Abstract: Disclosed is a forging device containing a die insert 1, a stationary die case 2, a movable part (Ram) 3, a punch holder 4, and a punch tool 5. The punch holder 4 contains upper and lower reference stud holes 14,15, upper and lower reference studs 7,8 loosely fitted in the respective holes 14,15 in the movable part 3, an alignment adjusting bolt 17T, etc. to be tightened into a direction of the stud 7 to move the punch holder 4 in an alignment direction, and clamping nuts 9 engaged with the respective studs 7,8, to fix the punch holder 4. A positioning nut 22T is received by a male screw portion 21 of at least one alignment transcription bolt 20T and fixed thereto, and the nut 22 is brought into contact with the punch holder 4 at a complete alignment position, whereby the bolt 20T and the punch tool 5 should be attached/detached as a pair.

Abstract: It is an object of the invention to provide a structure of an internal thread portion for preventing looseness which structure allows a reduction in the torque required for the threaded engagement with an external-thread member and prevents a seizure. An exit end portion of a self-locking nut is taperingly contracted over the entire circumference thereof so as to form a contracted internal thread portion having a conical section. In addition, ridges of the contracted internal thread portion are provided with corrugation continuing circumferentially. The diameter of an inscribed circle which links the extremities of projections in the corrugation is smaller than the minor diameter of the external-thread member which is to be engaged threadedly with the internal thread portion.

Abstract: It is an object of the invention to provide a structure of an internal thread portion for preventing looseness which structure allows a reduction in the torque required for the threaded engagement with an external-thread member and prevents a seizure.

Abstract: The nut has a tool engaging region or a hexagonal region and a flange region provided on a thread end of the hexagonal region. A sloped step sloping at an angle to the center line of the nut is provided on the thread end. The sloped step (surface) is thus shaped of the annular form on the inner wall of the nut adjacent to the nut opening which faces outwardly of the nut and substantially extends along the loop.

Abstract: A hub nut with a washer, characterized in that an annular band of alternating ridges and grooves is formed by knurling circumferentially a part of the outer surface of a cylindrical part projectingly provided on the nut base and a washer with at least partially an inner diameter smaller than the outer diameter of the ridges of the knurled part is press-fitted thereover between the nut base and the knurled part.