GB853073A - Improvements in or relating to casting building units - Google Patents

Abstract

853,073. Casting building units. BRUNTON, J. E. C. Oct. 16, 1958 [May 22, 1958], No. 16509/58. Class 87(2). [Also in Group X] On a bed A of porous material, e.g. sand, mould walls are laid, in the form of strips B which may be produced by extrusion and which are of a material which is friable when dry, e.g. lime, clay, or Roman cement. A wet mixture of cement and light weight aggregate is poured into the mould so formed from a hopper which runs on rails X and so can traverse the moulds. (The mould walls of separators may also be extruded from a mobile container). Excess water is soaked away by the porous bed and atmospheric pressure assists in compacting the concrete into castings of low water/cement ratio. As the concrete sets it is tamped, vibrated, and if desired impressed with a suface pattern. Grooves and other depressions may be formed on the underside of the casting by laying cores on the bed in the same manner as the strips B. When the concrete has set the separating strips B are machined away and the edges of the castings, e.g. panels, are machined, e.g. grooved so that the joint between two panels is tubular, allowing grouting material to be forced in through a tube, the machine tools for these purposes being mounted on a carriage which runs on one set of rails. The castings may also be given a finishing coat. A carriage P, running on the upper set of rails Z, carries suction pads R which lift the castings from the bed and hold them up while they are cleaned by revolving brushes H on a carriage O running on the middle rails Y. The truck O also carries suction means for removing sand and other particles into receptacles, for re-use. The carriage O then moves clear and a conveyer truck M moves below the panels which are lowered on to it. Reinforcement may be incorporated by depositing a layer of concrete about one-third the required thickness from a hopper on a first carriage, laying thereon reinforcement paid out under tension from a roll on a second carriage, and laying a final layer of concrete from a hopper on a third carriage. Emulsified bitumen may be laid instead of, or with, the reinforcement. For making cavities in the casting the first concrete-laying carriage is followed by a carriage carrying an air compressor, and a revolving drum wound with rubber tubes is located at a suitable place, e.g. in a pit. The tubes are inflated from one end and their other ends are fitted with nipples with reducing bores, and at intervals along their length, thus reducing the pressure by stages and enabling the tubes to be drawn easily through the concrete.