Step-by-step pre-fastening expansion bolt

Abstract

The invention provides a step-by-step pre-fastening expansion bolt, and relates to a bolt fastener. The expansion bolt specifically comprises a screw rod and an expansion sleeve arranged outside the screw rod, and the rear end of the screw rod is connected with a nut. A plurality of conical bosses are arranged on the screw rod, and the long-radius bottom face of the boss at the foremost end of thescrew rod is back onto to the nut; and the long-radius bottom faces of the other bosses face the nut. A plurality of expansion ring openings are formed in the expansion sleeve, and the positions of the expansion ring openings correspond to the bosses on the screw rod. The screw rod is further sleeved with a pressing sleeve, and the pressing sleeve is located between the expansion sleeve and the nut. After entering a wall body, the step-by-step pre-tightening expansion bolt conducts step-by-step pre-fastening and reinforced fastening in advance to form a stable whole with the wall body; and full-drilling anchoring can be achieved, the fixing effect is good, and the strength is effectively improved.

Description

technical field [0001] The invention relates to a bolt fastener, in particular to a step-by-step pre-tightening expansion bolt. Background technique [0002] At present, the expansion bolts on the market generally use the tapered end of the bolt to expand the expansion sleeve to achieve expansion and fixation. This expansion principle has many defects: first, the end of the bolt is flush with the head, and it is difficult to place it in the hole; second, The expansion multiple is small, and the expansion friction point is small. The fixing strength is too low and too unstable; moreover, when installing and fixing the hanging parts, because it cannot be pre-fastened, it is very difficult to achieve pre-fastening when fixing the hanging parts. Difficult to tighten nuts. When fastening the bolt, the screw rod is always pulled out from the inside to the outside, the anchorage section is shallow, the bearing point is only on the surface of the wall, the anchorage strength is low...

AI Technical Summary

Problems solved by technology

[0002] At present, the expansion bolts on the market generally use the tapered end of the bolt to expand the expansion sleeve to achieve expansion and fixation. This expansion principle has many defects: first, the end of the bolt is flush with the head, and it is difficult to place it in the hole; second, The expansion multiple is small, and the expansion friction point is small. The fixing strength is too low and too unstable; moreover, when installing and fixing the hanging parts, because it cannot be pre-fastened, it is very difficult to achieve pre-fastening when fixing the hanging parts. Difficult to tighten nuts

When tightening the bolts, the screw rod is always pulled out from the inside to the outside, the anchorage section is shallow, the bearing point is only on the surface of the wall, the anchorage strength is low, and the safety hazard is great; in short, the fixing effect is very poor

In the later period, there are certain safety risks and waste of re-installation or maintenance during use, and even damage the wall

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