Abstract: In a bolt of the present invention, a guide portion having a small diameter is formed at the distal end of a shaft portion and ridge having an inverted direction screw configuration relative to the ridge formed on a constant diameter portion is formed. When the bolt is inserted obliquely into a nut and the ridge gets into engagement with a female screw portion of the nut, an effect of floating the bolt is generated, and the bolt cannot be driven into the nut unless it is set in an appropriate tightening posture. Consequently, biting and seizing of the bolt to the nut can be prevented securely. If the ridge is formed into a double threaded screw having an inverted direction screw configuration, the effect can be further intensified.

Abstract: In a bolt of the present invention, a guide portion (116) having a small diameter is formed at the distal end of a shaft portion (15) and ridge (31) having an inverted direction screw configuration relative to the ridge (30) formed on a constant diameter portion (115) is formed. When the bolt (1) is inserted obliquely into a nut (100) and the ridge (31) gets into engagement with a female screw portion (105) of the nut (100), an effect of floating the bolt (1) is generated, and the bolt 1 cannot be driven into the nut 100 unless it is set in an appropriate tightening posture. Consequently, biting and seizing of the bolt 1 to the nut can be prevented securely. If the ridge (31) is formed into a double threaded screw having an inverted direction screw configuration, the effect can be further intensified.

Abstract: A tapping screw fastened to a subject member in which a thread portion formed in a shaft portion of the tapping screw is used to form a female screw thread in a prepared hole of the subject member. An angle of a thread ridge is approximately 30 degrees, a plurality of notches are formed in a top portion of the thread portion over a predetermined range of an entire length of the shaft portion, and a joint portion for connecting the top portion and a bottom portion of the thread portion is formed to have a circular arc shape in an area having a smaller diameter than a diameter of the prepared hole of the subject matter, as viewed in a cross section including a shaft center of the tapping screw.

Abstract: The tapping screw has a screw thread having a non-circular shape. Accordingly, when the tapping screw is screwed into the prepared hole formed in the attached member such as a steel plate, etc., the contact area of the screw thread and the circumferential face of the prepared hole of the attached member can be reduced in comparison with the screw thread having a circular outer shape. Accordingly, the screwing torque can be reduced. Further, since the top portion of the screw thread of the square outer shape has a rising shape without being broken, the biting property of the screw thread with respect to the prepared hole formed in the attached member is improved so that a female screw can be precisely threaded on the inner circumferential face of the prepared hole by the screw thread.

Abstract: A tapping screw fastened to a subject member in which a thread portion formed in a shaft portion of the tapping screw is used to form a female screw thread in a prepared hole of the subject member. An angle of a thread ridge is approximately 30 degrees, a plurality of notches are formed in a top portion of the thread portion over a predetermined range of an entire length of the shaft portion, and a joint portion for connecting the top portion and a bottom portion of the thread portion is formed to have a circular arc shape in an area having a smaller diameter than a diameter of the prepared hole of the subject matter, as viewed in a cross section including a shaft center of the tapping screw.

Abstract: A bolt is provided with a head part and a shank part. The shank part includes a first constant diameter cylindrical part, a transition part, a cylindrical connection part, and a second constant diameter cylindrical part concentrically extending from the first constant diameter cylindrical part to the second constant diameter cylindrical part. The first constant diameter cylindrical part has a screw thread with a predetermined pitch formed on the side surface thereof. The transition part has a tapered shape and has a screw thread with a predetermined pitch formed on the side surface thereof. The cylindrical connection part has a diameter smaller than that of the first constant diameter part. The second constant diameter cylindrical part has a diameter smaller than the first constant diameter part, and has a screw thread with a predetermined pitch formed on the side surface thereof. The crest part of the screw thread formed on the side surface of the transition part is truncated.

Abstract: An object of the present invention is to provide a bolt and a nut capable of appropriately adjusting the orientation of the bolt and fastening the bolt and the nut without fastening defects such as slipping and seizure even when the bolt is obliquely inserted into the nut.