GB651617A - Improvements relating to the manufacture of moulded building blocks - Google Patents

Abstract

651,617. Moulding hollow building blocks. OBO CONSTRUCTION CO., Ltd., and OATLEY, A. E. Sept. 29, 1948, No. 25404. [Class 87 (ii)] In moulding hollow building blocks, the cores for forming the cavities are longer than the required cavities and are withdrawn to their required positions during the filling of the mould, so as to draw in and consolidate the moulding material. Mould box 18, divided by partitions 33 to contain four blocks, rests on a table 17 which is in turn supported on a framework by means. of rubber blocks 16. Projections and recesses in the blocks are produced by means of profile strips 34, 36 whilst the cavities are formed by means of hollow cores 37 mounted rigidly on a platen 38 moved by a hydraulic ram. The platen is first raised to the position shown in Fig. 5 in which the cores 37 project above the top of the mould box 18 into a feeding box 76 fitted on to the top of the mould box. As concrete is poured into the mould, vibrators 77 underneath table 17 are set in motion and the cores 37 are lowered until their upper ends are level with the top of the mould box 18. The vibration is then stopped, the concrete tamped, and surplus removed. Next, the cores are lowered below the table 17 to a position in which the upper ends of guide-rods 44 are situated just inside holes 47, Fig. 4, in brackets 48 on the mould 18. Apertured slidebars 49 which do not normally obstruct the passage of the rods 44 are slid to a position in which they block the holes 47. Therefore, when the platen is again raised, the moulding box 18 containing the four moulded blocks 24 supported upon bars 74, is lifted off the table 17 catches 56 engage the bracket 48 as shown in broken lines on Fig. 4. A metal frame (not shown) carrying four wooden pallets is then slid into the gap between the bottom of the mould box and the table 17. The slide-bars 49 are then pulled rearwardly so that the guide-rods 44 have an uninterrupted upward path and the supporting bars 74 are withdrawn. The platen is again raised until the blocks 24 supported upon their platens have been ejected from the moulding box 18, and are withdrawn.