Its fixing principle The expansion screw is fixed by the use of a wedge-shaped inclination to promote the expansion of the frictional gripping force to achieve a fixed effect. One end of the screw is threaded and one is tapered. A metal sheet (some steel tubes) is on the outside. There are several incisions in the iron cylinder (steel tube). Put them together into a hole in the wall. Then lock the nut. Pull the nut outward and pull the taper into the metal cylinder. The metal cylinder was stretched, and it was tightly fixed to the wall. It was generally used for the fastening of fences, awnings, air conditioners, etc. on cement, brick and other materials. However, its fixation is not very reliable. If the load has a large vibration, loosening may occur, so it is not recommended for installing ceiling fans.
Four expansion screws also known as: four geckos.
The grade of expansion bolts is divided into: 45, 50, 60, 70, 80,
Expansion screw material: mainly austenitic A1, A2, A4,
Martensite and ferrite C1, C2, C4,
Its representation method is for example A2-70,
"--" before and after the bolt material and strength grade, the following is a complete expansion bolt specification table.
(1) Bolt materials Common materials: Q215, Q235, 25, and 45 steels. For important or special-purpose threaded joints, alloy steels with higher mechanical properties such as 15Cr, 20Cr, 40Cr, 15MnVB, and 30CrMrSi may be used.
(2) Permissible stress The allowable stress and load properties (static, variable load) of the screw coupling, whether the coupling is tightened, and whether the pre-tightening force needs to be controlled and the material and structural dimensions of the screw coupling are related.
According to the actual situation of the wall, choose different expansion screws. There are generally the following 6*60, 6*80, 6*120, 6*150.
6*60: Total length 60 mm, sleeve length 45 mm, diameter 8 mm, wall thickness 0.7 mm, surface zinc plated; screw length 60 mm, diameter 6 mm, part of thread 35 mm, bottom rod 8 mm cone The surface is zinc plated; the octagonal shape of the outer diameter of the nut is 10 mm, the thickness is 5 mm, and the surface is plated with white zinc; the outer diameter of the gasket is 13 mm, thickness is 1 mm, and the inner diameter is 6 mm; the surface is plated with white zinc; 9 mm, inner diameter 6 mm, thickness 1.6 mm ring.
6*80: Total length 80 mm, sleeve length 65 mm, diameter 8 mm, wall thickness 0.7 mm, color zinc plating on the surface; screw length, nuts, washers, and springs are the same as above.
6*120: total length 120mm, casing length 105mm, diameter 8 mm, wall thickness 0.7 mm, surface color zinc plating; screw length, nut, gasket, shrapnel Ibid.
6*150: total length 150mm, casing length 135mm, diameter 8 mm, wall thickness 0.7 mm, surface color zinc plating; screw length, nut, gasket, shrapnel Ibid.
Edit this paragraph use principle
The expansion screw is composed of a screw, an expansion tube and the like. The screw tail is conical. The inner diameter of the cone is larger than the inner diameter of the expansion tube. When the nut is tightened, the screw moves outwards, and the conical part moves by the axial movement of the thread, and then the expansion tube Peripheral surface
Bolted composite cable bracket
Bolted composite cable bracket
The formation of a large positive pressure, combined with a small angle of the cone, so that the walls, expansion tubes and cones form a frictional self-locking, and then achieve a fixed effect. If it is through the walls, expansion tubes and cones form a friction lock, and then achieve a fixed effect.