GB1395303A - Concrete finishing method and machine - Google Patents

Abstract

1395303 Moulding ribs on concrete panels W D PATON and T W STEENSON 25 July 1973 35495/73 Heading B5A [Also in Division F2] The surface of a concrete panel 14 (Fig. 1) is ribbed by moving over the surface a plurality of discs supported at intervals along a shaft 22, the discs being rotated in a direction 48 (Fig. 3) such that their rotational movement relative to the concrete at their lower extremities is in the same direction as the movement 50 due to their advance across the concrete. The discs drive a furrow 52 of wet concrete in front of them, and cause aggregate to move to the tops of the ribs, probably by suction. As described, concrete comprising a coarse aggregate, e.g. small pieces of stone having rounded corners, and a facing mix are cast in a mould having adjustableheight mould sides 10, guards 42 to keep in excess concrete, and steel transverse and longitudinal partitions (not illustrated). A wheeled carriage 16 runs on tracks 20 in either direction propelled by a variable speed motor 29. At each end of the carriage is supported a shaft 22 carrying discs, the shafts being rotated by a motor 28 and being adjustable in height by hand cranks 26. The first run of the carriage 16 levels the concrete. On the second run, the leading set of discs is rotated to form the ribs and move the aggregate to the rib tops, while the trailing disc set is lower than and rotates in opposition to the first set, to press in the formed ribs. An operator seated on the carriage adjusts the speed of disc rotation continuously as the concrete slump varies. Sand blasting or acid etching removes the film of cement covering the aggregate in the rib tops. The disc faces are straight or tapered and their spacing and penetration are adjusted to control the suction set up; variable disc widths and spacing can be used along each shaft 22.