In a method for the documented tightening or tightening up of a heavily loaded screw connection of a threaded bolt and a nut screwed on the threaded bolt by using an axially operating tensioning device and a process control unit provided with a documentation module, the screw connection is identified by scanning an identification provided on the screw connection and data determined by scanning the identification is stored in the documentation module. The screw connection is lengthened by the tensioning device by axially pulling on a threaded end of the threaded bolt and a tightening force (F.sub.A) and/or a tightening pressure (P.sub.A) exerted by axially pulling on the threaded end is stored in the documentation module. After lengthening, the nut is turned by using a hand torque wrench and an actually exerted hand torque applied for turning the nut is stored in the documentation module.

In a fastening device for fastening a bolt, a male thread is formed on a side surface of a bolt head part, and a part to be engaged is formed on a top surface of the bolt head part. The fastening device includes a bit having a tension rod having a rod female thread part, and an engaging part installed inside the tension rod and engaging the engaged part, the bit causing the bolt to rotate where the engaged part and engaging part are engaged; a supporter surrounding the tension rod in the circumferential direction such that the lower end part thereof protrudes below the lower end part; a sensor for sensing vertical compression force acting on the supporter; a first motor for causing the bit to rotate about the axis; and a second motor for causing the tension rod to rotate about the vertically extending axis.

A multi jack tensioner for applying tension to a fastener, the tensioner comprising: a body having at least one section, including a first body section formed to engage an elongate fastening member or integrally formed therewith; a load bearing member for applying force to a workpiece to be fastened and arranged for location about said fastening member adjacent the body; a plurality of pressure chambers between the load bearing member and the body arranged to displace the at least one body section axially relative to the load bearing member in response to hydraulic pressure; and a plurality of jack bolts extending between the body section and the load bearing member for further displacing the first body section from the load bearing member; wherein application of hydraulic pressure to one or more of the plurality of pressure chambers displaces the first body section from the load bearing member thereby tensioning said fastening member and whereby subsequent tensioning of the fastening member is applied by operation of the jack bolts.

In a method for documented tightening or retightening of a screw connection that includes a threaded bolt and a nut screwed onto the bolt and is supported on a flange surface, an exchangeable socket of a tensioning cylinder supported against the flange surface is screwed onto the free threaded end of the threaded bolt. The exchangeable socket is hydraulically tightened with longitudinal expansion of the threaded bolt while the nut is co-rotated by rotation of a rotary sleeve connected to the nut for conjoint rotation. Switching elements, in a first operating mode, allow only the exchangeable socket to be electrically driven and, in a second operating mode, allow only the rotary sleeve to be electrically driven. A process control unit provided with a documentation module is used to control the method.

A tensioning apparatus is provided that is arranged to simultaneously tension a plurality of jackbolts of a multi jackbolt tensioner (MJT). The tensioning apparatus has a housing that is arranged for receiving a drive gear from a drive unit. The tensioning apparatus includes one or more planetary gears that are retained within the housing and which mesh with the drive gear in use. A ring gear encircles the one or more planetary gears and meshes with them. A plurality of spindle gears is retained in the housing. Each of the spindle gears has a spindle for coupling to a respective one of the jackbolts. The spindle gears are located around the ring gear and mesh with teeth on an outside of the ring gear. In use the drive gear rotates the one or more planetary gears to thereby rotate the spindle gears via the ring gear to thereby tension the jackbolts. The tensioning apparatus may be made compact by overlapping gear disks of the spindle gears and acts as a torque multiplier between the planetary gears and the spindle gears.

A clamping device for stretching a threaded bolt by pulling on its threaded end section has a support tube surrounding the threaded end section, a cylinder disposed in extension of the support tube, a piston axially movable therein, a changeover bush to be screwed onto the threaded end section and carried along axially by the piston, a hydraulic device for the piston, and a signal link between hydraulic device and a device for detecting the extent of the thread engagement between the changeover bush and the threaded end section. A contactless measurement of the thread engagement between changeover bush and bolt to be clamped for measuring the thread engagement is provided in that the device for detecting the extent of the thread engagement includes a sensor element fastened on the changeover bush, which is positioned axially opposite the end face of the threaded bolt with axial separation.

A method and apparatus for pre-tensioning a bolt that joins two parts, each end of the bolt being threaded into a respective cavity of the two parts. According to one embodiment, the bolt including a double wedge pre-tensioning element, a washer disposed at each side of the double wedge and clamping elements fastening the wedges once the desired preloading has been attained. The bolt is pre-tensioned with a tensioning tool which acts on the pre-tensioning element, reducing a distance between the wedges while increasing the distance between the two parts to be joined and reducing a distance between the outer facing surfaces of the wedges and washers. The control system measures at least one of the distances described, with the tensioning tool acting in accordance with the measured distance.

In a tightening method for a screw connection of a bolt and a nut by using a tensioning device, a rotary drive, and a process control unit with documentation module, the nut is tightened with the rotary drive by a tightening moment required for the nut to bear against a support. The screw connection is elongated by exerting axial tension on a threaded end of the bolt protruding from the nut. The nut is further tightened while maintaining elongation, and a rotation angle covered during further tightening is detected by a rotation angle sensor. Lengthening of the bolt is calculated from the rotation angle and thread geometry of the screw connection. A longitudinal force in the threaded bolt is calculated from lengthening of the bolt, bolt diameter and bolt length. The calculated longitudinal force and an identifier identifying the screw connection are stored in the documentation module.

In a lifting and transporting device for lifting a load (13) and for transporting the same transversely to the lifting direction (8), for use in the production of a screwed flange connection (35), in order to bring a tensioning tool (13) into a tensioning position in which it is in engagement with a screw bolt connection (18) to be pretensioned, or into a transport position in which it is out of engagement with a screw bolt connection and can be transported to the next screw bolt connection, wherein the flange (36a, 36b) extends horizontally, comprising a frame (2) for picking up and for lifting a load (13), a holding device (3) for holding the load, wherein the holding device is movable relative to the frame in the lifting direction (8), and comprising a hoisting device (4) for lifting and lowering the holding device (3) with the load (13) attached thereto, wherein the frame (2) is mounted on a first and a second support bearing (5, 6) and the first support bearing (5) is designed for abutment against the flange upper side (14), the frame (2) is designed to extend from the flange upper side (14) along the flange face (15) to below the flange underside (16), the second support bearing (6) is designed for abutment against the flange upper side (14) or against the flange face (15), the holding device (3) is equipped to hold the tensioning tool (13) below the flange underside (16) with the engaging means directed upwards, and the hoisting device (4) is equipped to lift the holding device (3) with the tensioning tool (13) attached thereto from a lowered transport position into a tensioning position.

Robot (1) to move a support platform (6) along a series of nuts (2) pre-screwed on bolts (3) arranged in a linear or in particular curved flange connection (4). The bolts (3) project from the nuts (2) pre-screwed in substantially a nut plane (13) by a projection length (15). The robot (1) comprises a drive to move the robot (1) along the curved flange connection (4). The drive comprises at least one drive element (12) and holding means (11) both connected to the support platform (6), wherein the holding means (11) comprise at least one pair of guiding rails (16, 17) connected to the support platform (6) in a distance from each other of more than the diameter (D) of the bolts (3) and less than the width across flat (AF) of the nuts (2) and projecting more than the projection length (15) from the support platform (6).