Two-stage expansion bolt

Abstract

The invention discloses a two-stage expansion bolt. The two-stage expansion bolt comprises a bolt body (1), a nut (2), a spring washer (3), a flat washer (4), an upper expansion barrel (5), a conical sleeve (6) and a lower expansion barrel (8). The two-stage expansion bolt is characterized in that the expansion bolt further comprises an outer sleeve (7); an external thread (11) is arranged on the upper portion of the bolt body (1); a tail cone (12) is arranged on the lower portion of the bolt body (1); two or more first notching grooves (51) are formed in the lower portion of upper expansion barrel (5); two or more second notching grooves (81) are formed in the lower portion of lower expansion barrel (8); the lower expansion barrel (8), the conical sleeve (6), the upper expansion barrel (5), the flat washer (4), the spring washer (3) and the nut (2) are installed on the bolt body (1) from bottom to top in sequence; the outer sleeve (7) is installed on the outer surface of the lower expansion barrel (8) in a sleeving mode. The two-stage expansion bolt is simple in structure, accurate in positioning, large in expanding force, safe, reliable, low in cost and long in service life.

Description

technical field [0001] The present invention relates to fasteners, in particular to double-stage expansion bolts. Background technique [0002] The existing expansion bolts are composed of bolts, nuts, spring washers, flat washers and a single expansion cylinder. The expansion bolts with this structure are not easy to locate when installed, and tend to be skewed, resulting in stress concentration when the force is applied, which is unsafe; In recent years, there have also been two-stage expansion bolts consisting of bolts, nuts, spring washers, flat washers, upper expansion cylinders, intermediate cones, intermediate partitions and lower expansion cylinders. The expansion bolts of this structure, due to the lower expansion cylinder Axial displacement will occur during expansion, which will cause the upper expansion cylinder to not expand normally, thereby affecting the tightening effect, and sometimes loosening occurs, posing a safety hazard. Contents of the invention [...

AI Technical Summary

Problems solved by technology

[0002] The existing expansion bolts are composed of bolts, nuts, spring washers, flat washers and a single expansion cylinder. The expansion bolts with this structure are not easy to locate during installation, and tend to be skewed, resulting in stress concentration when the force is applied, which is unsafe; In recent years, there have also been two-stage expansion bolts consisting of bolts, nuts, spring washers, flat washers, upper expansion cylinders, intermediate cones, intermediate partitions and lower expansion cylinders. The expansion bolts of this structure, due to the lower expansion cylinder Axial displacement will occur during expansion, which will cause the upper expansion cylinder to not expand normally, thus affecting the tightening effect, and sometimes loosening occurs, posing a safety hazard

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