Abstract: A hydraulic tensioner (1), comprising: abase (2); a piston (3) mounted for sliding motion relative to the base (2), the base (2) and the piston (3) defining a pressure space (4) therebetween and being arranged to be urged apart along an axis (8) upon introduction of a fluid into the pressure space (4), the tensioner (1) having an internal bore (6) along the axis (8) having first and second ends along the axis and comprising a threaded component having an internally threaded portion (7) at the first end and coupled to the piston (3); the tensioner (1) further comprising: a threaded stud (10) having an exterior thread which engages the internally threaded portion (7) of the threaded component; and a drive mechanism (12) arranged to transmit rotational motion from the second end of the internal bore (9) to the threaded stud; the tensioner being arranged such that rotational motion applied to the drive mechanism (12) at the second end causes rotation of the stud (10) relative to the threaded component, with the e

Abstract: A hydraulic tensioner (1), comprising: abase (2); a piston (3) mounted for sliding motion relative to the base (2), the base (2) and the piston (3) defining a pressure space (4) therebetween and being arranged to be urged apart along an axis (8) upon introduction of a fluid into the pressure space (4), the tensioner (1) having an internal bore (6) along the axis (8) having first and second ends along the axis and comprising a threaded component having an internally threaded portion (7) at the first end and coupled to the piston (3); the tensioner (1) further comprising: a threaded stud (10) having an exterior thread which engages the internally threaded portion (7) of the threaded component; and a drive mechanism (12) arranged to transmit rotational motion from the second end of the internal bore (9) to the threaded stud; the tensioner being arranged such that rotational motion applied to the drive mechanism (12) at the second end causes rotation of the stud (10) relative to the threaded component, with the e

Abstract: A hydraulic tensioning apparatus for tensioning a threaded member (2) having a thread, comprising: a hydraulic tensioner (1), having a body (4) and a pressure space (13) for hydraulic fluid and having a thread engaging member (7) arranged to engage the thread of the threaded member (2) and to be urged away from the body (4) on introduction of hydraulic fluid into the pressure space (13) so as to tension the threaded member (2); a displacement sensor (11, 12) arranged to measure a linear displacement of the thread engaging member (7) relative to the base (4) and to provide an output indicative of the linear displacement; a rotation sensor (65, 66) arranged to determine a rotation of a nut (3) rotating on the threaded member (2) and arranged to produce output indicative of a rotation angle of the nut (3); and a control unit (80) arranged to take as inputs the outputs of the displacement sensor (11, 12) and the rotation sensor (65, 66), and to determine from the output of the displacement sensor (11, 12) a requi

Abstract: A tensioner, typically hydraulic, for threaded members, the tensioner comprising: a base (4) and a piston (6) defining a pressure space (13) therebetween, the base (4) and piston (6) being arranged to be urged apart along an axis (17) upon introduction of a fluid into the pressure space (13); and a thread-engaging member (7), comprising a body portion (8) of the form of a sleeve and having a threaded interior (30) for engagement with a threaded member (2) and a piston engaging portion (9) carrying a protrusion; in which the piston (6) bears against the protrusion such that the piston (6) exerts a force on the protrusion when urged apart from the base (4) by the introduction of fluid into the pressure space (13); the tensioner further comprising a displacement sensor arranged to determining the relative position of the body portion of the thread-engaging member and the base, the displacement sensor comprising a first part (12) carried on the base (4) and a second part (11) carried on the body portion (8); typi

Abstract: A fastening apparatus adapted for use with a chock and a roll which locates within the chock such that a first end of the roll projects through and beyond a first end of the chock and a second end of the chock is located relative to the roll. The apparatus comprises a housing, a piston movably situated within the housing to allow a plurality of circumferentially spaced locating portions of the piston to be retained within the housing or to project through corresponding openings in the housing, pressure means provided within the housing to act on the piston, and at least one fastening member attached to the housing. In an operative position of the apparatus the housing is placed between the first end of the chock and the first end of the roll, and the pressure means acts between the piston, forcing the locating portions of the piston into location with the first end of the chock, and, forcing the at least one fastening member into location with the first end of the roll.