Improvements in or relating to the manufacture of bricks or blocks

摘要

493,777. Moulding perforated concrete blocks &c. CLARKE, E. April 13, 1937, No. 10524. [Class 87 (ii)] In moulding concrete air bricks or blocks, the aggregate B is placed in a mould A, and compressed around its outer edges, as by a ring member, a portion of the aggregate is removed from the middle of the exposed face and a die or plunger I having prongs J is applied to compress and perforate the block. A palette C is placed in the mould bottom and is dished upwardly to form a central recess. The compressed portions E produced by the ring member form a recess which is subsequently filled with further concrete. The upper surface of concrete is hollowed out as at H by a depth gauge G having a projection G1 and sides G2 adapted to bear on the sides of the mould. The die I is then forced down so that the prongs J enter the concrete. The prongs J may engage holes C' in the palette C. There may be a number of moulds formed by partitions A1 in a frame. The dies I may be carried by a frame K. The die is heated to facilitate withdrawal which may also be assisted by vibration.