What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Currently, the method of fixing objects on cement is with cement nails or expansion screws. Cement nails are objects made of hard alloy steel that look like iron nails, which are composed of nail tips and nail bodies. Cement nails are hammered into the cement. Cement nails are easy to drive in, but not removable. The expansion screw is composed of a large end screw, a slotted sleeve, a gasket, a spring washer, and a nut. When using, first drill a hole in the cement with an electric hammer, put in the expansion screw, and tighten the nut to make the slotted sleeve expand at the tail of the big tail screw, so as to fix the expansion screw on the cement. At this time, unscrew the nut to install a fixed object on the expansion screw. Although this method can be disassembled, an electric hammer is required for the first installation, which is inconvenient.
The combination screw is actually a kind of screw, but it is special. It is generally a three-component or a two-component, but at least it can be called a combination screw. The main difference from ordinary screws is that they are equipped with one more spring washer or one more flat washer than ordinary screws. This is the main difference between the appearance of combination screws and ordinary screws. In addition to the obvious difference in appearance between combination screws and ordinary screws, the main difference is the difference in mechanical properties and uses. The combination screw is a three-component or two-component with a flat washer. Of course, it is equipped with a flat washer by an ordinary screw. When the spring flat pad is attached, the spring flat pad will not fall off. Fastened to form an assembly. In terms of mechanical performance, the combination screw is composed of three accessories, and in terms of performance, three fasteners must be used together. The mechanical properties of the combined screw are stronger when used. More convenient, the biggest advantage of the combined screw is that the production line can be operated conveniently and quickly, and the work efficiency can be improved. The difference between the use of combination screws and ordinary screws is mainly in the breadth of use. The use of ordinary screws is more extensive than that of combination screws. Basically, ordinary screws are used in industrial products, and combination screws! It is only useful for specific product materials. When the screw needs to be used with a spring washer and a flat washer, the combination screw can be used at this time.
T-slot bolts refer to the bolts installed in the T-slot. The installation process of T-slot bolts is usually as follows. When the T-slot (generally refers to the T-slot aluminum alloy profile) is set horizontally, the bolt The bolt head is placed in the T-slot in the horizontal direction, the bolt shaft is facing outward, and then the bolt is rotated 90 degrees axially, the bolt head becomes vertical and will not come out of the T-slot, and then install the mounting hole of the object Align the bolt rod and insert it and screw the nut on the bolt rod. During the tightening process of the nut, if the thread gap is small or the thread is damaged or there is dirt, the bolt will often rotate, and the rotation angle of the bolt is uncontrollable and impossible. Observe that when the rotation angle of the bolt is in the range of about 90 degrees, the bolt is in a state of being released from the T-shaped groove at any time. Even if the nut is tightened, the installation of the installation object is invalid and unreliable, and there is a serious safety hazard. , the actual situation is that when the rotation angle of the bolt exceeds 20-30 degrees, the installation of the installation object is already unreliable.
In order to solve the problem of nut loosening, various self-locking nuts have appeared, which have complex structure, high production cost, inconvenient installation and unsatisfactory anti-loosening effect. At present, the never-loosening nuts produced in Japan are mostly used, mainly in the form of double nuts. Each nut is provided with an eccentric cam protrusion, and each nut is provided with a groove and an inclined plane to squeeze the cam protrusion of each nut. When pressing, the cam protrusion of the nut will move to a small radius along the slope of the nut, so that the nut will not loosen, but whether it is a nut or a nut, it is always under the action of eccentric force. In addition, various non-loose nuts designed by many manufacturers are to increase the friction between the nut and the fastening workpiece or increase the barb to achieve the purpose of never loosening, but the effect is not ideal.
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