What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Countersunk head screws are mostly used after installation, and the surface of the parts cannot be raised, and the parts to be fastened have two thicknesses. Thickness, after the screw is tightened, there is still a part of the screw thread that does not enter the threaded hole. In this case, the countersunk head screw can definitely be tightened. There is usually a situation where the thickness of the fastened part is less than the height of the head of the countersunk head screw, which is commonly seen in sheet metal parts in mechanical equipment, such as the connection between the hinge of the chassis and the door and the box; the sheet metal of the equipment The connection of the cover to the equipment, etc. Due to the small thickness of the part, the tightened sheet metal part, the screw through hole completely becomes a conical hole, in this case, when the countersunk head screw is tightened, the screw head is not a tapered surface to press the sheet metal part , but the bottom of the screw head and the top of the threaded hole are squeezed. Although it feels that the screw is tightened, the sheet metal part is stuck instead of being pressed. In this case, although it feels that the screw is tightened, the sheet metal The gold pieces were indeed not tightened. This is a very common situation. Let’s talk about the reasons for the processing: the head cone of the countersunk screw has a 90° conical angle, and the apex angle of the newly bought drill is usually 118°-120°. Some workers who lack training do not know this angle is poor. It is often used to ream the hole with a 120° drill bit, which results in that when the countersunk head screw is tightened, it is not the conical surface of the head, but a line at the bottom of the screw head, which is one of the reasons why the so-called countersunk head screw cannot be tightened. , it's not the screw's fault.
As we all know, whether it is the necessities in people's life or the equipment in industrial production, there will be a structure of screws and screw holes on it. This kind of structure that can simply fix some components together has been widely used in various fields. For the installation and removal of screws, people invented manual screwdrivers, and then to electric screwdrivers and so on. For manual screwdrivers, the operator needs to manually install or remove the screws. When encountering small screws, it can still handle it. When encountering large screws, due to people's limited strength, they may not install the screws in place, so it was invented. Electric screw. When installing the screw, which is widely used in the market, the operator needs to hold the screw handle, fix the screw on the screw port, and then align the screw with the corresponding screw hole for screwing. The disadvantage of this kind of screw is that it is heavy in quality and laborious to operate, and secondly, the operator will be injured due to operating errors, and the consequences are extremely serious. In view of this deficiency, people fix the screws on a work frame, so that before installing the screws, the operator only needs to adjust the screws to the designated position, and then the screws can be installed, which is convenient and simple. However, there are still potential safety hazards. In the process of adjusting the screw, it is still possible that the power of the screw may be turned on by mistake due to operating errors, resulting in injury to the operator. In view of the above-mentioned defects, it is necessary to invent a screw installation method with an anti-missing function.
rivet is a nail-shaped object used to join two parts or components with a through hole and a cap on one end. In riveting, the riveted parts are connected by their own deformation or interference. There are many types of rivets, and they are informal. In today's product production, the slot holes on the same mounting surface often have different mounting slot depths. If a mechanical tool is used for quick screwing and installation, it will directly bring destructive effects to the brittle products, resulting in When the product is cracked and damaged, when connecting plastic shells, lightweight boards, insulating materials, circuit boards, or any other thin and light materials, the requirements for the installation process are also relatively high. The gripping force and bonding force of rivets are weaker than those of rivets that are screwed and installed by machinery. The bonding strength of rivets used in manual operations needs to be enhanced. The rivet structure needs to be improved and enhanced when installing thin, light-weight materials.
In the process of automatically locking the screw to the product, there are only three types of screw supply mechanisms in the traditional automatic screw locking machine: 1. Magnet sucks for screws; 2. Vacuum sucks for screws; 7. Air blows for screws. The above three methods require long-distance screw supply, resulting in slow screw supply, low efficiency and high manufacturing cost. To this end, we propose an automatic locking screw machine that can directly supply screws.
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