Main Types of Expansion Screws
A. Sleeve Expansion Screws
Sleeve expansion screws are one of the most common types. They consist of a screw, a metal sleeve, and a nut. When the screw is tightened, the sleeve expands outward, tightly pressing against the wall or base material. Sleeve expansion screws have strong load - bearing capacity and are suitable for a variety of materials, including concrete, brick walls, and solid wood. In building construction, they are often used to fix structural components such as beams, columns, and brackets. In furniture installation, sleeve expansion screws can firmly connect different parts of large - sized furniture, ensuring the stability and durability of the furniture.
B. Fish Scale Expansion Screws
Fish scale expansion screws have a unique design with a series of fish - scale - like protrusions on the outer surface of the expansion part. When inserted into the hole and tightened, these protrusions bite into the wall material, providing a strong fixing force. They are especially suitable for use in materials with relatively loose structures, such as aerated concrete blocks and lightweight partition walls. Fish scale expansion screws can effectively prevent the problem of loosening caused by the low density of the base material. They are widely used in the installation of interior partition wall decorations, electrical switch boxes, and other items in buildings constructed with new - type lightweight materials.
C. Hammer - in Expansion Screws
Hammer - in expansion screws, as the name implies, are installed by hammering. They usually have a pointed end and a flared tail. After the pre - drilled hole is made, the expansion screw is hammered into the hole. As it is driven in, the tail expands, gripping the surrounding material. Hammer - in expansion screws are simple and quick to install and are suitable for some emergency or temporary fixing work. For example, in outdoor construction sites, when quickly installing temporary safety fences or support structures, hammer - in expansion screws can be used to save installation time. However, their load - bearing capacity is relatively limited compared to some other types of expansion screws.
D. Self - Drilling Expansion Screws
Self - drilling expansion screws combine the functions of drilling and expansion. They are equipped with a drill - like tip, which can directly drill into the material during installation without the need for pre - drilling. This type of expansion screw is very convenient for installation, especially in some situations where it is difficult to perform pre - drilling, such as in thick metal plates or hard concrete surfaces. Self - drilling expansion screws are often used in industrial equipment installation, vehicle modification, and other fields, where high - efficiency and fast installation are required.
