groups, and each group is the confluence area of the material. The materials are divided by grooves, meet in the confluence area, and then divide and confluence. The principle is similar to the pin type. The characteristic of the separate screw is that in addition to the original screw thread (called the main screw) on the melting section, there is also an additional thread (called an additional thread) whose outer diameter is slightly smaller than the outer diameter of the main thread, and the main and auxiliary threads are With different leads, the secondary thread starts from the end of the feeding section (and connects with the feeding section here), and after several threads, gradually intersects the main thread of the homogenizing section. The screw groove depth and thread lead of this kind of screw change gradually from the beginning of the feeding section to the end of the homogenization, that is, the thread lead gradually narrows from the width, and the groove depth gradually becomes shallower from the depth, which can maximize the compression of the material.
Gaskets are divided into: flat washer - grade C, large washer - grade A and C, extra large washer - grade C, small washer - grade A, flat washer - grade A, flat washer - chamfer type - Grade A, high-strength washers for steel structure, spherical washers, cone washers, square bevel washers for I-beam, square bevel washers for channel steel, standard spring washers, light spring washers, heavy spring washers, internal tooth lock washers , Internal serrated lock washers, external serrated lock washers, external serrated lock washers, single-ear stop washers, double-ear stop washers, outer tongue stop washers and stop washers for round nuts, etc.
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