Post-installed anchor

Abstract

To provide a hybrid type post-installed anchor which cannot be pulled out and the anchor bar is cut if an attempt is made to pull it out forcefully. [Solution] By using a commercially available hexagonal bolt as the expanding base plate and using a double nut or a nut specifically designed to prevent loosening to secure the round washer, a reliable hybrid post-installed anchor is created that combines the advantages of a flared metal anchor and a flared adhesive anchor, and that cannot be pulled out, but will break the anchor bar if pulled out forcefully.

Description

[Technical Field]

[0001] This invention relates to post-installed anchors used for joining buildings and attaching equipment. [Background technology]

[0002] There are two types of post-installed anchors: metal and adhesive. With metal anchors, a circular hole is drilled perpendicular to the concrete surface using a hammer drill, and after inserting the anchor, the expansion section is expanded by driving or tightening to prevent the anchor from pulling out. On the other hand, with adhesive anchors, after drilling the hole, a capsule containing a base agent, hardener, and aggregate in a glass tube or a capsule containing cement mortar in a paper tube is inserted, and a pointed fully threaded bolt is rotated or driven in to break the capsule, allowing the mixture of resin base agent and hardener inside to harden, or a mixture of cement mortar and water to harden and fill the hole. Summary of the Invention [Problem to be solved by the invention]

[0003] Conventional metal-based post-installed anchors installed in highway tunnel ceilings have an expansion width of less than 1 mm in radius, and when anchors are used to hang heavy ceilings and are constantly subjected to wind pressure and vibration, there is a risk of the anchors coming loose. On the other hand, even with adhesive-based anchors, the rotation of a fully threaded bolt does not adequately mix the resin base, hardener, and aggregate. Furthermore, the holes are filled with broken capsule remains and air, and only a small amount of adhesive remains at the hole entrance, leaving the anchor at risk of easily coming loose. The anchors used in the Sasago Tunnel highway ceiling collapse accident that occurred in 2012 were adhesive-based anchors. Pull-out tests conducted by the Accident Investigation Committee showed that 9% of the anchors had a pull-out resistance of less than 12.2 kN, with some even reaching 0 kN. [Means for solving the problem]

[0004] The commercially available hex bolt is a fully threaded bolt with a hex nut firmly attached to the end by cold heading or forging. A commercially available hex bolt 2 was used as the metal anchor 1 of the anchor of this invention, which is a hybrid post-installed anchor that combines a flared metal anchor and a flared adhesive anchor.

[0005] To firmly secure the round washer 3, which is provided to prevent it from falling into the hole when the anchor is inserted, a double nut 6 consisting of an upper nut (type 1, thick) 4 and a lower nut (type 3, thin) 5, or a special anti-loosening nut 7 (many types are available on the market, such as U-nuts, hard lock nuts, and wedge lock nuts) was used.

[0006] Furthermore, when resin adhesive or non-shrink mortar adhesive 8 used as hole filling is applied to cover the gap 9 between the underside of the washer and the concrete surface, and the washer and the double nut or the nut specifically designed for preventing loosening, after hardening or solidification it becomes a resin or mortar molded product and adheres strongly to the concrete surface. [Effects of the Invention]

[0007] The anchor of this invention is a hybrid post-installed anchor that combines metal and adhesive systems, and combines the advantages of both. Furthermore, it has (1) a commercially available hexagonal bolt that is strongly joined by cold heading or forging, and (2) a washer that is firmly fixed with a double nut or a special nut for preventing loosening, and further, the washer and double nut or special nut for preventing loosening are strongly adhered to the concrete surface, so the anchor of this invention has a high tensile resistance, and if it is forcibly pulled out, the anchor bar will break, resulting in an anchor that cannot be pulled out. [Brief explanation of the drawings]

[0008] [Figure 1] An illustration of the installation of an anchor using a commercially available hex bolt and double nut of this invention [Figure 2] An illustration of the installation of an anchor using a commercially available hex bolt and a special locking nut (U-nut) of this invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be described below in detail with reference to the preferred embodiments thereof, but the present invention may be embodied in many different forms and is not limited to the specific examples set forth below.

[0010] First, we will explain the different anchor thicknesses: M12, M10, and M8. We selected the corresponding commercially available hex bolts: M12 x 120, M10 x 110, and M8 x 100. The corresponding holes were drilled using a Koki Holdings Co., Ltd. DH40MR hammer drill (old model) equipped with SDSmax shank drill bits with diameters of 25mm (M12), 22mm (M10), and 18mm (M8), with drilling depths of 70mm, 60mm, and 50mm (slightly longer than the anchorage length).

[0011] After inserting the metal anchor, an adhesive anchor is formed by pouring a mixture of the main agent and hardener of a resin adhesive such as epoxy resin, epoxy acrylate resin, or unsaturated polyester resin, or a mixture of non-shrink mortar and water into the gap, and the liquid is allowed to spread thoroughly so that no air remains.After the resin has hardened or the mortar has solidified, the entire contents of the hole will become a single molded mass, forming a hybrid, non-pullout, flared, post-installed anchor that is strongly adhered to the wall of the hole. [Explanation of symbols]

[0012] 1...Metal anchor 2...Commercially available hex bolt 3...Round washer 4...Top nut (type 1, thick) 5...Lower nut (3 types, thin) 6...Double nut 7...Special anti-loosening nut 8...Adhesive anchor (hole filling agent) 9...Gap between the bottom of the washer and the concrete surface

Claims

1. This is a hybrid type post-installed anchor that cannot be pulled out, combining a flared metal anchor and a flared adhesive anchor, and has a structure in which a commercially available hexagon bolt in which the bolt and nut are strongly joined is used as the metal anchor.

2. A structure that uses double nuts or special locking nuts to secure the round washer fitted into the anchor.

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