An expansion bolt, also known as an expansion anchor or mechanical anchor, is a type of fastener used to securely attach objects to various materials, including concrete, masonry, brick, or even certain types of stone or rock.
Expansion bolts are designed to provide a strong and reliable connection in applications where the material being anchored to is solid and substantial.
Other names: expansion anchor, expansion anchor, expanding anchor bolts, expansion bolt concrete, sleeve anchors, sleeve anchor bolts, concrete sleeve anchors, sleeve bolts
The structure of an expansion bolt consists of several key components designed to work together to securely fasten an object to a solid material like concrete or masonry. These components typically include:
- Threaded Bolt: This is the part of the expansion bolt that extends out from the material once the anchor is installed. It has external threads that allow for the attachment of nuts or other fasteners. The threaded bolt is also used to apply tightening force during installation.
- Anchor Body or Sleeve: The anchor body or sleeve is typically a cylindrical metal tube or sheath that encases the threaded bolt. It serves as the main component responsible for expanding and gripping the material when the bolt is tightened. The anchor body may have ridges, flutes, or other features designed to enhance its gripping capability.
- Expansion Plug or Wedge: This component is inserted inside the anchor body. It’s often wedge-shaped or tapered and is used to expand the anchor body when the threaded bolt is tightened. As the expansion plug or wedge is pulled into the anchor body, it pushes against the walls of the hole in the material, causing the anchor body to expand and grip the material securely.
- Nut: The nut is threaded onto the exposed end of the bolt and is used to apply the tightening force. Turning the nut clockwise tightens the expansion bolt, causing the expansion plug or wedge to engage and expand the anchor body.
- Washer (Optional): In some cases, a washer may be used under the nut to distribute the load more evenly and provide a larger bearing surface against the object being fastened.
The installation process involves drilling a hole into the material to accommodate the expansion bolt, inserting the expansion bolt into the hole, and then tightening the nut on the threaded bolt. As the nut is tightened, the expansion plug or wedge is drawn into the anchor body, causing it to expand and grip the material securely.
The specific design and materials of expansion bolts can vary depending on the manufacturer and the intended application. It’s essential to choose the right type and size of expansion bolt for the specific load and conditions of your project, and to follow manufacturer guidelines for proper installation to ensure a secure and reliable connection.
- Diameter (M): M8-> M16 mm
- Length (L): 60 ~ 200 mm
- ISO Grade: 8/ 5.6/ 6.8/ 8.8/ 10.9/ 12.9
- Material: Carbon steel ; Stainless steel 316/304/201
- Surface Finish: Electro-zinc-plated, Hot dip galvanized, Dacromet plated, Stainless steel 316/304/201
- Standard: DIN, JIS/ ASMT/ ISO/ KS/ GB/ TCVN/ …
Here’s how an expansion bolt typically works:
- Design: An expansion bolt consists of several components, including a threaded bolt, a metal sleeve or anchor body, and a separate component called an expansion plug or wedge.
- Installation: To install an expansion bolt, a hole is drilled into the material where the fastener will be placed. The size of the hole typically corresponds to the diameter of the expansion bolt.
- Insertion: The expansion bolt is inserted into the hole in the material, with the threaded bolt extending out. The expansion plug or wedge is then placed inside the sleeve or anchor body.
- Tightening: As the nut on the threaded bolt is tightened, it pulls the expansion plug or wedge into the anchor body. This action causes the anchor body to expand radially, pressing against the walls of the hole in the material.
- Securing: Once fully tightened, the expansion bolt provides a secure and load-bearing connection between the object and the material. The expansion of the anchor body creates friction and compression forces that hold it firmly in place.
Expansion bolts are commonly used in construction and building applications to attach items such as structural supports, handrails, machinery, and fixtures to concrete walls or floors. They are also used in various other industries and applications where a strong and reliable anchor point is needed.
Selecting the appropriate type and size of expansion bolt is crucial to ensure the anchor’s performance matches the load and environmental conditions of the application. Installation should be done following manufacturer guidelines and recommendations to achieve maximum anchoring strength and safety.
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