Abstract: A system includes a washer, a nut, a retainer structure, and a gasket. The washer has a bore extending between a distal end and a proximal end. A first section of the bore extends from the distal end to a shoulder portion. A second section of the bore extends from the shoulder portion to the proximal end. The shoulder portion defines an aperture. The nut is configured to be received in the first section of the bore. The nut includes a threaded bore configured to threadably engage a threaded shaft of a bolt. The retainer structure is configured to axially retain the nut in the first section of the bore of the washer. The gasket has a through-bore axially aligned with the bore of the washer and the threaded bore of the nut. The gasket is configured to be axially retained in the second section of bore of the washer.

Abstract: A regulating valve includes a valve body having a cylindrical portion, a valve stem, and a locking member. The valve body includes a female screw formed on the inner wall of the cylindrical portion and at least one chamfered portion formed on the outer wall of the cylindrical portion. The valve stem includes a first male screw and a second male screw formed on the surface close to the other end of the valve stem. The locking member includes a nut corresponding to the second male screw and a tongue portion formed integrally with the nut, extends in a direction orthogonal to an axial line S from one end portion of the nut, and is bendable in the direction parallel to the axial line.

Abstract: A duplex threaded body having a right-handed and left-handed thread on the circumferential surface of a single solid member. A single-nut or double-nut type internally-threaded body demonstrates a locking effect at an intermediate position without substantially loosening by using a combination of a duplex externally-threaded body and one or more internally-threaded bodies. Moreover, a screw structure in which a pair of internally-threaded bodies can only be removed once they are mutually coupled when screwed onto a duplex externally-threaded body, making it possible to impart tamper-proof characteristics and a locking effect. The duplex externally-threaded body has, on the outer circumferential surface, an overlapping region with a clockwise spiral right-handed thread and a counter-clockwise spiral left-handed thread in an overlapping manner.