A screw structure includes a screw and a washer mounted on the screw. The bottom face of the screw head is provided with a plurality of pressing portions. Each of the pressing portions has a top provided with a first plane and a bottom provided with a second plane having an area smaller than that of the first plane. Each of the pressing portions is provided with a first inclined face and a first steep arcuate face. The first inclined face is directed toward a clockwise direction of the screw when the screw is screwed. The first steep arcuate face is directed toward the external thread. When the screw is screwed into an article, the pressing portions press the washer, and an outer diameter of the washer is expanded outward and forms an expansion.

A screw structure includes a screw and a washer mounted on the screw. The bottom face of the screw head is provided with a plurality of pressing portions. Each of the pressing portions has a top provided with a first plane and a bottom provided with a second plane having an area smaller than that of the first plane. Each of the pressing portions is provided with a first inclined face and a first steep arcuate face. The first inclined face is directed toward a clockwise direction of the screw when the screw is screwed. The first steep arcuate face is directed toward the external thread. When the screw is screwed into an article, the pressing portions press the washer, and an outer diameter of the washer is expanded outward and forms an expansion.

A fluid end having its fluid flow bores sealed without threading a retaining nut into the walls of each bore. The fluid ends may be assembled using a plurality of different kits, each kit comprising a fluid end body, a component, a retainer element, and a fastening system. The retainer element holds the component within each of the bores formed in the fluid end body and the fastening system secures the retainer element to the body. The fastening system comprises a plurality of externally threaded studs, washers and nuts in some embodiments. In other embodiments, the fastening system comprises a plurality of screws.

A bolt connection is provided for connecting two flanges. The bolt connection includes a threaded bar extending through a hole of a first flange and a hole of a second flange, the first flange abutting the second flange; an anti-fatigue sleeve; and a nut. The anti-fatigue sleeve is disposed on the threaded bar on the side of the first flange between the nut and the first flange, the nut is configured to be screwed onto the threaded bar and is configured to press the anti-fatigue sleeve against the first flange to fasten the first flange and the second flange together.

A bolt connection is provided for connecting two flanges. The bolt connection includes a threaded bar extending through a hole of a first flange and a hole of a second flange, the first flange abutting the second flange; an anti-fatigue sleeve; and a nut. The anti-fatigue sleeve is disposed on the threaded bar on the side of the first flange between the nut and the first flange, the nut is configured to be screwed onto the threaded bar and is configured to press the anti-fatigue sleeve against the first flange to fasten the first flange and the second flange together.

In implementations of a pressure lock retention fastener, the fastener assembly includes an insert sized for insertion into a fastener hole in a first panel. The fastener assembly has a threaded collet sized to slide in the insert and has expandable flanges that extend below the insert. The expandable flanges are sized for insertion into an aligned hole in a second panel. The fastener assembly also includes a screw installable through the insert to engage the threaded collet. The screw exerts a force that pushes the expandable flanges outward as screw rotation drives the screw into the threaded collet, and ridge locks of the expandable flanges seat up against the second panel effective to fasten the panels together. In implementations, a plate is installable between the panels with slotted holes having anti-rotation tabs that prevent a fastener assembly from spinning in the panel holes.

The present invention is an adjustable connector with hidden threads for securing and adjusting a glass panel to a structure. The connector has an internally threaded retainer mounted on a fastener which is secured by a fastener and receives an externally threaded telescope. A nut shape lock installed inside the telescope to lock the telescope. By turning the lock, it moves towards the fastener and locks the telescope by pushing the fastener. The lock is a security feature to hold the adjustable standoff in adjusted position and prevents unscrewing the telescope once the cap is uninstalled. The telescope and retainer are threaded internally which are not exposed.

A fastener for a corrugated sheet includes a cylindrical assembly including elongated, plate shaped fastening members assembled as a hollow cylinder, the fastening member tapered to one end to form a hook at one end and having a curved groove on an outer surface, and a curved trough on the outer surface at the other end of the fastening member, the curved troughs assembled to form an annular recess; a retainer ring secured to the annular recess; a ring-shaped elastic member secured to the curved groove; a first sealing member put on the retainer ring; and a washer; a threaded bolt driven through the washer, the retainer ring, and the fastening member; and an expansion nut having a multi-sided outer surface and moveably secured to the threaded bolt.

A fastener for a corrugated sheet includes a cylindrical assembly including elongated, plate shaped fastening members assembled as a hollow cylinder, the fastening member tapered to one end to form a hook at one end and having a curved groove on an outer surface, and a curved trough on the outer surface at the other end of the fastening member, the curved troughs assembled to form an annular recess; a retainer ring secured to the annular recess; a ring-shaped elastic member secured to the curved groove; a first sealing member put on the retainer ring; and a washer; a threaded bolt driven through the washer, the retainer ring, and the fastening member; and an expansion nut having a multi-sided outer surface and moveably secured to the threaded bolt.

A fastener for a corrugated sheet includes at least one support on a top of the corrugated sheet; at least one steel member on a bottom of the corrugated sheet; a cylindrical assembly including elongated, plate shaped fastening members assembled as a hollow cylinder, each fastening member tapered to one end to form a hook and having a curved groove on an outer surface, and a curved trough on the outer surface at the other end, the curved troughs assembled to form an annular recess; a retainer ring secured to the annular recess; and a ring-shaped elastic member secured to the curved groove; a threaded bolt driven through the retainer ring, the fastening members, the support, and the corrugated sheet into the steel member; an expansion nut moveably secured to the threaded bolt; and a ring-shaped first sealing member fastened between the support and the corrugated sheet.