What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Hexagon nuts are also called hexagon nuts. Generally, there are many types of nuts, such as hexagon nuts, round nuts, square nuts and so on. Some standards for nuts are still relatively clear. Some specifications and size standards, material requirements standards, electroplating standards, etc. are relatively clear. Different types of nuts also have different standards. Let's introduce the specifications and standards of the nuts in detail.
The spring washer usually includes a washer body and a raised claw head punched and formed on the washer body. The spring washer is often placed between the bolt head of the bolt and the connected parts, wherein the raised claw head is connected to the part to be connected. The surfaces of the connecting parts are in contact, and the plane on the gasket body, opposite to the lifting direction of the raised claw head, is in contact with the bolt head. After the bolt head is tightened, the elastic reaction force generated by the raised claw head after flattening makes the The screwed threads are pressed tightly, and at the same time, the raised claw head is pressed against the bolt head and the supporting surface of the connected parts, which has the effect of preventing loosening. However, the traditional spring washer is a single-claw type. When tightening, the raised claw head will cause great damage to the surface of the connected parts, so it is not suitable for the anti-loosening treatment of parts with small surface hardness.
In CN203807560, nails and bolts are used to connect the plates, but the heads of the nails and the bolts are enlarged ends that are wider than the rods, and the heads of the nails and the bolts cannot penetrate into the interior of the door body, so in terms of appearance, the more More nails and bolts will leave more spots on the surface of the door that are not suitable for the door itself. In the prior art, the treatment method for these spots is generally to paint with paint, which can only make the door panel consistent with the head of the nail and the bolt in color, but cannot change the shape of the head of the nail and the bolt, and the appearance is still good. Obvious spots were noticed, which made the door panels connected by nails and bolts to the panels, which could not be used as door panels for household doors.
As my digital TV technology becomes more and more mature, more and more people with digital-to-analog signal conversion function enter people's lives. Therefore, the number of production and processing is also increasing day by day. There are many requirements for the form, reliability and cost of PCB fixing screws in production. One of the existing fixing methods is to fix by means of bolts and nuts. The operation steps are to place the PCB board on the inner threaded copper column connected to the casing, and pass through the bolts with fine teeth. Screw holes on the PCB board, and then fix them on the copper posts with nuts. The connection method of this solution is reliable, but its manufacturing cost is high, and the copper column and the metal shell need to be screwed together, resulting in low production efficiency and high cost. In addition, there is also a common way that the PCB is supported by a plastic column, and the self-tapping screw is passed through the screw hole on the PCB board, and the PCB board and the metal bottom shell are connected by the self-tapping thread on the screw. The main disadvantage of this solution is that after the screw is fixed on the metal shell, the screw head is exposed at the bottom of the machine. If the user is not careful during use, the hand scratching phenomenon will occur, which will bring changes and harm to the user's use. . And when the machine slides on the desktop, if the screw head is too exposed, it will scratch the desktop. Therefore, how to provide a PCB fixing method with convenient operation, reliable connection and low production cost is a technical problem to be solved urgently in the industry.
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