A tool assembly (1) for tensioning tower bolts (12) of a wind turbine tower is disclosed. The tool assembly (1) comprises a connecting arrangement (2, 13, 14) configured to connect the tool assembly (1) to a part of a wind turbine tower, and a tool holding part (3) arranged to hold a tool (5) for tensioning tower bolts (12). The tool holding part (3) is attached to the connecting arrangement (2, 13, 14) in a rotatable manner, thereby allowing the tool (5) to be rotated between at least a first orientation and a second orientation. The connecting arrangement (2, 13, 14) may retain the tool assembly (1) relative to a tower wall by means of a magnet (17).

A tightening device for a screw connection and a safety device assigned to the tightening device are provided. The screw connection has a bolt and a nut resting on a support surface. The tightening device has a cylinder housing, a hydraulically driven piston arranged in the cylinder housing and moveable along an axis, an exchangeable bush which can be carried on the axis and screwed to the threaded bolt, and a carrier connectable to the threaded nut by force fit or form fit. To prevent jumping of the tightening device on breakage of the bolt, the safety device has a threaded sleeve and a protective arm. The threaded sleeve is arranged outside the cylinder housing and has an internal thread for engaging a threaded bolt adjacent to the bolt. The protective arm is attached to the threaded sleeve and extends over the cylinder housing of the tightening device.

Systems and methods can include applying, using a nut assembly including a first nut and a plurality of fasteners provided in respective threaded holes of the first nut, a first tensioning force for a stud of a hammer assembly. The systems and methods can also include applying, using the nut assembly, a second tensioning force for the stud of the hammer assembly. The first tensioning force can be applied with the first nut in a first orientation whereby a first end surface of the first nut faces a first direction and a second end surface of the first nut faces a second direction opposite the first direction. The second tensioning force can be applied with the first nut in a second orientation whereby the first end surface of the first nut faces the second direction and the second end surface of the first nut faces the first direction. The second tensioning force can be greater than the first tensioning force.

A multi jack tensioner including: a body portion 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 portion; a pressure chamber between the load bearing member and the body portion arranged to displace the body portion from the load bearing member in response to hydraulic pressure; and a plurality of jack bolts extending between the body portion and the load bearing member for further displacing the body portion from the load bearing member; wherein application of hydraulic pressure to the hydraulic chamber displaces the body portion from the load bearing member for tensioning said fastening member and whereby subsequent tensioning of the fastening member is applied by operation of the jack bolts.

The invention relates to a method for the controlled and automatic tensioning of bolts pre-installed in a flange joint between a hub and a main shaft in a nacelle of a wind turbine as well as to a bolt tensioning system for such method. The method comprises arranging a fixture inside the nacelle and mounting a bolt tensioning tool to the fixture which is mounted movable in an axial direction and in a working area perpendicularly hereto. First the flange joint is rotated to position a first set of bolts within the working area of the bolt tensioning tool, and then the bolt tensioning tool is controlled alternately to move the tensioning tool into a position for tensioning a bolt and to tension the bolt, until all bolts of the first set of bolts have been tensioned. The rotation of the flange joint may be controlled by operating a rotation tool operably connected to the main shaft, gearbox, and/or generator.

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.

For tightening screwed connections by a multi-screwing device with first and second screwing tools, each with rotary drive for screwing an exchangeable bushing on and off, a device for longitudinally straining a threaded bolt, and a tool for retightening the nut, the screwing tools are moved at right angles relative to tool axes by an actuating drive. When the bushings of the screwing tools are both screwed onto a threaded bolt, these steps are performed: a) bushing of first screwing tool is unscrewed from threaded bolt and raised; b) first screwing tool is moved relative to the second into a position in which tool axis of first screwing tool is aligned with screw axis of a further threaded bolt; c) first screwing tool is lowered and screwed onto further threaded bolt; d) threaded bolt is longitudinally strained, and e) steps a) to d) are repeated for second tool.

A device for tightening a screw connection on a flange connection is provided with a tool carrier movable along the flange connection and provided with a traction drive. A tool is arranged on the tool carrier for tightening the screw connection and rotating the nut relative to the flange connection. A control unit is provided for moving the tool carrier in longitudinal direction of the tool carrier into a working position by traction drive control signals. In the working position, the tool is opposite the screw connection to be tightened. The control unit performs, by tool control signals, tightening of the screw connection and rotating of the nut. The control unit has a travel control module with travel controller for moving the tool carrier into the working position. The travel controller stops the traction drive after a predefined travel length has been reached that is a target variable.

System for supplying hydraulic pressure to a bolt elongation tool, comprising the bolt elongation tool with at least one pressure chamber and a tool piston, a hydraulic medium supply system and a hydraulic actuator with an actuator cylinder housing an actuator piston. The actuator cylinder is attached to the at least one pressure chamber, wherein the hydraulic actuator is an electro-hydraulic actuator comprising an electric motor built to generate the power of the electro-hydraulic actuator, and wherein the actuator piston is built to supply, with one stroke of an actuator stroke height of the actuator piston, at least the amount of hydraulic pressure that is needed to move the tool piston for the amount of one tool stroke height of the tool piston.

A Tool for tightening a nut on a bolt to form a fixed connection, consisting of an air-driven hydraulic pump which transfers oil pressure to a hydraulic cylinder with a piston connected to a shaft which by means of an air-driven motor (90′) is caused to screw on the threads of the bolt where the nut is connected to a second separate air-driven motor (91′) that screws the nut on the said bolt as the bolt is stretched.