Abstract: An expansion anchor including an anchor stem having a holding flange and a lock member having a corrugated portion is inserted into a fitting hole bored in concrete or another rigid material. The anchor is secured in the bore by forcing the lock member to squash the corrugated portion. The corrugated portion thus squashed expands into engagement with the inner surface defining the bore so that the expansion anchor is steadily secured in a non-removable state.

Abstract: In a mist-spouting type drilling device having a mist passage extending through a hollow drill and a hollow shaft, a slender throat nozzle is disposed inside the drill, and a slender anti-counterflow nozzle having an orifice portion is disposed inside the hollow nozzle. The anti-counterflow nozzle is connected to a mist supply pipe through a joint member having a seal. With the orifice portion placed midway of the mist passage nozzles, little atomized water introduced into the mist passage through the mist supply pipe flows backward and is prevented from leaking.

Abstract: An exterior material, such as a tile, which is likely to flake due to cracks or other possible defects in the wall base of a concrete structure, can be effectively repaired by boring an anchor hole extending from the surface of the exterior material to the concrete wall base, and inserting and expanding an expansion anchor bolt in the anchor hole. By using a drilling device capable of spouting out a cooling fluid while drilling, even hard nonmetallic material, such as ceramic tile, can be effectively bored to form a suitable anchor hole.

Abstract: Atomized water is produced by an atomizer mounted on a drilling device and introduced through a mist flow passage formed in a hollow drill. By applying the atomized water flowing from the atomizer to a cutting bit at the leading end of the drill through the mist flow passage, the cutting bit heated and reaching a high temperature in drilling is cooled. Thus, a rigid material of concrete or the like can be efficiently drilled without being stained with wetting.