Patent GB-837243-A (GB)
Title: Improvements in or relating to processes and means for the manufacture of tubular bodies of reinforced concrete or the like
IPC: B28B21/44
Filed: 1958-02-03
Abstract: 837,243. Moulding reinforced concrete pipes &c. VIANINI-TOLOMEI, L. Feb. 3, 1958 [Feb. 11, 1957], No. 3402/58. Class 87(2). [Also in Groups X and XXVIII] Reinforced concrete pipes are made by violently projecting a concrete mixture of minimum water content on to a rotating core and smoothing the material on the core to the required thickness, at the same time applying circumferential and longitudinally reinforcement. The apparatus comprises a horizontal shaft 48 to rotate the core, which is contractible; a mixing device 18 for producing and delivering the concrete mixture ; conveyers 20, 22 to supply the mixture to a mixture projecting device 24, in any position thereof ; the mixture projecting device 24, which is movable on guides 32 parallel to the axis of the core ; a device 36 for levelling and smoothing the concrete on the core, and movable on guides  34 ; a conveyer 46 to recover the material removed in the levelling and smoothing operation ; coils 44 of thin reinforcing wires, supported by a frame 42 movable on guides 40 ; members 92, 98 to anchor longitudinal reinforcing wires 102 ; and means 96 for forcing apart the members 92, 98 to put the wires into tension. The shaft 48 is supported at each end by rollers 16 and is driven through a clutch 14. The core comprises a cylindrical shell in three parts 50, 52, 54 of which part 50 is secured to the shaft 48 through rigid connections 56, the parts 52 and 54 being connected with the part 50 through hinges 58 and 60. Between each of the parts 52, 54 and the shaft 48 is a set of hydraulic jacks 62. To collapse the core at the conclusion of the operation the jacks 62 are operated to rotate the parts 52, 54 around the hinges 58, 60, the rotation of the parts 52, 54 also being controlled by return springs 72. In a modification the core shell comprises two parts 74, 76, Fig. 6, with longitudinal keys 78 between them. To collapse the core the keys 78 are removed and the parts 74, 76 are contracted by jacks 80, which may be screw-jacks. In another modification the core comprises a hollow steel cylinder with a coating of wax, resin, or low melting point allow which is removed when required by eating the cylinder, e.g. by steam or electrically. As the concrete mixture is moved on the conveyer 22 it is halted by a scraper 26 according to the position of the projecting device 24, in which a paddle wheel 30 rotates at a speed sufficient to project a jet of mixture violently on to the core. The smoothing device 36 includes a milling or grinding tool 38 preferably in the form of a worm screw. The frame 42 carrying the coils of reinforcement wire is also movable vertically, to enable the wire to be wound spirally on the rotating core as the frame 42 traverses backwards and forwards. When a certain wall thickness is reached, the wires 102 are inserted in grooves 94, 100 in the members 92, 98, the wires 102 having end heads 104, and the members 92, 98 are driven from each other by the jacks 96 so that the wires 102 are stretched to the required length. Instead of having heads on the ends of the wires suitable clamps may be used. In operation, the device 24 starts first to travel along the core from one end ; it is followed by the device 36 and then by the frame 42 with the wire coils 44. The device 24 is stopped when it reaches the far end of the core, the device 36 is stopped immediately beyond the end of the core, and as soon as the wire coils reach the end of the core, their movement is stopped, the device 24 is again started in the reverse direction, immediately followed by the device 36 which has been radially retracted by a distance corresponding to the thickness of a new layer to be formed, and finally the frame 42 is started on its reverse travel, so that the wires will always lie on a suitably prepared surface. The invention may also be used for the manufacture of poles and other bodies having a conical or tapered form from end to end.