GB1143641A - - Google Patents

Abstract

1,143,641. Wire tensioning devices. MAX PAUL & SOHNE MASCHINENFABRIK. 5 May, 1966 [5 May, 1965], No. 19846/66. Heading F2G. A jack-anchor plate assembly for prestressing and anchoring steel wires 1 or bundles of steel wires in prestressed concrete consists of an anchor plate 3 provided with a plurality of bores 9 in which the wires are anchored by wedge members 4, and an hydraulic jack comprising an annular piston 6 working in a cylinder 7 having provided in the bottom 12 thereof a plurality of bores 13 for pistons 14, the bottom 10 of the piston 6 having a corresponding number of bores 11 receiving conical wedges 8 and annular wedge-operating pistons 15. The plate 3 being secured to a structural part, the wires are first connected to the plate by the wedges 4 and also passed through the wedges 8 whereby the jack is brought to bear on the plate. Hydraulic fluid admitted to the pistons 15 causes the wedges 8 to clamp the wires fast to the piston bottom 10. Hydraulic fluid admitted to the cylinder via the pipe 22 moves the piston in the direction of the arrow 28 to tension the wires, and hydraulic fluid is then applied to the pistons 14 to drive the wedges 4 to secure the wires in the plate 3. By introducing hydraulic fluid via the pipe 26 to the cylinder space 29 the piston 6 moves back to the position shown whereby the wedges 8 are brought into abutment with the cylinder bottom 12 to free the wires from the wedges and to allow withdrawal of the jack.