Abstract: A hydraulic nut for tensioning an assembly comprises a mechanical threaded locking collar to minimize load loss during transfer of hydraulic load to the locking collar, an annular piston, an annular pressure area to generate an axial load under hydraulic pressure, a hydraulic pressure port and preferably metallic seals to maintain the hydraulic pressure within the annular pressure area that operates in an elastic region and continues to actuate hydraulic pressure after repeated operating temperature cycles. The seals of the hydraulic nut have a ‘U’ or ‘C’ shaped cross-section.

Abstract: A tensioner for tensioning foundation bolts generally used in securing large utility towers is provided. The tensioner generally comprises a hollow outer body through which the foundation bolt can extend. The lower end of the body, which is adapted to abut onto the foundation surface from which the bolt extends, is provided with an opening allowing access to a foundation nut threaded onto the foundation bolt. The upper end of the outer body slidingly receives therein an inner body with which it defines an annular hydraulic piston, the inner body being configured with a seat portion for receiving and engaging a split nut mounted to the foundation bolt. Upon providing hydraulic fluid to the tensioner, the hydraulic piston urges the split nut, engaged to the foundation bolt, upwardly, thereby tensioning the foundation bolt. The load in the bolt is then maintained by threading down the foundation nut until it abuts onto the foundation surface.

Abstract: A unibody hydraulic nut for tensioning multiple threaded fasteners includes an unibody containing two or more pistons to generate a clamping load, castellated locking collars with angled vertical castellations to engage a socket with matching castellations to enable easy turning by remotely operated means to capture the clamping load, internal hydraulic ports contained within the unibody linking each piston, seals to maintain the hydraulic pressure within the multiple annular pressure areas and an external hydraulic pressure port extending through the hydraulic nut unibody to the first pressure area and adapted to be connected to an external pressure source.

Abstract: A tensioner for tensioning foundation bolts generally used in securing large utility towers is provided. The tensioner generally comprises a hollow outer body through which the foundation bolt can extend. The lower end of the body, which is adapted to abut onto the foundation surface from which the bolt extends, is provided with an opening allowing access to a foundation nut threaded onto the foundation bolt. The upper end of the outer body slidingly receives therein an inner body with which it defines an annular hydraulic piston, the inner body being configured with a seat portion for receiving and engaging a split nut mounted to the foundation bolt. Upon providing hydraulic fluid to the tensioner, the hydraulic piston urges the split nut, engaged to the foundation bolt, upwardly, thereby tensioning the foundation bolt. The load in the bolt is then maintained by threading down the foundation nut until it abuts onto the foundation surface.

Abstract: A unibody hydraulic nut for tensioning multiple threaded fasteners includes an unibody containing two or more pistons to generate a clamping load, castellated locking collars with angled vertical castellations to engage a socket with matching castellations to enable easy turning by remotely operated means to capture the clamping load, internal hydraulic ports contained within the unibody linking each piston, seals to maintain the hydraulic pressure within the multiple annular pressure areas and an external hydraulic pressure port extending through the hydraulic nut unibody to the first pressure area and adapted to be connected to an external pressure source

Abstract: A hydraulic nut for tensioning an assembly comprises a mechanical threaded locking collar to minimize load loss during transfer of hydraulic load to the locking collar, an annular piston, an annular pressure area to generate an axial load under hydraulic pressure, a hydraulic pressure port and preferably metallic seals to maintain the hydraulic pressure within the annular pressure area that operates in an elastic region and continues to actuate hydraulic pressure after repeated operating temperature cycles. The seals of the hydraulic nut have a ‘U’ or ‘C’ shaped cross-section.

Abstract: A hydraulic nut for tensioning an assembly includes a mechanical threaded locking collar to minimize load loss during transfer of hydraulic load to the locking collar, a Z shaped annual piston to minimize height of the hydraulic nut, an annular pressure area to generate an axial load under hydraulic pressure, a hydraulic pressure port and metallic seals to maintain the hydraulic pressure within the annular pressure area that operates in an elastic region and continues to actuate hydraulic pressure after repeated operating temperature cycles.