Patent attributes
A tensioning device for extending a threaded bolt by tensioning the threaded end section has a supporting tube surrounding the threaded end section, a cylinder arranged in continuation of the supporting tube and having at least one piston axially movable therein, an exchange socket which is screwable to the threaded end section and is configured such that it can be carried along axially by the piston, and a pin arranged in an axially movable manner in a longitudinal guide in the exchange socket. The pin end is axially supportable against that end of the threaded bolt that has the threaded end section. In order to assess the actually usable thread projection even in cases in which known tensioning devices provide imprecise results, the pin is formed in a radially widened manner at its pin end compared with the pin cross section.