The expansion screw generally refers to the metal expansion screw, and its fixing principle: the fixation of the expansion screw is to use the wedge-shaped slope to promote the expansion to generate frictional gripping force to achieve the fixing effect.
The screw is threaded on one end and tapered on the other. The outside is covered with an iron sheet, an iron sheet cylinder, half of which has several cuts, and they are inserted into the hole made in the wall, then lock the nut, the nut pulls the screw out, and the taper is pulled into the iron sheet cylinder, and the iron sheet cylinder is expanded. open, so it is tightly fixed on the wall, generally used for the fastening of guardrails, awnings, air conditioners, etc. on cement, bricks and other materials.
Disadvantages: The fixation is not very reliable. If the load has a large vibration, it may loosen, so it is not recommended for installing ceiling fans.