Why couplers are needed in self-drilling anchoring systems

Self-drilling anchoring system is a common control technology of bolt drilling in modern construction engineering. It anchors through its own drilling ability and is a complete rock bolt system. In this system, the coupler is one of the key components.
The location of the coulers in the anchoring system

The coupler is a hollow metal tube that has a threaded hole at each end. It can connect two self-drilling anchor bars together, increase the connection strength and ensure the stability of the whole anchoring system. The material of the coupler is usually high-quality metal, such as carbon steel, stainless steel, etc., which is very strong and durable.


The coupler is the link between the two anchor bars and is located after the centering device when it is available. The coupler plays a connecting role in the self-drilling hollow anchoring system, and because of this position and construction application, the coupler needs to withstand torque and impact.

Why couplers are needed to use in construction?

Couplers are an integral part of the self-drilling anchoring system and are required during construction in order to maintain the stability of the self-drilling anchoring system. Its role in a self-drilling anchoring system includes the following:

Equal strong to the anchor bolts, increase the connection strength of the anchoring system

Self-drilling anchor bolts are usually connected to the couplers using a threaded structure, which can effectively increase the connection strength of the anchoring system. The mechanical properties of the couplers and the anchor bolts are equal and do not affect the energy transfer. It avoids the problems of fracture and misalignment of the anchor rod after lengthening and ensures the normal use of the anchor bolt.

Good sealing performance of couplers, no energy loss during construction

The couplers realizes the end-to-end connection of anchor bolts and has good sealing performance, which can effectively prevent the concrete slurry from leaking, thus ensuring the maximum impact energy of the drill bit part.

Extending the length of anchor bars used

Self-drilling anchor bars are limited in length. When it is necessary to extend the length of anchor bars, multiple anchor bars can be connected together using a coupler. This method can improve the flexibility and range of use of self-drilling anchor bars, which are widely used in both engineering construction and mine control fields.

Improving construction efficiency

Without the use of a coupler, two self-drilling anchor bars would need to be joined together during construction using different types of tools, which would increase the cost and duration of construction. The use of a coupler allows the anchor bars to be connected quickly, simplifies the process, reduces the labor intensity of the workers, increases the efficiency of the construction, and reduces the possibility of failure, which saves time and cost for the whole project.

Classification of couplers for self-drilling hollow anchor

According to the use of different scenarios and needs, couplers can be classified in different ways. Our coupler products can be divided into three categories according to the product series, the following is a detailed classification introduction of our products:


Coulomb X

Coulomb S

Coulomb E

Mechanical Property

Meet with the standard value of anchor bar tensile strength equal strength


316L/304/S460 and other special materials



Equipped with sealing ring and recess to ensure good sealing

No sealing ring, no recess

Surface Treatment

No surface treatment is required for 316L/304.

S460:surface coating/galvanizing/double anti-corrosion treatment

surface coating/galvanizing/double anti-corrosion treatment


Couplers play a crucial role in self-drilling anchoring systems, increasing the strength of the connection, reducing friction, increasing the flexibility of the project, and also saving time and costs. The classification of couplers can be selected according to different needs, making this key component applicable to different rock anchoring systems and facilitating construction.

Sinorock, as a company specializing in the development, production, and sales of rock anchor products, offers a wide range of different models of couplers, including Coulomb X, Coulomb S, Coulomb E, and other different series to meet the needs of different engineering projects. If you have any needs or questions about self-drilling anchor systems and their applications, please feel free to contact us at sinorock@sinorockco.com.


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