Self-expanded mechanical anchor bolt

Abstract

The invention discloses a self-expanded mechanical anchor bolt in the field of anchor bolts. The self-expanded mechanical anchor bolt comprises an anchor bolt screw and a sleeve. The anchor bolt screwcomprises an unthreaded rod, an expanded portion and a threaded portion, wherein the expanded portion and the threaded portion are arranged on the two sides of the unthreaded rod. The outer side of the anchor bolt screw is sleeved with the sleeve. A nut is arranged on the threaded portion in a sleeved manner. The expanded portion comprises a horn-shaped inverted cone head. The outer end of the inverted cone head is connected with the unthreaded rod through an inverted cone face in an inward concave arc shape, a convex attachment face is arranged at the inner end of the inverted cone head, andthe inverted cone heat is connected with the attachment face through a transition plane. Multiple evenly-distributed radial open strips are arranged at the inner end of the sleeve, an expansion sheetis formed between every two adjacent open strips, cutting blade tooth sets are arranged on the outer walls of the front end of the expansion sheets, grinding areas are arranged on the inner walls ofthe expansion sheets, horn mouths are arranged at the front ends of the grinding areas, and the horn mouths are connected with the outermost sides of the cutting blade tooth sets to form wedge structures. According to the self-expanded mechanical anchor bolt, convenience and visualization of sleeve expansion sheet expansion and anchor bolt embedding are improved, and the problem about stress concentration caused by the situation that screw and sleeve expansion parts expand to bear loads is reduced.

Description

technical field [0001] The invention relates to the field of anchor bolts, in particular to a self-expanding bottom-type mechanical anchor bolt. Background technique [0002] The mechanical anchor bolt is a component anchored on the concrete base material by the friction between the anchor bolt and the drill hole or the key effect. The main force-bearing parts are fasteners (screws, nuts, washers) made of metal materials, cones Head, expansion parts (expansion sleeve or expansion piece), etc., mechanical anchors are divided into: expansion anchors, bottom expansion anchors, self-tapping anchors, etc. Since the expansion anchor bolt forms a lock key relative to the expansion anchor bolt, the mechanical engagement force is used as the anchoring force, and the stress distribution is similar to that of the big head embedded part. It has the characteristics of small stress area, small edge distance, and small spacing, and has strong reliability. It can output a large force value...

AI Technical Summary

Problems solved by technology

[0004] (1) There are many steps to install the anchor bolts of the mold expansion bottom. In order to improve the installation efficiency, the workers often install them directly without pre-expanding the holes, and convert the inverted tapered lock keys of the mold expansion bottom into the friction between the sleeve expansion piece and the concrete wall. , affecting engineering safety

[0005] (2) Self-expanding bottom anchor bolts have expansion parts with blades, which are difficult or insufficient to expand, difficult to install, and unsatisfactory force output

[0006] (3) if figure 1 , the inverted cone lock key is shown in the left box in the figure, the screw rod of the existing self-expanding bottom anchor bolt is a triangular inverted cone, and the connection between the anchor rod and the inverted cone has obvious junctions and angles

When the anchor bolt bears the load, the triangular inverted cone surface is easy to bend the sleeve at the bending part, and the bending amount is too large, which will cause serious stretching or extrusion of the bending part of the sleeve, and the stress on the bending part of the sleeve Concentration will also form a cavity at the bend, so that it cannot be supported by the inverted cone facing the sleeve; in the actual installation, the inverted cone head stretches outward, and the triangular inverted cone surface will expand Squeeze the sheet, so that the bending amount continues to increase, and the expanded sleeve expansion sheet will concentrate on supporting the triangular inverted cone head, and at the same time, through the stretching of the screw, a tension will be formed at the intersection of the screw rod and the inverted cone head. Stress concentration area; the angle of the triangular reverse cone of the screw is steep, and the end and inner wall of the sleeve are likely to scratch the triangular surface during installation, which increases the difficulty of installation and hinders the full expansion of the expansion piece of the sleeve

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