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Expansion Bolt
Expansion screws are generally composed of a screw, an expansion sleeve (or expansion cone), a washer, a nut and other parts. Among them, the tail of the screw presents a conical shape, and the diameter of the inner edge of the cone is larger than that of the inner edge of the expansion tube.
Overview of expansion bolts
Expansion screws, also known as expansion bolts or expansion bolts, are mechanical fasteners used to fix objects in hard materials such as concrete and brick walls. Through its special structural design, it generates an expansion force during installation, thereby achieving a firm support for objects.
Working principle
It mainly relies on its unique structure, including parts such as the screw, expansion sleeve (or expansion cone), washer and nut. When the nut is tightened, the screw drives the expansion sleeve to move along the axis direction. The outer surface of the sleeve is made with special diagonal or serrated structures, which will tightly lock into the wall or other installation base materials under the action of external force. As the nut is continuously tightened, the expansion sleeve gradually opens, forming a firm anchoring effect, thereby achieving stable support for the object.
Advantage comparison
Compared with traditional wooden or steel nails, the advantages of expansion screws are mainly reflected in the following aspects
Stronger load-bearing capacity
Due to its special anchoring mechanism, expansion screws can provide greater support without damaging the base material, making them particularly suitable for applications that need to bear heavy loads.
Wide adaptability
Whether it is hard or soft materials, there are corresponding types of expansion screws available for selection, with a wider range of applications.
Easy to disassemble and adjust
Compared with the feature of traditional nails that are difficult to remove once driven in, expansion screws can be easily disassembled by reverse rotation, which is convenient for maintenance or position adjustment.
Reduce damage to the substrate
Expansion screws have less invasiveness to the base material during installation, which is particularly important for fragile or materials that need to maintain their appearance intact.
Anti-loosening design
Some high-end expansion screws also have an anti-loosening function to ensure the safety and stability of long-term use.
Type and Material
Expansion screws can be classified into various types based on different usage requirements and environmental conditions
Metal expansion screw
The most common type is suitable for hard materials such as concrete and brick walls, and it has excellent tensile strength.
Plastic expansion screw
It is usually used in lightweight walls or environments where corrosion needs to be avoided. It is easy to install but has a relatively low load-bearing capacity.
Chemical anchor bolt
It combines with the substrate through chemical reactions, providing extremely high bonding strength and is suitable for applications with extremely high safety requirements.
Car repair gecko
Designed specifically for lightweight walls such as hollow bricks and gypsum boards, it enhances the fixation effect by increasing friction through a special structure.
Instructions for use
The depth of the hole should be approximately 5 millimeters deeper than the length of the sleeve to ensure that the expansion screw can be completely fixed.
The size of the holes should be determined based on the outer diameter of the expansion tube. For instance, a 6-millimeter expansion screw should have a 10-millimeter hole, and an 8-millimeter expansion screw should have a 12-millimeter hole.
The environmental requirement for expansion screws is that the harder they are, the better. At the very least, they should meet the force requirements of the objects to be fixed. For instance, the force-bearing strength installed in concrete is five times that in brick bodies.
When tightening the nut, first tighten it 2 to 3 turns. Only when you feel that the expansion bolt is relatively tight and not loose should you continue to tighten it to ensure the fixing effect!
In conclusion, expansion screws are powerful and widely used fasteners. Their unique design and various types make them play an irreplaceable role in modern industrial and civil fields.
