Patent ID: 8702066

Claim:
A device for controlling a prestressing jack during tensioning of a tension member as a function of a tensioning force of a reference tension member, the device comprising: a hollow cylindrical housing in which a piston coupled to the reference tension member is mounted to be longitudinally displaceable along an axis; a pressure space formed by an enclosure of the housing and the piston, the pressure space being adapted to be pressurized with a pressure medium through an inlet in order to carry out an axial stroke motion of the piston in opposition to the tensioning force of the reference tension member and that is connectable to the prestressing jack through an outlet; a valve unit configured to control a pressurization of the prestressing jack with the pressure medium, wherein the valve unit is controllable directly by the stroke motion of the piston and a component for anchoring the reference tension member, a portion of the component having a conical shaped outer surface, the conical shaped outer surface portion being provided within the piston, wherein the piston has an axial through-hole for passage of the reference tension member.