| 摘要 |
1,211,207. Tensioning wires. CONENCO CANADA Ltd. 21 Nov., 1967 [23 Nov., 1966], No. 52958/67. Heading F2G. Apparatus for prestressing cables 11, 11b embedded in concrete 10 and having opposing ends extending out of facing surfaces defining a pocket 13 in the concrete comprises a rigid frame 20 adapted to be rested on the concrete over the pocket, a first hydraulic jack 24 having a piston-rod 24a fixed to the frame and a cylinder casing 24b linearly movable relative to the piston-rod longitudinally of cable 11, said casing carrying an attachment 30 for engaging the cable end, and a second independently operable hydraulic jack 27 having a piston-rod 27a fixed to the frame and cylinder casing 27b linearly movable with respect to piston-rod 27a in opposing direction to the cylinder casing 24a, said casing 27b carrying an attachment 31 for engaging the end of cable 11b so that expansion of the jacks forces the cable ends towards each other to tension the cables. The frame comprises elongated side plates 21, 22 and welded end plates 23a, 236 at opposite ends. The side plates are formed with upper and lower inwardly-extending transverse lips to function as guide rails for plates 26 and 28 secured to the cylinder casings to constrain the latter for linear movement. The attachments 30, 31, Fig. 2, each comprise side plates 31a, 31b welded to the respective cylinder casings and reinforced by cross-plates 31d. Each side plate is provided with a keying projection 33 adapted to engage a corresponding recess in a head 12 secured to each respective cable end. If it is desired to exert an additional tensile force on one of the cables only, say cable 11b, locking blocks 40, 41 which are adjustably carried on four threaded longitudinally-extending rods 36-39 fixed to each end plate and which are guided by the outer sides of guide rails 21, 22, are positioned to bear against the extreme right wall of the pocket. Hydraulic jack 27 is then further expanded to apply the necessary additional tensile force to cable 11b. After tensioning the cable, as indicated by the upper portion of Fig. 1, the cable heads are connected by a bolt 14. |
