Self-drilling expansion anchor bolt

Abstract

The invention provides a self-drilling expansion anchor bolt. The self-drilling expansion anchor bolt comprises a drill bit used for drilling, an anchor rod connected with the drill bit and an expansion sleeve arranged on the anchor rod in a sleeving mode, an expansion cone is arranged at the first end, adjacent to the drill bit, of the anchor rod, and a neck area is continuously arranged behind the expansion cone. The second end, away from the drill bit, of the neck area is provided with a threaded section, when the expansion cone is pulled into the expansion sleeve, the expansion cone expands the expansion sleeve in the radial direction, a transition part is arranged between the drill bit and the expansion cone of the anchor rod, and the maximum diameter of the transition part is smaller than the hole diameter of a drill hole formed by the drill bit. In the anchoring process, good friction fit is formed among the expansion sleeve, the hole wall and the transition part, so that the anchoring effect of the self-drilling anchor bolt is greatly improved.

Description

technical field [0001] The invention relates to an anchor bolt for construction engineering, and more specifically, to an expansion anchor bolt with self-drilling function. Background technique [0002] Existing self-drilling anchor bolts are usually used in mining ore mining industry, and the anchor bolts are huge in volume, and the drill bits used for drilling are usually made of relatively hard materials. In general, in the construction industry, the anchors used for the fixed connection of concrete, stone, wood, etc. generally do not have the self-drilling function. The most commonly used method is to have a preformed drill hole on the base material, and then insert the expansion anchor bolt. The expansion anchor bolt is covered with a high-strength sleeve with longitudinal slits on the rod body. The sleeve has strong elasticity due to its slit structure. , the sleeve is extruded into the borehole, and the surface of the sleeve is frictionally fitted with the inner surf...

AI Technical Summary

Problems solved by technology

[0004] However, in the self-drilling anchor bolt disclosed in the aforementioned patent, in the process of pulling the bolt 12 outward by tightening the nut 15, the casing 11 slides along the tapered thickened portion 13, because the drill bit 16 and the thickened portion 13 is slightly larger than the diameter of the casing 11, then the casing 11 will collide with the hole wall when it does not reach the junction of the thickened portion 13 and the drill bit 16

The result is that if the strength of the material forming the hole wall is small, the anchor bolt 10 will be pulled out of the hole entirely, and if the strength of the material forming the hole wall is very high, the front end of the casing will lean against the hole wall and cannot be in contact with the hole wall. The hole wall forms a good frictional fit, which greatly reduces the anchor bolt's bearable fastening tension.

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