Fixing principle of expansion screw
Fixing principle of expansion screw: the fixing of expansion screw is to use the V-shaped inclination to promote expansion to generate friction and binding force, so as to achieve the fixing effect. One end of the screw is threaded and the other end is tapered. The bread is covered with steel skin, and the half of the iron cylinder has a number of cuts. Put them together into the hole punched in the wall, and then lock the nut. The nut pulls the screw outward, and pulls the vertebral degree into the steel skin cylinder, which is expanded, so it is tightly fixed on the wall. It is generally used to fasten the protective fence, awning, air conditioner, etc. on cement, brick and other materials. However, its fixing is not very reliable, and if the load has great vibration, it may come loose, so it is not recommended to install ceiling fans. The principle of expansion bolt is that after the expansion bolt is hit into the hole on the ground or wall, the nut on the expansion bolt is tightened with a wrench, and the bolt goes out, but the outer metal sleeve does not move. Therefore, the big head under the bolt expands the metal sleeve to make it fill the whole hole, and at this time, the expansion bolt cannot be drawn out.
The fixing of telescopic screws is to make use of the inclinations of various shapes, so as to promote the telescopic friction grip, so as to achieve the fixing effect. Its screw has a thread at one end and a vertebral body at the other. The outer part is covered with a layer of steel skin, and the iron cylinder has several cuts. Plug it into the hole punched in the wall one by one, then lock the nut, which pulls the screw outward, pulls the screw into the cylinder, and pulls the cylinder onto the steel skin. The steel cylinder is expanded and clings to the wall, which is generally used to fix materials such as cement and bricks such as guardrails, awnings and air conditioners. However, its fixation is not very reliable, and it may come loose if it is subjected to large stress and vibration, so it is not recommended for ceiling fan installation. The principle is that after the expansion bolt is driven into a hole in the ground or wall, the nut on the bolt is tightened with a wrench, and the bolt moves outward, but the metal hole outside does not move. Therefore, the big head under the bolt lifts the metal hole to fill the whole hole. At this time, the expansion bolt cannot be drawn out. Expansion bolts are composed of countersunk bolts, expansion tubes, flat pads, spring pads and hexagonal nuts. In more than 10 grades, there are 3.6, 4.6 and 4.8, 5.6 and 6.8, 8.8, 9.8, 10.9 and 12.9 respectively. Numbers before and after decimals respectively indicate the nominal tensile strength and yield ratio of bolt materials. For example, an expansion bolt with a performance level of 4.6 contains the following meanings: 1, the nominal tensile strength of bolt material reaches more than 400 MPa; 2. The yield ratio of expansion bolt material is 0.6; 3. The yield strength of expansion bolt material is 400×0.6=240 MPa.
The expansion screw is composed of a screw and an expansion tube, the tail of the screw is conical, and the inner diameter of the cone is larger than that of the expansion tube. When the nut is tightened, the screw moves outward, and the conical part moves through the axial movement of the thread, thus forming a great positive pressure on the outer circumferential surface of the expansion pipe. In addition, the angle of the cone is very small, so that the wall, the expansion pipe and the conical part form friction self-locking, thus achieving a fixed effect. The spring pad on the expansion screw is a standard part. Because its opening is staggered and elastic, it is called a spring washer. The function of the spring washer is to pierce the nut and the flat pad with the sharp corners of the wrong opening to prevent the nut from loosening.
Post time: Jun-27-2022